Tuberculous pyomyositis in a renal transplant recipient.

Abstract

A 27-year-old Afghanistan man with a transplanted kidney, chronic hepatitis C virus infection and corticosteroid induced type 2 diabetes presented with 2 weeks of fever and bilateral thigh pain. He had undergone living donor transplantation in Pakistan 3 years previously and immunosuppression was maintained with prednisolone, cyclosporine and mycophenolate mofetil. A recent allograft biopsy, undertaken for progressive graft dysfunction, had revealed evidence of IgA nephropathy and early diabetic glomerulopathy. He denied chest symptoms and a plain chest radiograph was unremarkable. Repeated blood cultures were negative and serum creatine kinase was not elevated. An initial magnetic resonance imaging (MRI) scan of the thighs showed diffuse enhancement of the quadriceps bilaterally suggestive of myositis. A muscle biopsy showed non-specific inflammatory change, but uncovered a purulent collection in the left thigh musculature, which was aspirated with symptomatic benefit. A repeat MRI and single photon emission computed tomography (SPECT) scan showed clear evidence of abscesses within the adductor musculature bilaterally (Figure ​(Figure1).1). Acid and alcohol fast bacilli were discovered on microscopy of aspirated fluid and Mycobacterium tuberculosis (TB) was confirmed by culture. Treatment with antituberculous quadruple therapy was commenced, and a subsequent MRI 1 year later showed almost complete resolution of inflammation (Figure ​(Figure22). Fig. 1. (A) Short T1 inversion recovery (STIR) MRI showing extensive bilateral muscular oedema with evidence of more focal collections within the adductor muscles of both thighs. (B) SPECT scan showing bilateral ‘hotspots’ in the adductor musculature ... Fig. 2. STIR MRI upon completion of 1 year of antituberculous chemotherapy, showing almost complete resolution of the inflammatory changes. Tuberculous pyomyositis usually follows contiguous spread from bone or joint, or haematogenous seeding, and treatment is by drainage of focal collections and antituberculous chemotherapy. The renal allograft, transplanted in a country where TB is endemic, was suspected as a source of infection in this case, although the recent kidney biopsy did not show histological features of disease.