<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 Psoriasis and explain in detail? [/INST] Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by raised areas of abnormal skin. These areas are red, or purple on some people with darker skin, dry, itchy, and scaly. Psoriasis varies in severity from small, localized patches to complete body coverage. Injury to the skin can trigger psoriatic skin changes at that spot, which is known as the Koebner phenomenon.The five main types of psoriasis are plaque, guttate, inverse, pustular, and erythrodermic. Plaque psoriasis, also known as psoriasis vulgaris, makes up about 90% of cases. It typically presents as red patches with white scales on top. Areas of the body most commonly affected are the back of the forearms, shins, navel area, and scalp. Guttate psoriasis has drop-shaped lesions. Pustular psoriasis presents as small, noninfectious, pus-filled blisters. Inverse psoriasis forms red patches in skin folds. Erythrodermic psoriasis occurs when the rash becomes very widespread, and can develop from any of the other types. Fingernails and toenails are affected in most people with psoriasis at some point in time. This may include pits in the nails or changes in nail color.Psoriasis is generally thought to be a genetic disease that is triggered by environmental factors. If one twin has psoriasis, the other twin is three times more likely to be affected if the twins are identical than if they are nonidentical. This suggests that genetic factors predispose to psoriasis. Symptoms often worsen during winter and with certain medications, such as beta blockers or NSAIDs. Infections and psychological stress can also play a role.  The underlying mechanism involves the immune system reacting to skin cells. Diagnosis is typically based on the signs and symptoms.There is no known cure for psoriasis, but various treatments can help control the symptoms. These treatments include steroid creams, vitamin D3 cream, ultraviolet light, and immunosuppressive drugs, such as methotrexate. About 75% of skin involvement improves with creams alone. The disease affects 2–4% of  the population. Men and women are affected with equal frequency. The disease may begin at any age, but typically starts in adulthood. Psoriasis is associated with an increased risk of psoriatic arthritis, lymphomas, cardiovascular disease, Crohns disease, and depression. Psoriatic arthritis affects up to 30% of individuals with psoriasis.The word "psoriasis" is from Greek ψωρίασις, meaning "itching condition" or "being itchy" from psora, "itch", and -iasis, "action, condition".

Signs and symptoms
Plaque psoriasis
Psoriasis vulgaris (also known as chronic stationary psoriasis or plaque-like psoriasis) is the most common form and affects 85–90% of people with psoriasis. Plaque psoriasis typically appears as raised areas of inflamed skin covered with silvery-white, scaly skin. These areas are called plaques and are most commonly found on the elbows, knees, scalp, and back.

Other forms
Additional types of psoriasis comprise about 10% of cases. They include pustular, inverse, napkin, guttate, oral, and seborrheic-like forms.

Pustular psoriasis
Pustular psoriasis appears as raised bumps filled with noninfectious pus (pustules). The skin under and surrounding the pustules is red and tender. Pustular psoriasis can either be localized or more widespread throughout the body. Two types of localized pustular psoriasis include psoriasis pustulosa palmoplantaris and acrodermatitis continua of Hallopeau; both forms are localized to the hands and feet.

Inverse psoriasis
Inverse psoriasis (also known as flexural psoriasis) appears as smooth, inflamed patches of skin. The patches frequently affect skin folds, particularly around the genitals (between the thigh and groin), the armpits, in the skin folds of an overweight abdomen (known as panniculus), between the buttocks in the intergluteal cleft, and under the breasts in the inframammary fold. Heat, trauma, and infection are thought to play a role in the development of this atypical form of psoriasis.

Napkin psoriasis
Napkin psoriasis is a subtype of psoriasis common in infants characterized by red papules with silver scale in the diaper area that may extend to the torso or limbs. Napkin psoriasis is often misdiagnosed as napkin dermatitis (diaper rash).

Guttate psoriasis
Guttate psoriasis is characterized by numerous small, scaly, red or pink, droplet-like lesions (papules). These numerous spots of psoriasis appear over large areas of the body, primarily the trunk, but also the limbs and scalp. Guttate psoriasis is often triggered by a streptococcal infection, typically streptococcal pharyngitis.

Erythrodermic psoriasis
Psoriatic erythroderma (erythrodermic psoriasis) involves widespread inflammation and exfoliation of the skin over most of the body surface, often involving greater than 90% of the body surface area. It may be accompanied by severe dryness, itching, swelling, and pain. It can develop from any type of psoriasis. It is often the result of an exacerbation of unstable plaque psoriasis, particularly following the abrupt withdrawal of systemic glucocorticoids. This form of psoriasis can be fatal as the extreme inflammation and exfoliation disrupt the bodys ability to regulate temperature and perform barrier functions.

Mouth
Psoriasis in the mouth is very rare, in contrast to lichen planus, another common papulosquamous disorder that commonly involves both the skin and mouth. When psoriasis involves the oral mucosa (the lining of the mouth), it may be asymptomatic, but it may appear as white or grey-yellow plaques. Fissured tongue is the most common finding in those with oral psoriasis and has been reported to occur in 6.5–20% of people with psoriasis affecting the skin. The microscopic appearance of oral mucosa affected by geographic tongue (migratory stomatitis) is very similar to the appearance of psoriasis. However, modern studies have failed to demonstrate any link between the two conditions.

Seborrheic-like psoriasis
Seborrheic-like psoriasis is a common form of psoriasis with clinical aspects of psoriasis and seborrheic dermatitis, and it may be difficult to distinguish from the latter. This form of psoriasis typically manifests as red plaques with greasy scales in areas of higher sebum production such as the scalp, forehead, skin folds next to the nose, the skin surrounding the mouth, skin on the chest above the sternum, and in skin folds.

Psoriatic arthritis
Psoriatic arthritis is a form of chronic inflammatory arthritis that has a highly variable clinical presentation and frequently occurs in association with skin and nail psoriasis. It typically involves painful inflammation of the joints and surrounding connective tissue, and can occur in any joint, but most commonly affects the joints of the fingers and toes.  This can result in a sausage-shaped swelling of the fingers and toes known as dactylitis. Psoriatic arthritis can also affect the hips, knees, spine (spondylitis), and sacroiliac joint (sacroiliitis). About 30% of individuals with psoriasis will develop psoriatic arthritis. Skin manifestations of psoriasis tend to occur before arthritic manifestations in about 75% of cases.

Nail changes
Psoriasis can affect the nails and produces a variety of changes in the appearance of fingers and toenails. Nail psoriasis occurs in 40–45% of people with psoriasis affecting the skin, and has a lifetime incidence of 80–90% in those with psoriatic arthritis. These changes include pitting of the nails (pinhead-sized depressions in the nail is seen in 70% with nail psoriasis), whitening of the nail, small areas of bleeding from capillaries under the nail, yellow-reddish discoloration of the nails known as the oil drop or salmon spots, dryness, thickening of the skin under the nail (subungual hyperkeratosis), loosening and separation of the nail (onycholysis), and crumbling of the nail.

Medical signs
In addition to the appearance and distribution of the rash, specific medical signs may be used by medical practitioners to assist with diagnosis. These may include Auspitzs sign (pinpoint bleeding when scale is removed), Koebner phenomenon (psoriatic skin lesions induced by trauma to the skin), and itching and pain localized to papules and plaques.

Causes
The cause of psoriasis is not fully understood, but many theories exist.

