Subacute Infective Endocarditis Misdiagnosed as Polymyalgia Rheumatica: A Case Report.

Infective endocarditis (IE) is a rare disease with a myriad of signs and symptoms that overlap with other systemic inflammatory disorders. We present the case of an otherwise healthy 57-year-old male patient with a three-month history of back pain, muscle weakness, and weight loss that was initially misdiagnosed as polymyalgia rheumatica (PMR), when in fact he had been suffering from subacute IE due to viridans streptococci. The patient's diagnosis was delayed until there was clinically apparent valve destruction. Our case highlights the crucial importance of excluding clinically subacute bacterial infection in patients with vague constitutional and musculoskeletal symptoms, especially before commencing immunosuppression.