<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 Tracheal intubation and explain in detail? [/INST] Tracheal intubation, usually simply referred to as intubation, is the placement of a flexible plastic tube into the trachea (windpipe) to maintain an open airway or to serve as a conduit through which to administer certain drugs. It is frequently performed in critically injured, ill, or anesthetized patients to facilitate ventilation of the lungs, including mechanical ventilation, and to prevent the possibility of asphyxiation or airway obstruction.
The most widely used route is orotracheal, in which an endotracheal tube is passed through the mouth and vocal apparatus into the trachea. In a nasotracheal procedure, an endotracheal tube is passed through the nose and vocal apparatus into the trachea. Other methods of intubation involve surgery and include the cricothyrotomy (used almost exclusively in emergency circumstances) and the tracheotomy, used primarily in situations where a prolonged need for airway support is anticipated.
Because it is an invasive and uncomfortable medical procedure, intubation is usually performed after administration of general anesthesia and a neuromuscular-blocking drug. It can, however, be performed in the awake patient with local or topical anesthesia or in an emergency without any anesthesia at all. Intubation is normally facilitated by using a conventional laryngoscope, flexible fiberoptic bronchoscope, or video laryngoscope to identify the vocal cords and pass the tube between them into the trachea instead of into the esophagus.  Other devices and techniques may be used alternatively.
After the trachea has been intubated, a balloon cuff is typically inflated just above the far end of the tube to help secure it in place, to prevent leakage of respiratory gases, and to protect the tracheobronchial tree from receiving undesirable material such as stomach acid. The tube is then secured to the face or neck and connected to a T-piece, anesthesia breathing circuit, bag valve mask device, or a mechanical ventilator. Once there is no longer a need for ventilatory assistance or protection of the airway, the tracheal tube is removed; this is referred to as extubation of the trachea (or decannulation, in the case of a surgical airway such as a cricothyrotomy or a tracheotomy).
For centuries, tracheotomy was considered the only reliable method for intubation of the trachea. However, because only a minority of patients survived the operation, physicians undertook tracheotomy only as a last resort, on patients who were nearly dead. It was not until the late 19th century, however, that advances in understanding of anatomy and physiology, as well an appreciation of the germ theory of disease, had improved the outcome of this operation to the point that it could be considered an acceptable treatment option. Also at that time, advances in endoscopic instrumentation had improved to such a degree that direct laryngoscopy had become a viable means to secure the airway by the non-surgical orotracheal route. By the mid-20th century, the tracheotomy as well as endoscopy and non-surgical tracheal intubation had evolved from rarely employed procedures to becoming essential components of the practices of anesthesiology, critical care medicine, emergency medicine, and laryngology.
Tracheal intubation can be associated with complications such as broken teeth or lacerations of the tissues of the upper airway. It can also be associated with potentially fatal complications such as pulmonary aspiration of stomach contents which can result in a severe and sometimes fatal chemical aspiration pneumonitis, or unrecognized intubation of the esophagus which can lead to potentially fatal anoxia. Because of this, the potential for difficulty or complications due to the presence of unusual airway anatomy or other uncontrolled variables is carefully evaluated before undertaking tracheal intubation. Alternative strategies for securing the airway must always be readily available.

Indications
Tracheal intubation is indicated in a variety of situations when illness or a medical procedure prevents a person from maintaining a clear airway, breathing, and oxygenating the blood. In these circumstances, oxygen supplementation using a simple face mask is inadequate.

Depressed level of consciousness
Perhaps the most common indication for tracheal intubation is for the placement of a conduit through which nitrous oxide or volatile anesthetics may be administered. General anesthetic agents, opioids, and neuromuscular-blocking drugs may diminish or even abolish the respiratory drive. Although it is not the only means to maintain a patent airway during general anesthesia, intubation of the trachea provides the most reliable means of oxygenation and ventilation and the greatest degree of protection against regurgitation and pulmonary aspiration.Damage to the brain (such as from a massive stroke, non-penetrating head injury, intoxication or poisoning) may result in a depressed level of consciousness. When this becomes severe to the point of stupor or coma (defined as a score on the Glasgow Coma Scale of less than 8), dynamic collapse of the extrinsic muscles of the airway can obstruct the airway, impeding the free flow of air into the lungs. Furthermore, protective airway reflexes such as coughing and swallowing may be diminished or absent. Tracheal intubation is often required to restore patency (the relative absence of blockage) of the airway and protect the tracheobronchial tree from pulmonary aspiration of gastric contents.

Hypoxemia
Intubation may be necessary for a patient with decreased oxygen content and oxygen saturation of the blood caused when their breathing is inadequate (hypoventilation), suspended (apnea), or when the lungs are unable to sufficiently transfer gasses to the blood. Such patients, who may be awake and alert, are typically critically ill with a multisystem disease or multiple severe injuries. Examples of such conditions include cervical spine injury, multiple rib fractures, severe pneumonia, acute respiratory distress syndrome (ARDS), or near-drowning. Specifically, intubation is considered if the arterial partial pressure of oxygen (PaO2) is less than 60 millimeters of mercury (mm Hg) while breathing an inspired O2 concentration (FIO2) of 50% or greater. In patients with elevated arterial carbon dioxide, an arterial partial pressure of CO2 (PaCO2) greater than 45 mm Hg in the setting of acidemia would prompt intubation, especially if a series of measurements demonstrate a worsening respiratory acidosis. Regardless of the laboratory values, these guidelines are always interpreted in the clinical context.

Airway obstruction
Actual or impending airway obstruction is a common indication for intubation of the trachea. Life-threatening airway obstruction may occur when a foreign body becomes lodged in the airway; this is especially common in infants and toddlers. Severe blunt or penetrating injury to the face or neck may be accompanied by swelling and an expanding hematoma, or injury to the larynx, trachea or bronchi. Airway obstruction is also common in people who have suffered smoke inhalation or burns within or near the airway or epiglottitis. Sustained generalized seizure activity and angioedema are other common causes of life-threatening airway obstruction which may require tracheal intubation to secure the airway.

Manipulation of the airway
Diagnostic or therapeutic manipulation of the airway (such as bronchoscopy, laser therapy or stenting of the bronchi) may intermittently interfere with the ability to breathe; intubation may be necessary in such situations.

Newborns
Syndromes such as respiratory distress syndrome, congenital heart disease, pneumothorax, and shock may lead to breathing problems in newborn infants that require endotracheal intubation and mechanically assisted breathing (mechanical ventilation). Newborn infants may also require endotracheal intubation during surgery while under general anaesthesia.

Equipment
Laryngoscopes
The vast majority of tracheal intubations involve the use of a viewing instrument of one type or another. The modern conventional laryngoscope consists of a handle containing batteries that power a light and a set of interchangeable blades, which are either straight or curved. This device is designed to allow the laryngoscopist to directly view the larynx. Due to the widespread availability of such devices, the technique of blind intubation of the trachea is rarely practiced today, although it may still be useful in certain emergency situations, such as natural or man-made disasters. In the prehospital emergency setting, digital intubation may be necessitated if the patient is in a position that makes direct laryngoscopy impossible. For example, digital intubation may be used by a paramedic if the patient is entrapped in an inverted position in a vehicle after a motor vehicle collision with a prolonged extrication time.
The decision to use a straight or curved laryngoscope blade depends partly on the specific anatomical features of the airway, and partly on the personal experience and preference of the laryngoscopist. The Macintosh blade is the most widely used curved laryngoscope blade, while the Miller blade is the most popular style of straight blade. Both Miller and Macintosh laryngoscope blades are available in sizes 0 (infant) through 4 (large adult). There are many other styles of straight and curved blades, with accessories such as mirrors for enlarging the field of view and even ports for the administration of oxygen. These specialty blades are primarily designed for use by anesthetists and otolaryngologists, most commonly in the operating room.Fiberoptic laryngoscopes have become increasingly available since the 1990s. In contrast to the conventional laryngoscope, these devices allow the laryngoscopist to indirectly view the larynx. This provides a significant advantage in situations where the operator needs to see around an acute bend in order to visualize the glottis, and deal with otherwise difficult intubations. Video laryngoscopes are specialized fiberoptic laryngoscopes that use a digital video camera sensor to allow the operator to view the glottis and larynx on a video monitor. Other "noninvasive" devices which can be employed to assist in tracheal intubation are the laryngeal mask airway (used as a conduit for endotracheal tube placement) and the Airtraq.

