<s> [INST] <<SYS>> You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information. <</SYS>> What is Preterm birth and explain in detail? [/INST] Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 weeks, very early preterm birth is between 28 and 32 weeks, early preterm birth occurs between 32 and 36 weeks, late preterm birth is between 34 and 36 weeks gestation. These babies are also known as premature babies or colloquially preemies (American English) or premmies (Australian English). Symptoms of preterm labor include uterine contractions which occur more often than every ten minutes and/or the leaking of fluid from the vagina before 37 weeks. Premature infants are at greater risk for cerebral palsy, delays in development, hearing problems and problems with their vision. The earlier a baby is born, the greater these risks will be.The cause of spontaneous preterm birth is often not known. Risk factors include diabetes, high blood pressure, multiple gestation (being pregnant with more than one baby), being either obese or underweight, vaginal infections, air pollution exposure, tobacco smoking, and psychological stress. For a healthy pregnancy, medical induction of labor or cesarean section are not recommended before 39 weeks unless required for other medical reasons. There may be certain medical reasons for early delivery such as preeclampsia.Preterm birth may be prevented in those at risk if the hormone progesterone is taken during pregnancy. Evidence does not support the usefulness of bed rest. It is estimated that at least 75% of preterm infants would survive with appropriate treatment, and the survival rate is highest among the infants born the latest in gestation. In women who might deliver between 24 and 37 weeks, corticosteroid treatment may improve outcomes. A number of medications, including nifedipine, may delay delivery so that a mother can be moved to where more medical care is available and the corticosteroids have a greater chance to work. Once the baby is born, care includes keeping the baby warm through skin-to-skin contact or incubation, supporting breastfeeding and/or formula feeding, treating infections, and supporting breathing. Preterm babies sometimes require intubation.Preterm birth is the most common cause of death among infants worldwide. About 15 million babies are preterm each year (5% to 18% of all deliveries). Late preterm birth accounts for 75% of all preterm births. This rate is inconsistent across countries. In the United Kingdom 7.9% of babies are born pre-term and in the United States 12.3% of all births are before 37 weeks gestation. Approximately 0.5% of births are extremely early periviable births (20–25 weeks of gestation), and these account for most of the deaths. In many countries, rates of premature births have increased between the 1990s and 2010s. Complications from preterm births resulted in 0.81 million deaths in 2015, down from 1.57 million in 1990. The chance of survival at 22 weeks is about 6%, while at 23 weeks it is 26%, 24 weeks 55% and 25 weeks about 72%. The chances of survival without any long-term difficulties are lower.

Signs and symptoms
Signs and symptoms of preterm labor include four or more uterine contractions in one hour. In contrast to false labour, true labor is accompanied by cervical dilatation and effacement. Also, vaginal bleeding in the third trimester, heavy pressure in the pelvis, or abdominal or back pain could be indicators that a preterm birth is about to occur. A watery discharge from the vagina may indicate premature rupture of the membranes that surround the baby. While the rupture of the membranes may not be followed by labor, usually delivery is indicated as infection (chorioamnionitis) is a serious threat to both fetus and mother. In some cases, the cervix dilates prematurely without pain or perceived contractions, so that the mother may not have warning signs until very late in the birthing process.

Causes
The main categories of causes of preterm birth are preterm labor induction and spontaneous preterm labor.

Risk factors
The exact cause of spontaneous preterm birth is difficult to determine and it may be caused by many different factors at the same time as labor is a complex process. Four different pathways have been identified that can result in preterm birth and have considerable evidence: precocious fetal endocrine activation, uterine overdistension (placental abruption), decidual bleeding, and intrauterine inflammation or infection.Identifying women at high risk of giving birth early would enable the health services to provide specialized care for these women and their babies, for example a hospital with a special care baby unit such as a neonatal intensive care unit (NICU). In some instances, it may be possible to delay the birth. Risk scoring systems have been suggested as an approach to identify those at higher risk, however, there is no strong research in this area so it is unclear whether the use of risk scoring systems for identifying mothers would prolong pregnancy and reduce the numbers of preterm births or not.

Maternal factors
Risk factors in the mother have been identified that are linked to a higher risk of a preterm birth. These include age (either very young or older), high or low body mass index (BMI), length of time between pregnancies,  previous spontaneous (i.e., miscarriage) or surgical abortions, unintended pregnancies, untreated or undiagnosed celiac disease, fertility difficulties, heat exposure, and genetic variables.Studies on type of work and physical activity have given conflicting results, but it is opined that stressful conditions, hard labor, and long hours are probably linked to preterm birth. Obesity does not directly lead to preterm birth; however, it is associated with diabetes and hypertension which are risk factors by themselves. To some degree those individuals may have underlying conditions (i.e., uterine malformation, hypertension, diabetes) that persist. Couples who have tried more than 1 year versus those who have tried less than 1 year before achieving a spontaneous conception have an adjusted odds ratio of 1.35 (95% confidence interval 1.22-1.50) of preterm birth. Pregnancies after IVF confers a greater risk of preterm birth than spontaneous conceptions after more than 1 year of trying, with an adjusted odds ratio of 1.55 (95% CI 1.30-1.85).Certain ethnicities may have a higher risk as well. For example, in the U.S. and the UK, Black women have preterm birth rates of 15–18%, more than double than that of the white population. Many Black women have higher preterm birth rates due to multiple factors but the most common is high amounts of chronic stress, which can eventually lead to premature birth. Adult chronic disease isnt always the case with premature birth in Black women, which makes the main factor of premature birth challenging to identify. Filipinos are also at high risk of premature birth, and it is believed that nearly 11–15% of Filipinos born in the U.S. (compared to other Asians at 7.6% and whites at 7.8%) are premature. Filipinos being a big risk factor is evidenced with the Philippines being the eighth-highest ranking in the world for preterm births, the only non-African country in the top 10. This discrepancy is not seen in comparison to other Asian groups or Hispanic immigrants and remains unexplained. Genetic make-up is a factor in the causality of preterm birth. Genetics has been a big factor into why Filipinos have a high risk of premature birth as the Filipinos have a large prevalence of mutations that help them be predisposed to premature births. An intra- and transgenerational increase in the risk of preterm delivery has been demonstrated. No single gene has been identified.
Marital status is associated with risk for preterm birth. A study of 25,373 pregnancies in Finland revealed that unmarried mothers had more preterm deliveries than married mothers (P=0.001). Pregnancy outside of marriage was associated overall with a 20% increase in total adverse outcomes, even at a time when Finland provided free maternity care. A study in Quebec of 720,586 births from 1990 to 1997 revealed less risk of preterm birth for infants with legally married mothers compared with those with common-law wed or unwed parents.

Factors during pregnancy
Medications during pregnancy, living conditions, air pollution, smoking, illicit drugs or alcohol, infection, or physical trauma may also cause a preterm birth.
Air pollution: Living in an area with a high concentration of air pollution is a major risk factor for preterm labor, including living near major roadways or highways where vehicle emissions are high from traffic congestion or are a route for diesel trucks that tend to emit more pollution.The use of fertility medication that stimulates the ovary to release multiple eggs and of IVF with embryo transfer of multiple embryos has been implicated as a risk factor for preterm birth.  Often labor has to be induced for medical reasons; such conditions include high blood pressure, pre-eclampsia, maternal diabetes, asthma, thyroid disease, and heart disease.
Certain medical conditions in the pregnant mother may also increase the risk of preterm birth. Some women have anatomical problems that prevent the baby from being carried to term. These include a weak or short cervix (the strongest predictor of premature birth). Women with vaginal bleeding during pregnancy are at higher risk for preterm birth. While bleeding in the third trimester may be a sign of placenta previa or placental abruption—conditions that occur frequently preterm—even earlier bleeding that is not caused by these conditions is linked to a higher preterm birth rate. Women with abnormal amounts of amniotic fluid, whether too much (polyhydramnios) or too little (oligohydramnios), are also at risk. Anxiety and depression have been linked as risk factors for preterm birth.The use of tobacco, cocaine, and excessive alcohol during pregnancy increases the chance of preterm delivery. Tobacco is the most commonly used drug during pregnancy and contributes significantly to low birth weight delivery. Babies with birth defects are at higher risk of being born preterm.Passive smoking and/or smoking before the pregnancy influences the probability of a preterm birth. The World Health Organization published an international study in March 2014.Presence of anti-thyroid antibodies is associated with an increased risk preterm birth with an odds ratio of 1.9 and 95% confidence interval of 1.1–3.5.Intimate violence against the mother is another risk factor for preterm birth.Physical trauma may case a preterm birth. The Nigerian cultural method of abdominal massage has been shown to result in 19% preterm birth among women in Nigeria, plus many other adverse outcomes for the mother and baby. This ought not be confused with massage therapy conducted by a fully trained and certified/licensed massage therapist or by significant others trained to provide massage during pregnancy, which—in a study involving pregnant females with prenatal depression—has been shown to have numerous positive results during pregnancy, including the reduction of preterm birth, less depression, lower cortisol, and reduced anxiety. In healthy women, however, no effects have been demonstrated in a controlled study.

