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General Information about Sarcoidosis

Sarcoidosis Week

Who is at risk? Studies show some genetic association such that monozygotic (identical) twins have higher concordance for disease than dizygotic (non-identical).  African Americans (blacks) are at higher risk (3-4x) than other races/ethnicities.  Sarcoidosis does run in families to some extent.  Sarcoidosis is thought to affect 1-40 people per 100,000 population, so is reasonably common particularly in a pulmonary clinic.  Roughly 2.5% of blacks in the USA will ultimately develop sarcoidosis during their lifetime.  Sarcoidosis usually affects people between ages 20-40 years (in 70-90% of cases), however, it can develop at any age.

Causes: Nobody knows what causes sarcoidosis, although there are a number of theories about various viruses or bacteria (some related to TB) or molds/dust exposures.  Sarcoidosis is not contagious.  There are likely multiple pathways which ultimately lead to a similar appearing disease.

Diagnosis: Sarcoidosis is a diagnosis of exclusion, i.e. other causes of disease —such as fungal infection— need to be ruled out before the diagnosis can be established.  Usually a biopsy is required to make the diagnosis although sometimes the diagnosis can be made presumptively if there is a classic presentation.  Bronchoscopy can be performed (in which a rubber tube is inserted into the windpipe) to obtain lung tissue.  A transbronchial biopsy involves the acquisition of a small amount of lung tissue using a small forceps inserted through the bronchoscope.  Patients are given a small amount of sedation for the procedure and apart from some coughing, the procedure is very well tolerated.  There is a small risk to the biopsy which can involve bleeding (making the patient cough up blood) or lung collapse (which is quite rare but can lead to shortness of breath and may require a chest tube between the ribs to drain the air from the lining of the lung).

Treatment: The optimal treatment of sarcoidosis is unclear.  There are many sarcoidosis patients who do well with no treatment.  In patients who have major symptoms or progressive disease, steroids (like prednisone) are the mainstay of therapy.  Other treatments are used as steroid-sparing agents (like methotrexate) to reduce inflammation without creating steroid-induced side effects.  TNF antibodies (such as infliximab) also have a role in treatment as several studies have shown important benefits.  Treatment of fatigue in sarcoidosis (e.g. with stimulants) is also being increasing appreciated since many patients feel better when this symptom is addressed adequately.

Prognosis: The mortality of sarcoidosis is <5%.  If people do succumb to this illness, it is usually from progressive scarring of the lung, or in some cases heart rhythm abnormalities.  Lung transplant is sometimes performed for these patients, although it may return in the transplanted lung despite the immunosuppression provided to these patients.

Source: Atul Malhotra, MD, Chair, ATS Assembly on Sleep and Respiratory Neurobiology

Source: Foundation for Sarcoidosis Research

Four Facts About Sarcoidosis

  1. What is Sarcoidosis? Sarcoidosis is an inflammatory disease that can affect almost any organ in the body.  It causes heightened immunity, which means that a person’s immune system, which normally protects the body from infection and disease, overreacts, resulting in damage to the body’s own tissues.

  2. How does Sarcoidosis Affect the Body?  In the United States, sarcoidosis most commonly affects the lungs and lymph nodes, but the disease can and usually does affect other organs including (but not limited to) the skin, eyes, liver, salivary glands, sinuses, kidneys, hearts, the muscles and bones and the brain and nervous system.   Symptoms typically depend on which organ the disease affects.

  3. What Causes Sarcoidosis?  No one knows exactly what causes sarcoidosis, but it is probably due to a combination of factors.  Some research suggests that an environmental exposure might trigger the disease.  Such triggers, although usually harmless in most people, might provoke the immune system to develop the inflammation associated with sarcoidosis in individuals with the right genetic disposition.

  4. Who Gets Sarcoidosis?  Once thought rare, sarcoidosis is now known to be common and affects people worldwide.  The disease can affect people of any age, race and gender.  However, it is most common among adults between the ages of 20 and 40 and in certain ethnic groups.

    1. In the United States, sarcoidosis is most common in African Americans and people of European – particularly Scandinavian – descent.

    2. In the United States, sarcoidosis frequently occurs more often and more severely among African Americans than among Caucasians.

    3. Among African Americans, the most affected U.S. group, the estimated lifetime risk of developing sarcoidosis might be as high as 3 percent.

    4. Most studies suggest a higher disease rate for women.