The air-fluid level in cavitary pulmonary tuberculosis.

Pulmonary tuberculosis has long been associated with the formation of cavities in the lung. Many reports in the literature indicate that the occurrence of air-fluid levels in tuberculosis is unusual. The authors present 18 cases of proved active cavitary tuberculosis where air-fluid levels occurred during the active phase of the disease. The consideration of tuberculosis in the differential diagnosis of an air-fluid containing pulmonary cavity is emphasized and the pathogenesis of cavity formation is discussed.