Infection
The frequency of infection in preterm birth is inversely related to the gestational age. Mycoplasma genitalium infection is associated with increased risk of preterm birth, and spontaneous abortion.Infectious microorganisms can be ascending, hematogeneous, iatrogenic by a procedure, or retrograde through the Fallopian tubes. From the deciduas they may reach the space between the amnion and chorion, the amniotic fluid, and the fetus. A chorioamnionitis also may lead to sepsis of the mother. Fetal infection is linked to preterm birth and to significant long-term disability including cerebral palsy.It has been reported that asymptomatic colonization of the decidua occurs in up to 70% of women at term using a DNA probe suggesting that the presence of micro-organism alone may be insufficient to initiate the infectious response.
As the condition is more prevalent in black women in the U.S. and the UK, it has been suggested to be an explanation for the higher rate of preterm birth in these populations. It is opined that bacterial vaginosis before or during pregnancy may affect the decidual inflammatory response that leads to preterm birth. The condition known as aerobic vaginitis can be a serious risk factor for preterm labor; several previous studies failed to acknowledge the difference between aerobic vaginitis and bacterial vaginosis, which may explain some of the contradiction in the results.Untreated yeast infections are associated with preterm birth.A review into prophylactic antibiotics (given to prevent infection) in the second and third trimester of pregnancy (13–42 weeks of pregnancy) found a reduction in the number of preterm births in women with bacterial vaginosis. These antibiotics also reduced the number of waters breaking before labor in full-term pregnancies, reduced the risk of infection of the lining of the womb after delivery (endometritis), and rates of gonococcal infection. However, the women without bacterial vaginosis did not have any reduction in preterm births or pre-labor preterm waters breaking. Much of the research included in this review lost participants during follow-up so did not report the long-term effects of the antibiotics on mothers or babies. More research in this area is needed to find the full effects of giving antibiotics throughout the second and third trimesters of pregnancy.A number of maternal bacterial infections are associated with preterm birth including pyelonephritis, asymptomatic bacteriuria, pneumonia, and appendicitis. A review into giving antibiotics in pregnancy for asymptomatic bacteriuria (urine infection with no symptoms) found the research was of very low quality but that it did suggest that taking antibiotics reduced the numbers of preterm births and babies with low birth weight. Another review found that one dose of antibiotics did not seem as effective as a course of antibiotics but fewer women reported side effects from one dose. This review recommended that more research is needed to discover the best way of treating asymptomatic bacteriuria.A different review found that preterm births happened less for pregnant women who had routine testing for low genital tract infections than for women who only had testing when they showed symptoms of low genital tract infections. The women being routinely tested also gave birth to fewer babies with a low birth weight. Even though these results look promising, the review was only based on one study so more research is needed into routine screening for low genital tract infections.Also periodontal disease has been shown repeatedly to be linked to preterm birth. In contrast, viral infections, unless accompanied by a significant febrile response, are considered not to be a major factor in relation to preterm birth.

Genetics
There is believed to be a maternal genetic component in preterm birth. Estimated heritability of timing-of-birth in women was 34%. However, the occurrence of preterm birth in families does not follow a clear inheritance pattern, thus supporting the idea that preterm birth is a non-Mendelian trait with a polygenic nature.

Prenatal Care
The absence of prenatal care has been associated with higher rates of preterm births. Analysis of 15,627,407 live births in the United States in 1995–1998 concluded that the absence of prenatal care carried a 2.9 (95%CI 2.8, 3.0) times higher risk of preterm births. This same study found statistically significant relative risks of maternal anemia, intrapartum fever, unknown bleeding, renal disease, placental previa, hydramnios, placenta abruption, and pregnancy-induced hypertension with the absence of prenatal care. All these prenatal risks were controlled for other high-risk conditions, maternal age, gravidity, marital status, and maternal education. The absence of prenatal care prior to and during the pregnancy is primarily a function of  socioeconomic factors (low family income and education), access to medical consultations (large distance from the place of residence to the healthcare unit and transportation costs), quality of healthcare, and social support. Efforts to decrease rates of preterm birth should aim to increase the deficits posed by the aforementioned barriers and to increase access to prenatal care.

Diagnosis
Placental alpha microglobulin-1
Placental alpha microglobulin-1 (PAMG-1) has been the subject of several investigations evaluating its ability to predict imminent spontaneous preterm birth in women with signs, symptoms, or complaints suggestive of preterm labor. In one investigation comparing this test to fetal fibronectin testing and cervical length measurement via transvaginal ultrasound, the test for PAMG-1 (commercially known as the PartoSure test) has been reported to be the single best predictor of imminent spontaneous delivery within 7 days of a patient presenting with signs, symptoms, or complaints of preterm labor. Specifically, the PPV, or positive predictive value, of the tests were 76%, 29%, and 30% for PAMG-1, fFN and CL, respectively (P < 0.01).

Fetal fibronectin
Fetal fibronectin (fFN) has become an important biomarker—the presence of this glycoprotein in the cervical or vaginal secretions indicates that the border between the chorion and deciduas has been disrupted. A positive test indicates an increased risk of preterm birth, and a negative test has a high predictive value. It has been shown that only 1% of women in questionable cases of preterm labor delivered within the next week when the test was negative.

Ultrasound
Obstetric ultrasound has become useful in the assessment of the cervix in women at risk for premature delivery. A short cervix preterm is undesirable: A cervical length of less than 25 mm at or before 24 weeks of gestational age is the most common definition of cervical incompetence.

Classification
In humans, the usual definition of preterm birth is birth before a gestational age of 37 complete weeks. In the normal human fetus, several organ systems mature between 34 and 37 weeks, and the fetus reaches adequate maturity by the end of this period. One of the main organs greatly affected by premature birth is the lungs. The lungs are one of the last organs to mature in the womb; because of this, many premature babies spend the first days and weeks of their lives on ventilators. Therefore, a significant overlap exists between preterm birth and prematurity. Generally, preterm babies are premature and term babies are mature. Preterm babies born near 37 weeks often have no problems relating to prematurity if their lungs have developed adequate surfactant, which allows the lungs to remain expanded between breaths. Sequelae of prematurity can be reduced to a small extent by using drugs to accelerate maturation of the fetus, and to a greater extent by preventing preterm birth.

Prevention
Historically efforts have been primarily aimed to improve survival and health of preterm infants (tertiary intervention). Such efforts, however, have not reduced the incidence of preterm birth. Increasingly primary interventions that are directed at all women, and secondary intervention that reduce existing risks are looked upon as measures that need to be developed and implemented to prevent the health problems of premature infants and children. Smoking bans are effective in decreasing preterm births. Different strategies are used in the administration of prenatal care, and future studies need to determine if the focus can be on screening for high-risk women, or widened support for low-risk women, or to what degree these approaches can be merged.

Before pregnancy
Adoption of specific professional policies can immediately reduce risk of preterm birth as the experience in assisted reproduction has shown when the number of embryos during embryo transfer was limited.
Many countries have established specific programs to protect pregnant women from hazardous or night-shift work and to provide them with time for prenatal visits and paid pregnancy-leave. The EUROPOP study showed that preterm birth is not related to type of employment, but to prolonged work (over 42 hours per week) or prolonged standing (over 6 hours per day). Also, night work has been linked to preterm birth. Health policies that take these findings into account can be expected to reduce the rate of preterm birth. Preconceptional intake of folic acid is recommended to reduce birth defects. There is also some evidence that folic acid supplement preconceptionally (before becoming pregnant) may reduce premature birth. Reducing smoking is expected to benefit pregnant women and their offspring.

During pregnancy
Self-care methods to reduce the risk of preterm birth include proper nutrition, avoiding stress, seeking appropriate medical care, avoiding infections, and the control of preterm birth risk factors (e.g. working long hours while standing on feet, carbon monoxide exposure, domestic abuse, and other factors). Reducing physical activity during pregnancy has not been shown to reduce the risk of a preterm birth. Healthy eating can be instituted at any stage of the pregnancy including nutritional adjustments and consuming suggested vitamin supplements. Calcium supplementation in women who have low dietary calcium may reduce the number of negative outcomes including preterm birth, pre-eclampsia, and maternal death. The World Health Organization (WHO) suggests 1.5–2 g of calcium supplements daily, for pregnant women who have low levels of calcium in their diet. Supplemental intake of C and E vitamins have not been found to reduce preterm birth rates.While periodontal infection has been linked with preterm birth, randomized trials have not shown that periodontal care during pregnancy reduces preterm birth rates. Smoking cessation has also been shown to reduce the risk. The use of personal at home uterine monitoring devices to detect contractions and possible preterm births in women at higher risk of having a preterm baby have been suggested. These home monitors may not reduce the number of preterm births, however, using these devices may increase the number of unplanned antenatal visits and may reduce the number of babies admitted to special care when compared with women receiving normal antenatal care. Support from medical professionals, friends, and family during pregnancy may be beneficial at reducing caesarean birth and may reduce prenatal hospital admissions, however, these social supports alone may not prevent preterm birth.

Screening during pregnancy
Screening for asymptomatic bacteriuria followed by appropriate treatment reduces pyelonephritis and reduces the risk of preterm birth. Extensive studies have been carried out to determine if other forms of screening in low-risk women followed by appropriate intervention are beneficial, including screening for and treatment of Ureaplasma urealyticum, group B streptococcus, Trichomonas vaginalis, and bacterial vaginosis did not reduce the rate of preterm birth. Routine ultrasound examination of the length of the cervix may identify women at risk of preterm labour and tentative evidence suggests ultrasound measurement of the length of the cervix in those with preterm labor can help adjust management and results in the extension of pregnancy by about 4 days. Screening for the presence of fibronectin in vaginal secretions is not recommended at this time in women at low risk of preterm birth.

Reducing existing risks
Women are identified to be at increased risk for preterm birth on the basis of their past obstetrical history or the presence of known risk factors. Preconception intervention can be helpful in selected patients in a number of ways. Patients with certain uterine anomalies may have a surgical correction (i.e. removal of a uterine septum), and those with certain medical problems can be helped by optimizing medical therapies prior to conception, be it for asthma, diabetes, hypertension, and others.

Multiple pregnancies
In multiple pregnancies, which often result from use of assisted reproductive technology, there is a high risk of preterm birth. Selective reduction is used to reduce the number of fetuses to two or three.

Reducing indicated preterm birth
A number of agents have been studied for the secondary prevention of indicated preterm birth. Trials using low-dose aspirin, fish oil, vitamin C and E, and calcium to reduce preeclampsia demonstrated some reduction in preterm birth only when low-dose aspirin was used. Even if agents such as calcium or antioxidants were able to reduce preeclampsia, a resulting decrease in preterm birth was not observed.

