A Case of Cryoglobulinemic Membranoproliferative Glomerulonephritis Induced by Hepatitis C Virus

A 61-year-old man with bilateral purpura of the lower limbs and subsequent edema, was hospitalization after renal dysfunction developed. The presence of hepatitis C virus (HCV) RNA and cryoglobulin and the finding of membranoproliferative glomerulonephritis on renal biopsy led to a diagnosis of HCV-related glomerulonephritis due to cryoglobulinemia. Because of the pre-existence of nephrotic syndrome and the continuously increasing serum level of creatinine, treatment with cryofiltration, interferon, and steroids was started. After 5 cryofiltration sessions, the cryocrit level had decreased to 1% and the levels of serum creatinine and proteinuria had also decreased. However, 3 weeks after the start of treatment, nephrotic syndrome developed again and was accompanied by lower-extremity mononeuropathy and renal dysfunction. Thereafter, the patient showed disorientation, an affective disorder, and delirium, and his condition gradually deteriorated. Radiological examination of the head and examination of the cerebrospinal fluid showed no abnormalities. Despite the withdrawal of the interferon therapy and the reduction of the steroid dose, the patient's conditions remained unchanged, and the level of consciousness deteriorated. Although cryofiltration had beneficial effects and plasma exchange was continuously performed, the patient died on the 74th hospital day. Because of the significant changes due to ventilatory support and hemorrhage associated with disseminated intravascular coagulation, the autopsy findings did not allow us to definitively determine whether the symptoms had been caused by the HCV-related membranoproliferative glomerulonephritis or the interferon therapy or both. We have reported this case to provide insight into whether interferon therapy should be administered for HCV-related membranoproliferative glomerulonephritis with marked neurological symptoms due to cryoglobulinemia.