Constrictive pericarditis is a complication of tuberculous pericarditis that necessitates surgical intervention. In this study, we sought to identify echocardiographic features that could predict the development of constrictive pericarditis from acute or subacute pericarditis. From January 1988 through May 1998, all patients with a discharge diagnosis of tuberculous pericarditis were enrolled in the study, and their clinical features, laboratory findings, sonographic images, treatments, and outcomes were analyzed. Tuberculous pericarditis was demonstrated on the basis of positive Mycobacterium tuberculosis cultures from pericardial fluid or tissue in 11 patients; pericardial biopsy specimens demonstrating caseating granulomas in seven; and bacteriologic or histologic evidence of active extra-pericardial tuberculosis in conjunction with major pericardial effusion in four. Seventeen patients had effusive tuberculous pericarditis and five had constrictive tuberculous pericarditis as the initial diagnosis. The echocardiographic findings of effusive pericarditis were classified as shaggy-type effusion (n = 8) and non-shaggy-type effusion (9). Shaggy effusion was defined as the presence of multiple fibrin strands or a mass-like exudate coating the pericardium and bridging the pericardial effusion. Non-shaggy effusion was characterized by an anechoic pericardial space with or without a thickened pericardium, but no shaggy exudative coating. The mean duration between the onset of symptoms and diagnosis was longer in patients with shaggy-type effusion (39.6 +/- 8.7 vs 21.0 +/- 13.9 days, p < 0.05). Prednisolone (20-30 mg/d) was used in addition to antituberculous chemotherapy in 11 of the 17 patients with effusive pericarditis. Two of 11 patients (18%) who received steroid therapy, and five of the six patients (83%) who did not, developed constrictive pericarditis in the following year. Therefore, we concluded that adjuvant therapy with steroids significantly decreased the risk of constrictive pericarditis in patients with non-shaggy, but not shaggy, effusion.