Reducing spontaneous preterm birth
Reduction in activity by the mother—pelvic rest, limited work, bed rest—may be recommended although there is no evidence it is useful with some concerns it is harmful. Increasing medical care by more frequent visits and more education has not been shown to reduce preterm birth rates. Use of nutritional supplements such as omega-3 polyunsaturated fatty acids is based on the observation that populations who have a high intake of such agents are at low risk for preterm birth, presumably as these agents inhibit production of proinflammatory cytokines. A randomized trial showed a significant decline in preterm birth rates, and further studies are in the making.

Antibiotics
While antibiotics can get rid of bacterial vaginosis in pregnancy, this does not appear to change the risk of preterm birth. It has been suggested that chronic chorioamnionitis is not sufficiently treated by antibiotics alone (and therefore they cannot ameliorate the need for preterm delivery in this condition).

Progestogens
Progestogens—often given in the form of vaginal progesterone or hydroxyprogesterone caproate—relax the uterine musculature, maintain cervical length, and possess anti-inflammatory properties; all of which invoke physiological and anatomical changes considered to be beneficial in reducing preterm birth. Two meta-analyses demonstrated a reduction in the risk of preterm birth in women with recurrent preterm birth by 40–55%.Progestogen supplementation also reduces the frequency of preterm birth in pregnancies where there is a short cervix. A short cervix is one that is less than 25mm, as detected during a transvaginal cervical length assessment in the midtrimester. However, progestogens are not effective in all populations, as a study involving twin gestations failed to see any benefit. Despite extensive research related to progestogen effectiveness, uncertainties remain concerning types of progesterone and routes of administration.

Cervical cerclage
In preparation for childbirth, the womans cervix shortens. Preterm cervical shortening is linked to preterm birth and can be detected by ultrasonography. Cervical cerclage is a surgical intervention that places a suture around the cervix to prevent its shortening and widening. Numerous studies have been performed to assess the value of cervical cerclage and the procedure appears helpful primarily for women with a short cervix and a history of preterm birth. Instead of a prophylactic cerclage, women at risk can be monitored during pregnancy by sonography, and when shortening of the cervix is observed, the cerclage can be performed.

Management (Treatment)
Tertiary interventions are aimed at women who are about to go into preterm labor, or rupture the membranes or bleed preterm. The use of the fibronectin test and ultrasonography improves the diagnostic accuracy and reduces false-positive diagnosis. While treatments to arrest early labor where there is progressive cervical dilatation and effacement will not be effective to gain sufficient time to allow the fetus to grow and mature further, it may defer delivery sufficiently to allow the mother to be brought to a specialized center that is equipped and staffed to handle preterm deliveries. In a hospital setting women are hydrated via intravenous infusion (as dehydration can lead to premature uterine contractions).If a baby has cardiac arrest at birth and is before 23 weeks or less than 400 g attempts at resuscitation are not indicated.

Steroids
Severely premature infants may have underdeveloped lungs because they are not yet producing their own surfactant. This can lead directly to respiratory distress syndrome, also called hyaline membrane disease, in the neonate. To try to reduce the risk of this outcome, pregnant mothers with threatened premature delivery prior to 34 weeks are often administered at least one course of glucocorticoids, an antenatal steroid that crosses the placental barrier and stimulates the production of surfactant in the lungs of the baby. Steroid use up to 37 weeks is also recommended by the American Congress of Obstetricians and Gynecologists. Typical glucocorticoids that would be administered in this context are betamethasone or dexamethasone, often when the pregnancy has reached viability at 23 weeks.
In cases where premature birth is imminent, a second "rescue" course of steroids may be administered 12 to 24 hours before the anticipated birth. There are still some concerns about the efficacy and side effects of a second course of steroids, but the consequences of RDS are so severe that a second course is often viewed as worth the risk. A 2015 Cochrane review (updated in 2022) supports the use of repeat dose(s) of prenatal corticosteroids for women still at risk of preterm birth seven days or more after an initial course.A Cochrane review from 2020 recommends the use of a single course of antenatal corticosteroids to accelerate fetal lung maturation in women at risk of preterm birth. Treatment with antenatal corticosteroids reduces the risk of perinatal death, neonatal death and respiratory distress syndrome and probably reduces the risk of IVH.Concerns about adverse effects of prenatal corticosteroids include increased risk for maternal infection, difficulty with diabetic control, and possible long-term effects on neurodevelopmental outcomes for the infants. There is ongoing discussion about when steroids should be given (i.e. only antenatally or postnatally too) and for how long (i.e. single course or repeated administration). Despite these unknowns, there is a consensus that the benefits of a single course of prenatal glucocorticosteroids vastly outweigh the potential risks.

Antibiotics
The routine administration of antibiotics to all women with threatened preterm labor reduces the risk of the baby to get infected with group B streptococcus and has been shown to reduce related mortality rates.When membranes rupture prematurely, obstetrical management looks for development of labor and signs of infection. Prophylactic antibiotic administration has been shown to prolong pregnancy and reduced neonatal morbidity with rupture of membranes at less than 34 weeks. Because of concern about necrotizing enterocolitis, amoxicillin or erythromycin has been recommended, but not amoxicillin + clavulanic acid (co-amoxiclav).

Tocolysis
A number of medications may be useful to delay delivery including: nonsteroidal anti-inflammatory drugs, calcium channel blockers, beta mimetics, and atosiban. Tocolysis rarely delays delivery beyond 24–48 hours. This delay, however, may be sufficient to allow the pregnant woman to be transferred to a center specialized for management of preterm deliveries and give administered corticosteroids to reduce neonatal organ immaturity. Meta-analyses indicate that calcium-channel blockers and an oxytocin antagonist can delay delivery by 2–7 days, and β2-agonist drugs delay by 48 hours but carry more side effects. Magnesium sulfate does not appear to be useful to prevent preterm birth. Its use before delivery, however, does appear to decrease the risk of cerebral palsy.

Mode of delivery
The routine use of caesarean section for early delivery of infants expected to have very low birth weight is controversial, and a decision concerning the route and time of delivery probably needs to be made on a case-by-case basis.

Neonatal care
In developed countries premature infants are usually cared for in a NICU. The physicians who specialize in the care of very sick or premature babies are known as neonatologists. In the NICU, premature babies are kept under radiant warmers or in incubators (also called isolettes), which are bassinets enclosed in plastic with climate control equipment designed to keep them warm and limit their exposure to germs. Modern neonatal intensive care involves sophisticated measurement of temperature, respiration, cardiac function, oxygenation, and brain activity. After delivery, plastic wraps or warm mattresses are useful to keep the infant warm on their way to the neonatal intensive care unit (NICU). Treatments may include fluids and nutrition through intravenous catheters, oxygen supplementation, mechanical ventilation support, and medications. In developing countries where advanced equipment and even electricity may not be available or reliable, simple measures such as kangaroo care (skin to skin warming), encouraging breastfeeding, and basic infection control measures can significantly reduce preterm morbidity and mortality. Kangaroo mother care (KMC) can decrease the risk of neonatal sepsis, hypothermia, hypoglycemia and increase exclusive breastfeeding Bili lights may also be used to treat newborn jaundice (hyperbilirubinemia).
Water can be carefully provided to prevent dehydration but not so much to increase risks of side effects.

Breathing support
In terms of respiratory support, there may be little or no difference in the risk of death or chronic lung disease between high flow nasal cannulae (HFNC) and continuous positive airway pressure (CPAP) or nasal intermittent positive pressure ventilation (NPPV). For extremely preterm babies (born before 28 weeks gestation), targeting a higher versus a lower oxygen saturation range makes little or no difference overall to the risk of death or major disability. Babies born before 32 weeks probably have a lower risk of death from bronchopulmonary dysplasia if they have CPAP immediately after being born, compared to receiving either supportive care or assisted ventilation.There is insufficient evidence for or against placing preterm stable twins in the same cot or incubator (co-bedding).

Nutrition
Meeting the appropriate nutritional needs of preterm infants is important for long-term health. Optimal care may require a balance of meeting nutritional needs and preventing complications related to feeding. The ideal growth rate is not known, however, preterm infants usually require a higher energy intake compared to babies who are born at term. The recommended amount of milk is often prescribed based on approximated nutritional requirements of a similar aged fetus who is not compromised. An immature gastrointestinal tract (GI tract), medical conditions (or co-morbidities), risk of aspirating milk, and necrotizing enterocolitis may lead to difficulties in meeting this high nutritional demand and many preterm infants have nutritional deficits that may result in growth restrictions.  In addition, very small preterm infants cannot coordinate sucking, swallowing, and breathing. Tolerating a full enteral feeding (the prescribed volume of milk or formula) is a priority in neonatal care as this reduces the risks associated with venous catheters including infection, and may reduce the length of time the infant requires specialized care in the hospital. Different strategies can be used to optimize feeding for preterm infants. The type of milk/formula and fortifiers, route of administration (by mouth, tube feeding, venous catheter), timing of feeding, quantity of milk, continuous or intermittent feeding, and managing gastric residuals are all considered by the neonatal care team when optimizing care. The evidence in the form of high quality randomized trials is generally fairly weak in this area, and for this reason different neonatal intensive care units may have different practices and this results in a fairly large variation in practice. The care of preterm infants also varies in different countries and depends on resources that are available.

Human breast milk and formula
The American Academy of Pediatrics recommended feeding preterm infants human milk, finding "significant short- and long-term beneficial effects," including lower rates of necrotizing enterocolitis (NEC). In the absence of evidence from randomised controlled trials about the effects of feeding preterm infants with formula compared with mothers own breast milk, data collected from other types of studies suggest that mothers own breast milk is likely to have advantages over formula in terms of the babys growth and development. When a mothers breast milk is not available, formula is probably better than donor breast milk for preterm babies in terms of weight gain, linear growth and head growth but there may be little or no difference in terms of neuro-developmental disability, death or necrotising enterocolitis.