Stylets
An intubating stylet is a malleable metal wire designed to be inserted into the endotracheal tube to make the tube conform better to the upper airway anatomy of the specific individual. This aid is commonly used with a difficult laryngoscopy. Just as with laryngoscope blades, there are also several types of available stylets, such as the Verathon Stylet, which is specifically designed to follow the 60° blade angle of the GlideScope video laryngoscope.The Eschmann tracheal tube introducer (also referred to as a "gum elastic bougie") is specialized type of stylet used to facilitate difficult intubation. This flexible device is 60 cm (24 in) in length, 15 French (5 mm diameter) with a small "hockey-stick" angle at the far end. Unlike a traditional intubating stylet, the Eschmann tracheal tube introducer is typically inserted directly into the trachea and then used as a guide over which the endotracheal tube can be passed (in a manner analogous to the Seldinger technique). As the Eschmann tracheal tube introducer is considerably less rigid than a conventional stylet, this technique is considered to be a relatively atraumatic means of tracheal intubation.The tracheal tube exchanger is a hollow catheter, 56 to 81 cm (22.0 to 31.9 in) in length, that can be used for removal and replacement of tracheal tubes without the need for laryngoscopy. The Cook Airway Exchange Catheter (CAEC) is another example of this type of catheter; this device has a central lumen (hollow channel) through which oxygen can be administered. Airway exchange catheters are long hollow catheters which often have connectors for jet ventilation, manual ventilation, or oxygen insufflation.  It is also possible to connect the catheter to a capnograph to perform respiratory monitoring.
The lighted stylet is a device that employs the principle of transillumination to facilitate blind orotracheal intubation (an intubation technique in which the laryngoscopist does not view the glottis).

Tracheal tubes
A tracheal tube is a catheter that is inserted into the trachea for the primary purpose of establishing and maintaining a patent (open and unobstructed) airway. Tracheal tubes are frequently used for airway management in the settings of general anesthesia, critical care, mechanical ventilation, and emergency medicine. Many different types of tracheal tubes are available, suited for different specific applications. An endotracheal tube is a specific type of tracheal tube that is nearly always inserted through the mouth (orotracheal) or nose (nasotracheal). It is a breathing conduit designed to be placed into the airway of critically injured, ill or anesthetized patients in order to perform mechanical positive pressure ventilation of the lungs and to prevent the possibility of aspiration or airway obstruction. The endotracheal tube has a fitting designed to be connected to a source of pressurized gas such as oxygen. At the other end is an orifice through which such gases are directed into the lungs and may also include a balloon (referred to as a cuff). The tip of the endotracheal tube is positioned above the carina (before the trachea divides to each lung) and sealed within the trachea so that the lungs can be ventilated equally. A tracheostomy tube is another type of tracheal tube; this 2–3-inch-long (51–76 mm) curved metal or plastic tube is inserted into a tracheostomy stoma or a cricothyrotomy incision.Tracheal tubes can be used to ensure the adequate exchange of oxygen and carbon dioxide, to deliver oxygen in higher concentrations than found in air, or to administer other gases such as helium, nitric oxide, nitrous oxide, xenon, or certain volatile anesthetic agents such as desflurane, isoflurane, or sevoflurane. They may also be used as a route for administration of certain medications such as bronchodilators, inhaled corticosteroids, and drugs used in treating cardiac arrest such as atropine, epinephrine, lidocaine and vasopressin.Originally made from latex rubber, most modern endotracheal tubes today are constructed of polyvinyl chloride. Tubes constructed of silicone rubber, wire-reinforced silicone rubber or stainless steel are also available for special applications. For human use, tubes range in size from 2 to 10.5 mm (0.1 to 0.4 in) in internal diameter. The size is chosen based on the patients body size, with the smaller sizes being used for infants and children. Most endotracheal tubes have an inflatable cuff to seal the tracheobronchial tree against leakage of respiratory gases and pulmonary aspiration of gastric contents, blood, secretions, and other fluids. Uncuffed tubes are also available, though their use is limited mostly to children (in small children, the cricoid cartilage is the narrowest portion of the airway and usually provides an adequate seal for mechanical ventilation).In addition to cuffed or uncuffed, preformed endotracheal tubes are also available. The oral and nasal RAE tubes (named after the inventors Ring, Adair and Elwyn) are the most widely used of the preformed tubes.There are a number of different types of double-lumen endo-bronchial tubes that have endobronchial as well as endotracheal channels (Carlens, White and Robertshaw tubes). These tubes are typically coaxial, with two separate channels and two separate openings. They incorporate an endotracheal lumen which terminates in the trachea and an endobronchial lumen, the distal tip of which is positioned 1–2 cm into the right or left mainstem bronchus. There is also the Univent tube, which has a single tracheal lumen and an integrated endobronchial blocker. These tubes enable one to ventilate both lungs, or either lung independently. Single-lung ventilation (allowing the lung on the operative side to collapse) can be useful during thoracic surgery, as it can facilitate the surgeons view and access to other relevant structures within the thoracic cavity.The "armored" endotracheal tubes are cuffed, wire-reinforced silicone rubber tubes. They are much more flexible than polyvinyl chloride tubes, yet they are difficult to compress or kink. This can make them useful for situations in which the trachea is anticipated to remain intubated for a prolonged duration, or if the neck is to remain flexed during surgery. Most armored tubes have a Magill curve, but preformed armored RAE tubes are also available. Another type of endotracheal tube has four small openings just above the inflatable cuff, which can be used for suction of the trachea or administration of intratracheal medications if necessary. Other tubes (such as the Bivona Fome-Cuf tube) are designed specifically for use in laser surgery in and around the airway.

Methods to confirm tube placement
No single method for confirming tracheal tube placement has been shown to be 100% reliable. Accordingly, the use of multiple methods for confirmation of correct tube placement is now widely considered to be the standard of care. Such methods include direct visualization as the tip of the tube passes through the glottis, or indirect visualization of the tracheal tube within the trachea using a device such as a bronchoscope. With a properly positioned tracheal tube, equal bilateral breath sounds will be heard upon listening to the chest with a stethoscope, and no sound upon listening to the area over the stomach. Equal bilateral rise and fall of the chest wall will be evident with ventilatory excursions. A small amount of water vapor will also be evident within the lumen of the tube with each exhalation and there will be no gastric contents in the tracheal tube at any time.Ideally, at least one of the methods utilized for confirming tracheal tube placement will be a measuring instrument. Waveform capnography has emerged as the gold standard for the confirmation of tube placement within the trachea. Other methods relying on instruments include the use of a colorimetric end-tidal carbon dioxide detector, a self-inflating esophageal bulb, or an esophageal detection device. The distal tip of a properly positioned tracheal tube will be located in the mid-trachea, roughly 2 cm (1 in) above the bifurcation of the carina; this can be confirmed by chest x-ray. If it is inserted too far into the trachea (beyond the carina), the tip of the tracheal tube is likely to be within the right main bronchus—a situation often referred to as a "right mainstem intubation". In this situation, the left lung may be unable to participate in ventilation, which can lead to decreased oxygen content due to ventilation/perfusion mismatch.

Special situations
Emergencies
Tracheal intubation in the emergency setting can be difficult with the fiberoptic bronchoscope due to blood, vomit, or secretions in the airway and poor patient cooperation. Because of this, patients with massive facial injury, complete upper airway obstruction, severely diminished ventilation, or profuse upper airway bleeding are poor candidates for fiberoptic intubation. Fiberoptic intubation under general anesthesia typically requires two skilled individuals. Success rates of only 83–87% have been reported using fiberoptic techniques in the emergency department, with significant nasal bleeding occurring in up to 22% of patients. These drawbacks limit the use of fiberoptic bronchoscopy somewhat in urgent and emergency situations.Personnel experienced in direct laryngoscopy are not always immediately available in certain settings that require emergency tracheal intubation. For this reason, specialized devices have been designed to act as bridges to a definitive airway. Such devices include the laryngeal mask airway, cuffed oropharyngeal airway and the esophageal-tracheal combitube (Combitube). Other devices such as rigid stylets, the lightwand (a blind technique) and indirect fiberoptic rigid stylets, such as the Bullard scope, Upsher scope and the WuScope can also be used as alternatives to direct laryngoscopy. Each of these devices have its own unique set of benefits and drawbacks, and none of them is effective under all circumstances.

