[Hepatitis C infection with false negative serology in a patient with mixed cryoglobulinemic vasculitis].
Keywords
Abstract
METHODS
A 72-year-old man with nausea, fever and elevated inflammatory parameters was transferred for further diagnostic assessment and treatment. On examination a palpable purpura was obvious without any signs of infection.
METHODS
Creatininekinase was 350 mmol/l with a proteinuria of 20 g per day. Histological examination revealed hypersensitivity vasculitis in the cutis and a membranoproliferative glomerulonephritis. In addition there was a mixed cryoglobulinemia with a negative test for hepatitis C virus. Further investigation revealed hepatitis C virus RNA genotype 1 b in the cryoprecipitate.
METHODS
The patient was successfully treated with with interferon alpha for 12 month. The nephrotic syndrome improved and the proteinuria ceased
CONCLUSIONS
Mixed cryoglobulinemias are associated with hepatitis C virus infection in over 80% of cases. Normally it is easy to make the diagnosis serologically with an ELISA test. But in a few cases the virus RNA is only detectable in the cryoprecipitate. If there is a high suspicion of an hepatitis C infection with cryoglobulinemia but HCV serology is negative, it is essential that virus antigen and antibodies are searched for in the cryoprecipitate.