Fortified human breast milk and preterm/term formula
Breast milk or formula alone may not be sufficient to meet the nutritional needs of some preterm infants. Fortification of breast milk or formula by adding extra nutrients is an approach often taken for feeding preterm infants, with the goal of meeting the high nutritional demand. High quality randomized controlled trials are needed in this field to determine the effectiveness of fortification. It is unclear if fortification of breast milk improves outcomes in preterm babies, though it may speed growth. Supplementing human milk with extra protein may increase short-term growth but the longer-term effects on body composition, growth and brain development are uncertain. Higher protein formula (between 3 and 4 grams of protein per kilo of body weight) may be more effective than low protein formula (less than 3 grams per kilo per day) for weight gain in formula-fed low-birth-weight infants. There is insufficient evidence about the effect on preterm babies growth of supplementing human milk with carbohydrate, fat, and branched-chain amino acids.  Conversely, there is some indication that preterm babies who cannot breastfeed may do better if they are fed only with diluted formula compared to full strength formula but the clinical trial evidence remains uncertain.Individualizing the nutrients and quantities used to fortify enteral milk feeds in infants born with very low birth weight may lead to better short-term weight gain and growth but the evidence is uncertain for longer term outcomes and for the risk of serious illness and death. This includes targeted fortification (adjusting the level of nutrients in response to the results of a test on the breast milk) and adjustable fortification (adding nutrients based on testing the infant).Multi-nutrient fortifier used to fortify human milk and formula has traditionally been derived from bovine milk. Fortifier derived from humans is available, however, the evidence from clinical trials is uncertain and it is not clear if there are any differences between human-derived fortifier and bovine-derived fortifier in terms of neonatal weight gain, feeding intolerance, infections, or the risk of death.

Timing of feeds
For very preterm infants, most neonatal care centres start milk feeds gradually, rather than starting with a full enteral feeding right away, however, is not clear if starting full enteral feeding early effects the risk of necrotising enterocolitis. In these cases, the preterm infant would be receiving the majority of their nutrition and fluids intravenously. The milk volume is usually gradually increased over the following weeks. Research into the ideal timing of enteral feeding and whether delaying enteral feeding or gradually introducing enteral feeds is beneficial at improving growth for preterm infants or low birth weight infants is needed.  In addition, the ideal timing of enteral feeds to prevent side effects such as necrotising enterocolitis or mortality in preterm infants who require a packed red blood cell transfusion is not clear. Potential disadvantages of a more gradual approach to feeding preterm infants associated with less milk in the gut and include slower GI tract secretion of hormones and gut motility and slower microbial colonization of the gut.Regarding the timing of starting fortified milk, preterm infants are often started on fortified milk/formula once they are fed 100 mL/kg of their body weight. Other some neonatal specialists feel that starting to feed a preterm infant fortified milk earlier is beneficial to improve intake of nutrients. The risks of feeding intolerance and necrotising enterocolitis related to early versus later fortification of human milk are not clear. Once the infant is able to go home from the hospital there is limited evidence to support prescribing a preterm (fortified) formula.

Intermittent feeding versus continuous feeding
For infants who weigh less than 1500 grams, tube feeding is usually necessary. Most often, neonatal specialists feed preterm babies intermittently with a prescribed amount of milk over a short period of time. For example, a feed could last 10–20 minutes and be given every 3 hours. This intermittent approach is meant to mimic conditions of normal bodily functions involved with feeding and allow for a cyclic pattern in the release of gastrointestinal tract hormones to promote development of the gastrointestinal system. In certain cases, continuous nasogastric feeding is sometimes preferred. There is low to very low certainty evidence to suggest that low birth weight babies who receive continuous nasogastic feeding may reach the benchmark of tolerating full enteral feeding later than babies fed intermittently and it is not clear if continuous feeding has any effect on weight gain or the number of interruptions in feedings. Continuous feeding may have little to no effect on length of body growth or head circumference and the effects of continuous feeding on the risk of developing necrotising enterocolitis is not clear.Since preterm infants with gastro-oesophageal reflux disease do not have a fully developed antireflux mechanism, deciding on the most effective approach for nutrition is important. It is not clear if continuous bolus intragastric tube feeding is more effective compared to intermittent bolus intragastric tube feeding for feeding preterm infants with gastro-oesophageal reflux disease.For infants who would benefit from intermittent bolus feeding, some infants may be fed using the "push feed" method using a syringe to gently push the milk or formula into the stomach of the infant. Others may be fed using a gravity feeding system where the syringe is attached directly to a tube and the milk or formula drips into the infants stomach. It is not clear from medical studies which approach to intermittent bolus feeding is more effective or reduces adverse effects such as apnoea, bradycardia, or oxygen desaturation episodes.

High volume feeds
High-volume (more than 180 mL per kilogram per day) enteral feeds of fortified or non-fortified human breast milk or formula may improve weight gain while the pre-term infant is hospitalized, however, there is insufficient evidence to determine if this approach improves growth of the neonate and other clinical outcomes including length of hospital stay. The risks or adverse effects associated with high-volume enteral feeding of preterm infants including aspiration pneumonia, reflux, apnoea, and sudden oxygen desaturation episodes have not been reported in the trials considered in a 2021 systematic review.

Parenteral (intraveneous) nutrition
For preterm infants who are born after 34 weeks of gestation ("late preterm infants") who are critically ill and cannot tolerate milk, there is some weak evidence that the infant may benefit from including amino acids and fats in the intravenous nutrition at a later time point (72 hours or longer from hospital admission) versus early (less than 72 hours from admission to hospital), however further research is required to understand the ideal timing of starting intravenous nutrition.

Gastric residuals
For preterm infants in neonatal intensive care on gavage feeds, monitoring the volume and colour of gastric residuals, the milk and gastrointestinal secretions that remain in the stomach after a set amount of time, is common standard of care practice. Gastric residual often contains gastric acid, hormones, enzymes, and other substances that may help improve digestion and mobility of the gastrointestinal tract.  Analysis of gastric residuals may help guide timing of feeds. Increased gastric residual may indicate feeding intolerance or it may be an early sign of necrotizing enterocolitis. Increased gastric residual may be caused by an underdeveloped gastrointestinal system that leads to slower gastric emptying or movement of the milk in the intestinal tract, reduced hormone or enzyme secretions from the gastrointestinal tract, duodenogastric reflux, formula, medications, and/or illness. The clinical decision to discard the gastric residuals (versus re-feeding) is often individualized based on the quantity and quality of the residual. Some experts also suggest replacing the fresh milk or curded milk and bile-stained aspirates, but not replacing haemorrhagic residual. Evidence to support or refute the practice of re-feeding preterm infants with gastric residuals is lacking.

Hearing assessment
The Joint Committee on Infant Hearing (JCIH) state that for preterm infants who are in the neonatal intensive care unit (NICU) for a prolonged time should have a diagnostic audiologic evaluation before they are discharged from the hospital. Well babies follow a 1-2-3-month benchmark timeline where they are screened, diagnosed, and receiving intervention for a hearing loss. However, very premature babies it might not be possible to complete a hearing screen at one month of age due to several factors. Once the baby is stable an audiologic evaluation should be performed. For premature babies in the NICU, auditory brainstem response (ABR) testing is recommended. If the infant doesnt pass the screen, they should be referred for an audiologic evaluation by an audiologist. If the infant is on aminoglycosides such as gentamicin for less than five days they should be monitored and have a follow up 6–7 months of being discharged from the hospital to ensure there is no late onset hearing loss due to the medication.

Outcomes and prognosis
Preterm births can result in a range of problems including mortality and physical and mental delays.

Mortality and morbidity
In the U.S. where many neonatal infections and other causes of neonatal death have been markedly reduced, prematurity is the leading cause of neonatal mortality at 25%. Prematurely born infants are also at greater risk for having subsequent serious chronic health problems as discussed below.
The earliest gestational age at which the infant has at least a 50% chance of survival is referred to as the limit of viability. As NICU care has improved over the last 40 years, the limit of viability has reduced to approximately 24 weeks. Most newborns who die, and 40% of older infants who die, were born between 20 and 25.9 weeks (gestational age), during the second trimester.As risk of brain damage and developmental delay is significant at that threshold even if the infant survives, there are ethical controversies over the aggressiveness of the care rendered to such infants. The limit of viability has also become a factor in the abortion debate.

Specific risks for the preterm neonate
Preterm infants usually show physical signs of prematurity in reverse proportion to the gestational age. As a result, they are at risk for numerous medical problems affecting different organ systems.

Neurological problems include apnea of prematurity, hypoxic-ischemic encephalopathy (HIE), retinopathy of prematurity (ROP), developmental disability, transient hyperammonemia of the newborn, cerebral palsy and intraventricular hemorrhage, the latter affecting 25% of babies born preterm, usually before 32 weeks of pregnancy. Mild brain bleeds usually leave no or few lasting complications, but severe bleeds often result in brain damage or even death. Neurodevelopmental problems have been linked to lack of maternal thyroid hormones, at a time when their own thyroid is unable to meet postnatal needs.
Cardiovascular complications may arise from the failure of the ductus arteriosus to close after birth: patent ductus arteriosus (PDA).
Respiratory problems are common, specifically the respiratory distress syndrome (RDS or IRDS) (previously called hyaline membrane disease). Another problem can be chronic lung disease (previously called bronchopulmonary dysplasia or BPD).
Gastrointestinal and metabolic issues can arise from neonatal hypoglycemia, feeding difficulties, rickets of prematurity, hypocalcemia, inguinal hernia, and necrotizing enterocolitis (NEC).
Hematologic complications include anemia of prematurity, thrombocytopenia, and hyperbilirubinemia (jaundice) that can lead to kernicterus.
Infection, including sepsis, pneumonia, and urinary tract infection [1]

