ESSENTIALS OF DIAGNOSIS
Symptoms related to the lung, skin, eyes, peripheral nerves, liver, kidney, heart.
Demonstration of noncaseating granulomas in a biopsy specimen.
Sarcoidosis is a systemic disease of unknown etiology characterized in about 90% of patients by granulomatous inflammation of the lung. The incidence is highest in North American Black persons and northern European White persons. Among Black persons, women are more frequently affected than men. Onset of disease is usually in the third or fourth decade.
Patients may have malaise, fever, and dyspnea of insidious onset. Symptoms caused by skin involvement (erythema nodosum, lupus pernio [Figure 9–6]), iritis, peripheral neuropathy, arthritis (Chapter 20), or cardiomyopathy may also prompt the patient to seek care. Some individuals are asymptomatic and come to medical attention after abnormal findings on chest radiographs (typically bilateral hilar and paratracheal lymphadenopathy). Physical findings of interstitial lung disease with crackles are uncommon. Other symptoms and findings may include parotid gland enlargement, hepatosplenomegaly, and lymphadenopathy.
Skin involvement in sarcoidosis (lupus pernio), here involving the nasal rim. (Reproduced with permission from Richard P. Usatine, MD, in Usatine RP, Smith MA, Mayeaux EJ Jr, Chumley HS. The Color Atlas and Synopsis of Family Medicine, 3rd ed. McGraw-Hill, 2019.)
Laboratory tests may show leukopenia, an elevated ESR, and hypercalcemia (about 5% of patients) or hypercalciuria (20%). ACE levels are elevated in 40–80% of patients with active disease, though this finding is neither sensitive nor specific. Physiologic testing may reveal evidence of airflow obstruction or restriction with decreased lung volumes and diffusing capacity, or both. ECG may show heart block and dysrhythmias.
Radiographic findings are variable and include bilateral hilar adenopathy alone (radiographic stage I), hilar adenopathy and parenchymal involvement (radiographic stage II), parenchymal involvement alone (radiographic stage III), or advanced fibrotic changes principally in the upper lobes (radiographic stage IV). Parenchymal involvement is usually manifested radiographically by diffuse reticular infiltrates, but focal infiltrates, acinar shadows, nodules, and, rarely, cavitation may be seen. Pleural effusion is noted in less than 10% of patients.
The diagnosis of sarcoidosis generally requires histologic demonstration of noncaseating granulomas in biopsies from a patient with other typical associated manifestations. Other granulomatous diseases (eg, berylliosis, tuberculosis, fungal infections) and lymphoma must be excluded. Biopsy of easily accessible sites (eg, palpable lymph nodes, skin lesions, or salivary glands) may be an initial step. Transbronchial lung biopsy has a high yield (75–90%) as well, especially in patients with radiographic evidence of parenchymal involvement. Some clinicians believe that tissue biopsy ...