Rapid-sequence induction and intubation
Rapid sequence induction and intubation (RSI) is a particular method of induction of general anesthesia, commonly employed in emergency operations and other situations where patients are assumed to have a full stomach. The objective of RSI is to minimize the possibility of regurgitation and pulmonary aspiration of gastric contents during the induction of general anesthesia and subsequent tracheal intubation. RSI traditionally involves preoxygenating the lungs with a tightly fitting oxygen mask, followed by the sequential administration of an intravenous sleep-inducing agent and a rapidly acting neuromuscular-blocking drug, such as rocuronium, succinylcholine, or cisatracurium besilate, before intubation of the trachea.One important difference between RSI and routine tracheal intubation is that the practitioner does not manually assist the ventilation of the lungs after the onset of general anesthesia and cessation of breathing, until the trachea has been intubated and the cuff has been inflated. Another key feature of RSI is the application of manual cricoid pressure to the cricoid cartilage, often referred to as the "Sellick maneuver", prior to instrumentation of the airway and intubation of the trachea.Named for British anesthetist Brian Arthur Sellick (1918–1996) who first described the procedure in 1961, the goal of cricoid pressure is to minimize the possibility of regurgitation and pulmonary aspiration of gastric contents. Cricoid pressure has been widely used during RSI for nearly fifty years, despite a lack of compelling evidence to support this practice. The initial article by Sellick was based on a small sample size at a time when high tidal volumes, head-down positioning and barbiturate anesthesia were the rule. Beginning around 2000, a significant body of evidence has accumulated which questions the effectiveness of cricoid pressure. The application of cricoid pressure may in fact displace the esophagus laterally instead of compressing it as described by Sellick. Cricoid pressure may also compress the glottis, which can obstruct the view of the laryngoscopist and actually cause a delay in securing the airway.Cricoid pressure is often confused with the "BURP" (Backwards Upwards Rightwards Pressure) maneuver. While both of these involve digital pressure to the anterior aspect (front) of the laryngeal apparatus, the purpose of the latter is to improve the view of the glottis during laryngoscopy and tracheal intubation, rather than to prevent regurgitation. Both cricoid pressure and the BURP maneuver have the potential to worsen laryngoscopy.RSI may also be used in prehospital emergency situations when a patient is conscious but respiratory failure is imminent (such as in extreme trauma). This procedure is commonly performed by flight paramedics. Flight paramedics often use RSI to intubate before transport because intubation in a moving fixed-wing or rotary-wing aircraft is extremely difficult to perform due to environmental factors. The patient will be paralyzed and intubated on the ground before transport by aircraft.

Cricothyrotomy
A cricothyrotomy is an incision made through the skin and cricothyroid membrane to establish a patent airway during certain life-threatening situations, such as airway obstruction by a foreign body, angioedema, or massive facial trauma. A cricothyrotomy is nearly always performed as a last resort in cases where orotracheal and nasotracheal intubation are impossible or contraindicated. Cricothyrotomy is easier and quicker to perform than tracheotomy, does not require manipulation of the cervical spine and is associated with fewer complications.The easiest method to perform this technique is the needle cricothyrotomy (also referred to as a percutaneous dilational cricothyrotomy), in which a large-bore (12–14 gauge) intravenous catheter is used to puncture the cricothyroid membrane. Oxygen can then be administered through this catheter via jet insufflation. However, while needle cricothyrotomy may be life-saving in extreme circumstances, this technique is only intended to be a temporizing measure until a definitive airway can be established. While needle cricothyrotomy can provide adequate oxygenation, the small diameter of the cricothyrotomy catheter is insufficient for elimination of carbon dioxide (ventilation). After one hour of apneic oxygenation through a needle cricothyrotomy, one can expect a PaCO2 of greater than 250 mm Hg and an arterial pH of less than 6.72, despite an oxygen saturation of 98% or greater. A more definitive airway can be established by performing a surgical cricothyrotomy, in which a 5 to 6 mm (0.20 to 0.24 in) endotracheal tube or tracheostomy tube can be inserted through a larger incision.Several manufacturers market prepackaged cricothyrotomy kits, which enable one to use either a wire-guided percutaneous dilational (Seldinger) technique, or the classic surgical technique to insert a polyvinylchloride catheter through the cricothyroid membrane. The kits may be stocked in hospital emergency departments and operating suites, as well as ambulances and other selected pre-hospital settings.

Tracheotomy
Tracheotomy consists of making an incision on the front of the neck and opening a direct airway through an incision in the trachea. The resulting opening can serve independently as an airway or as a site for a tracheostomy tube to be inserted; this tube allows a person to breathe without the use of his nose or mouth. The opening may be made by a scalpel or a needle (referred to as surgical and percutaneous techniques respectively) and both techniques are widely used in current practice. In order to limit the risk of damage to the recurrent laryngeal nerves (the nerves that control the voice box), the tracheotomy is performed as high in the trachea as possible. If only one of these nerves is damaged, the patients voice may be impaired (dysphonia); if both of the nerves are damaged, the patient will be unable to speak (aphonia). In the acute setting, indications for tracheotomy are similar to those for cricothyrotomy. In the chronic setting, indications for tracheotomy include the need for long-term mechanical ventilation and removal of tracheal secretions (e.g., comatose patients, or extensive surgery involving the head and neck).

Children
There are significant differences in airway anatomy and respiratory physiology between children and adults, and these are taken into careful consideration before performing tracheal intubation of any pediatric patient. The differences, which are quite significant in infants, gradually disappear as the human body approaches a mature age and body mass index.For infants and young children, orotracheal intubation is easier than the nasotracheal route. Nasotracheal intubation carries a risk of dislodgement of adenoids and nasal bleeding. Despite the greater difficulty, nasotracheal intubation route is preferable to orotracheal intubation in children undergoing intensive care and requiring prolonged intubation because this route allows a more secure fixation of the tube. As with adults, there are a number of devices specially designed for assistance with difficult tracheal intubation in children. Confirmation of proper position of the tracheal tube is accomplished as with adult patients.Because the airway of a child is narrow, a small amount of glottic or tracheal swelling can produce critical obstruction. Inserting a tube that is too large relative to the diameter of the trachea can cause swelling. Conversely, inserting a tube that is too small can result in inability to achieve effective positive pressure ventilation due to retrograde escape of gas through the glottis and out the mouth and nose (often referred to as a "leak" around the tube). An excessive leak can usually be corrected by inserting a larger tube or a cuffed tube.The tip of a correctly positioned tracheal tube will be in the mid-trachea, between the collarbones on an anteroposterior chest radiograph. The correct diameter of the tube is that which results in a small leak at a pressure of about 25 cm (10 in) of water. The appropriate inner diameter for the endotracheal tube is estimated to be roughly the same diameter as the childs little finger. The appropriate length for the endotracheal tube can be estimated by doubling the distance from the corner of the childs mouth to the ear canal. For premature infants 2.5 mm (0.1 in) internal diameter is an appropriate size for the tracheal tube. For infants of normal gestational age, 3 mm (0.12 in) internal diameter is an appropriate size. For normally nourished children 1 year of age and older, two formulae are used to estimate the appropriate diameter and depth for tracheal intubation. The internal diameter of the tube in mm is (patients age in years + 16) / 4, while the appropriate depth of insertion in cm is 12 + (patients age in years / 2).

Newborn infants
Endotrachael suctioning is often used during intubation in newborn infants to reduce the risk of a blocked tube due to secretions, a collapsed lung, and to reduce pain. Suctioning is sometimes used at specifically scheduled intervals, "as needed", and less frequently. Further research is necessary to determine the most effective suctioning schedule or frequency of suctioning in intubated infants.In newborns free flow oxygen used to be recommended during intubation however as there is no evidence of benefit the 2011 NRP guidelines no longer do.

