Sarcoidosis

Alternative Names : Sarcoid, Besnier-Boeck disease or Besnier-Boeck-Schaumann disease

Definition:
Sarcoidosis (from sarc meaning flesh, -oid, like, and -osis, process)  is a disease in which abnormal collections of chronic inflammatory cells (granulomas) form as nodules in multiple organs. The cause of sarcoidosis is unknown. Granulomas most often appear in the lungs or the lymph nodes, but virtually any organ can be affected. Normally the onset is gradual. Sarcoidosis may be asymptomatic or chronic. It commonly improves or clears up spontaneously. More than 2/3 of people with lung sarcoidosis have no symptoms after 9 years. About 50% have relapses. About 10% develop serious disability. Lung scarring or infection may lead to respiratory failure and death.

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Sarcoidosis most commonly affects young adults of both sexes, although studies have reported more cases in females. Incidence is highest for individuals younger than 40 and peaks in the age-group from 20 to 29 years; a second peak is observed for women over 50.

Sarcoidosis occurs throughout the world in all races with an average incidence of 16.5/100,000 in men and 19/100,000 in women. The disease is most prevalent in Northern European countries, and the highest annual incidence of 60/100,000 is found in Sweden and Iceland. In the United States, sarcoidosis is more common in people of African descent than Caucasians, with annual incidence reported as 35.5 and 10.9/100,000, respectively. Sarcoidosis is less commonly reported in South America, Spain, India, Canada, and the Philippines.

The differing incidence across the world may be at least partially attributable to the lack of screening programs in certain regions of the world and the overshadowing presence of other granulomatous diseases, such as tuberculosis, that may interfere with the diagnosis of sarcoidosis where they are prevalent. There may also be differences in the severity of the disease between people of different ethnicities. Several studies suggest that the presentation in people of African origin may be more severe and disseminated than for Caucasians, who are more likely to have asymptomatic disease.

Manifestation appears to be slightly different according to race and sex. Erythema nodosum is far more common in men than in women and in Caucasians than in other races. In Japanese patients, ophthalmologic and cardiac involvement are more common than in other races.

Sarcoidosis is one of the few pulmonary diseases with a higher prevalence in non-smokers

Classification:
Sarcoidosis may be divided into the following types:

*Annular sarcoidosis
*Erythrodermic sarcoidosis
*Ichthyosiform sarcoidosis
*Hypopigmented sarcoidosis
*Löfgren syndrome
*Lupus pernio
*Morpheaform sarcoidosis
*Mucosal sarcoidosis
*Neurosarcoidosis
*Papular sarcoid
*Scar sarcoid
*Subcutaneous sarcoidosis
*Systemic sarcoidosis
*Ulcerative sarcoidosis

Symptoms:
Sarcoidosis is a systemic disease that can affect any organ. Common symptoms are vague, such as fatigue unchanged by sleep, lack of energy, weight loss, aches and pains, arthritis, dry eyes, swelling of the knees, blurry vision, shortness of breath, a dry hacking cough or skin lesions. Sarcoidosis and cancer may mimic one another, making the distinction difficult.  The cutaneous symptoms vary, and range from rashes and noduli (small bumps) to erythema nodosum or lupus pernio. It is often asymptomatic.

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The combination of erythema nodosum, bilateral hilar lymphadenopathy and arthralgia is called Löfgren syndrome. This syndrome has a relatively good prognosis.

Renal, liver (including portal hypertension), heart or brain involvement may cause further symptoms and altered functioning. Sarcoidosis affecting the brain or nerves is known as neurosarcoidosis.

Cardiac sarcoidosis:
Although cardiac involvement is present in 20% to 30% of patients with sarcoidosis, only about 5% of patients with systemic sarcoidosis are symptomatic.

The presentation of cardiac sarcoidosis can range from asymptomatic conduction abnormalities to fatal ventricular arrhythmia. Myocardial sarcoidosis can be a rare cause of sudden cardiac death.

