beryllium

Chronic beryllium disease is a delayed-type (type IV) hypersensitivity reaction to inhaled beryllium in genetically susceptible individuals (HLA-DPB1 Glu69 allele). Histology shows noncaseating granulomas with hilar lymphadenopathy and upper-lobe involvement, virtually indistinguishable from sarcoidosis. Diagnosis is by beryllium lymphocyte proliferation test (BeLPT) demonstrating beryllium-specific T-cell sensitization, combined with exposure history. Patients increase risk of bronchogenic and lung cancer. CXR/CT shows reticulonodular infiltrates, upper-lobe predominance, and hilar lymphadenopathy. Treatment is corticosteroids and removal from exposure. High-yield: pneumoconiosis question with aerospace/nuclear worker → think beryllium; cobalt → hard-metal lung disease; asbestos → lower-lobe disease + pleural plaques.