Atypical infective endocarditis

Background: Although infective endocarditis has changed in the recent past as a result of microbiologic and risk factors, it continues to be clinically challenging. The disease is characterized by the formation of septic masses of platelets on the surfaces of heart valves. Several mechanisms can cause or contribute to the development of endocarditis. Although risk factors for infective endocarditis are well known, patients with atypical signs and symptoms continue to challenge us. Methods: We describe a case report of a patient admitted to our inpatient service with back pain and presumed pyelonephritis. A MEDLINE literature search was conducted, using the key words "endocarditis," "back pain," and "bacterial," for the years 1986 to the present. Results and Conclusions: A 42-year-old woman with a history of intravenous drug abuse was admitted to the family practice service with back pain and pyelonephritis. She developed hypoxia and a new heart murmur and had continued fevers. Blood cultures drawn in the emergency department grew methicillin-resistant Staphylococcus aureus. A bone scan and magnetic resonance imaging led to the diagnosis of epidural abscess. What appeared to be a simple case of pyelonephritis with back pain be-came a case of infective endocarditis complicated by an epidural abscess.