Olga B. Vorozhbyt, Serge M. Chooklin Renal manifestations associated with hepatitis C virus infection.

Gut 2005; 54 (Suppl. V11) A208, 13th United Europen Gastroenterology Week, 15-19 October 2005, Copenhagen.

Background

Hepatitis C virus is estimated to infect 100 million people worldwide. Chronic infection occurs in 85% to 90% of persons exposed to the virus and may progress to chronic active hepatitis and cirrhosis. In addition to liver disease, HCV infection has been associated with a wide variety of extrahepatic manifestations, including mixed cryoglobulinemias and renal involvement. The most common renal manifestation is MPGN with or without cryoglobulinemia. Patients with glomerulonephritis may have no clinical evidence of systemic or liver involvement. Pathogenesis of HCV-associated MPGN is mediated by glomerular deposition of circulating immune complexes containing HCV and anti-HCV.

Methods

Fifty nine patients (32 female and 27 male, mean age 61.3 years) with chronic HCV infection and cryoglobulinaemia were recruited. Renal related symptoms were investigated by anamnesis and clinical evaluation. The anti-HCV was detected by EIA. HCV RNA was detected in the serum and in the cryoprecipitate of patients by polymerase chain reaction (PCR). The presence, concentration, and type of cryoglobulins were tested by immunofixation. Rheumatoid factor (RF) was also measured.

Results and conclusion

Cryoglobulinemic glomerulonephritis was diagnosed between the fifth and sixth decades of life in most patients, and it occurred slightly more often in women than in men. Only 20% of patients with cryoglobulinemia had physical signs of liver disease at the time of presentation, but 70% of patients had mildly elevated aminotransferase levels and evidenced of liver involvement on biopsy. Renal disease occurred in 48% of patients with mixed cryoglobulinemia associated with HCV infection. These patients presented with arthralgia, neuropathy, and abdominal pain secondary to mesenteric vasculitis.

Hypertension was present in the 62 % of patients at the onset of renal disease; it often was severe and difficult to control.

The most common presenting clinical syndrome was an isolated proteinuria with microscopic hematuria, which was associated with moderate renal insufficiency in 50% of cases. About 25% of affected patients present with nephrotic syndrome that involves massive proteinuria and hypoalbuminemia. These patients had not circulating cryoglobulins. Acute nephritis is present at onset in 17% of patients, characterized by rapid deterioration of renal function, proteinuria in the nephrotic range (protein, >3 gm/24 hr), and hematuria. This acute nephritic syndrome usually is concomitant with acute flare-ups of systemic signs of mixed cryoglobulinemia.

Although renal involvement is common in hepatitis C, its lack of clinical manifestations means it goes undiagnosed in the majority of patients. Renal involvement can occur early in the course of the disease and occasionally is the presenting symptom of HCV infection. The symptoms of mixed cryoglobulinemia often manifested years before a diagnosis of renal disease is made, but in some patients, renal and extrarenal manifestations appear concurrently. In a few patients, symptoms of mixed cryoglobulinemia were absent.