Large pericardial effusion: the differentiation of tuberculous from chronic idiopathic effusion.

AIMS Tuberculosis is a common cause of pericardial effusion in many parts of the world often presenting with tamponade. Its recognition is important but not always easy. This study was to prospectively compare the features of tuberculous with chronic idiopathic pericardial effusion. METHODOLOGY We studied 47 patients with large pericardial effusions or tamponade. All had pericardiocentesis and chest CT studies. Twenty-eight had tuberculous and 19 viral or idiopathic effusion. Pericardial biopsy was done in 26/28 and tuberculin skin test in 23/28 with tuberculosis and all received specific treatment. RESULTS Patients with idiopathic effusion were older with thinner pericardium. Tamponade was frequent in both groups (64%). Fever (p<0.001) and pericardial rub (p<0.002) were more with tuberculosis. The skin test measured 17 +/- 3.2 mm. On echocardiography pericardial deposits and strands in the pericardial space were more with tuberculosis. The fluid was similar in quantity and quality. Only and all 28 with tuberculosis had enlarged mediastinal lymph glands on CT measuring 19.5 +/- 8.3 mm. On follow up of 16 +/- 10.2 months glands disappeared in 81% and regressed in 19%. Lymphadenopathy was not seen in any patient with viral/idiopathic pericarditis. All patients in both groups were well at follow up. CONCLUSIONS Tamponade is frequent with large tuberculous and chronic idiopathic effusions. The quantity and quality of the effusion were similar. Fever and pericardial rub were more frequent with tuberculosis as also deposits and strands on echocardiography and patients had a strongly positive skin test. Mediastinal lymph gland enlargement on chest CT was found only and in all with tuberculous effusion.