Fever of unknown origin: Temporal arteritis presenting with persistent cough and elevated serum ferritin levels

Abstract

Fever of unknown origin (FUO) at the present time is most frequently caused by neoplasm and less commonly by infection. Currently, collagen vascular diseases (CVDs) are an uncommon cause of FUO because most are readily diagnosable by serologic methods and do not remain undiagnosed for sufficient time to present as FUOs. CVDs presenting as FUOs not readily diagnosable with specific tests include late-onset rheumatoid arthritis, adult juvenile rheumatoid arthritis, and polymyalgia rheumatica/temporal arteritis (TA). TA, or giant cell arteritis, is an uncommon arteritis of the mid- and large-sized extracranial arteries of the head and neck and is a rare cause of FUO. TA is characterized by headache, scalp tenderness, jaw pain on chewing, and sudden loss of vision. Fever, anorexia, weight loss, and night sweats may also be present. With TA, respiratory symptoms occur in 9% and are the presenting feature in 4%. Laboratory abnormalities associated with TA include a highly elevated erythrocyte sedimentation rate, anemia, and thrombocytosis, and mildly increased alkaline phosphatase/serum transaminases. We present a patient with FUO caused by TA whose predominant presenting symptom was persistent cough that overshadowed head and neck symptoms of TA. To the best of our knowledge, this is the first case of TA presenting as an FUO, with a highly elevated serum ferritin level. We conclude that highly elevated serum ferritin levels in patients with FUO should alert the clinician to consider TA in the differential diagnosis.