Fever of unknown origin: large vessel vasculitis diagnosed by PET/CT

Abstract

PET/CT is starting to play an important role in evaluating fever of unknown origin (FUO), due to its ability to localize and delineate areas of high metabolic activity, such as neoplastic proliferation and inflammation, including vasculitis. We present a case of giant cell arteritis (GCA) in a 72 year old female patient admitted to our department with a four month history of FUO, weight loss and fatigue, without specific symptoms or signs. Laboratory investigations suggested acute phase response, with a pronounced erythrocyte sedimentation rate (ESR), high CRP level and microcytic anemia. A thorough diagnostic evaluation was performed in order to exclude an unknown primary tumor which was initially suspected due to a positive family history of cancer. Surprisingly, PET/CT revealed large vessel vasculitis affecting the ascending, descending and abdominal aorta, as well as subclavian, proximal brachial and carotid arteries bilaterally. Biopsy of the superficial temporal artery confirmed the diagnosis of GCA. Treatment with methylprednisolone and azathioprine led to resolution of clinical symptoms and normalization of laboratory parameters. In addition to the use of PET/CT in the evaluation of FUO, its value as a method complementary to temporal artery biopsy is also discussed.

The diagnostic role of 18F fluorodeoxyglucose positron emission tomography in patients with fever of unknown origin

“…FDG PET/CT may also be helpful during evaluation of bilateral adrenal masses , or pancreatitis and FUO . In suspected temporal arteritis, the diagnostic role of FDG PET/CT is limited and is recommended that temporal artery biopsy performed prior to further evaluation of the FUO by PET/CT . However, FDG PET/CT may demonstrate inflammatory changes in larger arteries sized >4 mm during various other inflammatory processes of blood vessels .…”

Tumor Necrosis Factor-Alpha as Differential Diagnostic Marker for Patients with Fever of Unknown Origin

“…After infectious diseases, the leading position was occupied by malignant diseases that nowadays many authors consider as an important cause of long-term fever. More recent investigations show that a great impor-tance in the identification of the etiology of FUO has a positron emission tomography with fluoro-deoxy-glucose (FDG-PET), especially in the case of occult infections and tumor (23,24).…”

Diagnostic value of PET/CT for giant cell arteritis combined with pulmonary embolism presenting

“…[ 27 ] However, few authors provided data on SUV max and only in 4 (20%, 4/20) GCA cases (including our own case) PET/CT SUV is available with a mean SUV max of 4.2 ± 1.7. [ 6 – 8 ] Delineation by PET/CT would be clinically useful in identifying subtle cases of GCA and establishment of a cutoff SUV max would facilitate diagnosis of GCA cases. Future studies involving an adequate cohort size would be required to provide a meaningful answer.…”

“…In 4 cases (including our own case) where PET/CT standardized uptake values (SUV) is available, the mean SUV max was 4.2 ± 1.7 (range, 2.5–7.2). [ 6 – 8 ]…”