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For further information, see CMDT Part 9-22: Sarcoidosis
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Essentials of Diagnosis
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General Considerations
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Highest incidence in North American blacks and northern European whites
Among blacks, women are more frequently affected than men
Disease onset is usually in the third or fourth decade
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Malaise, fever, and insidious dyspnea
Symptoms from erythema nodosum, iritis, peripheral neuropathy, arthritis or cardiomyopathy may also prompt initial evaluation
Some patients are asymptomatic, and diagnosis is made after abnormal findings are noted on chest radiograph
Crackles are uncommon on chest examination
Parotid gland enlargement, hepatosplenomegaly, and lymphadenopathy may be noted
Myocardial sarcoidosis is found in 5% of patients and can lead to
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Differential Diagnosis
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Other granulomatous diseases must be excluded
Tuberculosis
Histoplasmosis
Coccidioidomycosis
Lymphoma (including lymphocytic interstitial pneumonitis)
Idiopathic pulmonary fibrosis
Pneumoconiosis (especially berylliosis)
Syphilis
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Leukopenia
Elevation of erythrocyte sedimentation rate
Hypercalcemia in 5%, hypercalciuria in 20%
Angiotensin-converting enzyme (ACE) levels
Physiologic testing may reveal evidence of airflow obstruction, but restrictive changes with decreased lung volumes and diffusing capacity are more common
Skin test anergy is present in 70%
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Radiographic findings are variable
Stage I: hilar adenopathy alone
Stage II: hilar adenopathy with parenchymal involvement
Stage III: parenchymal involvement alone
Stage IV: advanced fibrotic changes principally in the upper lobes
Parenchymal involvement usually manifests as diffuse reticular infiltrates, but focal infiltrates, acinar shadows, nodules, and rare cavitation are seen
Pleural effusion occurs in < 10% of patients
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Diagnostic Procedures
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ECG may show conduction disturbances and dysrhythmias
Biopsy demonstrating noncaseating granulomas is required for diagnosis
Easily accessible biopsy sites include lymph nodes, skin lesions, and salivary glands
Transbronchial biopsy has a yield of 75–90%
Some experts believe biopsy is unnecessary in stage I disease with a presentation highly suggestive of sarcoidosis
Bronchoalveolar lavage is usually characterized by an increase in lymphocytes with a high CD4/CD8 ratio; this may be used to follow disease activity, but not for diagnosis
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