Genetics
Around one-third of people with psoriasis report a family history of the disease, and researchers have identified genetic loci associated with the condition. Identical twin studies suggest a 70% chance of a twin developing psoriasis if the other twin has the disorder. The risk is around 20% for nonidentical twins. These findings suggest both a genetic susceptibility and an environmental response in developing psoriasis.Psoriasis has a strong hereditary component, and many genes are associated with it, but how those genes work together is unclear. Most of the identified genes relate to the immune system, particularly the major histocompatibility complex (MHC) and T cells. Genetic studies are valuable due to their ability to identify molecular mechanisms and pathways for further study and potential medication targets.Classic genome-wide linkage analysis has identified nine loci on different chromosomes associated with psoriasis. They are called psoriasis susceptibility 1 through 9 (PSORS1 through PSORS9). Within those loci are genes on pathways that lead to inflammation. Certain variations (mutations) of those genes are commonly found in psoriasis. Genome-wide association scans have identified other genes that are altered to characteristic variants in psoriasis. Some of these genes express inflammatory signal proteins, which affect cells in the immune system that are also involved in psoriasis. Some of these genes are also involved in other autoimmune diseases.The major determinant is PSORS1, which probably accounts for 35–50% of psoriasis heritability. It controls genes that affect the immune system or encode skin proteins that are overabundant with psoriasis. PSORS1 is located on chromosome 6 in the MHC, which controls important immune functions. Three genes in the PSORS1 locus have a strong association with psoriasis vulgaris: HLA-C variant HLA-Cw6, which encodes an MHC class I protein; CCHCR1, variant WWC, which encodes a coiled coil protein  overexpressed in psoriatic epidermis; and CDSN, variant allele 5, which encodes corneodesmosin, a protein expressed in the granular and cornified layers of the epidermis and upregulated in psoriasis.Two major immune system genes under investigation are interleukin-12 subunit beta (IL12B) on chromosome 5q, which expresses interleukin-12B; and IL23R on chromosome 1p, which expresses the interleukin-23 receptor, and is involved in T cell differentiation. Interleukin-23 receptor and IL12B have both been strongly linked with psoriasis. T cells are involved in the inflammatory process that leads to psoriasis.  These genes are on the pathway that upregulate tumor necrosis factor-α and nuclear factor κB, two genes involved in inflammation. The first gene directly linked to psoriasis was identified as the CARD14 gene located in the PSORS2 locus. A rare mutation in the gene encoding for the CARD14-regulated protein plus an environmental trigger was enough to cause plaque psoriasis (the most common form of psoriasis).

Lifestyle
Conditions reported as worsening the disease include chronic infections, stress, and changes in season and climate. Others factors that might worsen the condition include hot water, scratching psoriasis skin lesions, skin dryness, excessive alcohol consumption, cigarette smoking, and obesity. The effects of stopping cigarette smoking or alcohol misuse have yet to be studied as of 2019.

HIV
The rate of psoriasis in human immunodeficiency virus-positive (HIV) individuals is comparable to that of HIV-negative individuals, but psoriasis tends to be more severe in people infected with HIV. A much higher rate of psoriatic arthritis occurs in HIV-positive individuals with psoriasis than in those without the infection. The immune response in those infected with HIV is typically characterized by cellular signals from Th2 subset of CD4+ helper T cells, whereas the immune response in psoriasis vulgaris is characterized by a pattern of cellular signals typical of Th1 subset of CD4+ helper T cells and Th17 helper T cells. The diminished CD4+-T cell presence is thought to cause an overactivation of CD8+-T cells, which are responsible for the exacerbation of psoriasis in HIV-positive people. Psoriasis in those with HIV/AIDS is often severe and may be untreatable with conventional therapy. In those with long-term, well-controlled psoriasis, new HIV infection can trigger a severe flare-up of psoriasis and/or psoriatic arthritis.

Microbes
Psoriasis has been described as occurring after strep throat, and may be worsened by skin or gut colonization with Staphylococcus aureus, Malassezia spp., and Candida albicans. Guttate psoriasis often affects children and adolescents and can be triggered by a recent group A streptococcal infection (tonsillitis or pharyngitis).

Medications
Drug-induced psoriasis may occur with beta blockers, lithium, antimalarial medications, nonsteroidal anti-inflammatory drugs, terbinafine, calcium channel blockers, captopril, glyburide, granulocyte colony-stimulating factor, interleukins, interferons, lipid-lowering medications,: 197  and paradoxically TNF inhibitors such as infliximab or adalimumab. Withdrawal of corticosteroids (topical steroid cream) can aggravate psoriasis due to the rebound effect.

Pathophysiology
Psoriasis is characterized by an abnormally excessive and rapid growth of the epidermal layer of the skin. Abnormal production of skin cells (especially during wound repair) and an overabundance of skin cells result from the sequence of pathological events in psoriasis. The sequence of pathological events in psoriasis is thought to start with an initiation phase in which an event (skin trauma, infection, or drugs) leads to activation of the immune system and then the maintenance phase consisting of chronic progression of the disease. Skin cells are replaced every 3–5 days in psoriasis rather than the usual 28–30 days. These changes are believed to stem from the premature maturation of keratinocytes induced by an inflammatory cascade in the dermis involving dendritic cells, macrophages, and T cells (three subtypes of white blood cells). These immune cells move from the dermis to the epidermis and secrete inflammatory chemical signals (cytokines) such as interleukin-36γ, tumor necrosis factor-α, interleukin-1β, interleukin-6, and interleukin-22.  These secreted inflammatory signals are believed to stimulate keratinocytes to proliferate. One hypothesis is that psoriasis involves a defect in regulatory T cells, and in the regulatory cytokine interleukin-10. The inflammatory cytokines found in psoriatic nails and joints (in the case of psoriatic arthritis) are similar to those of psoriatic skin lesions, suggesting a common inflammatory mechanism.Gene mutations of proteins involved in the skins ability to function as a barrier have been identified as markers of susceptibility for the development of psoriasis.Deoxyribonucleic acid (DNA) released from dying cells acts as an inflammatory stimulus in psoriasis and stimulates the receptors on certain dendritic cells, which in turn produce the cytokine interferon-α.  In response to these chemical messages from dendritic cells and T cells, keratinocytes also secrete cytokines such as interleukin-1, interleukin-6, and tumor necrosis factor-α, which signal downstream inflammatory cells to arrive and stimulate additional inflammation.Dendritic cells bridge the innate immune system and adaptive immune system. They are increased in psoriatic lesions and induce the proliferation of T cells and type 1 helper T cells (Th1). Targeted immunotherapy, as well as psoralen and ultraviolet A (PUVA) therapy, can reduce the number of dendritic cells and favors a Th2 cell cytokine secretion pattern over a Th1/Th17 cell cytokine profile. Psoriatic T cells move from the dermis into the epidermis and secrete interferon-γ and interleukin-17. Interleukin-23 is known to induce the production of interleukin-17 and interleukin-22. Interleukin-22 works in combination with interleukin-17 to induce keratinocytes to secrete neutrophil-attracting cytokines.

Diagnosis
A diagnosis of psoriasis is usually based on the appearance of the skin. Skin characteristics typical for psoriasis are scaly, erythematous plaques, papules, or patches of skin that may be painful and itch. No special blood tests or diagnostic procedures are usually required to make the diagnosis.The differential diagnosis of psoriasis includes dermatological conditions similar in appearance such as discoid eczema, seborrheic eczema, pityriasis rosea (may be confused with guttate psoriasis), nail fungus (may be confused with nail psoriasis) or cutaneous T cell lymphoma (50% of individuals with this cancer are initially misdiagnosed with psoriasis). Dermatologic manifestations of systemic illnesses such as the rash of secondary syphilis may also be confused with psoriasis.If the clinical diagnosis is uncertain, a skin biopsy or scraping may be performed to rule out other disorders and to confirm the diagnosis. Skin from a biopsy shows clubbed epidermal projections that interdigitate with dermis on microscopy. Epidermal thickening is another characteristic histologic finding of psoriasis lesions. The stratum granulosum layer of the epidermis is often missing or significantly decreased in psoriatic lesions; the skin cells from the most superficial layer of skin are also abnormal as they never fully mature. Unlike their mature counterparts, these superficial cells keep their nuclei. Inflammatory infiltrates can typically be seen on microscopy when examining skin tissue or joint tissue affected by psoriasis. Epidermal skin tissue affected by psoriatic inflammation often has many CD8+ T cells, while a predominance of CD4+ T cells makes up the inflammatory infiltrates of the dermal layer of skin and the joints.

Classification
Morphological
Psoriasis is classified as a papulosquamous disorder and is most commonly subdivided into different categories based on histological characteristics. Variants include plaque, pustular, guttate, and flexural psoriasis. Each form has a dedicated ICD-10 code. Psoriasis can also be classified into nonpustular and pustular types.

Pathogenetic
Another classification scheme considers genetic and demographic factors. Type 1 has a positive family history, starts before the age of 40, and is associated with the human leukocyte antigen, HLA-Cw6. Conversely, type 2 does not show a family history, presents after age 40, and is not associated with HLA-Cw6. Type 1 accounts for about 75% of persons with psoriasis.The classification of psoriasis as an autoimmune disease has sparked considerable debate. Researchers have proposed differing descriptions of psoriasis and psoriatic arthritis; some authors have classified them as autoimmune diseases while others have classified them as distinct from autoimmune diseases and referred to them as immune-mediated inflammatory diseases.