Survival
The chance of survival at 22 weeks is about 6%, while at 23 weeks it is 26%, 24 weeks 55% and 25 weeks about 72% as of 2016. With extensive treatment up to 30% of those who survive birth at 22 weeks survive longer term as of 2019. The chances of survival without long-term difficulties is less. Of those who survive following birth at 22 weeks 33% have severe disabilities. In the developed world overall survival is about 90% while in low-income countries survival rates are about 10%.Some children will adjust well during childhood and adolescence, although disability is more likely nearer the limits of viability. A large study followed children born between 22 and 25 weeks until the age of 6 years old. Of these children, 46 percent had moderate to severe disabilities such as cerebral palsy, vision or hearing loss and learning disabilities, 34 percent had mild disabilities, and 20 percent had no disabilities. 12 percent had disabling cerebral palsy. Up to 15 out of 100 premature infants have significant hearing loss.As survival has improved, the focus of interventions directed at the newborn has shifted to reduce long-term disabilities, particularly those related to brain injury. Some of the complications related to prematurity may not be apparent until years after the birth. A long-term study demonstrated that the risks of medical and social disabilities extend into adulthood and are higher with decreasing gestational age at birth and include cerebral palsy, intellectual disability, disorders of psychological development, behavior, and emotion, disabilities of vision and hearing, and epilepsy. Standard intelligence tests showed that 41 percent of children born between 22 and 25 weeks had moderate or severe learning disabilities when compared to the test scores of a group of similar classmates who were born at full term. It is also shown that higher levels of education were less likely to be obtained with decreasing gestational age at birth. People born prematurely may be more susceptible to developing depression as teenagers.
Some of these problems can be described as being within the executive domain and have been speculated to arise due to decreased myelinization of the frontal lobes. Studies of people born premature and investigated later with MRI brain imaging, demonstrate qualitative anomalies of brain structure and grey matter deficits within temporal lobe structures and the cerebellum that persist into adolescence. Throughout life they are more likely to require services provided by physical therapists, occupational therapists, or speech therapists.Despite the neurosensory, mental and educational problems studied in school age and adolescent children born extremely preterm, the majority of preterm survivors born during the early years of neonatal intensive care are found to do well and to live fairly normal lives in young adulthood. Young adults born preterm seem to acknowledge that they have more health problems than their peers, yet feel the same degree of satisfaction with their quality of life.Beyond the neurodevelopmental consequences of prematurity, infants born preterm have a greater risk for many other health problems. For instance, children born prematurely have an increased risk for developing chronic kidney disease.

Epidemiology
Preterm birth complicates the births of infants worldwide affecting 5% to 18% of births. In Europe and many developed countries the preterm birth rate is generally 5–9%, and in the U.S. it has even risen to 12–13% in the last decades.As weight is easier to determine than gestational age, the World Health Organization tracks rates of low birth weight (< 2,500 grams), which occurred in 16.5 percent of births in less developed regions in 2000. It is estimated that one third of these low birth weight deliveries are due to preterm delivery. Weight generally correlates to gestational age; however, infants may be underweight for other reasons than a preterm delivery. Neonates of low birth weight (LBW) have a birth weight of less than 2,500 g (5 lb 8 oz) and are mostly but not exclusively preterm babies as they also include small for gestational age (SGA) babies. Weight-based classification further recognizes Very Low Birth Weight (VLBW) which is less than 1,500 g, and Extremely Low Birth Weight (ELBW) which is less than 1,000 g. Almost all neonates in these latter two groups are born preterm.
About 75% of nearly a million deaths due to preterm deliver would survive if provided warmth, breastfeeding, treatments for infection, and breathing support. Complications from preterm births resulted in 740,000 deaths in 2013, down from 1.57 million in 1990.

Society and culture
Economics
Preterm birth is a significant cost factor in healthcare, not even considering the expenses of long-term care for individuals with disabilities due to preterm birth. A 2003 study in the U.S. determined neonatal costs to be $224,400 for a newborn at 500–700 g versus $1,000 at over 3,000 g. The costs increase exponentially with decreasing gestational age and weight.
The 2007 Institute of Medicine report Preterm Birth found that the 550,000 premature babies born each year in the U.S. run up about $26 billion in annual costs, mostly related to care in neonatal intensive care units, but the real tab may top $50 billion.

Notable cases
James Elgin Gill (born on 20 May 1987 in Ottawa, Ontario, Canada) was the earliest premature baby in the world, until that record was broken in 2004. He was 128 days premature (21 weeks 5 days gestation) and weighed 624 g (1 lb 6 oz). He survived.In 2014, Lyla Stensrud, born in San Antonio, Texas, U.S. became the youngest premature baby in the world. She was born at 21 weeks 4 days and weighed 410 grams (less than a pound). Kaashif Ahmad resuscitated the baby after she was born. As of November 2018, Lyla was attending preschool. She had a slight delay in speech, but no other known medical issues or disabilities.Amillia Taylor is also often cited as the most premature baby. She was born on 24 October 2006 in Miami, Florida, U.S. at 21 weeks and 6 days gestation. This report has created some confusion as her gestation was measured from the date of conception (through in vitro fertilization) rather than the date of her mothers last menstrual period, making her appear 2 weeks younger than if gestation was calculated by the more common method. At birth, she was 23 cm (9 in) long and weighed 280 g (10 oz). She had digestive and respiratory problems, together with a brain hemorrhage. She was discharged from the Baptist Childrens Hospital on 20 February 2007.The record for the smallest premature baby to survive was held for a considerable amount of time by Madeline Mann, who was born in 1989 at 26 weeks, weighing 280 g (9+7⁄8 oz) and measuring 24 cm (9+1⁄2 in) long. This record was broken in September 2004 by Rumaisa Rahman, who was born in the same hospital, Loyola University Medical Center in Maywood, Illinois. at 25 weeks gestation. At birth, she was 20 cm (8 in) long and weighed 261 g (9+1⁄4 oz). Her twin sister was also a small baby, weighing 563 g (1 lb 3+7⁄8 oz) at birth. During pregnancy their mother had pre-eclampsia, requiring birth by caesarean section. The larger twin left the hospital at the end of December, while the smaller remained there until 10 February 2005 by which time her weight had increased to 1.18 kg (2 lb 9+5⁄8 oz). Generally healthy, the twins had to undergo laser eye surgery to correct vision problems, a common occurrence among premature babies.
In May 2019, Sharp Mary Birch Hospital for Women & Newborns in San Diego announced that a baby nicknamed "Saybie" had been discharged almost five months after being born at 23 weeks gestation and weighing 244 g (8+5⁄8 oz). Saybie was confirmed by Dr. Edward Bell of the University of Iowa, which keeps the Tiniest Babies Registry, to be the new smallest surviving premature baby in that registry.The worlds smallest premature boy to survive was born in February 2009 at Childrens Hospitals and Clinics of Minnesota in Minneapolis, Minnesota, U.S. Jonathon Whitehill was born at 25 weeks gestation with a weight of 310 g (10+7⁄8 oz). He was hospitalized in a neonatal intensive care unit for five months, and then discharged.In 2020, at the height of the COVID-19 pandemic, the worlds most premature baby was born. The baby, named Richard Hutchinson, was born at Childrens Hospitals and Clinics of Minnesota in Minneapolis, Minnesota, on June 5, 2020, at 21 weeks 2 days gestation. At birth he weighed 340 g (12 oz). He remained hospitalized until November 2020, when he was then discharged.Historical figures who were born prematurely include Johannes Kepler (born in 1571 at seven months gestation), Isaac Newton (born in 1642, small enough to fit into a quart mug, according to his mother), Winston Churchill (born in 1874 at seven months gestation), and Anna Pavlova (born in 1885 at seven months gestation).

Effect of the coronavirus pandemic
During the COVID-19 pandemic, a drastic drop in the rate of premature births has been reported in many countries, ranging from a 20% reduction to a 90% drop in the starkest cases. Studies in Ireland and Denmark first noticed the phenomenon, and it has been confirmed elsewhere. There is no universally accepted explanation for this drop as of August 2020. Hypotheses include additional rest and support for expectant mothers staying at home, less air pollution due to shutdowns and reduced car fumes, and reduced likelihood of catching other diseases and viruses in general due to the lockdowns.

Research
Brain injury is common among preterms, ranging from white matter injury to intraventricular and cerebellar haemorrhages. The characteristic neuropathology of preterms has been described as the "encephalopathy of prematurity". The number of preterms that receive special education is doubled compared to the general population. School marks are lower and so are verbal learning, executive function, language skills, and memory performance scores, as well as IQ scores. Behaviourally, adolescents who were born very preterm and/or very low birth weight have similar self-reports of quality of life, health status and self-esteem as term controls.Various structural magnetic resonance studies found consistent reductions in whole brain volume. The extensive list of particular regions with smaller volumes compared to controls includes many cortical areas (temporal, frontal, parietal, occipital and cingulate), the hippocampal regions, thalamus, basal ganglia, amygdala, brain stem, internal capsule, corpus callosum and cerebellum. Brain volume reduction seems to be present throughout the whole brain </s>