Predicting difficulty
Tracheal intubation is not a simple procedure and the consequences of failure are grave. Therefore, the patient is carefully evaluated for potential difficulty or complications beforehand. This involves taking the medical history of the patient and performing a physical examination, the results of which can be scored against one of several classification systems. The proposed surgical procedure (e.g., surgery involving the head and neck, or bariatric surgery) may lead one to anticipate difficulties with intubation. Many individuals have unusual airway anatomy, such as those who have limited movement of their neck or jaw, or those who have tumors, deep swelling due to injury or to allergy, developmental abnormalities of the jaw, or excess fatty tissue of the face and neck. Using conventional laryngoscopic techniques, intubation of the trachea can be difficult or even impossible in such patients. This is why all persons performing tracheal intubation must be familiar with alternative techniques of securing the airway. Use of the flexible fiberoptic bronchoscope and similar devices has become among the preferred techniques in the management of such cases. However, these devices require a different skill set than that employed for conventional laryngoscopy and are expensive to purchase, maintain and repair.When taking the patients medical history, the subject is questioned about any significant signs or symptoms, such as difficulty in speaking or difficulty in breathing. These may suggest obstructing lesions in various locations within the upper airway, larynx, or tracheobronchial tree. A history of previous surgery (e.g., previous cervical fusion), injury, radiation therapy, or tumors involving the head, neck and upper chest can also provide clues to a potentially difficult intubation. Previous experiences with tracheal intubation, especially difficult intubation, intubation for prolonged duration (e.g., intensive care unit) or prior tracheotomy are also noted.A detailed physical examination of the airway is important, particularly:
the range of motion of the cervical spine: the subject should be able to tilt the head back and then forward so that the chin touches the chest.
the range of motion of the jaw (the temporomandibular joint): three of the subjects fingers should be able to fit between the upper and lower incisors.
the size and shape of the upper jaw and lower jaw, looking especially for problems such as maxillary hypoplasia (an underdeveloped upper jaw), micrognathia (an abnormally small jaw), or retrognathia (misalignment of the upper and lower jaw).
the thyromental distance: three of the subjects fingers should be able to fit between the Adams apple and the chin.
the size and shape of the tongue and palate relative to the size of the mouth.
the teeth, especially noting the presence of prominent maxillary incisors, any loose or damaged teeth, or crowns.Many classification systems have been developed in an effort to predict difficulty of tracheal intubation, including the Cormack-Lehane classification system, the Intubation Difficulty Scale (IDS), and the Mallampati score. The Mallampati score is drawn from the observation that the size of the base of the tongue influences the difficulty of intubation. It is determined by looking at the anatomy of the mouth, and in particular the visibility of the base of palatine uvula, faucial pillars and the soft palate. Although such medical scoring systems may aid in the evaluation of patients, no single score or combination of scores can be trusted to specifically detect all and only those patients who are difficult to intubate. Furthermore, one study of experienced anesthesiologists, on the widely used Cormack–Lehane classification system, found they did not score the same patients consistently over time, and that only 25% could correctly define all four grades of the widely used Cormack–Lehane classification system. Under certain emergency circumstances (e.g., severe head trauma or suspected cervical spine injury), it may be impossible to fully utilize these the physical examination and the various classification systems to predict the difficulty of tracheal intubation. A recent Cochrane systematic review examined the sensitivity and specificity of various bedside tests commonly used for predicting difficulty in airway management. In such cases, alternative techniques of securing the airway must be readily available.

Complications
Tracheal intubation is generally considered the best method for airway management under a wide variety of circumstances, as it provides the most reliable means of oxygenation and ventilation and the greatest degree of protection against regurgitation and pulmonary aspiration. However, tracheal intubation requires a great deal of clinical experience to master and serious complications may result even when properly performed.Four anatomic features must be present for orotracheal intubation to be straightforward: adequate mouth opening (full range of motion of the temporomandibular joint), sufficient pharyngeal space (determined by examining the back of the mouth), sufficient submandibular space (distance between the thyroid cartilage and the chin, the space into which the tongue must be displaced in order for the larygoscopist to view the glottis), and adequate extension of the cervical spine at the atlanto-occipital joint. If any of these variables is in any way compromised, intubation should be expected to be difficult.Minor complications are common after laryngoscopy and insertion of an orotracheal tube. These are typically of short duration, such as sore throat, lacerations of the lips or gums or other structures within the upper airway, chipped, fractured or dislodged teeth, and nasal injury. Other complications which are common but potentially more serious include accelerated or irregular heartbeat, high blood pressure, elevated intracranial and introcular pressure, and bronchospasm.More serious complications include laryngospasm, perforation of the trachea or esophagus, pulmonary aspiration of gastric contents or other foreign bodies, fracture or dislocation of the cervical spine, temporomandibular joint or arytenoid cartilages, decreased oxygen content, elevated arterial carbon dioxide, and vocal cord weakness. In addition to these complications, tracheal intubation via the nasal route carries a risk of dislodgement of adenoids and potentially severe nasal bleeding. Newer technologies such as flexible fiberoptic laryngoscopy have fared better in reducing the incidence of some of these complications, though the most frequent cause of intubation trauma remains a lack of skill on the part of the laryngoscopist.Complications may also be severe and long-lasting or permanent, such as vocal cord damage, esophageal perforation and retropharyngeal abscess, bronchial intubation, or nerve injury. They may even be immediately life-threatening, such as laryngospasm and negative pressure pulmonary edema (fluid in the lungs), aspiration, unrecognized esophageal intubation, or accidental disconnection or dislodgement of the tracheal tube. Potentially fatal complications more often associated with prolonged intubation or tracheotomy include abnormal communication between the trachea and nearby structures such as the innominate artery (tracheoinnominate fistula) or esophagus (tracheoesophageal fistula). Other significant complications include airway obstruction due to loss of tracheal rigidity, ventilator-associated pneumonia and narrowing of the glottis or trachea. The cuff pressure is monitored carefully in order to avoid complications from over-inflation, many of which can be traced to excessive cuff pressure restricting the blood supply to the tracheal mucosa. A 2000 Spanish study of bedside percutaneous tracheotomy reported overall complication rates of 10–15% and procedural mortality of 0%, which is comparable to those of other series reported in the literature from the Netherlands and the United States.Inability to secure the airway, with subsequent failure of oxygenation and ventilation is a life-threatening complication which if not immediately corrected leads to decreased oxygen content, brain damage, cardiovascular collapse, and death. When performed improperly, the associated complications (e.g., unrecognized esophageal intubation) may be rapidly fatal. Without adequate training and experience, the incidence of such complications is high. The case of Andrew Davis Hughes, from Emerald Isle, NC is a widely known case in which the patient was improperly intubated and, due to the lack of oxygen, sustained severe brain damage and died. For example, among paramedics in several United States urban communities, unrecognized esophageal or hypopharyngeal intubation has been reported to be 6% to 25%. Although not common, where basic emergency medical technicians are permitted to intubate, reported success rates are as low as 51%. In one study, nearly half of patients with misplaced tracheal tubes died in the emergency room. Because of this, recent editions of the American Heart Associations Guidelines for Cardiopulmonary Resuscitation have de-emphasized the role of tracheal intubation in favor of other airway management techniques such as bag-valve-mask ventilation, the laryngeal mask airway and the Combitube.  However, recent higher quality studies have shown no survival or neurological benefit with endotracheal intubation over supraglottic airway devices (Laryngeal mask or Combitube).One complication—unintentional and unrecognized intubation of the esophagus—is both common (as frequent as 25% in the hands of inexperienced personnel) and likely to result in a deleterious or even fatal outcome. In such cases, oxygen is inadvertently administered to the stomach, from where it cannot be taken up by the circulatory system, instead of the lungs. If this situation is not immediately identified and corrected, death will ensue from cerebral and cardiac anoxia.
Of 4,460 claims in the American Society of Anesthesiologists (ASA) Closed Claims Project database, 266 (approximately 6%) were for airway injury. Of these 266 cases, 87% of the injuries were temporary, 5% were permanent or disabling, and 8% resulted in death. Difficult intubation, age older than 60 years, and female gender were associated with claims for perforation of the esophagus or pharynx. Early signs of perforation were present in only 51% of perforation claims, whereas late sequelae occurred in 65%.During the SARS and COVID-19 pandemics, tracheal intubation has been used with a ventilator in severe cases where the patient struggles to breathe. Performing the procedure carries a risk of the caregiver becoming infected.

