Sarcoidosis

Presentation

The typical presentation of sarcoidosis is variable and many patients are diagnosed following performance of a chest X-ray for an unrelated purpose (e.g., when undergoing a routine physical examination). Thirty to 60 percent of those diagnosed incidentally will remain asymptomatic and undergo spontaneous recovery without any treatment.

The most common clinical presentation of sarcoidosis involves cough and shortness of breath with or without chest pain. Many patients complain of nonspecific symptoms such as fatigue, muscle weakness, joint aches, weight loss, inability to exercise due to breathing problems, or localized symptoms such as painful nodules on the shins or skin lesions. Eye involvement, Bell's palsy, or parotid gland swelling has also been described in sarcoidosis.

Diagnosis

When sarcoidosis is suspected, a chest X-ray should be performed because approximately 90 percent will have lung involvement. Because of the large number of other diseases that can be confused with sarcoidosis, including infections and malignancy, a biopsy of affected tissue is routinely performed before the diagnosis of sarcoidosis is secured. A biopsy is obtained by removing an enlarged lymph node, obtaining a skin biopsy (abnormal areas), or via a technique called bronchoscopy. When isolated organ involvement involves the liver or heart, biopsies of those organs must be considered.

Bronchoscopy is particularly useful because the lungs are frequently involved by sarcoidosis. This procedure is performed by a pulmonologist and can be done as an outpatient. The patient is typically given “conscious sedation,” which refers to administration of intravenous sedation to a patient while maintaining the patient's ability to breathe for him- or herself. Following topical sedation with lidocaine (similar to what a dentist uses), a flexible bronchoscope (a tube the approximate diameter of a pencil eraser with a light and camera on the tip) is passed through the nose or mouth to the voice box, down between the vocal cords into the main breathing tube.

Biopsies of irregular areas and washings of the breathing tubes are obtained with very rare complication. These biopsies (up to 2–3 mm in size) are sent to the laboratory. The tissue is examined under the microscope for noncaseating granulomas (the classic feature of sarcoidosis) and stains and [Page 1520]cultures for tuberculosis and fungi are performed. Because sarcoidosis can be confused with other conditions, the diagnosis is only rendered after cultures for tuberculosis and fungi are determined to be negative and when there is no evidence of another diagnosis.

Treatment

Because asymptomatic patients will frequently undergo spontaneous remission, no therapy may be required. Specific indications for systemic corticosteroid therapy (oral or intravenous prednisone with continued therapy for 6 to 12 months) include the following: moderate or severe lung involvement, involvement of the central nervous system (brain or spinal cord), heart, eye (vision threatening), severely elevated levels of blood calcium, markedly elevated liver function tests, or pulmonary hypertension. These patients should receive systemic (oral) corticosteroids and consideration should be given to the addition of other therapies. Examples of therapies additive to corticosteroids include cyclophosphamide or azathioprine (chemotherapy drugs), antimalarial drugs, and thalidomide; the use of such agents should be monitored by specialists familiar with their usage.

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