Eye:
Manifestations in the eye include uveitis, uveoparotitis, and retinal inflammation, which may result in loss of visual acuity or blindness. The combination of anterior uveitis, parotitis, VII cranial nerve paralysis and fever is called uveoparotid fever, and is associated with Heerfordt-Waldenstrom syndrome. (D86.8)

Nervous system:
The central nervous system is involved in fewer than 1% of patients with sarcoidosis. There is usually granulomatous involvement of the basal meninges that subsequently affects the cranial nerves. Myelopathy may be the initial clinical presentation of intramedullary neurosarcoidosis.

Scalp:
Sarcoidosis of the scalp presents with diffuse or patchy hair loss.

Causes and pathophysiology:
The exact cause of sarcoidosis is not known. The current working hypothesis is that in genetically susceptible individuals sarcoidosis is caused through alteration in immune response after exposure to an environmental, occupational, or infectious agent.

Dysregulation of the immune system:
Granulomatous inflammation is characterized primarily by accumulation of monocytes, macrophages and activated T-lymphocytes, with increased production of key inflammatory mediators, TNF-alpha, IFN-gamma, IL-2 and IL-12, characteristic of a Th1-polarized response (T-helper lymphocyte-1 response). Sarcoidosis has paradoxical effects on inflammatory processes; it is characterized by increased macrophage and CD4 helper T-cell activation resulting in accelerated inflammation, however, immune response to antigen challenges such as tuberculin is suppressed. This paradoxic state of simultaneous hyper- and hypo- activity is suggestive of a state of anergy. The anergy may also be responsible for the increased risk of infections and cancer. It appears that regulatory T-lymphocytes in the periphery of sarcoid granulomas suppress IL-2 secretion which is hypothesized to cause the state of anergy by preventing antigen-specific memory responses.

While it is widely believed that TNF-alpha plays an important role in the formation of granulomas, it was observed that sarcoidosis can be triggered by treatment with the TNF-alpha antagonist etanercept.

Genetic associations:
Investigations of genetic susceptibility yielded many candidate genes but only few were confirmed by further investigations and no reliable genetic markers are known. Currently, the most interesting candidate gene is BTNL2; several HLA-DR risk alleles are also being investigated.  In persistent sarcoidosis the HLA haplotype HLA-B7-DR15 are either cooperating in disease or another gene between these two loci is associated. In non-persistent disease there is a strong genetic association with HLA DR3-DQ2.[19] Siblings have only a modestly increased risk (hazard ratio 5-6) of developing the disease, indicating that genetic susceptibility plays only a small role. The alternate hypothesis that family members share similar exposures to environmental pathogens is quite plausible to explain the apparent hereditary factor.

Infectious agents:
Several infectious agents appear to be significantly associated with sarcoidosis but none of the known associations is specific enough to suggest a direct causative role. Propionibacterium acnes can be found in bronchoalveolar lavage of approximately 70% patients and is associated with disease activity, however it can be also found in 23% of controls. A recent meta-analysis investigating the role of mycobacteria in sarcoidosis found it was present in 26.4% of cases, however the meta-analysis also detected a possible publication bias, so the results need further confirmation.

There have also been reports of transmission of sarcoidosis via organ transplants.

Vitamin D dysregulation:
Sarcoidosis frequently causes an increase in vitamin D production outside the kidney. Macrophages inside the granulomas convert vitamin D to its active form, resulting in elevated levels of the hormone 1,25-dihydroxyvitamin D and symptoms of hypervitaminosis D that may include fatigue, lack of strength or energy, irritability, metallic taste, temporary memory loss or cognitive problems. Physiological compensatory responses (e.g., suppression of the parathyroid hormone levels) may mean the patient does not develop frank hypercalcemia. This condition may be aggravated by high levels of estradiol and prolactin such as in pregnancy, leading to hypercalciuria and/or compensatory hypoparathyroidism.High levels of Vitamin D are also implicated in immune-system dysfunctions which tie into the sarcoid condition.

