BK virus nephropathy and multiorgan involvement in a child with heart transplantation

BK virus is a known cause of renal failure in kidney transplant recipients, but there is little data regarding its effect on native kidneys in heart transplant patients. Here, we describe the case of a child who underwent heart transplantation and was later diagnosed with BK virus with multiorgan involvement. This patient was diagnosed with dilated cardiomyopathy at 4 months of age and underwent heart transplantation at the age of 5 years. Before transplantation, the patient suffered from cardiac arrest and fungal pyelonephritis. The patient had no evidence of azotemia. Ten months after transplantation, the patient was diagnosed with diffuse large B-cell lymphoma associated with Epstein-Barr virus infection. She underwent chemotherapy, and later developed azotemia and BK viremia. The findings on renal biopsy were compatible with BK nephropathy. After the biopsy, she was treated with intravenous cidofovir, immunoglobulins, and oral leflunomide. The tacrolimus dose was also reduced. However, the patient's renal function continued to worsen. She developed end-stage renal disease and started peritoneal dialysis. After experiencing a seizure. the patient was found to have positive BK virus polymerase chain reaction in the cerebrospinal fluid. Brain magnetic resonance image revealed a new white matter lesion in the splenium. On immunohistochemistry, there was SV40-positive staining in gastric and heart biopsy specimens. Therefore, BK virus enteropathy and cardiac involvement were suspected. This case suggests that BK virus infection can lead to systemic involvement and can be fatal.