<s> [INST] <<SYS>> You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information. <</SYS>> What is Takotsubo cardiomyopathy and explain in detail? [/INST] Takotsubo cardiomyopathy or Takotsubo syndrome (TTS), also known as stress cardiomyopathy, is a type of non-ischemic cardiomyopathy in which there is a sudden temporary weakening of the muscular portion of the heart. It usually appears after a significant stressor, either physical or emotional; when caused by the latter, the condition is sometimes called broken heart syndrome. Examples of physical stressors that can cause TTS are sepsis, shock, and pheochromocytoma, and emotional stressors include bereavement, divorce, or the loss of a job. Reviews suggest that of patients diagnosed with the condition, about 70–80% recently experienced a major stressor, including 41–50% with a physical stressor and 26–30% with an emotional stressor. TTS can also appear in patients who have not experienced major stressors.The pathophysiology is not well understood, but a sudden massive surge of catecholamines such as adrenaline and norepinephrine from extreme stress or a tumor secreting these chemicals is thought to play a central role.  Excess catecholamines, when released directly by nerves that stimulate cardiac muscle cells, have a toxic effect and can lead to decreased cardiac muscular function or "stunning". Further, this adrenaline surge triggers the arteries to tighten, thereby raising blood pressure and placing more stress on the heart, and may lead to spasm of the coronary arteries that supply blood to the heart muscle. This impairs the arteries from delivering adequate blood flow and oxygen to the heart muscle. Together, these events can lead to congestive heart failure and decrease the hearts output of blood with each squeeze.Takotsubo cardiomyopathy occurs worldwide. The condition is thought to be responsible for 2% of all acute coronary syndrome cases presenting to hospitals. Although TTS has generally been considered a self-limiting disease, spontaneously resolving over the course of days to weeks, contemporary observations show that "a subset of TTS patients may present with symptoms arising from its complications, e.g. heart failure, pulmonary oedema, stroke, cardiogenic shock, or cardiac arrest". This does not imply that rates of shock/death of TTS are comparable to those of acute coronary syndrome (ACS), but that patients with acute complications may co-occur with TTS.  These cases of shock and death have been associated with the occurrence of TTS secondary to an enciting physical stressor such as hemorrhage, brain injury sepsis, pulmonary embolism or severe COPD.It occurs more commonly in postmenopausal women. The name "takotsubo" comes from the Japanese word takotsubo "octopus trap", because the left ventricle of the heart takes on a shape resembling an octopus trap when affected by this condition.A study published in the Journal of the American Heart Association in October 2021 found a steady annual increase in takotsubo cardiomyopathy among both women and men from 2006 to 2017, with the sharpest increases among women 50 and older.

Signs and symptoms
The typical presentation of takotsubo cardiomyopathy is chest pain with or without shortness of breath and associated electrocardiogram (ECG) changes mimicking a myocardial infarction of the anterior wall. During the course of evaluation of the patient, a bulging out of the left ventricular apex with a hypercontractile base of the left ventricle is often noted. It is the hallmark bulging-out of the apex of the heart with preserved function of the base that earned the syndrome its name takotsubo "octopus trap", in Japan, where it was first described.Stress is the main factor in takotsubo cardiomyopathy, with more than 85% of cases set in motion by either a physically or emotionally stressful event that prefaces the start of symptoms. Examples of emotional stressors include grief from the death of a loved one, fear of public speaking, arguing with a spouse, relationship disagreements, betrayal, and financial problems. Acute asthma, surgery, chemotherapy, and stroke are examples of physical stressors. In a few cases, the stress may be a happy event, such as a wedding, winning a jackpot, a sporting triumph, or a birthday.

Risk factors
Stress trigger
Although there have been documented cases of TTS without a triggering stressor, it is widely recognized that TTS is preceded by a stressful event.  Case series looking at large groups of patients report that some patients develop takotsubo cardiomyopathy after experiencing emotional stress. Some patients have a preceding clinical stressor (such as a brain injury, asthma attack or exacerbation of a chronic illness) and research has indicated that this type of stress may even occur more often than emotionally stressful triggers. Roughly one-third of patients have no preceding stressful event. A 2009 large case series from Europe found that takotsubo cardiomyopathy was slightly more frequent during the winter season. This may be related to two possible/suspected pathophysiological causes: coronary spasms of microvessels, which are more prevalent in cold weather, and viral infections – such as Parvovirus B19 – which occur more frequently during the winter.

Sex
Women, specifically postmenopausal women, are at greatest risk of developing TTS. This has led some researchers to theorize about the possible protective effects of estrogen in preventing TTS.

Genetic risk factors
It is currently being investigated if certain genetic traits associated with catecholamine receptors found on cardiac muscle cells play a role in the development of TTS.  There is limited evidence tying TTS directly to a specific genetic expression or mutation, however there is currently a widely held hypothesis supporting the idea of the interaction between environmental factors and the interplay of genetic predisposition leading to the susceptibility to microvascular alterations that contribute to the TTS disease process.

Hormonal dysregulation
Certain endocrine diseases including pheochromocytoma and thyrotoxicosis have been identified as potential risk factors for TTS. The relationship between thyroid function and stress cardiomyopathy is marked by a dual phenotype, where both impending primary hyperthyroidism and a high set point of thyroid homeostasis (encoding type 2 allostatic load) are common phenomena. A multi-centre observation study found normal thyroid function to be the exception rather than the rule in TTS. Especially hyperthyroidism is highly prevalent in takotsubo cardiomyopathy, and it seems to predict a poor prognosis in terms of complications and mortality.

Pathophysiology
The cause of takotsubo cardiomyopathy is not fully understood, but several mechanisms have been proposed.  It is well documented that elevated catecholamine levels have been implicated in the vast majority of TTS cases. Theories suggest a link between brain activation of stress-related biochemicals and the effects these chemicals have on areas of the heart.  More specifically, adrenal stimulation by the sympathetic nervous system has been noted in cases ranging from physical events such as ischemic stroke, to emotional events such as depression or loss of a loved-one. How these increased levels of catecholamines act in the body to produce the changes seen with TTS is not clearly understood.  Research supports the widely-held understanding that microvascular dysfunction and coronary vasospasm caused by a rapid influx of catecholamines to cardiac myocytes results in apical stunning and transient cardiomyopathy.
Microvascular dysfunction/Transient vasospasm: Some of the original researchers of takotsubo suggested that multiple simultaneous spasms of coronary arteries could cause enough loss of blood flow to cause transient stunning of the myocardium. Other researchers have shown that vasospasm is much less common than initially thought. It has been noted that when there are vasospasms, even in multiple arteries, that they do not correlate with the areas of myocardium that are not contracting. However, the idea of coronary artery vasospasm is still believed to contribute to the TTS disease process. The theory of vasospasm is not easily separated from that of microvascular dysfunction and in fact, microvascular dysfunction could explain vasospasticity. Impaired microvascular function is seen in a vast majority, if not all, of patients with TTS and is currently one of the most supported theories. Most of the dysfunction occurs as a result of abnormalities within the endothelial linings of blood vessels supplying the heart. In TTS, these highly sensitive interior linings of the vessels have reduced functionality which create dysregulation of vascular tone and predispose the individual to vasoconstriction. When the increased vasoconstrictor effects of catecholamines are introduced, the result is acute cardiac ischemia.
Catecholamine-induced myocyte injury: It has been suggested that the response to catecholamines (such as epinephrine and norepinephrine, released in response to stress) leads to heart muscle dysfunction that contributes to takotsubo cardiomyopathy. The effects of this toxicity can be greater in those with a predisposition to anxiety or panic disorders. Delivery of catecholamines (epinephrine, norepinephrine) via circulating blood and through direct delivery from cardiac nerves is increased by the stimulation of stress control centers of the brain. During an emotionally or physically stressful event, brain centers initiate the sympathetic nervous pathways and increase myocardial activity. Excessive catecholamine stimulation has a toxic effect on cardiac muscle cells which creates necrosis of the contractile units of cells similarly seen during acute myocardial infarction. The increased workload of cardiac muscle created by the stimulation of catecholamines, increases the need for more blood and oxygen to these muscles to sustain function. When these demands are unable to be met, the heart is starved of blood and oxygen and begins to die. Included in the cytotoxic sequela of catecholamine toxicity is the molecular transformation of the cardiac myocyte to produce apical stunning.
Mid-ventricular obstruction, apical stunning: It has been suggested that a mid-ventricular wall thickening with outflow obstruction is important in the pathophysiology. This stunning is largely seen as a protective effect produced by the flood of excess catecholamines into the cardiac muscle cell. Overstimulation of catecholamine receptors create physiological changes in the receptor which has an inverse effect on cardiac cellular function. Termed cellular-trafficking, this property of the cardiac muscle cell is actually a molecular transformation of the cell to produce a down-regulation of catecolaminergic sensitivity. This means that in the presence of excess epinephrine, a normal cardiac contraction is inhibited in an effort to reduce energy demands, prevent hyperactivity and spare the integrity of the cell. Further bolstering this idea is the concentration of these kinds of receptors in the heart. Higher concentrations of the receptor effected to produce cardiac stunning are found closer to the apex of the ventricle. This is what creates the classic ballooning effect of the ventricle.It is likely that there are multiple factors at play that could include some amount of vasospasm and failure of the microvasculature. These factors can overlap and create the complex sequela leading to ischemia and left ventricle contraction abnormality. For instance, estrogen, which confers protection to women by improving blood flow to heart muscle, is one biochemical pathway implicated in the TTS disease process. Once this protective mechanism is reduced through the decreased production of estrogen after menopause, there is thought to be an increase in endothelial dysfunction predisposing an individual to vasoconstriction and cardiac ischemia. An inciting stressful event elicits the release of catecholamines into the blood stream to create increased heart muscle activity and metabolism. This leads to further cardiac microvascular endothelial dysfunction through oxidative stress, alteration of ion-mediated channels, and electrolyte disturbances which ultimately alter myocardial cell membrane permeability and dysfunction. Coupled with direct heart muscle toxicity, this crescendo of factors are implicated in the ballooning and heart failure characteristically seen in TTS.A 2019 case involved a 60-year-old woman presenting with Takotsubo cardiomyopathy due to over-consumption of wasabi, mistaking it for avocado.

