Adult-onset Still's disease with haemorrhagic pericarditis and tamponade preceded by acute Lyme disease.

A 61-year-old Caucasian man presented with a fever of unknown origin, a transient erythematous rash on his right upper extremity and chest pressure after being treated for erythema migrans (Lyme disease). Echocardiogram demonstrated a large pericardial effusion with tamponade. He underwent pericardiostomy with tube placement. Workup for infectious and malignant etiologies was negative. Histology of the pericardium showed acute on chronic fibrinous haemorrhagic pericarditis. The patient met criteria for adult-onset Still's disease. Symptoms resolved following treatment with methylprednisolone and anakinra. We believe this is the first case of adult-onset Still's disease precipitated by acute Lyme disease.