Abstract
BACKGROUND: Black sputum is scarce in clinical work. Pulmonary cavities with black sputum are more common in fungal infections and inhalation of a large amount of dust rarely. CASE REPORT: A 58-year-old young man went to the hospital several times because of Black sputum after being infected with COVID-19 and was diagnosed with pulmonary tuberculosis. The chest computerized tomography (CT) showed multiple high-density mass shadows in both lungs, accompanied by cavity formation. Bronchoscopy showed carbon foam was deposited in bilateral bronchial mucosa without new organisms, and the bronchial lavage fluid is medium black mucus, which gene X-PERT/rifampicin resistance test, fungal and pathological examination were negative. According to medical history, the patient has been engaged in underground work in coal mines three times, without any preventive measures. The final diagnosis was pneumoconiosis. The symptoms were relieved after two alveolar lavage treatments within 1 month, and the black sputum disappeared. Chest CT showed lung cavity lesions are stable 3 months later. CONCLUSION: Occupational dust exposure should not be ignored when treating patients with hollow lungs and black sputum. Pneumoconiosis is always diagnosed at an advanced stage, either as a milia nodular disease in chest imaging, or it progresses to PMF (progressive bulk fibrotic), with or without cavitation. There are currently no reported cases of pneumoconiosis combined with COVID-19 infection. Patients with pneumoconiosis have become susceptible to COVID-19 infection due to pulmonary interstitial fibrosis and low immunity. PMF cases of COVID-19 are atypical, and their clinical symptoms, laboratory examinations, and imaging manifestations are allIt exhibits atypical properties, and because the fungal test is negative, infection with COVID-19 may accelerate the production of unexplained tracheal mucus and black sputum in microbiological examinations.