Alternatives
Although it offers the greatest degree of protection against regurgitation and pulmonary aspiration, tracheal intubation is not the only means to maintain a patent airway. Alternative techniques for airway management and delivery of oxygen, volatile anesthetics or other breathing gases include the laryngeal mask airway, i-gel, cuffed oropharyngeal airway, continuous positive airway pressure (CPAP mask), nasal BiPAP mask, simple face mask, and nasal cannula.General anesthesia is often administered without tracheal intubation in selected cases where the procedure is brief in duration, or procedures where the depth of anesthesia is not sufficient to cause significant compromise in ventilatory function. Even for longer duration or more invasive procedures, a general anesthetic may be administered without intubating the trachea, provided that patients are carefully selected, and the risk-benefit ratio is favorable (i.e., the risks associated with an unprotected airway are believed to be less than the risks of intubating the trachea).Airway management can be classified into closed or open techniques depending on the system of ventilation used. Tracheal intubation is a typical example of a closed technique as ventilation occurs using a closed circuit. Several open techniques exist, such as spontaneous ventilation, apnoeic ventilation or jet ventilation. Each has its own specific advantages and disadvantages which determine when it should be used.
Spontaneous ventilation has been traditionally performed with an inhalational agent (i.e. gas induction or inhalational induction using halothane or sevoflurane) however it can also be performed using intravenous anaesthesia (e.g. propofol, ketamine or dexmedetomidine). SponTaneous Respiration using IntraVEnous anaesthesia and High-flow nasal oxygen (STRIVE Hi) is an open airway technique that uses an upwards titration of propofol which maintains ventilation at deep levels of anaesthesia. It has been used in airway surgery as an alternative to tracheal intubation.

History
TracheotomyThe earliest known depiction of a tracheotomy is found on two Egyptian tablets dating back to around 3600 BC. The 110-page Ebers Papyrus, an Egyptian medical papyrus which dates to roughly 1550 BC, also makes reference to the tracheotomy. Tracheotomy was described in the Rigveda, a Sanskrit text of ayurvedic medicine written around 2000 BC in ancient India. The Sushruta Samhita from around 400 BC is another text from the Indian subcontinent on ayurvedic medicine and surgery that mentions tracheotomy. Asclepiades of Bithynia (c. 124–40 BC) is often credited as being the first physician to perform a non-emergency tracheotomy. Galen of Pergamon (AD 129–199) clarified the anatomy of the trachea and was the first to demonstrate that the larynx generates the voice. In one of his experiments, Galen used bellows to inflate the lungs of a dead animal. Ibn Sīnā (980–1037) described the use of tracheal intubation to facilitate breathing in 1025 in his 14-volume medical encyclopedia, The Canon of Medicine. In the 12th century medical textbook Al-Taisir, Ibn Zuhr (1092–1162)—also known as Avenzoar—of Al-Andalus  provided a correct description of the tracheotomy operation.The first detailed descriptions of tracheal intubation and subsequent artificial respiration of animals were from Andreas Vesalius (1514–1564) of Brussels. In his landmark book published in 1543, De humani corporis fabrica, he described an experiment in which he passed a reed into the trachea of a dying animal whose thorax had been opened and maintained ventilation by blowing into the reed intermittently. Antonio Musa Brassavola (1490–1554) of Ferrara successfully treated a patient with peritonsillar abscess by tracheotomy. Brassavola published his account in 1546; this operation has been identified as the first recorded successful tracheotomy, despite the many previous references to this operation. Towards the end of the 16th century, Hieronymus Fabricius (1533–1619) described a useful technique for tracheotomy in his writings, although he had never actually performed the operation himself. In 1620 the French surgeon Nicholas Habicot (1550–1624) published a report of four successful tracheotomies. In 1714, anatomist Georg Detharding (1671–1747) of the University of Rostock performed a tracheotomy on a drowning victim.Despite the many recorded instances of its use since antiquity, it was not until the early 19th century that the tracheotomy finally began to be recognized as a legitimate means of treating severe airway obstruction. In 1852, French physician Armand Trousseau (1801–1867) presented a series of 169 tracheotomies to the Académie Impériale de Médecine. 158 of these were performed for the treatment of croup, and 11 were performed for "chronic maladies of the larynx". Between 1830 and 1855, more than 350 tracheotomies were performed in Paris, most of them at the Hôpital des Enfants Malades, a public hospital, with an overall survival rate of only 20–25%. This compares with 58% of the 24 patients in Trousseaus private practice, who fared better due to greater postoperative care.In 1871, the German surgeon Friedrich Trendelenburg (1844–1924) published a paper describing the first successful elective human tracheotomy to be performed for the purpose of administration of general anesthesia. In 1888, Sir Morell Mackenzie (1837–1892) published a book discussing the indications for tracheotomy. In the early 20th century, tracheotomy became a life-saving treatment for patients affected with paralytic poliomyelitis who required mechanical ventilation. In 1909, Philadelphia laryngologist Chevalier Jackson (1865–1958) described a technique for tracheotomy that is used to this day.
Laryngoscopy and non-surgical techniques
In 1854, a Spanish singing teacher named Manuel García (1805–1906) became the first man to view the functioning glottis in a living human. In 1858, French pediatrician Eugène Bouchut (1818–1891) developed a new technique for non-surgical orotracheal intubation to bypass laryngeal obstruction resulting from a diphtheria-related pseudomembrane. In 1880, Scottish surgeon William Macewen (1848–1924) reported on his use of orotracheal intubation as an alternative to tracheotomy to allow a patient with glottic edema to breathe, as well as in the setting of general anesthesia with chloroform. In 1895, Alfred Kirstein (1863–1922) of Berlin first described direct visualization of the vocal cords, using an esophagoscope he had modified for this purpose; he called this device an autoscope.In 1913, Chevalier Jackson was the first to report a high rate of success for the use of direct laryngoscopy as a means to intubate the trachea. Jackson introduced a new laryngoscope blade that incorporated a component that the operator could slide out to allow room for passage of an endotracheal tube or bronchoscope </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 Epididymitis and explain in detail? [/INST] Epididymitis is a medical condition characterized by inflammation of the epididymis, a curved structure at the back of the testicle. Onset of pain is typically over a day or two. The pain may improve with raising the testicle. Other symptoms may include swelling of the testicle, burning with urination, or frequent urination. Inflammation of the testicle is commonly also present.In those who are young and sexually active gonorrhea and chlamydia are frequently the underlying cause. In older males and men who practice insertive anal sex, enteric bacteria are a common cause. Diagnosis is typically based on symptoms. Conditions that may result in similar symptoms include testicular torsion, inguinal hernia, and testicular cancer. Ultrasound can be useful if the diagnosis is unclear.Treatment may include pain medications, NSAIDs, and elevation. Recommended antibiotics in those who are young and sexually active are ceftriaxone and doxycycline. Among those who are older, ofloxacin may be used. Complications include infertility and chronic pain. People aged 15 to 35 are most commonly affected, with about 600,000 people within this age group affected per year in the United States.

Signs and symptoms
Those aged 15 to 35 are most commonly affected. The acute form usually develops over the course of several days, with pain and swelling frequently in only one testis, which will hang low in the scrotum.  There will often be a recent history of dysuria or urethral discharge.  Fever is also a common symptom.  In the chronic version, the patient may have painful point tenderness but may or may not have an irregular epididymis upon palpation, though palpation may reveal an indurated epididymis.  A scrotal ultrasound may reveal problems with the epididymis, but such an ultrasound may also show nothing unusual.  The majority of patients who present with chronic epididymitis have had symptoms for over five years.: p.311

Complications
Untreated, acute epididymitiss major complications are abscess formation and testicular infarction.  Chronic epididymitis can lead to permanent damage or even destruction of the epididymis and testicle (resulting in infertility and/or hypogonadism), and infection may spread to any other organ or system of the body.  Chronic pain is also an associated complication for untreated chronic epididymitis.