Severity
No consensus exists about how to classify the severity of psoriasis. Mild psoriasis has been defined as a percentage of body surface area (BSA)≤10, a Psoriasis Area and Severity Index (PASI) score ≤10, and a Dermatology Life Quality Index (DLQI)  score ≤10. Moderate to severe psoriasis was defined by the same group as BSA >10 or PASI score >10 and a DLQI score >10.The DLQI is a 10-question tool used to measure the impact of several dermatologic diseases on daily functioning. The DLQI score ranges from 0 (minimal impairment) to 30 (maximal impairment) and is calculated with each answer being assigned 0–3 points with higher scores indicating greater social or occupational impairment.The PASI is the most widely used measurement tool for psoriasis. It assesses the severity of lesions and the area affected and combines these two factors into a single score from 0 (no disease) to 72 (maximal disease). Nevertheless, the PASI can be too unwieldy to use outside of research settings, which has led to attempts to simplify the index for clinical use.

Management
While no cure is available for psoriasis, many treatment options exist. Topical agents are typically used for mild disease, phototherapy for moderate disease, and systemic agents for severe disease. There is no evidence to support the effectiveness of conventional topical and systemic drugs, biological therapy, or phototherapy for acute guttate psoriasis or an acute guttate flare of chronic psoriasis.

Topical agents
Topical corticosteroid preparations are the most effective agents when used continuously for eight weeks; retinoids and coal tar were found to be of limited benefit and may be no better than placebo. Greater benefit has been observed with very potent corticosteroids when compared to potent corticosteroids.
Vitamin D analogues such as paricalcitol are superior to placebo. Combination therapy with vitamin D and a corticosteroid are superior to either treatment alone and vitamin D is superior to coal tar for chronic plaque psoriasis.For psoriasis of the scalp, a 2016 review found dual therapy (vitamin D analogues and topical corticosteroids) or corticosteroid monotherapy to be more effective and safer than topical vitamin D analogues alone. Due to their similar safety profiles and minimal benefit of dual therapy over monotherapy, corticosteroid monotherapy appears to be an acceptable treatment for short-term treatment.Moisturizers and emollients such as mineral oil, petroleum jelly, calcipotriol, and decubal (an oil-in-water emollient) were found to increase the clearance of psoriatic plaques. Some emollients have been shown to be even more effective at clearing psoriatic plaques when combined with phototherapy. Certain emollients, though, have no impact on psoriasis plaque clearance or may even decrease the clearance achieved with phototherapy, e.g. the emollient salicylic acid is structurally similar to para-aminobenzoic acid, commonly found in sunscreen, and is known to interfere with phototherapy in psoriasis. Coconut oil, when used as an emollient in psoriasis, has been found to decrease plaque clearance with phototherapy.  Medicated creams and ointments applied directly to psoriatic plaques can help reduce inflammation, remove built-up scale, reduce skin turnover, and clear affected skin of plaques. Ointment and creams containing coal tar, dithranol, corticosteroids (i.e. desoximetasone), fluocinonide, vitamin D3 analogues (for example, calcipotriol), and retinoids are routinely used. (The use of the finger tip unit may be helpful in guiding how much topical treatment to use.)Vitamin D analogues may be useful with steroids; steroids alone have a higher rate of side effects. Vitamin D analogues may allow less steroids to be used.Another topical therapy used to treat psoriasis is a form of balneotherapy, which involves daily baths in the Dead Sea. This is usually done for four weeks with the benefit attributed to sun exposure and specifically UVB light. This is cost-effective and it has been propagated as an effective way to treat psoriasis without medication. Decreases of PASI scores greater than 75% and remission for several months have commonly been observed. Side effects may be mild such as itchiness, folliculitis, sunburn, poikiloderma, and a theoretical risk of nonmelanoma cancer or melanoma has been suggested. Some studies indicate no increased risk of melanoma in the long term. Data are inconclusive with respect to nonmelanoma skin cancer risk, but support the idea that the therapy is associated with an increased risk of benign forms of sun-induced skin damage such as, but not limited to, actinic elastosis or liver spots. Dead Sea balneotherapy is also effective for psoriatic arthritis. Tentative evidence indicates that balneophototherapy, a combination of salt bathes and exposure to ultraviolet B-light (UVB), in chronic plaque psoriasis is better than UVB alone.

UV phototherapy
Phototherapy in the form of sunlight has long been used for psoriasis. UVB wavelengths of 311–313 nanometers are most effective, and special lamps have been developed for this application. The exposure time should be controlled to avoid overexposure and burning of the skin. The UVB lamps should have a timer that turns off the lamp when the time ends. The amount of light used is determined by a persons skin type. Increased rates of cancer from treatment appear to be small. Narrowband UVB therapy has been demonstrated to have similar efficacy to psoralen and ultraviolet A phototherapy (PUVA). A 2013 meta-analysis found no difference in efficacy between NB-UVB and PUVA in the treatment of psoriasis, but NB-UVB is usually more convenient.One of the problems with clinical phototherapy is the difficulty many people have gaining access to a facility. Indoor tanning resources are almost ubiquitous today and could be considered as a means for people to get UV exposure when dermatologist-provided phototherapy is not available. Indoor tanning is already used by many people as a treatment for psoriasis; one indoor facility reported that 50% of its clients were using the center for psoriasis treatment; another reported 36% were doing the same thing. However, a concern with the use of commercial tanning is that tanning beds that primarily emit UVA might not effectively treat psoriasis. One study found that plaque psoriasis is responsive to erythemogenic doses of either UVA or UVB, as exposure to either can cause dissipation of psoriatic plaques. It does require more energy to reach erythemogenic dosing with UVA.UV light therapies all have risks; tanning beds are no exception, being listed by the World Health Organization as carcinogens. Exposure to UV light is known to increase the risks of melanoma and squamous cell and basal cell carcinomas; younger people with psoriasis, particularly those under age 35, are at increased risk from melanoma from UV light treatment. A review of studies recommends that people who are susceptible to skin cancers exercise caution when using UV light therapy as a treatment.A major mechanism of NB-UVB is the induction of DNA damage in the form of pyrimidine dimers. This type of phototherapy is useful in the treatment of psoriasis because the formation of these dimers interferes with the cell cycle and stops it. The interruption of the cell cycle induced by NB-UVB opposes the characteristic rapid division of skin cells seen in psoriasis. The activity of many types of immune cells found in the skin is also effectively suppressed by NB-UVB phototherapy treatments. The most common short-term side effect of this form of phototherapy is redness of the skin; less common side effects of NB-UVB phototherapy are itching and blistering of the treated skin, irritation of the eyes in the form of conjunctival inflammation or inflammation of the cornea, or cold sores due to reactivation of the herpes simplex virus in the skin surrounding the lips. Eye protection is usually given during phototherapy treatments.PUVA combines the oral or topical administration of psoralen with exposure to ultraviolet A (UVA) light. The mechanism of action of PUVA is unknown, but probably involves activation of psoralen by UVA light, which inhibits the abnormally rapid production of the cells in psoriatic skin.  There are multiple mechanisms of action associated with PUVA, including effects on the skins immune system. PUVA is associated with nausea, headache, fatigue, burning, and itching. Long-term treatment is associated with squamous cell carcinoma (but not with melanoma).  A combination therapy for moderate to severe psoriasis using PUVA plus acitretin resulted in benefit, but acitretin use has been associated with birth defects and liver damage.