Diagnosis
Several well regarded institutions of medical research have produced clinical criteria useful in diagnosing TTS. One of the first sets of guidelines was initially published in 2004 and again in 2008 by the Mayo Clinic. Other research institutions proposing diagnostic criteria include the Japanese Takotsubo Cardiomyopathy Study Group, Gothenburg University, Johns Hopkins University, the Takotsubo Italian Network and the Heart Failure Associates TTS Taskforce of the European Society of Cardiology. All of the research institutions agree on at least two main criteria needed to accurately diagnose TTS: 1) transient left ventricular wall motion abnormality and 2) the absence of a condition obviously explaining this wall motion abnormality (coronary artery lesion, hypoperfusion, myocarditis, toxicity, etc.). Other commonly acknowledged criteria necessary for diagnosis include characteristic EKG changes and mild to modest elevation in cardiac troponin.Transient apical ballooning syndrome or takotsubo cardiomyopathy is found in 1.7–2.2% of patients presenting with acute coronary syndrome. While the original case studies reported on individuals in Japan, takotsubo cardiomyopathy has been noted more recently in the United States and Western Europe. It is likely that the syndrome previously went undiagnosed before it was described in detail in the Japanese literature. Evaluation of individuals with takotsubo cardiomyopathy typically includes a coronary angiogram to rule out occlusion of the left anterior descending artery, which will not reveal any significant blockages that would cause the left ventricular dysfunction. Provided that the individual survives their initial presentation, the left ventricular function improves within two months.The diagnosis of takotsubo cardiomyopathy may be difficult upon presentation. The ECG findings often are confused with those found during an acute anterior wall myocardial infarction. It classically mimics ST-segment elevation myocardial infarction, and is characterised by acute onset of transient ventricular apical wall motion abnormalities (ballooning) accompanied by chest pain, shortness of breath, ST-segment elevation, T-wave inversion or QT-interval prolongation on ECG. Cardiac enzymes are usually negative and are moderate at worst, and cardiac catheterization usually shows absence of significant coronary artery disease.The diagnosis is made by the pathognomonic wall motion abnormalities, in which the base of the left ventricle is contracting normally or is hyperkinetic while the remainder of the left ventricle is akinetic or dyskinetic. This is accompanied by the lack of significant coronary artery disease that would explain the wall motion abnormalities. Although apical ballooning has been described classically as the angiographic manifestation of takotsubo, it has been shown that left ventricular dysfunction in this syndrome includes not only the classic apical ballooning, but also different angiographic morphologies such as mid-ventricular ballooning and, rarely, local ballooning of other segments.The ballooning patterns were classified by Shimizu et al. as takotsubo type for apical akinesia and basal hyperkinesia, reverse takotsubo for basal akinesia and apical hyperkinesia, mid-ventricular type for mid-ventricular ballooning accompanied by basal and apical hyperkinesia, and localised type for any other segmental left ventricular ballooning with clinical characteristics of takotsubo-like left ventricular dysfunction.In short, the main criteria for the diagnosis of takotsubo cardiomyopathy are: the patient must have experienced a stressor before the symptoms began to arise; the patients ECG reading must show abnormalities from a normal heart; the patient must not show signs of coronary blockage or other common causes of heart troubles; the levels of cardiac enzymes in the heart must be elevated or irregular; and the patient must recover complete contraction and be functioning normally in a short amount of time.

Treatment
The treatment of takotsubo cardiomyopathy is generally supportive in nature, for it is considered a transient disorder. Treatment is dependent on whether patients experience heart failure or acute hypotension and shock. In many individuals, left ventricular function normalizes within two months. Aspirin and other heart drugs also appear to help in the treatment of this disease, even in extreme cases. After the patient has been diagnosed, and myocardial infarction (heart attack) ruled out, the aspirin regimen may be discontinued, and treatment becomes that of supporting the patient. There is currently no internationally agreed protocol for treatment of this condition.While medical treatments are important to address the acute symptoms of takotsubo cardiomyopathy, further treatment includes lifestyle changes. It is important that the individual stay physically healthy while learning and maintaining methods to manage stress, and to cope with future difficult situations.Although the symptoms of takotsubo cardiomyopathy usually go away on their own and the condition completely resolves itself within a few weeks, some serious short and long-term complications can happen that must be treated. These most commonly include congestive heart failure and very low blood pressure, and less commonly include blood clotting in the apex of the left ventricle, irregular heart beat, and tearing of the heart wall.

Heart failure
For patients in acute heart failure, ACE inhibitors, angiotensin receptor blockers, and beta blockers, are considered mainstays of heart failure treatment. But use of beta blockers specifically for takotsubo cardiomyopathy is controversial, because they may confer no benefit.

Low blood pressure
For people with cardiogenic shock, medical treatment is based on whether a left ventricular outflow tract (LVOT) obstruction is present. Therefore, early echocardiography is necessary to determine proper management. For those with obstructed LVOTs inotropic agents should not be used, but instead should be managed like patients with hypertrophic cardiomyopathy, (e.g. phenylephrine and fluid resuscitation). For cases in which the LVOT is not obstructed, inotropic therapy (e.g. dobutamine and dopamine) may be used, but with the consideration that takotsubo is caused by excess catecholamines.Furthermore, mechanical circulatory support (MCS) with an intra-aortic balloon pump (IABP) is well-established as supportive treatment.

Prognosis
Despite the grave initial presentation in some of the patients, most of the patients survive the initial acute event, with a very low rate of in-hospital mortality or complications. Once a patient has recovered from the acute stage of the syndrome, they can expect a favorable outcome and the long-term prognosis is excellent for most. Even when ventricular systolic function is heavily compromised at presentation, it typically improves within the first few days and normalises within the first few months. Although infrequent, recurrence of the syndrome has been reported and seems to be associated with the nature of the trigger. Stress cardiomyopathy is now a well-recognized cause of acute congestive heart failure, lethal abnormal heart rhythms, and rupture of the heart wall.

Epidemiology
Takotsubo cardiomyopathy is common, affecting between 1.2% and 2.2% of people in Japan and 2% to 3% in Western countries who experience a myocardial infarction. It also affects far more women than men with 90% of cases being women, most postmenopausal. Scientists believe one reason is that estrogen causes the release of catecholamine and glucocorticoid in response to mental stress. It is not likely for the same recovered patient to experience the syndrome twice, although it has happened in rare cases. The average ages at onset are between 58 and 75 years. Less than 3% of cases occurred in patients under age 50.

History
Rees, et al. wrote in 1967 that the death of a close relative increases the risk of dying within one year by a factor of seven.Engel wrote about sudden and rapid death during psychological stress in 1971 and itemized 8 causation categories: (1) on the impact of the collapse or death of a close person; (2) during acute grief; (3) on threat of loss of a close person; (4) during mourning or on an anniversary; (5) on loss of status or self-esteem; (6) personal danger or threat of injury; (7) after the danger is over; (8) reunion, triumph, or happy ending. He proposed these events provoke neurovegetative responses, involving both the flight-fight and conservation-withdrawal systems, conducive to lethal cardiac events, particularly in individuals with preexisting cardiovascular disease.Although the first scientific description of takotsubo cardiomyopathy was not until the 1990s, Cebelin and Hirsch wrote about human stress cardiomyopathy in 1980. The two looked at homicidal assaults that had happened in Cuyahoga County, Ohio, the past 30 years, specifically those with autopsies who had no internal injury, but had died of physical assault. They found that 11 of 15 had myofibrillar degeneration similar to animal stress studies. In the end, they concluded their data supported "the theory of catecholamine mediation of these myocardial changes in man and of the lethal potential of stress through its effect on the heart".The first studied case of takotsubo cardiomyopathy was in Japan in 1991 by Sato et al. More cases of the syndrome appeared in Japan within the next decade, although western medicine had still not acknowledged it. The syndrome finally occurred in 1997 when Pavin, et al., wrote about two cases of "reversible LV dysfunction precipitated by acute emotional stress". The western world had not heard of such a thing at the time, as it was incredibly rare and often misdiagnosed. The Japanese at last reported about the syndrome to the west in 2001 under the name "transient LV apical ballooning" though at this point the west had already heard of numerous cases. The syndrome reached international audiences through the media in 2005 when the New England Journal of Medicine wrote about the syndrome.In the bible, when Jacob was told his long lost son, Joseph, is still alive, "his heart faltered, because he did not believe them". The medieval  commentator, Nachmanides, further explains: "This condition is known when joy suddenly comes upon one, and it is mentioned in the books of medicines that old or feeble persons cannot withstand the shock, for many of them faint when joy comes to them very suddenly. The heart widens and opens suddenly, and its natural heat goes out and scatters throughout the outer parts of the body, and the heart thus ceases to function because of its coolness."

In popular culture
The name and title track of the 2021 album Tako Tsubo by French band LImpératrice refers to the intense emotional stress which may provoke this syndrome.

See also
Widowhood effect

References
External links
Krishnan, Lakshmi; Marchalik, Daniel (8 September 2018). "Understanding Heartbreak: From Takotsubo to Wuthering Heights" </s>


<s> [INST] <<SYS>> You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information. <</SYS>> What is Trismus and explain in detail? [/INST] Trismus, commonly called lockjaw as associated with tetanus, is a condition of limited jaw mobility. It may be caused by spasm of the muscles of mastication or a variety of other causes. Temporary trismus occurs much more frequently than permanent trismus. It is known to interfere with eating, speaking, and maintaining proper oral hygiene. This interference, specifically with an inability to swallow properly, results in an increased risk of aspiration. In some instances, trismus presents with altered facial appearance.  The condition may be distressing and painful. Examination and treatments requiring access to the oral cavity can be limited, or in some cases impossible, due to the nature of the condition itself.

Definition
Trismus is defined as painful restriction in opening the mouth due to a muscle spasm, however it can also refer to limited mouth opening of any cause. Another definition of trismus is simply a limitation of movement. Historically and commonly, the term lockjaw was sometimes used as a synonym for both trismus and tetanus.Normal mouth-opening ranges from 35 to 45 mm. Males usually have slightly greater mouth opening than females. (40–60 mm, average of 50 mm). The normal lateral movement is 8–12 mm, and normal protrusive movement is approximately 10 mm. Some have distinguished mild trismus as 20–30 mm interincisal opening, moderate as 10–20 mm and severe as less than 10 mm.Trismus is derived from the Greek word trigmos/trismos meaning "a scream; a grinding, rasping or gnashing".

Differential diagnosis
Traditionally causes of trismus are divided into intra-articular (factors within the temporomandibular joint [TMJ]) and extra-articular (factors outside the joint, see table).