Causes
Though urinary tract infections in men are rare, bacterial infection is the most common cause of acute epididymitis. The bacteria in the urethra back-track through the urinary and reproductive structures to the epididymis. In rare circumstances, the infection reaches the epididymis via the bloodstream.In sexually active men, Chlamydia trachomatis is responsible for two-thirds of acute cases, followed by Neisseria gonorrhoeae and E. coli (or other bacteria that cause urinary tract infection). Particularly among men over age 35 in whom the cause is E. coli, epididymitis is commonly due to urinary tract obstruction. Less common microbes include Ureaplasma, Mycobacterium, and cytomegalovirus, or Cryptococcus in patients with HIV infection. E. coli is more common in boys before puberty, the elderly, and men who have sex with men.  In the majority of cases in which bacteria are the cause, only one side of the scrotum or the other is the locus of pain.Non-infectious causes are also possible. Reflux of sterile urine (urine without bacteria) through the ejaculatory ducts may cause inflammation with obstruction. In children, it may be a response following an infection with enterovirus, adenovirus or Mycoplasma pneumoniae.  Rare non-infectious causes of chronic epididymitis include sarcoidosis (more prevalent in black men) and Behçets disease.: p.311 Any form of epididymitis can be caused by genito-urinary surgery, including prostatectomy and  urinary catheterization. Congestive epididymitis is a long-term complication of vasectomy. Chemical epididymitis may also result from drugs such as amiodarone.

Diagnosis
Diagnosis is typically based on symptoms. Conditions that may result in similar symptoms include testicular torsion, inguinal hernia, and testicular cancer. Ultrasound can be useful if the diagnosis is unclear.Epididymitis usually has a gradual onset. Typical findings are redness, warmth and swelling of the scrotum, with tenderness behind the testicle, away from the middle (this is the normal position of the epididymis relative to the testicle). The cremasteric reflex (elevation of the testicle in response to stroking the upper inner thigh) remains normal. This is a useful sign to distinguish it from testicular torsion. If there is pain relieved by elevation of the testicle, this is called Prehns sign, which is, however, non-specific and is not useful for diagnosis.
Before the advent of sophisticated medical imaging techniques, surgical exploration was the standard of care. Today, Doppler ultrasound is a common test: it can demonstrate areas of blood flow and can distinguish clearly between epididymitis and torsion. However, as torsion and other sources of testicular pain can often be determined by palpation alone, some studies have suggested that the only real benefit of an ultrasound is to assure the person that they do not have testicular cancer.: p.237  Nuclear testicular blood flow testing is rarely used.Additional tests may be necessary to identify underlying causes. In younger children, a urinary tract anomaly is frequently found. In sexually active men, tests for sexually transmitted diseases may be done. These may include microscopy and culture of a first void urine sample, Gram stain and culture of fluid or a swab from the urethra, nucleic acid amplification tests (to amplify and detect microbial DNA or other nucleic acids) or tests for syphilis and HIV.

Classification
Epididymitis can be classified as acute, subacute, and chronic, depending on the duration of symptoms.

Chronic epididymitis
Chronic epididymitis is epididymitis that is present for more than 3 months. Chronic epididymitis is characterized by inflammation even when there is no infection present. Tests are needed to distinguish chronic epididymitis from a range of other disorders that can cause constant scrotal pain including testicular cancer (though this is often painless), enlarged scrotal veins (varicocele), calcifications, and a possible cyst within the epididymis. Some research has found that as much as 80% of visits to a urologist for scrotal pain are for chronic epididymitis.: p.311  As a further complication, the nerves in the scrotal area are closely connected to those of the abdomen, sometimes causing abdominal pain similar to a hernia (see referred pain).
Chronic epididymitis is most commonly associated with lower back pain, and the onset of pain often co-occurs with activity that stresses the low back (i.e., heavy lifting, long periods of car driving, poor posture while sitting, or any other activity that interferes with the normal curve of the lumbar lordosis region).: p.237

Treatment
In both the acute and chronic forms, antibiotics are used if an infection is suspected.  The treatment of choice is often azithromycin and cefixime to cover both gonorrhoeae and chlamydia.  Fluoroquinolones are no longer recommended due to widespread resistance of gonorrhoeae to this class.  Doxycycline may be used as an alternative to azithromycin.  In chronic epididymitis, a four- to six-week course of antibiotics may be prescribed to ensure the complete eradication of any possible bacterial cause, especially the various chlamydiae.
For cases caused by enteric organisms (such as E. coli), ofloxacin or levofloxacin are recommended.In children, fluoroquinolones and doxycycline are best avoided. Since bacteria that cause urinary tract infections are often the cause of epididymitis in children, co-trimoxazole or suited penicillins (for example, cephalexin) can be used.Household remedies such as elevation of the scrotum and cold compresses applied regularly to the scrotum may relieve the pain in acute cases. Painkillers or anti-inflammatory drugs are often used for treatment of both chronic and acute forms. Hospitalisation is indicated for severe cases, and check-ups can ensure the infection has cleared up. Surgical removal of the epididymis is rarely necessary, causes sterility, and only gives relief from pain in approximately 50% of cases.  However, in acute suppurating epididymitis (acute epididymitis with a discharge of pus), an epididymotomy may be recommended; in refractory cases, a full epididymectomy may be required.  In cases with unrelenting testicular pain, removal of the entire testicle—orchiectomy—may also be warranted.
It is generally believed that most cases of chronic epididymitis will eventually "burn out" of patients system if left untreated, though this might take years or even decades.  However, some prostate-related medications have proven effective in treating chronic epididymitis, including doxazosin.

Epidemiology
Epididymitis makes up 1 in 144 visits for medical care (0.69 percent) in men 18 to 50 years old or 600,000 cases in males between 18 and 35 in the United States.It occurs primarily in those 16 to 30 years of age and 51 to 70 years </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 Esophagitis and explain in detail? [/INST] Esophagitis, also spelled oesophagitis, is a disease characterized by inflammation of the esophagus. The esophagus is a tube composed of a mucosal lining, and longitudinal and circular smooth muscle fibers. It connects the pharynx to the stomach; swallowed food and liquids normally pass through it.Esophagitis can be asymptomatic; or can cause epigastric and/or substernal burning pain, especially when lying down or straining; and can make swallowing difficult (dysphagia). The most common cause of esophagitis is the reverse flow of acid from the stomach into the lower esophagus: gastroesophageal reflux disease (GERD).

Signs and symptoms
The symptoms of esophagitis include:
Heartburn – a burning sensation in the lower mid-chest
Nausea
Dysphagia – swallowing is painful, with difficulty passing or inability to pass food through the esophagus
Vomiting (emesis)
Abdominal pain
Cough

Complications
If the disease remains untreated, it can cause scarring and discomfort in the esophagus. If the irritation is not allowed to heal, esophagitis can result in esophageal ulcers. Esophagitis can develop into Barretts esophagus and can increase the risk of esophageal cancer.

Causes
Esophagitis cannot be spread. However, infections can be spread by those who have infectious esophagitis. Esophagitis can develop due to many causes. GERD is the most common cause of esophagitis because of the backflow of acid from the stomach, which can irritate the lining of the esophagus.
Other causes include:

Medicines – Can cause esophageal damage that can lead to esophageal ulcers
Nonsteroidal anti-inflammatory drugs (NSAIDS) – aspirin, naproxen sodium, and ibuprofen. Known to irritate the GI tract.
Antibiotics – doxycycline and tetracycline
Quinidine
Bisphosphonates – used to treat osteoporosis
Steroids
Potassium chloride

Chemical injury by alkaline or acid solutions
Physical injury resulting from nasogastric tubes.
Alcohol use disorder – Can wear down the lining of the esophagus.
Crohns disease – a type of IBD and an autoimmune disease that can cause esophagitis if it attacks the esophagus.
Stress – Can cause higher levels of acid reflux
Radiation therapy - Can affect the immune system.
Allergies (food, inhalants) – Allergies can stimulate eosinophilic esophagitis.
Infection - People with an immunodeficiencies have a higher chance of developing esophagitis.
Vitamins and supplements (iron, vitamin C, and potassium) – Supplements and minerals can be hard on the GI tract.
Vomiting – Acid can irritate esophagus.
Hernias – A hernia can poke through the diaphragm muscle and can inhibit the stomach acid and food from draining quickly.
Surgery
Eosinophilic esophagitis, a more chronic condition with a theorized autoimmune component

Mechanism
The esophagus is a muscular tube made of both voluntary and involuntary muscles. It is responsible for peristalsis of food. It is about 8 inches long and passes through the diaphragm before entering the stomach. The esophagus is made up of three layers:  from the inside out, they are the mucosa, submucosa, muscularis externa. The mucosa, the inner most layer and lining of the esophagus, is composed of stratified squamous epithelium, lamina propria, and muscularis mucosae. At the end of the esophagus is the lower esophageal sphincter, which normally prevents stomach acid from entering the esophagus.
If the sphincter is not sufficiently tight, it may allow acid to enter the esophagus, causing inflammation of one or more layers. Esophagitis may also occur if an infection is present, which may be due to bacteria, viruses, or fungi; or by diseases that affect the immune system.Irritation can be caused by GERD, vomiting, surgery, medications, hernias, and radiation injury. Inflammation can cause the esophagus to narrow, which makes swallowing food difficult and may result in food bolus impaction.

