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Description
A 75-year-old man with a 6-month history of unexplained weight loss and malaise presented with fever and rigours, severe thigh pain and proximal myopathy. C-reactive protein and erythrocyte sedimentation rate were raised (373 mg/dL and 58 mm/hour, respectively) with a normal creatine kinase. A diagnosis of giant cell arteritis (GCA) was considered despite the absence of typical cranial symptoms and a temporal artery biopsy (TAB) was performed. TAB showed an unusual perivascular inflammatory pattern felt to be in keeping with the clinical picture of vasculitis but did not demonstrate the classical transmural inflammation typically seen in GCA.
In view of the lower limb symptoms, fluorodeoxyglucose-positron emission tomography/CT imaging was performed which showed increased tracer uptake, compatible with vasculitis, predominantly affecting the peripheral lower limb vessels (figure 1) with relative sparing of larger vessels in the lower extremities. Axillary and subclavian artery involvement, more typical for GCA, was clearly demonstrated on imaging (figure 2).
Axial image through the thighs shows increased activity within vessels and a relative paucity of muscular uptake on fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT.
Whole-body maximum intensity projection (MIP) demonstrates increased tracer uptake in the larger vessels of the lower limbs with sparing of the aorta, iliac and femoral arteries. Increased uptake is also displayed in the axillary and subclavian arteries.
Commencement of high-dose oral prednisolone (60 mg daily) resulted in the complete resolution of symptoms within 24 hours and symptoms have remained quiescent following a gradual steroid taper.
GCA is the most common form of large vessel vasculitis affecting around 1 in 5000 people over the age of 50.1 Predominant lower extremity involvement is an unusual pattern in GCA, which more typically involves the aorta, aortic arch and branches thereof with the temporal vessels most commonly symptomatic. Patients with lower extremity involvement may not exhibit cranial symptoms such as headache despite the presence of positive TAB.2 While symptomatic lower limb vasculitis is rare, it can be associated with significant morbidity due to the potential for critical limb ischaemia.3
Learning points
Giant cell arteritis is a recognised cause of fever of unknown origin and can present with predominant lower limb involvement in the absence of typical cranial symptoms.
Fluorodeoxyglucose-positron emission tomography/CT scanning can be helpful in identifying vascular inflammation that is not clinically evident, enabling prompt treatment to prevent ischaemic complications.
Footnotes
Contributors AM contributed to conception and design, acquisition of data analysis, literature reviews with citations, and drafting and revision of manuscript. MK was involved in patient care, extraction of images, figure captions, and drafting and revision of manuscript. JLM was involved in patient care, patient consent, and drafting and revision of manuscript. All authors (AM, MK, JLM) are in full agreement and take full responsibility for the article and ensure that all questions regarding the accuracy and integrity of the article were investigated and resolved.
Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.