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Hyperprolactinemia:
Prolactin is frequently increased in sarcoidosis, between 3–32% cases have hyperprolactinemia,  this frequently leads to amenorrhea, galactorrhea or nonpuerperal mastitis in women. Prolactin also has a broad spectrum of effects on the immune system and increased prolactin levels are associated with disease activity or may exacerbate symptoms in many autoimmune diseases and treatment with prolactin lowering medication has been shown effective in some cases. However it is unknown if this relation holds in sarcoidosis and the gender predilection in sarcoidosis is less pronounced than in some other autoimmune diseases where such relation has been established. In pregnancy, the effects of prolactin and estrogen counteract each other to some degree, with a slight trend to improve pulmonary manifestations of sarcoidosis while lupus, uveitis and arthralgia might slightly worsen.   Lupus, uveitis and arthralgia are known to be in some cases associated with increased prolactin levels and respond to bromocriptin treatment but so far this has not been investigated specifically for sarcoidosis. The reasons for increased prolactin levels in sarcoidosis are uncertain. It has been observed that prolactin is produced by T-lymphocytes in some autoimmune disorders in amounts high enough to affect the feedback by the hypothalamic dopaminergic system.

The extrapituitary prolactin is believed to play a role as a cytokine like proinflammatory factor. Prolactin antibodies are believed to play a role in hyperprolactinemia in other autoimmune disorders and high prevalence endocrine autoimmunity has been observed in patients with sarcoidosis.[30] It may also be a consequence of renal disease or treatment with steroids. Neurosarcoidosis may occasionally cause hypopituiarism but has not been reported to cause hyperprolactinemia.

Thyroid disease:
In women, a substantial association of thyroid disease and sarcoidosis has been reported. The association is less marked but still significant for male patients. Female patients have a significantly elevated risk for hypothyroidism, hyperthyroidism and thyroid autoimmunity and it appears that autoimmunity is very important in the pathogenesis of thyroid disease in this population. Thyroid granulomatosis on the other hand is uncommon.

Hypersensitivity/autoimmune:
Association of autoimmune disorders has been frequently observed. The exact mechanism of this relation is not known but some evidence supports the hypothesis that this is a consequence of Th1 lymphokine prevalence.

Sarcoidosis has been associated with celiac disease. Celiac disease is a condition in which there is a chronic reaction to certain protein chains, commonly referred to as glutens, found in some cereal grains. This reaction causes destruction of the villi in the small intestine, with resulting malabsorption of nutrients.

An association with type IV hypersensitivity has been described. Tests of delayed cutaneous hypersensitivity have been used to measure progression.

Other:
While disputed, some cases have been associated with inhalation of the dust from the collapse of the World Trade Center after the September 11, 2001 attacks . Chicago comedian, Bernie Mac, suffered from sarcoidosis and died of pneumonia as a result of his compromised immune system. Reggie White, a former standout National Football League player, also suffered from sarcoidosis, and the disease played a major role in his death.

Risk Factors:
While anyone can develop sarcoidosis, factors that may increase your risk include:

*Age and sex. Sarcoidosis usually occurs between the ages of 20 and 40. Women are slightly more likely to develop the disease than are men.

*Race. Black Americans have a higher incidence of sarcoidosis than do white Americans. Also, sarcoidosis may be more severe in blacks and more likely to cause skin problems.

*Ethnicity. Worldwide, sarcoidosis is most commonly reported in people whose families originally came from Northern Europe — particularly Scandinavia and Britain. People with Japanese ancestry are more likely to develop eye or cardiac complications from sarcoidosis.

*Family history. If someone in your family has had sarcoidosis, you are more likely to develop the disease yourself.

Complications:
In about two-thirds of people with sarcoidosis, the condition resolves with no lasting consequences. But in some people, sarcoidosis can become chronic and lead to complications that may affect different parts of our body, such as : Lungs,Eyes,Kidneys,Heart, Nervous system  and Reproductive system.