Diagnosis
Esophagitis can be diagnosed by upper endoscopy, biopsy, upper GI series (or barium swallow), and laboratory tests.An upper endoscopy is a procedure to look at the esophagus by using an endoscope. While looking at the esophagus, the doctor is able to take a small biopsy. The biopsy can be used to confirm inflammation of the esophagus.
An upper GI series uses a barium contrast, fluoroscopy, and an X-ray. During a barium X-ray, a solution with barium or pill is taken before getting an X-ray. The barium makes the organs more visible and can detect if there is any narrowing, inflammation, or other abnormalities that can be causing the disease. The upper GI series can be used to find the cause of GI symptoms. An esophagram is if only the throat and esophagus are looked at.Laboratory tests can be done on biopsies removed from the esophagus and can help determine the cause of the esophagitis. Laboratory tests can help diagnose a fungal, viral, or bacterial infection. Scanning for white blood cells can help diagnose eosinophil esophagitis.
Some lifestyle indicators for this disease include stress, unhealthy eating, smoking, drinking, family history, allergies, and immunodeficiency.

Types
Reflux esophagitis
Although it usually assumed that inflammation from acid reflux is caused by the irritant action on the mucosa by hydrochloric acid, one study suggests that the pathogenesis of reflux esophagitis may be cytokine-mediated.

Infectious esophagitis
Esophagitis happens due to a viral, fungal, parasitic or bacterial infection. More likely to happen to people who have an immunodeficiency. Types include:
Fungal

Candida (Esophageal candidiasis)Viral

Herpes simplex (Herpes esophagitis)
CytomegalovirusDrug-induced esophagitis
Damage to the esophagus due to medications. If the esophagus is not coated or if the medicine is not taken with enough liquid, it can damage the tissues.

Eosinophilic esophagitis
Eosinophilic esophagitis is caused by a high concentration of eosinophils in the esophagus. The presence of eosinophils in the esophagus may be due to an allergen and is often correlated with GERD. The direction of cause and effect between inflammation and acid reflux is poorly established, with recent studies (in 2016) hinting that reflux does not cause inflammation. This esophagitis can be triggered by allergies to food or to inhaled allergens. This type is still poorly understood.
Lymphocytic esophagitis
Lymphocytic esophagitis is a rare and poorly understood entity associated with an increased amount of lymphocytes in the lining of the esophagus. It was first described in 2006. Disease associations may include Crohns disease, gastroesophageal reflux disease and coeliac disease. It causes similar changes on endoscopy as eosinophilic esophagitis including esophageal rings, narrow-lumen esophagus, and linear furrows.
Caustic esophagitis
Caustic esophagitis is the damage of tissue via chemical origin. This occasionally occurs through occupational exposure (via breathing of fumes that mix into the saliva which is then swallowed) or through pica. It occurred in some teenagers during the fad of intentionally eating Tide pods.

By severity
The severity of reflux esophagitis is commonly classified into four grades according to the Los Angeles Classification:

Prevention
Since there can be many causes underlying esophagitis, it is important to try to find the cause to help to prevent esophagitis. To prevent reflux esophagitis, avoid acidic foods, caffeine, eating before going to bed, alcohol, fatty meals, and smoking. To prevent drug-induced esophagitis, drink plenty of liquids when taking medicines, take an alternative drug, and do not take medicines while lying down, before sleeping, or too many at one time </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 Erysipelas and explain in detail? [/INST] Erysipelas () is a relatively common bacterial infection of the superficial layer of the skin (upper dermis), extending to the superficial lymphatic vessels within the skin, characterized by a raised, well-defined, tender, bright red rash, typically on the face or legs, but which can occur anywhere on the skin. It is a form of cellulitis and is potentially serious.Erysipelas is usually caused by the bacteria Streptococcus pyogenes, also known as group A β-hemolytic streptococci, through a break in the skin such as from scratches or an insect bite. It is more superficial than cellulitis, and is typically more raised and demarcated. The term is from Greek ἐρυσίπελας (erysípelas), meaning "red skin".In animals, erysipelas is a disease caused by infection with the bacterium Erysipelothrix rhusiopathiae. The disease caused in animals is called Diamond Skin Disease, which occurs especially in pigs. Heart valves and skin are affected. Erysipelothrix rhusiopathiae can also infect humans, but in that case, the infection is known as erysipeloid.

Signs and symptoms
Symptoms often occur suddenly. Affected individuals may develop a fever, shivering, chills, fatigue, headaches, vomiting and be generally unwell within 48 hours of the initial infection. The red plaque enlarges rapidly and has a sharply demarcated, raised edge. It may appear swollen, feel firm, warm and tender to touch and may have a consistency similar to orange peel. Pain may be extreme.More severe infections can result in vesicles (pox or insect bite-like marks), blisters, and petechiae (small purple or red spots), with possible skin necrosis (death). Lymph nodes may be swollen, and lymphedema may occur. Occasionally, a red streak extending to the lymph node can be seen.The infection may occur on any part of the skin, including the face, arms, fingers, legs and toes; it tends to favour the extremities. The umbilical stump and sites of lymphoedema are also common sites affected.Fat tissue and facial areas, typically around the eyes, ears, and cheeks, are most susceptible to infection. Repeated infection of the extremities can lead to chronic swelling (lymphoedema).

Cause
Most cases of erysipelas are due to Streptococcus pyogenes, also known as group A β-hemolytic streptococci, less commonly by group C or G streptococci and rarely due to Staphylococcus aureus. Newborns may contract erysipelas due to Streptococcus agalactiae, also known as group B streptococcus or GBS.The infecting bacteria can enter the skin through minor trauma, human, insect or animal bites, surgical incisions, ulcers, burns and abrasions. There may be underlying eczema or athletes foot (tinea pedis), and it can originate from streptococci bacteria in the subjects own nasal passages or ear.The rash is due to an exotoxin, not the Streptococcus bacteria, and is found in areas where no symptoms are present; e.g., the infection may be in the nasopharynx, but the rash is found usually on the epidermis and superficial lymphatics.

Diagnosis
Erysipelas is usually diagnosed by the clinician looking at the characteristic well-demarcated rash following a history of injury or recognition of one of the risk factors.Tests, if performed, may show a high white cell count, raised CRP or positive blood culture identifying the organism.Erysipelas must be differentiated from herpes zoster, angioedema, contact dermatitis, erythema chronicum migrans of early Lyme disease, gout, septic arthritis, septic bursitis, vasculitis, allergic reaction to an insect bite, acute drug reaction, deep venous thrombosis and diffuse inflammatory carcinoma of the breast.

Differentiating from cellulitis
Erysipelas can be distinguished from cellulitis by two particular features; its raised advancing edge and its sharp borders. The redness in cellulitis is not raised and its border is relatively indistinct. Bright redness of erysipelas has been described as a third differentiating feature.Erysipelas does not affect subcutaneous tissue. It does not release pus, only serum or serous fluid. Subcutaneous edema may lead the physician to misdiagnose it as cellulitis.