Systemic agents
Psoriasis resistant to topical treatment and phototherapy may be treated with systemic therapies including medications by mouth or injectable treatments. People undergoing systemic treatment must have regular blood and liver function tests to check for medication toxicities. Pregnancy must be avoided for most of these treatments. The majority of people experience a recurrence of psoriasis after systemic treatment is discontinued.
Non-biologic systemic treatments frequently used for psoriasis include methotrexate, ciclosporin, hydroxycarbamide, fumarates such as dimethyl fumarate, and retinoids. Methotrexate and ciclosporin are medications that suppress the immune system; retinoids are synthetic forms of vitamin A. These agents are also regarded as first-line treatments for psoriatic erythroderma. Oral corticosteroids should not be used, for they can severely flare psoriasis upon their discontinuation.Biologics are manufactured proteins that interrupt the immune process involved in psoriasis. Unlike generalized immunosuppressive medical therapies such as methotrexate, biologics target specific aspects of the immune system contributing to psoriasis. These medications are generally well-tolerated, and limited long-term outcome data have demonstrated biologics to be safe for long-term use in moderate to severe plaque psoriasis. However, due to their immunosuppressive actions, biologics have been associated with a small increase in the risk for infection.Guidelines regard biologics as third-line treatment for plaque psoriasis following inadequate response to topical treatment, phototherapy, and non-biologic systemic treatments. The safety of biologics during pregnancy has not been assessed. European guidelines recommend avoiding biologics if a pregnancy is planned; anti-TNF therapies such as infliximab are not recommended for use in chronic carriers of the hepatitis B virus or individuals infected with HIV.Several monoclonal antibodies target cytokines, the molecules that cells use to send inflammatory signals to each other. TNF-α is one of the main executor inflammatory cytokines.  Four monoclonal antibodies (MAbs) (infliximab, adalimumab, golimumab, and certolizumab pegol) and one recombinant TNF-α decoy receptor, etanercept, have been developed to inhibit TNF-α signaling.  Additional monoclonal antibodies, such as ixekizumab, have been developed against pro-inflammatory cytokines and inhibit the inflammatory pathway at a different point than the anti-TNF-α antibodies.  IL-12 and IL-23 share a common domain, p40, which is the target of the FDA-approved ustekinumab. In 2017 the US FDA approved guselkumab for plaque psoriasis. There have been few studies of the efficacy of anti-TNF medications for psoriasis in children. One randomized control study suggested that 12 weeks of etanercept treatment reduced the extent of psoriasis in children with no lasting adverse effects.Two medications that target T cells are efalizumab and alefacept. Efalizumab is a monoclonal antibody that specifically targets the CD11a subunit of LFA-1. It also blocks the adhesion molecules on the endothelial cells that line blood vessels, which attract T cells. Efalizumab was voluntarily withdrawn from the European market in February 2009, and from the U.S. market in June 2009, by the manufacturer due to the medications association with cases of progressive multifocal leukoencephalopathy. Alefacept also blocks the molecules that dendritic cells use to communicate with T cells and even causes natural killer cells to kill T cells as a way of controlling inflammation. Apremilast may also be used.Individuals with psoriasis may develop neutralizing antibodies against monoclonal antibodies. Neutralization occurs when an antidrug antibody prevents a monoclonal antibody such as infliximab from binding antigen in a laboratory test. Specifically, neutralization occurs when the anti-drug antibody binds to infliximabs antigen binding site instead of TNF-α. When infliximab no longer binds tumor necrosis factor alpha, it no longer decreases inflammation, and psoriasis may worsen. Neutralizing antibodies have not been reported against etanercept, a biologic medication that is a fusion protein composed of two TNF-α receptors. The lack of neutralizing antibodies against etanercept is probably secondary to the innate presence of the TNF-α receptor, and the development of immune tolerance.A 2021 meta-analysis found that ixekizumab, secukinumab, brodalumab, guselkumab, certolizumab, and ustekinumab were the most effective biologics for treating psoriasis. In general, anti-IL17, anti-IL12/23, anti-IL23, and anti-TNF alpha biologics were found to be more effective than traditional systemic treatments. The immunologic pathways of psoriasis involve Th9, Th17, Th1 lymphocytes, and IL-22. The aforementioned biologic agents hinder different aspects of these pathways.Another treatment for moderate to severe psoriasis is fumaric acid esters (FAE) which may be similar in effectiveness to methotrexate.It has been theorized that antistreptococcal medications may improve guttate and chronic plaque psoriasis; however, the limited studies do not show that antibiotics are effective.

Surgery
Limited evidence suggests removal of the tonsils may benefit people with chronic plaque psoriasis, guttate psoriasis, and palmoplantar pustulosis.

Diet
Uncontrolled studies have suggested that individuals with psoriasis or psoriatic arthritis may benefit from a diet supplemented with fish oil rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). A low-calorie diet appears to reduce the severity of psoriasis. Diet recommendations include consumption of cold water fish (preferably wild fish, not farmed) such as salmon, herring, and mackerel; extra virgin olive oil; legumes; vegetables; fruits; and whole grains; and avoid consumption of alcohol, red meat, and dairy products (due to their saturated fat). The effect of consumption of caffeine (including coffee, black tea, mate, and dark chocolate) remains to be determined.Many patients report improvements after consuming less tobacco, caffeine, sugar, nightshades (tomatoes, eggplant, peppers, paprika and white potatoes) and taking probiotics and oral Vitamin D.There is a higher rate of celiac disease among people with psoriasis. When adopting a gluten-free diet, disease severity generally decreases in people with celiac disease and those with anti-gliadin antibodies.

Prognosis
Most people with psoriasis experience nothing more than mild skin lesions that can be treated effectively with topical therapies.Psoriasis is known to hurt the quality of life of both the affected person and the individuals family members. Depending on the severity and location of outbreaks, individuals may experience significant physical discomfort and some disability. Itching and pain can interfere with basic functions, such as self-care and sleep. Participation in sporting activities, certain occupations, and caring for family members can become difficult activities for those with plaques located on their hands and feet. Plaques on the scalp can be particularly embarrassing, as flaky plaque in the hair can be mistaken for dandruff.Individuals with psoriasis may feel self-conscious about their appearance and have a poor self-image that stems from fear of public rejection and psychosexual concerns. Psoriasis has been associated with low self-esteem and depression is more common among those with the condition. People with psoriasis often feel prejudiced against due to the commonly held incorrect belief that psoriasis is contagious. Psychological distress can lead to significant depression and social isolation; a high rate of thoughts about suicide has been associated with psoriasis. Many tools exist to measure the quality of life of people with psoriasis and other dermatological disorders. Clinical research has indicated individuals often experience a diminished quality of life. Children with psoriasis may encounter bullying.Several conditions are associated with psoriasis. These occur more frequently in older people. Nearly half of individuals with psoriasis over the age of 65 have at least three comorbidities (concurrent conditions), and two-thirds have at least two comorbidities.

Cardiovascular disease
Psoriasis has been associated with obesity and several other cardiovascular and metabolic disturbances. The number of new cases per year of diabetes is 27% higher in people affected by psoriasis than in those without the condition. Severe psoriasis may be even more strongly associated with the development of diabetes than mild psoriasis. Younger people with psoriasis may also be at increased risk for developing diabetes. Individuals with psoriasis or psoriatic arthritis have a slightly higher risk of heart disease and heart attacks when compared to the general population. Cardiovascular disease risk appeared to be correlated with the severity of psoriasis and its duration. There is no strong evidence to suggest that psoriasis is associated with an increased risk of death from cardiovascular events. Methotrexate may provide a degree of protection for the heart.The odds of having hypertension are 1.58 times ( i.e. 58%) higher in people with psoriasis than those without the condition; these odds are even higher with severe cases of psoriasis. A similar association was noted in people who have psoriatic arthritis—the odds of having hypertension were found to be 2.07 times ( i.e. 107%) greater when compared to odds of the general population. The link between psoriasis and hypertension is not currently understood. Mechanisms hypothesized to be involved in this relationship include the following: dysregulation of the renin–angiotensin system, elevated levels of endothelin 1 in the blood, and increased oxidative stress. The number of new cases of the heart rhythm abnormality atrial fibrillation is 1.31 times ( i.e. 31%) higher in people with mild psoriasis and 1.63 times ( i.e. 63%) higher in people with severe psoriasis.  There may be a slightly increased risk of stroke associated with psoriasis, especially in severe cases. Treating high levels of cholesterol with statins has been associated with decreased psoriasis severity, as measured by PASI score, and has also been associated with improvements in other cardiovascular disease risk factors such as markers of inflammation. These cardioprotective effects are attributed to ability of statins to improve blood lipid profile and because of their anti-inflammatory effects. Statin use in those with psoriasis and hyperlipidemia was associated with decreased levels of high-sensitivity C-reactive protein and TNFα as well as decreased activity of the immune protein LFA-1. Compared to individuals without psoriasis, those affected by psoriasis are more likely to satisfy the criteria for metabolic syndrome.

