Sarcoidosis

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Category: Miscellaneous Articles Published on Wednesday, 25 June 2008 Written by Yong Tsai, MD
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John, a 35-year-old African American man, experienced a cough, low-grade fever and joint pain in both knees, as well as several red tender nodules on his legs and a chest x-ray, which showed "hilar lymph node enlargement." When John saw a rheumatologist, a diagnosis of sarcoidosis with lung, skin and joint involvement was made, treatment with corticosteroids was started, and assurance of a good prognosis was given.

Sarcoidosis, a systemic, chronic, granulomatous disease of unknown etiology can affect any organs and can mimic many rheumatic diseases such as rheumatoid arthritis, systemic lupus erythematous or spondyloarthropathies (inflammation in the spine).

Think about what happens when mycobacterium tuberculosis enters our lungs; our immune cells, including T and B cells, macrophages and other cells interact with each other, form nodule-like tissue surrounding the mycobacteria, and then kill them.

Similarly, sarcoidosis is produced by an abnormal immune response, but unlike tuberculosis, no bacteria or offending organisms can be identified as the trigger. In many cases of sarcoidosis, granuloma can widely occur affecting the lungs, lymph nodes, liver, spleen, heart, kidneys, bone marrow and even brain, damaging tissue by a release of chemical (cytokinases) or compressing surrounding tissue.

Typically, sarcoidosis strikes individuals between 20 to 40 years of age.  Most commonly seen in African Americans and Northern European Caucasians, sarcoidosis is more prevalent amongst African Americans at 40/10,000, eight times higher than for white Americans.

The most common complaints of patients with sarcoidosis are respiratory symptoms such as dry cough, shortness of breath, chest pain, and coughing up blood, in addition to fever, weight loss and fatigue.  The degree of pulmonary involvement, which varies from asymptomatic lymph node enlargement to dispersed involvement, is what can affect a prognosis.

In 10-15% of patients with sarcoidosis, acute arthritis may occur in one or both ankles, occasionally spreading to the knees, hands, wrists and elbows.   Patients with acute arthritis, red and tender nodules of the lower legs (erythema nodosum) and bilateral hilar adenopathy have an excellent prognosis at a 90 % chance of remission.  Others may experience chronic arthritis beginning six months or more after onset. Eye inflammation (uveitis) or other skin involvement (cutaneous sarcoidosis) is also common.

For patients with minimal symptoms, no treatment may be required.  However, to suppress severe inflammation associated with arthritis, ocular disease, pulmonary and central nerve system involvement corticosteroids are commonly used.  Chloroquine or hydroxychloroquine may be helpful for cutaneous sarcoidosis, while methotrexate, azathioprine and cyclosporine are used for severe sarcoidosis.

Thankfully, most patients with sarcoidosis do well.  However, some patients develop severe pulmonary impairment or chronic disabling arthritis.  The key point is to have sarcoidosis diagnosed and treated early, so that long-term complications can be minimized and even prevented.

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