A challenging case of pyrexia of unknown origin


Aine Gorman, Clarissa Fang, Tommy Tung, Trevor Duffy1, Maurice Barry, Carl Orr


Rheumatology Department, Connolly Hospital, Blanchardstown, Dublin 15.


We present a case of a patient with lower limb pain and weakness. He went on to develop pyrexia of unknown origin The year prior to his presentation he had two admissions to hospital with pneumonia and with femoral plexus neuritis.


A 69-year-old male presented with pain and weakness in both lower limbs in association with pitting oedema and weight loss for three months. The only positive features on clinical examination were marked tenderness in his lower limbs bilaterally, significant weakness and the absence of extensor hallux longus power. There was clear evidence of significant muscle wasting, especially in the thighs. He had widespread moderate wheeze on examination of his respiratory system. During his admission, he was noted to be pyrexial to 38.5C on a daily basis. He was initially treated with IVIG for likely Guillen-Barre syndrome.

His background history included asthma/COPD overlap syndrome. One year prior, he was admitted to hospital with evidence of a rash on his left lower limb consistent with varicella-zoster virus infection. Magnetic resonance imaging during that admission confirmed the presence of right femoral plexus neuritis. Six months later he had an inpatient admission with community-acquired pneumonia treated with antibiotics and steroids.


ESR and CRP were raised at 51mm/hour() and 235 (0-5mg/L) respectively, with an associated neutrocytosis. Renal and liver blood profiles were normal. He was extensively cultured (blood x8, urine, CSF), microbiology serology and PCR, as well as imaging (CT TAP, TTE and TOE) did not reveal an infective aetiology. CK, complement, ANA were normal. Anti-MPO was positive at moderate titre. Whole-body MRI indicated ‘myositis’ of thigh muscles.

Biopsy of his left vastus medialis muscle revealed a possible vasculitis. A second biopsy was retrieved, and the neuropathologists concurred with the diagnosis of a small vessel vasculitis.


He was treated as an ANCA-associated vasculitis- likely microscopic polyangiitis. After three months of tapering dose prednisolone and methotrexate, he has made a near-complete recovery.


This case highlights the challenges in diagnosing a defining disease in patients with non-specific symptoms and multiple presentations to hospital.

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