Other diseases
The rates of Crohn disease and ulcerative colitis are increased when compared with the general population, by a factor of 3.8 and 7.5 respectively. People with psoriasis also have a higher risk of celiac disease. Few studies have evaluated the association of multiple sclerosis with psoriasis, and the relationship has been questioned. Psoriasis has been associated with a 16% increase in overall relative risk for non-skin cancer, thought to be attributed to systemic therapy, particularly methotrexate. People treated with long term systemic therapy for psoriasis have a 52% increased risk cancers of the lung and bronchus, a 205% increase in the risk of developing cancers of the upper gastrointestinal tract, a 31% increase in the risk of developing cancers of the urinary tract, a 90% increase in the risk of developing liver cancer, and a 46% increase in the risk of developing pancreatic cancer. The risk for development of non-melanoma skin cancers is also increased. Psoriasis increases the risk of developing squamous cell carcinoma of the skin by 431% and increases the risk of basal cell carcinoma by 100%. There is no increased risk of melanoma associated with psoriasis. People with psoriasis have a higher risk of developing cancer.

Epidemiology
Psoriasis is estimated to affect 2–4% of the population of the western world. The rate of psoriasis varies according to age, region and ethnicity; a combination of environmental and genetic factors is thought to be responsible for these differences. It can occur at any age, although it most commonly appears for the first time between the ages of 15 and 25 years. Approximately one third of people with psoriasis report being diagnosed before age 20. Psoriasis affects both sexes equally.Psoriasis affects about 6.7 million Americans and occurs more frequently in adults.Psoriasis is about five times more common in people of European descent than in people of Asian descent.People with inflammatory bowel disease such as Crohn disease or ulcerative colitis are at an increased risk of developing psoriasis. Psoriasis is more common in countries farther from the equator. Persons of white European ancestry are more likely to have psoriasis and the condition is relatively uncommon in African Americans and extremely uncommon in Native Americans.

History
Scholars believe psoriasis to have been included among the various skin conditions called tzaraath (translated as leprosy) in the Hebrew Bible, a condition imposed as a punishment for slander. The person was deemed "impure" (see tumah and taharah) during their affected phase and is ultimately treated by the kohen. However, it is more likely that this confusion arose from the use of the same Greek term for both conditions. The Greeks used the term lepra (λεπρα) for scaly skin conditions. They used the term psora to describe itchy skin conditions. It became known as Willans lepra in the late 18th century when English dermatologists Robert Willan and Thomas Bateman differentiated it from other skin diseases. Leprosy, they said, is distinguished by the regular, circular form of patches, while psoriasis is always irregular. Willan identified two categories: leprosa graecorum and psora leprosa.Psoriasis is thought to have first been described in Ancient Rome by Cornelius Celsus. The British dermatologist Thomas Bateman described a possible link between psoriasis and arthritic symptoms in 1813.The history of psoriasis is littered with treatments of dubious effectiveness and high toxicity. In the 18th and 19th centuries, Fowlers solution, which contains a poisonous and carcinogenic arsenic compound, was used by dermatologists as a treatment for psoriasis. Mercury was also used for psoriasis treatment during this time period. Sulfur, iodine, and phenol were also commonly used treatments for psoriasis during this era when it was incorrectly believed that psoriasis was an infectious disease. Coal tars were widely used with ultraviolet light irradiation as a topical treatment approach in the early 1900s. During the same time period, psoriatic arthritis cases were treated with intravenously administered gold preparations in the same manner as rheumatoid arthritis.

Society and culture
The International Federation of Psoriasis Associations (IFPA) is the global umbrella organization for national and regional psoriasis associations and also gathers the leading experts in psoriasis and psoriatic arthritis research for scientific conferences every three years. The Psoriasis International Network, a program of the Fondation René Touraine, gathers dermatologists, rheumatologists and other caregivers involved in the management of psoriasis. Non-profit organizations like the National Psoriasis Foundation in the United States, the Psoriasis Association in the United Kingdom, and Psoriasis Australia offer advocacy and education about psoriasis in their respective countries.

Cost
The annual cost for treating psoriasis in the United States is estimated as high as $32.5 billion, including $12.2 billion in direct costs. Pharmacy costs are the main source of direct expense, with biologic therapy the most prevalent. These costs increase significantly when co-morbid conditions such as heart disease, hypertension, diabetes, lung disease and psychiatric disorders are factored in </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 Infantile cerebral and cerebellar atrophy with postnatal progressive microcephaly and explain in detail? [/INST]  </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 Guillain–Barré syndrome and explain in detail? [/INST] Guillain–Barré syndrome (GBS) is a rapid-onset muscle weakness caused by the immune system damaging the peripheral nervous system. Typically, both sides of the body are involved, and the initial symptoms are changes in sensation or pain often in the back along with muscle weakness, beginning in the feet and hands, often spreading to the arms and upper body. The symptoms may develop over hours to a few weeks. During the acute phase, the disorder can be life-threatening, with about 15% of people developing weakness of the breathing muscles and, therefore, requiring mechanical ventilation. Some are affected by changes in the function of the autonomic nervous system, which can lead to dangerous abnormalities in heart rate and blood pressure.Although the cause is unknown, the underlying mechanism involves an autoimmune disorder in which the bodys immune system mistakenly attacks the peripheral nerves and damages their myelin insulation. Sometimes this immune dysfunction is triggered by an infection or, less commonly, by surgery, and rarely, by vaccination. The diagnosis is usually based on the signs and symptoms through the exclusion of alternative causes and supported by tests such as nerve conduction studies and examination of the cerebrospinal fluid. There are a number of subtypes based on the areas of weakness, results of nerve conduction studies, and the presence of certain antibodies. It is classified as an acute polyneuropathy.In those with severe weakness, prompt treatment with intravenous immunoglobulins or plasmapheresis, together with supportive care, will lead to good recovery in the majority of cases. Recovery may take weeks to years, with about a third having some permanent weakness. Globally, death occurs in approximately 7.5% of those affected. Guillain–Barré syndrome is rare, at 1 or 2 cases per 100,000 people every year. Both sexes and all parts of the world have similar rates of disease.The syndrome is named after the French neurologists Georges Guillain and Jean Alexandre Barré, who, together with French physician André Strohl, described the condition in 1916.

Signs and symptoms
The first symptoms of Guillain–Barré syndrome are numbness, tingling, and pain, alone or in combination. This is followed by weakness of the legs and arms that affects both sides equally and worsens over time. The weakness can take half a day to over two weeks to reach maximum severity, and then becomes steady. In one in five people, the weakness continues to progress for as long as four weeks. The muscles of the neck may also be affected, and about half experience involvement of the cranial nerves that supply the head and face; this may lead to weakness of the muscles of the face, swallowing difficulties and sometimes weakness of the eye muscles. In 8%, the weakness affects only the legs (paraplegia or paraparesis). Involvement of the muscles that control the bladder and anus is unusual. In total, about a third of people with Guillain–Barré syndrome continue to be able to walk. Once the weakness has stopped progressing, it persists at a stable level ("plateau phase") before improvement occurs. The plateau phase can take between two days and six months, but the most common duration is a week. Pain-related symptoms affect more than half, and include back pain, painful tingling, muscle pain, and pain in the head and neck relating to irritation of the lining of the brain.Many people with Guillain–Barré syndrome have experienced the signs and symptoms of an infection in the 3–6 weeks before the onset of the neurological symptoms. This may consist of upper respiratory tract infection (rhinitis, sore throat), or diarrhea.

In children, particularly those younger than six years old, the diagnosis can be difficult and the condition is often initially mistaken (sometimes for up to two weeks) for other causes of pains and difficulty walking, such as viral infections, or bone and joint problems.On neurological examination, characteristic features are the reduced strength of muscles and reduced or absent tendon reflexes (hypo- or areflexia, respectively). However, a small proportion have normal reflexes in affected limbs before developing areflexia, and some may have exaggerated reflexes. In the Miller Fisher variant of Guillain–Barré syndrome (see below), a triad of weakness of the eye muscles, abnormalities in coordination, as well as absent reflexes can be found. The level of consciousness is normally unaffected in Guillain–Barré syndrome, but the Bickerstaff brainstem encephalitis subtype may feature drowsiness, sleepiness, or coma.

Respiratory failure
A quarter of all people with Guillain–Barré syndrome develop weakness of the breathing muscles leading to respiratory failure, the inability to breathe adequately to maintain healthy levels of oxygen, and/or carbon dioxide in the blood. This life-threatening scenario is complicated by other medical problems such as pneumonia, severe infections, blood clots in the lungs, and bleeding in the digestive tract in 60% of those who require artificial ventilation.