Diagnosis:
Sarcoidosis can be difficult to diagnose, partly because the disease produces few signs and symptoms in its early stages. And when symptoms do occur, they vary by organ system affected and can mimic those of other disorders. A variety of diagnostic tests can narrow the possibilities and rule out other conditions.

Imaging tests
*X-ray. A simple chest X-ray can reveal evidence of lung damage or enlarged lymph nodes in your chest. In fact, some people have been diagnosed with sarcoidosis before they have any symptoms — from the evidence provided by chest X-rays taken for other reasons.

*CT scan. Computerized tomography (CT) uses a computer to combine a large number of X-rays views taken from many different directions into detailed, cross-sectional images of your internal structures.

Lab tests
Samples of your blood may be tested to check your general health and to see how well your kidneys and liver are functioning.

Lung function tests
These tests typically measure:

…#The volume of your lungs
…#How much air you can breathe in and out
…#How fast you can breathe air out
…#How well your lungs deliver oxygen to your blood

Biopsies
A biopsy is a small sample of tissue taken from a part of your body believed to be affected by sarcoidosis. The sample can be tested for the types of granulomas that are commonly seen in sarcoidosis. Biopsies can most easily be taken from your skin, from lymph nodes right under the skin, or from the outer membrane of your eye.

Lung biopsies can be obtained during a bronchoscopy (brong-KOS-kuh-pee). This procedure uses a thin, flexible tube that contains a fiber-optic camera and a grasping tool. After the tube is inserted down your throat, a doctor uses the grasping tool to remove a small sample of lung tissue — about the size of a grain of rice. The sample is sent to a microbiology laboratory to look for specific organisms.

Treatment :
Currently, there’s no cure for sarcoidosis. For one in ten people the disease slowly gets worse over time and for one in 50 it proves fatal. However, for the majority of those with the disorder – around eight out of every ten people, in fact – the condition resolves spontaneously after a few years and never comes back.

Relief from symptoms can be found with anti-inflammatory painkillers, and steroids can also prove extremely effective. When used to treat chronic sarcoidosis, steroids may need to be used at a low dose for many months, sometimes a year or more. During this time, regular blood and lung function tests and chest x-rays are performed to monitor how well the treatment is working. In more severe cases, immunosuppressive drugs such as methotrexate are used. Newer drugs such as infliximab may also be prescribed.

Prognosis:
The disease can remit spontaneously or become chronic, with exacerbations and remissions. In some patients, it can progress to pulmonary fibrosis and death. Approximately half of the cases resolve without treatment or can be cured within 12–36 months and most within 5 years. Some cases persist several decades.  Where the heart is involved, the prognosis is poor.   Patients with sarcoidosis appear to be at significantly increased risk for cancer, in particular lung cancer, malignant lymphomas,[40] and cancer in other organs known to be affected in sarcoidosis.   In sarcoidosis-lymphoma syndrome, sarcoidosis is followed by the development of a lymphoproliferative disorder such as non-Hodgkin lymphoma. This may be attributed to the underlying immunological abnormalities that occur during the sarcoidosis disease process.  Sarcoidosis can also follow cancer   or occur concurrently with cancer. There have been reports of hairy cell leukemia,  acute myeloid leukemia,  and acute myeloblastic leukemia   associated with sarcoidosis.
In pregnancy:
Sarcoidosis generally does not prevent successful pregnancy and delivery; the endogenous estrogen in pregnancy may even have a slightly beneficial immunomodulatory effect. In most cases the course of sarcoidosis is unaffected by pregnancy; there is improvement in a few cases and worsening of symptoms in very few cases.
Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.

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Resources:
http://en.wikipedia.org/wiki/Sarcoidosis
http://www.bbc.co.uk/health/physical_health/conditions/sarcoidosis1.shtml
http://www.mayoclinic.com/health/sarcoidosis/DS00251

http://www.metrohealth.org/body.cfm?id=1554

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