Panaortitis: diagnosis via fluorodeoxyglucose positron emission tomography

A 57-year-old woman was admitted with a 2-month history of low-grade fever, malaise, and weight loss. Physical examination findings were unremarkable except for a systolic murmur of a known mild aortic regurgitation. Laboratory tests revealed only mild leukocytosis and an elevated sedimentation rate. Serology tests for viral and bacterial pathogens, blood and urine cultures, and immunology tests had negative results. Total body computed tomography, transesophageal echocardiography, and biopsies of bone, liver, and temporal arteries were normal. Wide-spectrum antibiotics effected no change in the patient's illness. Low-dose steroids given for a suspected polymyalgia rheumatica caused only minimal and transient improvement. Re-evaluation showed no new findings. Fluorodeoxyglucose positron emission tomography (FDG-PET) was done and showed an abnormally increased uptake along the aortic arch, the descending aorta, and bilaterally in the subclavian and carotid arteries, compatible with arteritis. High-dose steroids and later methotrexate were given and caused obvious improvement, with complete resolution of symptoms. We conclude that FDG-PET should be a part of the usual work-up of fever of unknown origin, especially in cases in which routine investigation reveals no cause.