Autonomic dysfunction
The autonomic or involuntary nervous system, which is involved in the control of body functions such as heart rate and blood pressure, is affected in two-thirds of people with Guillain–Barré syndrome, but the impact is variable. Twenty percent may experience severe blood-pressure fluctuations and irregularities in the heart beat, sometimes to the point that the heart beat stops and requires pacemaker-based treatment. Other associated problems are abnormalities in perspiration and changes in the reactivity of the pupils. Autonomic nervous system involvement can affect even those who do not have severe muscle weakness.

Causes
Infection onset
Two-thirds of people with Guillain–Barré syndrome have experienced an infection before the onset of the condition. Most commonly, these are episodes of gastroenteritis or a respiratory tract infection. In many cases, the exact nature of the infection can be confirmed. Approximately 30% of cases are provoked by Campylobacter jejuni bacteria, which cause diarrhea. A further 10% are attributable to cytomegalovirus (CMV, HHV-5). Despite this, only very few people with Campylobacter or CMV infections develop Guillain–Barré syndrome (0.25–0.65 per 1000 and 0.6–2.2 per 1000 episodes, respectively). The strain of Campylobacter involved may determine the risk of GBS; different forms of the bacteria have different lipopolysaccharides on their surface, and some may induce illness (see below) while others will not.Links between other infections and GBS are less certain. Two other herpes viruses (Epstein–Barr virus/HHV-4 and varicella zoster virus/HHV-3) and the bacterium Mycoplasma pneumoniae have been associated with GBS. GBS is known to occur after influenza, and influenza vaccination has been demonstrated to be associated with a reduced risk. The tropical flaviviral infections dengue fever and Zika virus have also been associated with episodes of GBS. Previous hepatitis E virus infection has been found to be more common in people with GBS.

Vaccine onset
An increased incidence of Guillain–Barré syndrome followed influenza immunization that followed the 1976 swine flu outbreak (H1N1 A/NJ/76); 8.8 cases per million (0.0088 per 1000) recipients developed it as a complication. GBS cases occurred in 362 patients during the 6 weeks after influenza vaccination of 45 million persons, an 8.8-fold increase over normal rates. The 1976 swine flu vaccination-induced GBS was an outlier; small increases in incidence have been observed in subsequent vaccination campaigns, but not to the same extent. The 2009 flu pandemic vaccine against pandemic swine flu virus H1N1/PDM09 did not cause a significant increase in cases. In fact, "studies found a small increase of approximately 1 case per million vaccines above the baseline rate, which is similar to that observed after administration of seasonal influenza vaccines over the past several years." The benefits to the population as a whole of vaccination in preventing influenza outweigh the small risks to individuals of that group of GBS after vaccination. Natural influenza infection is a stronger risk factor for the development of GBS than is influenza vaccination and the vaccination reduced the risk of GBS overall by lowering the risk of catching influenza.In the United States, GBS after seasonal influenza vaccination is listed on the federal governments vaccine injury table. On March 24, 2021, after reviewing several post-marketing observational studies, where an increased risk of Guillain–Barré syndrome was observed after 42 days following vaccination with the Zoster vaccine Shingrix, the FDA required safety label changes from the manufacturer GlaxoSmithKline to include warnings for risk of Guillain–Barré syndrome.

COVID-19 infection or vaccine related
GBS has been reported in association with COVID-19, and may be a potential neurological complication of the disease.
GBS has been reported as a very rare side effect of the Janssen and the Oxford–AstraZeneca COVID-19 vaccine for COVID-19 and European Medicines Agency (EMA) had issued warning to the patients and healthcare providers. The incidence of GBS following the vaccination with the Oxford-AstraZeneca vaccine was originally reported as being lower than the incidence of GBS following a COVID-19 infection. More recent studies, however, found no measurable link between COVID-19 infection and GBS, while correlations with a first dose of AstraZeneca or Janssen vaccines were still positive.COVID-19 has been reported as causing peripheral neuropathy and more recently some evidence of aggravation of autoimmune disorders including GBS. Some studies are now finding Parkinsons Disease is more common in infection survivors.

Drug induced
Zimelidine, an antidepressant, had a very favorable safety profile but as a result of rare case reports of Guillain–Barré syndrome was withdrawn from the market.

Mechanism
The nerve dysfunction in Guillain–Barré syndrome is caused by an immune attack on the nerve cells of the peripheral nervous system and their support structures. The nerve cells have their body (the soma) in the spinal cord and a long projection (the axon) that carries electrical nerve impulses to the neuromuscular junction, where the impulse is transferred to the muscle. Axons are wrapped in a sheath of Schwann cells that contain myelin. Between Schwann cells are gaps (nodes of Ranvier) where the axon is exposed. Different types of Guillain–Barré syndrome feature different types of immune attack. The demyelinating variant (AIDP, see below) features damage to the myelin sheath by white blood cells (T lymphocytes and macrophages); this process is preceded by activation of a group of blood proteins known as complement. In contrast, the axonal variant is mediated by IgG antibodies and complement against the cell membrane covering the axon without direct lymphocyte involvement.Various antibodies directed at nerve cells have been reported in Guillain–Barré syndrome. In the axonal subtype, these antibodies have been shown to bind to gangliosides, a group of substances found in peripheral nerves. A ganglioside is a molecule consisting of ceramide bound to a small group of hexose-type sugars and containing various numbers of N-acetylneuraminic acid groups. The key four gangliosides against which antibodies have been described are GM1, GD1a, GT1a, and GQ1b, with different antiganglioside antibodies being associated with particular features; for instance, GQ1b antibodies have been linked with Miller Fisher variant GBS and related forms including Bickerstaff encephalitis. The production of these antibodies after an infection probably is the result of molecular mimicry, where the immune system is reacting to microbial substances, but the resultant antibodies also react with substances occurring naturally in the body. After a Campylobacter infection, the body produces antibodies of the IgA class; only a small proportion of people also produce IgG antibodies against bacterial substance cell wall substances (e.g. lipooligosaccharides) that cross react with human nerve cell gangliosides. It is not currently known how this process escapes central tolerance to gangliosides, which is meant to suppress the production of antibodies against the bodys own substances. Not all antiganglioside antibodies cause disease, and it has recently been suggested that some antibodies bind to more than one type of epitope simultaneously (heterodimeric binding) and that this determines the response. Furthermore, the development of pathogenic antibodies may depend on the presence of other strains of bacteria in the bowel.It has been suggested that a poor injection technique may also cause a direct injury to the axillary nerves adjacent to the injection site in deltoid muscle that may lead to peripheral neuropathy. The consequent vaccine transfection and translation in the nerves may spur an immune response against nerve cells potentially causing an autoimmune nerve damage, leading to conditions like Guillain–Barré syndrome.

Diagnosis
The diagnosis of Guillain–Barré syndrome depends on findings such as rapid development of muscle paralysis, absent reflexes, absence of fever, and absence of a likely cause. Cerebrospinal fluid analysis (through a lumbar spinal puncture) and nerve conduction studies are supportive investigations commonly performed in the diagnosis of GBS. Testing for antiganglioside antibodies is often performed, but their contribution to diagnosis is usually limited. Blood tests are generally performed to exclude the possibility of another cause for weakness, such as a low level of potassium in the blood. An abnormally low level of sodium in the blood is often encountered in Guillain–Barré syndrome. This has been attributed to the inappropriate secretion of antidiuretic hormone, leading to relative retention of water.In many cases, magnetic resonance imaging of the spinal cord is performed to distinguish between Guillain–Barré syndrome and other conditions causing limb weakness, such as spinal cord compression. If an MRI scan shows enhancement of the nerve roots, this may be indicative of GBS. In children, this feature is present in 95% of scans, but it is not specific to Guillain–Barré syndrome, so other confirmation is also needed.

Spinal fluid
Cerebrospinal fluid envelops the brain and the spine, and lumbar puncture or spinal tap is the removal of a small amount of fluid using a needle inserted between the lumbar vertebrae. Characteristic findings in Guillain–Barré syndrome are an elevated protein level, usually greater than 0.55 g/L, and fewer than 10 white blood cells per cubic millimeter of fluid ("albuminocytological dissociation"). This pattern distinguishes Guillain–Barré syndrome from other conditions (such as lymphoma and poliomyelitis) in which both the protein and the cell count are elevated. Elevated CSF protein levels are found in approximately 50% of patients in the first 3 days after onset of weakness, which increases to 80% after the first week.Repeating the lumbar puncture during the disease course is not recommended. The protein levels may rise after treatment has been administered.

