Sarcoidosis

SARCOIDOSIS

Sarcoidosis is a systemic granulomatous disease of uncertain etiology. The diseaseaffects females more than males, with typical age 20–60. It is most common in African American women. Clinical presentation varies. It may be asymptomatic, or presenting symptoms may include cough and shortness of breath; fatigue and malaise; skin lesions; eye irritation or pain; and fever or night sweats. Most often, the disease is first detected on chest x-ray as bilateral hilar lymphadenopathy or parenchymal infiltrates.

The noncaseating granulomas that are characteristic of sarcoidosis may occur in anyorgan of the body. In the lung, they typically form diffuse scattered granulomas;lymph node involvement may cause hilar and mediastinal adenopathy. Skin, liver and/or spleen, heart, central nervous system, bone marrow, and gastrointestinal tract are also frequent targets of the disease. Eye involvement can be seen in Mikulicz syndrome (involvement of the uvea and parotid).

The diagnosis of sarcoidosis can be suggested by clinical studies. In the laboratory, serum angiotensin converting enzyme (ACE), which is synthesized by endothelial cells and macrophages, may be elevated. X-ray studies frequently show bilateral hilar lymphadenopathy.

Sarcoidosis is considered to be a diagnosis of exclusion. In practice, this means that the diagnosis is considered when a biopsy shows features characteristic of sarcoidosis (such as noncaseating granulomas, Schaumann bodies [laminated dystrophic calci-fication], and asteroid bodies [stellate giant cell cytoplasmic inclusions]). There are no pathognomonic microscopic features though, and the diagnosis requires clini-copathologic correlation.

The prognosis is favorable with a variable clinical course. Most patients completely recover but some succumb to respiratory compromise.

OBSTRUCTIVE VERSUS RESTRICTIVE LUNG DISEASE