A 9-year-old boy with systemic onset juvenile rheumatoid arthritis (JRA) 
presented with fever and chest pain and rapidly developed pericarditis and 
cardiac tamponade. Despite corticosteroid treatment and pericardiocentesis, 
rapid deterioration necessitated the emergency placement of a pericardial 
window. This is the first reported instance of this type of emergency surgical 
intervention for JRA. Of 220 children with JRA followed for 12 years (7% 
systemic onset), 8 had evidence of acute pericarditis but no other had definite 
evidence of tamponade.