Neurophysiology
Directly assessing nerve conduction of electrical impulses can exclude other causes of acute muscle weakness, as well as distinguish the different types of Guillain–Barré syndrome. Needle electromyography (EMG) and nerve conduction studies may be performed. In the first two weeks, these investigations may not show any abnormality. Neurophysiology studies are not required for the diagnosis.Formal criteria exist for each of the main subtypes of Guillain–Barré syndrome (AIDP and AMAN/AMSAN, see below), but these may misclassify some cases (particularly where there is reversible conduction failure) and therefore changes to these criteria have been proposed. Sometimes, repeated testing may be helpful.

Clinical subtypes
A number of subtypes of Guillain–Barré syndrome are recognized. Despite this, many people have overlapping symptoms that can make the classification difficult in individual cases. All types have partial forms. For instance, some people experience only isolated eye-movement or coordination problems; these are thought to be a subtype of Miller Fisher syndrome and have similar antiganglioside antibody patterns.
Other diagnostic entities are often included in the spectrum of Guillain–Barré syndrome. Bickerstaffs brainstem encephalitis (BBE), for instance, is part of the group of conditions now regarded as forms of Miller Fisher syndrome (anti-GQ1b antibody syndrome), as well as a related condition labelled "acute ataxic hypersomnolence" where coordination problems and drowsiness are present but no muscle weakness can be detected. BBE is characterized by the rapid onset of ophthalmoplegia, ataxia, and disturbance of consciousness, and may be associated with absent or decreased tendon reflexes and as well as Babinskis sign. The course of the disease is usually monophasic, but recurrent episodes have been reported. MRI abnormalities in the brainstem have been reported in 11%.Whether isolated acute sensory loss can be regarded as a form of Guillain–Barré syndrome is a matter of dispute; this is a rare occurrence compared to GBS with muscle weakness but no sensory symptoms.

Treatment
Immunotherapy
Plasmapheresis and intravenous immunoglobulins (IVIG) are the two main immunotherapy treatments for GBS. Plasmapheresis attempts to reduce the bodys attack on the nervous system by filtering antibodies out of the bloodstream. Similarly, administration of IVIG neutralizes harmful antibodies and inflammation. These two treatments are equally effective, but a combination of the two is not significantly better than either alone. Plasmapheresis speeds recovery when used within four weeks of the onset of symptoms. IVIG works as well as plasmapheresis when started within two weeks of the onset of symptoms, and has fewer complications. IVIG is usually used first because of its ease of administration and safety; the risks include occasionally causing liver inflammation, or in rare cases, kidney failure. Glucocorticoids alone have not been found to be effective in speeding recovery and could potentially delay recovery.

Respiratory failure
Respiratory failure may require intubation of the trachea and breathing support through mechanical ventilation, generally on an intensive care unit. The need for ventilatory support can be anticipated by measurement of two spirometry-based breathing tests: the forced vital capacity (FVC) and the negative inspiratory force (NIF). An FVC of less than 15 mL per kilogram body weight or an NIF of less than 60 cmH2O are considered markers of severe respiratory failure.

Pain
While pain is common in people with Guillain–Barré syndrome, studies comparing different types of pain medication are insufficient to make a recommendation as to which should be used.

Rehabilitation
Following the acute phase, around 40% of people require intensive rehabilitation with the help of a multidisciplinary team to focus on improving activities of daily living (ADLs). Studies into the subject have been limited, but it is likely that intensive rehabilitation improves long-term symptoms. Teams may include physical therapists, occupational therapists, speech language pathologists, social workers, psychologists, other allied health professionals and nurses. The team usually works under the supervision of a neurologist or rehabilitation physician directing treatment goals.Physiotherapy interventions include strength, endurance, and gait training with graduated increases in mobility, maintenance of posture and alignment as well as joint function. Occupational therapy aims to improve everyday function with domestic and community tasks as well as driving and work. Home modifications, gait aids, orthotics, and splints may be provided. Speech-language pathology input may be required in those with speech and swallowing problems, as well as to support communication in those who require ongoing breathing support (often through a tracheostomy). Nutritional support may be provided by the team and by dietitians. Psychologists may provide counseling and support. Psychological interventions may also be required for anxiety, fear, and depression.

Prognosis
Guillain–Barré syndrome can lead to death as a result of many complications: severe infections, blood clots, and cardiac arrest likely due to autonomic neuropathy. Despite optimum care, this occurs in about 5% of cases.There is a variation in the rate and extent of recovery. The prognosis of Guillain–Barré syndrome is determined mainly by age (those over 40 may have a poorer outcome), and by the severity of symptoms after two weeks. Furthermore, those who experienced diarrhea before the onset of the disease have a worse prognosis. On the nerve conduction study, the presence of conduction block predicts poorer outcome at 6 months. In those who have received intravenous immunoglobulins, a smaller increase in IgG in the blood two weeks after administration is associated with poorer mobility outcomes at six months than those whose IgG level increased substantially. If the disease continues to progress beyond four weeks, or there are multiple fluctuations in the severity (more than two in eight weeks), the diagnosis may be chronic inflammatory demyelinating polyneuropathy, which is treated differently.In research studies, the outcome from an episode of Guillain–Barré syndrome is recorded on a scale from 0 to 6, where 0 denotes completely healthy; 1 very minor symptoms but able to run; 2 able to walk but not to run; 3 requiring a stick or other support; 4 confined to bed or chair; 5 requiring long-term respiratory support; 6 death.The health-related quality of life (HRQL) after an attack of Guillain–Barré syndrome can be significantly impaired. About a fifth are unable to walk unaided after six months, and many experience chronic pain, fatigue and difficulty with work, education, hobbies and social activities. HRQL improves significantly in the first year.

Epidemiology
In Western countries, the number of new episodes per year has been estimated to be between 0.89 and 1.89 cases per 100,000 people. Children and young adults are less likely to be affected than the elderly: the relative risk increases by 20% for every decade of life. Men are more likely to develop Guillain–Barré syndrome than women; the relative risk for men is 1.78 compared to women.The distribution of subtypes varies between countries. In Europe and the United States, 60–80% of people with Guillain–Barré syndrome have the demyelinating subtype (AIDP), and AMAN affects only a small number (6–7%). In Asia and Central and South America, that proportion is significantly higher (30–65%). This may be related to the exposure to different kinds of infection, but also the genetic characteristics of that population. Miller Fisher variant is thought to be more common in Southeast Asia.

History
Jean-Baptiste Octave Landry first described the disorder in 1859. In 1916, Georges Guillain, Jean Alexandre Barré, and André Strohl diagnosed two soldiers with the illness and described the key diagnostic abnormality—albuminocytological dissociation—of increased spinal fluid protein concentration but a normal cell count.C. Miller Fisher described the variant that bears his name in 1956. British neurologist Edwin Bickerstaff described the encephalitis type in 1951 and made further contributions with another paper in 1957. Guillain had reported on some of these features before their full description in 1938. Further subtypes have been described since then, such as the form featuring pure ataxia and the type causing pharyngeal-cervical-brachial weakness. The axonal subtype was first described in 1986.Diagnostic criteria were developed in the late 1970s after the series of cases associated with swine flu vaccination. These were refined in 1990. The case definition was revised by the Brighton Collaboration for vaccine safety in 2009, but is mainly intended for research. Plasma exchange was first used in 1978, and its benefit was confirmed in larger studies in 1985 </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 Phacodonesis and explain in detail? [/INST]  </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 Trisomy 22 and explain in detail? [/INST] Trisomy 22 is a chromosomal disorder in which  three copies of chromosome 22 are present rather than two. It is a frequent cause of spontaneous abortion during the first trimester of pregnancy. Progression to the second trimester and live birth are rare. This disorder is found in individuals with an extra copy or a variation of chromosome 22 in some or all cells of their bodies.