Joint problems
Ankylosis
True bony ankylosis: can result from trauma to chin, infections and from prolonged immobilization following condylar fracture
Treatment – several surgical procedures are used to treat bony ankylosis, e.g.: Gap arthroplasty using interpositional materials between the cut segments.
Fibrous ankylosis: usually results due to trauma and infection
Treatment – trismus appliances in conjunction with physical therapy.

Arthritis synovitis
Meniscus pathology
Extra-articular causes
Infection
Odontogenic- Pulpal
Periodontal
Pericoronal
Non-odontogenic- Peritonsillar abscess
Tetanus
Meningitis
Brain abscess
Parotid abscess
The hallmark of a masticatory space infection is trismus or infection in anterior compartment of lateral pharyngeal space results in trismus. If these infections are unchecked, can spread to various facial spaces of the head and neck and lead to serious complications such as cervical cellulitis or mediastinitis.
Treatment: Elimination of etiologic agent along with antibiotic coverage
Trismus or lock jaw due to masseter muscle spasm, can be a primary presenting symptom in tetanus, Caused by Clostridium tetani, where tetanospasmin (toxin) is responsible for muscle spasms.
Prevention: primary immunization (DPT)

Dental treatment
Dental trismus is characterized by a difficulty in opening the jaw. It is a temporary condition with a duration usually not longer than two weeks. Dental trismus results from some sort of insult to the muscles of mastication, such as opening the jaw for a period of time or having a needle pass through a muscle. Typical dental anesthesia to the lower jaw often involves the needle passing into or through a muscle. In these cases it is usually the medial pterygoid or the buccinator muscles.
Oral surgery procedures, as in the extraction of lower molar teeth, may cause trismus as a result either of inflammation to the muscles of mastication or direct trauma to the TMJ.
Barbing of needles at the time of injection followed by tissue damage on withdrawal of the barbed needle causes post-injection persistent paresthesia, trismus and paresis.
Treatment: in acute phase:
Heat therapy
Analgesics
A soft diet
Muscle relaxants (if necessary)
Note: When acute phase is over the patient should be advised to initiate physiotherapy for opening and closing mouth.

Trauma
Fractures, particularly those of the mandible and fractures of zygomatic arch and zygomatic arch complex, accidental incorporation of foreign bodies due to external traumatic injury.
Treatment: fracture reduction, removal of foreign bodies with antibiotic coverage

TMJ disorders
Extra-capsular disorders – Myofascial pain dysfunction syndrome
Intra-capsular problems – Disc displacement, arthritis, fibrosis,  etc.
Acute closed locked conditions – displaced meniscus

Tumors and oral care
Rarely, trismus is a symptom of nasopharyngeal or infratemporal tumors/ fibrosis of temporalis tendon, when patient has limited mouth opening, always premalignant conditions like oral submucous fibrosis (OSMF) should also be considered in differential diagnosis.

Drug therapy
Succinyl choline, phenothiazines and tricyclic antidepressants causes trismus as a secondary effect </s>


<s> [INST] <<SYS>> You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information. <</SYS>> What is Acute intermittent porphyria and explain in detail? [/INST] Acute intermittent porphyria (AIP) is a rare metabolic disorder affecting the production of heme resulting from a deficiency of the porphobilinogen deaminase. It is the most common of the acute porphyrias.

Signs and symptoms
The clinical presentation of AIP is highly variable and non-specific. The patients are typically asymptomatic, with most gene carriers having no family history because the condition had remained latent for several generations. The syndrome marked by acute attacks affects only 10% of gene carriers. The mean age at diagnosis is 33 years old. Like other porphyrias, AIP is more likely to present in women. A distinguishing feature of AIP that separates it from other porphyrias is the absence of photosensitive cutaneous symptoms that occur in addition to acute attacks.

Acute attacks
AIP is one of the four porphyrias that presents as an acute attack. 90% of affected individuals never experience an acute attack and are asymptomatic, while an estimated 5% of affected individuals experience repeat attacks. Attacks are most common in young adult women and are rare before puberty or after menopause. Severe acute attacks may require hospitalization. Patients usually experience symptoms in attacks that last from several hours to a few days. Between attacks, patients are asymptomatic.The most frequent presenting symptoms are abdominal pain and tachycardia. The abdominal pain is typically severe, colicky, poorly localized, and often associated with pain in back and legs. Patients may also present with vomiting and constipation, but diarrhea is unusual. The onset of back and leg pain is characterized by severe pain and stiffness in back and thighs followed by loss of tendon reflexes and paralysis. Psychiatric symptoms are present, such as paranoid schizophrenia-like features but rarely psychosis and hallucinations. The acute attacks classically present with dark-red photosensitive urine (often called port-wine urine), but this is a nonspecific symptom. Physical examination often shows no abnormalities.Hyponatremia is the most common electrolyte abnormality during acute attacks, occurring in 40% of patients and presenting as SIADH. Hypomagnesemia is also common. There are no pathognomonic signs or symptoms.The most common identified triggers for acute attacks are medications, weight loss diets, and surgery. Many medications have been associated with AIP including antibiotics, hormonal contraceptives, seizure medications, anesthetics, and HIV treatment drugs.

Cause
Porphyrias are caused by mutations in genes that encode enzymes in heme synthesis.  In normal physiology, heme synthesis begins in the mitochondrion, proceeds into the cytoplasm, and finishes back in the mitochondrion. Heme is produced in all cells, but 80% of all heme is produced in erythropoietic cells in bone marrow and 15% in parenchymal cells in the liver, where turnover of hemoproteins is high. In AIP, over 100 mutations have been identified on the long arm of chromosome 11 at the HMBS gene, which codes for the cytoplasmic enzyme porphobilinogen deaminase. This deficiency prevents heme synthesis, which can not be completed and the metabolite porphobilinogen accumulates in the cytoplasm.AIP is an autosomal dominant porphyria resulting in about 50% normal activity of the affected enzyme. The penetrance of AIP is incomplete with only 10% of gene carriers experiencing acute attacks suggesting role for other modifying genes or environment.The exact mechanism of acute attacks is not clear. The most favored hypothesis is that porpholobilinogen buildup causes a toxic effects on neurons. The autonomic and peripheral nervous system are more vulnerable than the central nervous system because they are not protected by the blood-brain barrier. This explains findings such as abdominal pain and tachycardia. Some individuals may be more likely to develop paresis based on increased susceptibility of neurons to toxins.

Genetics
Inheritance
AIP has an autosomal dominant pattern of inheritance. The dominance pattern is a result of partial deficiencies from the heme biosynthesis enzymes, hydroxymethylbilane synthase  (HMBS;  EC  2.5.1.61). Due to the rarity of this disease it is difficult to estimate the prevalence of AIP and the inclusion criteria differs widely among studies causing varying statistics. AIP has a low penetrance when considering the general population, but within families the penetrance increases. This is indicative of another interaction affecting the inheritance pattern. It is speculated that this pattern is due to AIP propensity caused by the inheritance of an additional gene mutation, HMBS, in addition to other genetic and environmental influences. There have been 421 HMBS mutations that have been linked to AIP. This suggests that AIP inheritance instead follows an oligogenic or polygenic inheritance pattern. Research shows that HMBS mutations are estimated to occur in approximately 1 in 1700 caucasians (there is not enough data in other populations) while AIP symptoms are shown to be present in approximately 1 in 200,000 caucasians. It can be inferred that the penetrance of AIP is approximately 1% of the HMBS heterozygous community, concluding that there are other factors needed to induce AIP symptoms.

Variants of AIP
There have been more than 400 mutations in the heme biosynthesis identified to cause AIP. In the erythroid variant, mutations in the exon 1 sequence of the housekeeping gene, splicing of exon 1, and splicing of exon 3 causes an alternative form of AIP wherein there is decreased activity of the liver enzyme but erythroid cells have regular activity. HMBS has two isoforms, housekeeping and erythroid. Additionally, there is also the non-erythroid variant of AIP in which there are mutations in exons 3-15 and there is decreased activity in both isozymes. Most individuals with AIP have mutations in exons 3–15. Loss of function mutations of HMBS cause decreased activity of the enzymes normally present.

Diagnosis
The initial diagnosis of acute porphyria is confirmed by urinalysis, including the common method, the Watson-Schwartz test. Elevated urine porphobilinogen confirms diagnosis of AIP, hereditary coproporphyria (HCP), or variegate porphyria (VP). A positive test should be indicated with an increase of five times normal, not just a slight increase which can occur with dehydration. To distinguish between AIP from HCP and VP, fecal porphyrin levels are normal in AIP but elevated in HCP and VP.Rapid, accurate diagnosis is important. Delays in diagnosis may result in permanent neurological damage or death.

Diagnosis with Genetic Testing
With advancement and increased accessibility to genetic testing and follow up counseling, the morbidity of AIP has decreased because of early diagnosis. The combination of targeted mutation analysis and biochemical activity tracking have provided positive results for identifying the risk of AIP development. Mutation analysis has a 95% sensitivity and a 100% specificity for confirmation of pathogenicity of a mutation. Genetic testing can detect AIP in patients with symptoms that would have otherwise gone undiagnosed or misdiagnosed. The biochemical analysis route of detection is slightly less accurate compared to genetic testing, which has 84% sensitivity and 71% specificity, but is still chosen over other alternatives and can provide some of the predictive information that genetic testing does. Patients diagnosed with genetic testing at the asymptomatic stage were less likely to develop symptoms throughout their life. Additionally, individuals who were diagnosed at the symptomatic stage encountered more mild attacks after diagnosis, although they still had symptoms. Genetic testing availability has decreased the rate of patients seeking treatment by medical staff, as patients experiencing less severe symptoms instead opt to self treat at home.

Treatment
If drugs have caused the attack, discontinuing the offending substances is essential. A high-carbohydrate (10% glucose) infusion is recommended, which may aid in recovery.

Hematin and heme arginate is the treatment of choice during an acute attack. Heme is not a curative treatment, but can shorten attacks and reduce the intensity of an attack. Side-effects are rare but can be serious </s>