Treatment
Depending on the severity, treatment involves either oral or intravenous antibiotics, using penicillins, clindamycin, or erythromycin. While illness symptoms resolve in a day or two, the skin may take weeks to return to normal.
The USA Food and Drug Administration has approved 4 antibiotics-- omadacycline (Nuzyra), oritavancin (Orbactiv), dalbavancin (Dalvance), and tedizolid (Sivextro) --for the treatment of acute bacterial skin and skin structure infections.
Because of the risk of reinfection, prophylactic antibiotics are sometimes used after resolution of the initial condition.

Prognosis
The disease prognosis includes:

Spread of infection to other areas of body can occur through the bloodstream (bacteremia), including septic arthritis. Glomerulonephritis can follow an episode of streptococcal erysipelas or other skin infection, but not rheumatic fever.
Recurrence of infection: Erysipelas can recur in 18–30% of cases even after antibiotic treatment. A chronic state of recurrent erysipelas infections can occur with several predisposing factors including alcoholism, diabetes, and athletes foot. Another predisposing factor is chronic cutaneous edema, such as can in turn be caused by venous insufficiency or heart failure.
Lymphatic damage
Necrotizing fasciitis, commonly known as "flesh-eating" bacterial infection, is a potentially deadly exacerbation of the infection if it spreads to deeper tissue.

Epidemiology
There is currently no validated recent data on the worldwide incidence of erysipelas. From 2004 to 2005, UK hospitals reported 69,576 cases of cellulitis and 516 cases of erysipelas. One book stated that several studies have placed the prevalence rate between one and 250 in every 10,000 people. The development of antibiotics, as well as increased sanitation standards, has contributed to the decreased rate of incidence. Erysipelas caused systemic illness in up to 40% of cases reported by UK hospitals and 29% of people had recurrent episodes within three years </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 Erysipeloid and explain in detail? [/INST] In humans, Erysipelothrix rhusiopathiae infections most commonly present in a mild cutaneous form known as erysipeloid  or fish poisoning.  E. rhusiopathiae can cause an indolent cellulitis, more commonly in individuals who handle fish and raw meat </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 Esotropia and explain in detail? [/INST] Esotropia is a form of strabismus in which one or both eyes turns inward. The condition can be constantly present, or occur intermittently, and can give the affected individual a "cross-eyed" appearance. It is the opposite of exotropia and usually involves more severe axis deviation than esophoria. Esotropia is sometimes erroneously called "lazy eye", which describes the condition of amblyopia; a reduction in vision of one or both eyes that is not the result of any pathology of the eye and cannot be resolved by the use of corrective lenses. Amblyopia can, however, arise as a result of esotropia occurring in childhood: In order to relieve symptoms of diplopia or double vision, the childs brain will ignore or "suppress" the image from the esotropic eye, which when allowed to continue untreated will lead to the development of amblyopia. Treatment options for esotropia include glasses to correct refractive errors (see accommodative esotropia below), the use of prisms and/or orthoptic exercises and/or eye muscle surgery. The term is from Greek eso meaning "inward" and trope meaning "a turning".

Types
Concomitant esotropia
Concomitant esotropia – that is, an inward squint that does not vary with the direction of gaze – mostly sets in before 12 months of age (this constitutes 40% of all strabismus cases) or at the age of three or four. Most patients with "early-onset" concomitant esotropia are emmetropic, whereas most of the "later-onset" patients are hyperopic. It is the most frequent type of natural strabismus not only in humans, but also in monkeys.Concomitant esotropia can itself be subdivided into esotropias that are either constant, or intermittent.

Constant esotropia
A constant esotropia, as the name implies, is present all the time.
Intermittent esotropia
Intermittent esotropias, again as the name implies, are not always present.  In very rare cases, they may only occur in repeated cycles of one day on, one day off (Cyclic Esotropia). However, the vast majority of intermittent esotropias are accommodative in origin.A patient can have a constant esotropia for reading, but an intermittent esotropia for distance (but rarely vice versa).

Accommodative esotropia
Accommodative esotropia (also called refractive esotropia) is an inward turning of the eyes due to efforts of accommodation. It is often seen in patients with moderate amounts of hyperopia. The person with hyperopia, in an attempt to "accommodate" or focus the eyes, converges the eyes as well, as convergence is associated with activation of the accommodation reflex. The over-convergence associated with the extra accommodation required to overcome a hyperopic refractive error can precipitate a loss of binocular control and lead to the development of esotropia.The chances of an esotropia developing in a hyperopic child will depend to some degree on the amount of hyperopia present. Where the degree of error is small, the child will typically be able to maintain control because the amount of over-accommodation required to produce clear vision is also small. Where the degree of hyperopia is large, the child  may not be able to produce clear vision no matter how much extra-accommodation is exerted and thus no incentive exists for the over-accommodation and convergence that can give rise to the onset of esotropia. However, where the degree of error is small enough to allow the child to generate clear vision by over-accommodation, but large enough to disrupt their binocular control, esotropia will result.
Only about 20% of children with hyperopia greater than +3.5 diopters develop strabismus.Where the esotropia is solely a consequence of uncorrected hyperopic refractive error, providing the child with the correct glasses and ensuring that these are worn all the time, is often enough to control the deviation. In such cases, known as fully accommodative esotropias, the esotropia will only be seen when the child removes their glasses. Many adults with childhood esotropias of this type make use of contact lenses to control their squint. Some undergo refractive surgery for this purpose.
A second type of accommodative esotropia also exists, known as convergence excess esotropia. In this condition the child exerts excessive accommodative convergence relative to their accommodation. Thus, in such cases, even when all underlying hyperopic refractive errors have been corrected, the child will continue to squint when looking at very small objects or reading small print. Even though they are exerting a normal amount of accommodative or focusing effort, the amount of convergence associated with this effort is excessive, thus giving rise to esotropia. In such cases an additional hyperopic correction is often prescribed in the form of bifocal lenses, to reduce the degree of accommodation, and hence convergence, being exerted. Many children will gradually learn to control their esotropias, sometimes with the help of orthoptic exercises. However, others will eventually require extra-ocular muscle surgery to resolve their problems.

Congenital esotropia
Congenital esotropia, or infantile esotropia, is a specific sub-type of primary concomitant esotropia. It is a constant esotropia of large and consistent size with onset between birth and six months of age. It is not associated with hyperopia, so the exertion of accommodative effort will not significantly affect the angle of deviation. It is, however, associated with other ocular dysfunctions including oblique muscle over-actions, Dissociated Vertical Deviation (DVD), Manifest Latent Nystagmus, and defective abduction, which develops as a consequence of the tendency of those with infantile esotropia to cross fixate. Cross fixation involves the use of the right eye to look to the left and the left eye to look to the right; a visual pattern that will be natural for the person with the large angle esotropia whose eye is already deviated towards the opposing side.
The origin of the condition is unknown, and its early onset means that the affected individuals potential for developing binocular vision is limited. The appropriate treatment approach remains a matter of some debate. Some ophthalmologists favour an early surgical approach as offering the best prospect of binocularity whilst others remain unconvinced that the prospects of achieving this result are good enough to justify the increased complexity and risk associated with operating on those under the age of one year.

Incomitant esotropia
Incomitant esotropias are conditions in which the esotropia varies in size with direction of gaze. They can occur in both childhood and adulthood, and arise as a result of neurological, mechanical or myogenic problems. These problems may directly affect the extra-ocular muscles themselves, and may also result from conditions affecting the nerve or blood supply to these muscles or the bony orbital structures surrounding them. Examples of conditions giving rise to an esotropia might include a VIth cranial nerve (or Abducens) palsy, Duanes syndrome or orbital injury.

Diagnosis
Classification
Right, left or alternating
Someone with esotropia will squint with either the right or the left eye but never with both eyes simultaneously. In a left esotropia, the left eye squints, and in a right esotropia the right eye squints. In an alternating esotropia, the patient is able to alternate fixation between their right and left eye so that at one moment the right eye fixates and the left eye turns inward, and at the next the left eye fixates and the right turns inward. This alteration between the left and right eye is mostly spontaneous, but may be voluntary in some cases. Where a patient tends to consistently fixate with one eye and squint with the other, the eye that squints is likely to develop some amblyopia. Someone whose squint alternates is very unlikely to develop amblyopia because both eyes will receive equal visual stimulation. It is possible to encourage alternation through the use of occlusion or patching of the dominant or fixating eye to promote the use of the other </s>