Associated disorders
Many kinds of disorders are associated with trisomy 22:

Emanuel syndrome is named after the genetic contributions made by researcher Dr. Beverly Emanuel. This condition is assigned to individuals born with an unbalanced 11/22 translocation. That is, a fragment of chromosome 11 is moved, or translocated, to chromosome 22.
22q11 deletion syndrome is a rare condition which occurs in about one in 4000 births. This condition is identified when a band in the q11.2 section of the arm of chromosome 22 is missing or deleted. This condition has several different names: 22q11.2 deletion syndrome, velocardiofacial syndrome, DiGeorge syndrome, conotruncal anomaly face syndrome, Opitz G/BBB syndrome, and Cayler cardiofacial syndrome. The effects of this disorder are different in each individual, but similarities exist, such as heart defects, immune system problems, a distinctive facial appearance, learning challenges, cleft palate, hearing loss, kidney problems, hypocalcemia, and sometimes psychiatric issues.
22q11 microduplication syndrome is the opposite of the 22q11 deletion syndrome; in this condition, a band of q.11.2 section of chromosome 22 is duplicated. Individuals carrying this deficiency are relatively "normal", as in they do not possess any major birth defects or major medical illnesses. This microduplication is more common than the deletion; this might relate to the milder phenotype of the individuals.
22q13 deletion syndrome (Phelan–McDermid syndrome) is a condition caused by the deletion of the tip of the q arm on chromosome 22. Most individuals with this disorder experience cognitive delays, low muscle tone, and sleeping, eating, and behavioural issues.
Chromosome ring 22 is a rare disorder caused by the break and rejoining of both ends of chromosome 22, forming a ring. The effects on the individual with this disorder are dependent on the amount of genetic information lost during the process. Major characteristics for this disorder are intellectual disability, muscle weakness, and lack of coordination.
Cat eye syndrome (Schmid Fraccaro syndrome) is a condition caused by a partial trisomy or tetrasomy in chromosome 22. A small extra chromosome is found, made up of the top half of chromosome 22 and a portion of the q arm at the q11.2 break. This chromosome can be found three or four times. This syndrome is referred as "cat eye" due to the eye appearance of reported affected individuals who have coloboma of the iris, but this feature is only seen in about half of the cases.
Mosaic trisomy 22 is a disorder in which an extra chromosome 22 is found only in some cells of the body. The severity of each case is determined by the number of cells with this extra copy </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 Aortopulmonary window and explain in detail? [/INST]  </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 Carnosinemia and explain in detail? [/INST] Carnosinemia is a rare autosomal recessive metabolic disorder caused by a deficiency of carnosinase, a dipeptidase (a type of enzyme that splits dipeptides into their two amino acid constituents).Carnosine is a dipeptide composed of beta-alanine and histidine, and is found in skeletal muscle and cells of the nervous system. This disorder results in an excess of carnosine in the urine, cerebrospinal fluid, blood, and nervous tissue. Neurological disorders associated with a deficiency of carnosinase, and the resulting carnosinemia ("carnosine in the blood") are common.

Symptoms and signs
A variety of neurological symptoms have been associated with carnosinemia. They include: hypotonia, developmental delay, intellectual disability, degeneration of axons, sensory neuropathy, tremors, demyelinization, gray matter anomalies, myoclonic seizures, and loss of purkinje fibers.

Genetics
The gene for carnosinase is located on chromosome 18, an autosome. The carnosine dipeptidase-1 gene (CNDP1) controls tissue and serum carnosinase. Mutations in CNDP1 are  responsible for carnosinase deficiency, resulting in carnosinemia.Carnosinemia is an autosomal recessive disorder, which means the defective gene is located on an autosome, and two copies of the defective gene - one from each parent - are required to inherit the disorder </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 Tenosynovitis and explain in detail? [/INST] Tenosynovitis is the inflammation of the fluid-filled sheath (called the synovium) that surrounds a tendon, typically leading to joint pain, swelling, and stiffness. Tenosynovitis can be either infectious or noninfectious. Common clinical manifestations of noninfectious tenosynovitis include de Quervain tendinopathy and stenosing tenosynovitis (more commonly known as trigger finger)

Signs and symptoms
Infectious tenosynovitis occurs between 2.5% and 9.4% of all hand infections. Kanavels cardinal signs is used to diagnose infectious tenosynovitis. They are: tenderness to touch along the flexor aspect of the finger, fusiform enlargement of the affected finger, the finger being held in slight flexion at rest, and severe pain with passive extension. Fever may also be present but is uncommon.

Pathogenesis
Infectious tenosynovitis is the infection of closed synovial sheaths in the flexor tendons of the fingers. It is usually caused by trauma, but bacteria can spread from other sites of the body. Although tenosynovitis usually affects the flexor tendon of the fingers, the disease can also affect the extensor tendons occasionally. The clinical presentation is therefore as acute infection following trauma. The infection can be mono- or polymicrobial and can vary depending on the nature of the trauma. The most common pathogenic agent is Staphylococcus aureus introduced from the skin. Other bacteria linked to infectious tenosynovitis include Pasteurella multocida (associated with animal bites), Eikenella spp. (associated with IV drug use), and Mycobacterium marinum (associated with wounds exposed to fresh or salt water). Additionally, sexually active patients are at risk for hematogenous spread due to Neisseria gonorrhoeae (see infectious arthritis).
Common noninfectious tenosynovitis are: stenosing tenosynovitis, intersection syndrome, extensor pollicis longus (EPL) tenosynovitis, de Quervains and fourth compartment tenosynovitis.

Diagnosis
Diagnosis of tenosynovitis is typically made clinically after a thorough patient history and physical exam </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 Chromosome abnormality and explain in detail? [/INST] A chromosomal abnormality, chromosomal anomaly, chromosomal aberration, chromosomal mutation, or chromosomal disorder, is a missing, extra, or irregular portion of chromosomal DNA. These can occur in the form of numerical abnormalities, where there is an atypical number of chromosomes, or as structural abnormalities, where one or more individual chromosomes are altered. Chromosome mutation was formerly used in a strict sense to mean a change in a chromosomal segment, involving more than one gene. Chromosome anomalies usually occur when there is an error in cell division following meiosis or mitosis. Chromosome abnormalities may be detected or confirmed by comparing an individuals karyotype, or full set of chromosomes, to a typical karyotype for the species via genetic testing.

Numerical abnormality
An abnormal number of chromosomes is called aneuploidy, and occurs when an individual is either missing a chromosome from a pair (resulting in monosomy) or has more than two chromosomes of a pair (trisomy, tetrasomy, etc.). Aneuploidy can be full, involving a whole chromosome missing or added, or partial, where only part of a chromosome is missing or added. Aneuploidy can occur with sex chromosomes or autosomes.An example of trisomy in humans is Down syndrome, which is a developmental disorder caused by an extra copy of chromosome 21; the disorder is therefore also called trisomy 21.An example of monosomy in humans is Turner syndrome, where the individual is born with only one sex chromosome, an X.

Sperm aneuploidy
Exposure of males to certain lifestyle, environmental and/or occupational hazards may increase the risk of aneuploid spermatozoa. In particular, risk of aneuploidy is increased by tobacco smoking, and occupational exposure to benzene, insecticides, and perfluorinated compounds. Increased aneuploidy is often associated with increased DNA damage in spermatozoa.

Structural abnormalities
When the chromosomes structure is altered, this can take several forms:
Deletions: A portion of the chromosome is missing or has been deleted. Known disorders in humans include Wolf–Hirschhorn syndrome, which is caused by partial deletion of the short arm of chromosome 4; and Jacobsen syndrome, also called the terminal 11q deletion disorder.
Duplications: A portion of the chromosome has been duplicated, resulting in extra genetic material. Known human disorders include Charcot–Marie–Tooth disease type 1A, which may be caused by duplication of the gene encoding peripheral myelin protein 22 (PMP22) on chromosome 17.
Inversions: A portion of the chromosome has broken off, turned upside down, and reattached, therefore the genetic material is inverted.
Insertions: A portion of one chromosome has been deleted from its normal place and inserted into another chromosome.
Translocations: A portion of one chromosome has been transferred to another chromosome. There are two main types of translocations:
Reciprocal translocation: Segments from two different chromosomes have been exchanged.
Robertsonian translocation: An entire chromosome has attached to another at the centromere - in humans, these only occur with chromosomes 13, 14, 15, 21, and 22.
Rings: A portion of a chromosome has broken off and formed a circle or ring. This can happen with or without the loss of genetic material.
Isochromosome: Formed by the mirror image copy of a chromosome segment including the centromere.Chromosome instability syndromes are a group of disorders characterized by chromosomal instability and breakage. They often lead to an increased tendency to develop certain types of malignancies.

Inheritance
Most chromosome abnormalities occur as an accident in the egg cell or sperm, and therefore the anomaly is present in every cell of the body. Some anomalies, however, can happen after conception, resulting in Mosaicism (where some cells have the anomaly and some do not) </s>