Successful Management of Combined BK Nephropathy and Nocardiosis in a Renal Transplant Recipient: Case Report.

Nocardiosis is a life-threatening infection in immunocompromised patients. The prevalence of the disease ranges from 2.3% to 5% in renal allograft recipients. Here, we describe a case of BK nephropathy associating with nocardiosis with successful recovery. The 54-year-old male patient had end-stage kidney disease due to diabetic nephropathy associated with diabetic retinopathy, hypertension, and dyslipidemia. He started hemodialysis in October 2017; 2 years later, he underwent a deceased donor kidney transplant with 2 HLA mismatches and high panel reactive antibodies. He received desensitization with intravenous immunoglobulin and rituximab, received thymoglobulin as induction, and was maintained on prednisolone, mycophenolate mofetil, and tacrolimus. His serum creatinine decreased to a nadir of 90 μmol/L. He developed graft dysfunction, which was proven to be due to BK nephropathy. Therefore, mycophenolate mofetil was replaced with leflunomide in addition to intravenous immunoglobulin therapy. Ten months later, he had an accidental fall and sought an orthopedic evaluation. Magnetic resonance imaging of the lumbar spine and pelvis revealed lumbar spondylosis, avascular necrosis of the femoral head, and obturator muscle abscess. He was explored surgically, but the surgeon found no abscess or avascular hip necrosis. The patient's blood grew Nocardia, and he was readmitted and started imipenem and linezolid empirically. Brain and chest computed tomography scans ruled out any central nervous system or pulmonary involvement, but a bone scan revealed osteomyelitis of the right superior pubic ramus and prepubic swelling, which was confirmed by computed tomography to be an abscess in both obturator externus and internus. He continued the same antibiotics for 6 months based on culture and sensitivity. At follow-up, the patient has shown stable graft function (creatinine 155 μmol/L) with improved BK viremia with immunosuppression minimization. In renal transplant recipients, successful management of combined BK nephropathy and nocardiosis was feasible with minimization of immunosuppression and proper antimicrobial therapy.