Hepatitis and HIV infection during haemodialysis.

ABSTRACT

Viral hepatitis and human immunodeficiency virus (HIV) infection are important causes of mortality and morbidity in patients treated by haemodialysis (HD). Both are further promoted by the characteristic immunological dysfunction that develops in renal failure and interferes with the patient's ability to eliminate these viruses. The hepatotropic viruses A through G remain the causative agents in 60 to 80% of hepatitis. But, as far as HD is concerned, hepatitis B virus (HBV) and hepatitis C virus (HCV) are the two most important organisms responsible for almost all the patients' morbidity. In HD, both patients as well as staff are at a high risk of acquiring hepatitis B infection. The prevalence of HBV in the dialysis population in India is reported to range between 3.4% and 42%. The acute course of the infection is often anicteric and peak transaminase concentration is significantly less than in patients with normal renal function. Up to 60% of dialysis patients with HBV infection develop chronic hepatitis with persistence of hepatitis B surface antigen (HBsAg) and infectivity. The risk of transmission of HBV infection due to blood from one patient to another is mostly because of inadequate precautions taken by the dialysis staff. Combined therapy with interferon (6-10 million units) three times a week and lamivudine (100-300 mg/day) would be more effective in controlling viral replication. The most important modality for prevention of HBV infection is induction of immunity by hepatitis B vaccination. Administration of 40 microg doses at months 0, 1, 2 and 6 is the most rapid immunogenic schedule. The prevalence of HCV in HD patients ranges from 6% in the United Kingdom to 60% in Poland and Eastern Europe, 8-36% in North America. HD patients in different parts of India exhibit high anti-HCV positivity (12.1%, 45.2%, 33.3% and 41.9%) in various studies. The incidence and prevalence of HCV infection among patients on dialysis in developed countries are steadily declining because of (i) reduction in post-transfusion HCV infection, (ii) infection control measures to prevent nosocomial infection. Among HD patients with HCV infection, serum alanine aminotransferase (ALT, SGPT) levels are elevated in only 4 to 67% patients who are positive for anti-HCV, in only 12 to 31% patients with HCV RNA and only in one-third of those with biopsy proven hepatitis. Number of blood transfusion, duration of HD treatment, and mode of dialysis are important risk factors. Patient to patient transmission of HCV occurs in HD units by needle stick injury, breakdown in standard infection control practices, physical proximity to an infected patient, dialysis machines, dialysis membranes and HD ultrafiltrate and reprocessing of dialyser. The prevalence of HIV infection in dialysis populations varies according to different countries and geographic areas, 0% and 13% in 1990 and 1995 respectively. There was no evidence of transmission within the centre transmission, from patient to patient or patient to staff. Antiretroviral therapy is the corner-stone of the HIV infection in end stage renal disease (ESRD). Most commonly, zidovudine (AZT) has been used in these patients. Currently recommended dose of 200 mg three times a day is probably safe in these patients.