Two cases of Haemophilus influenzae type B pericarditis are presented which 
demonstrate the major clinical features and sequelae of this serious illness. 
These cases are analyzed together with 77 others from the literature to 
characterize the clinical features, natural history, and optimal therapy. H. 
influenzae pericarditis is an increasingly frequent disease of young children. A 
mild prodromal illness is often followed by rapid progression of cardiac 
compromise until death ensues, unless pericarditis is diagnosed and treated 
appropriately. The development of cardiomegaly in a febrile patient with a 
Haemophilus infection is an indication for echocardiography, which is diagnostic 
of the pericardial effusion. Initial cultures of pericardial aspirates will be 
positive in 75% of cases even when antibiotic therapy has been initiated. Use of 
appropriate parenterally administered antibiotics, in combination with early 
surgical pericardial drainage or partial pericardiectomy, should minimize 
morbidity and mortality and prevent acute constrictive sequelae.