Viral hepatitis refers to an inflammation of the liver by one of a number of different viruses, such as hepatitis A, B, C, D, or E. In addition, some other viruses that normally affect other areas of the body can also affect the liver – these viruses are CMV (cytomegalovirus), EBV (Epstein Barr virus), HSV (Herpes Simplex Virus), and VZV (Varicella Zoster virus, which causes shingles and chicken pox).
Hepatitis A is a virus transmitted through contaminated water or food. Although it can cause an acute infection, with symptoms of stomach and muscle pain, fatigue, and jaundice. It often resolves with rest and fluids. Hepatitis A can generally be prevented by vaccination. The vaccine is recommended in all patients with underlying liver disease, regardless of whether they have cirrhosis or not, as patients with underlying liver disease do not tolerate a second hepatic insult very well.
Hepatitis B can cause both an acute hepatitis, or can cause chronic hepatitis. Generally, the older one is when one acquires the infection, the less likely it is to cause chronic hepatitis and its complications. Hepatitis B is spread through the exchange of, or contact with, infected bodily fluids. Thus, risk factors for the acquisition of hepatitis B are exposure to infected blood (either through a transfusion, or from infected needles or medical equipment), unprotected sexual intercourse with an infected partner, or from an infected mother to the child during pregnancy or breast-feeding.
Hepatitis B is treated with medications such as interferon, lamivudine, tenofovir, adefovir, or telbivudine. Currently, the University of Calgary Liver Unit is involved in a number of studies examining new potential treatments for hepatitis B.
Vaccinating for Hepatitis B generally results in an immunity to, and protection against, developing hepatitis B in patients who have not had the virus. Patients who have had previous exposure to hepatitis B and have cleared it will have a positive hepatitis B surface antibody (HBsAb), as well as a positive core antibody, but will not have a positive hepatitis B surface antigen (HBsAg). The decision to treat a patient is made on the levels of HBV DNA, the presence of hepatic fibrosis, and presence of hepatocyte inflammation (as indicated by elevated liver enzymes). Patients undergoing immunosuppressive therapy, such as chemotherapy, treatment with immunomodulators for their IBD or rheumatoid arthritis, or those who are to be placed on steroids should all be tested for prior exposure to hepatitis B, as this can reactivate in the immunocompromised setting and can result in liver failure.
Hepatitis C, like Hepatitis B, can cause both an acute hepatitis and a chronic hepatitis. It is generally transmitted through blood, and therefore risks for transmission are blood transfusion, tattoos and piercings done with a needle used previously by an infected person, and sharing dirty needles or drug paraphernalia.
Treatment of Hepatitis C is a fast evolving area. In the past, we used a combination of two medications – interferon and ribavirin. Response to treatment varies based on the type (genotype), the amount of scarring in patient’s liver, and a number of other factors. Some genotypes are harder to treat, and take longer to treat than others. Recently, however, newer drugs have arrived on the market. Some of these drugs are used to addition to standard therapy to increase rates of response, and other drugs are used in patients who can not tolerate interferon. The University of Calgary currently runs a number of trials examining the effect and efficacy of various new, experimental drugs in patients with hepatitis C, both in patients who have been treated before and failed, and in patients who have never undergone treatment.
Initial testing for HCV is through the HCV antibody. However, any previous exposure to HCV will result in lifelong positivity of this antibody, even in patients who have been previously successfully treated or have innate immunity from clearing it on their own. Therefore, if the HCV antibody is positive, the next step prior to hepatology referral is to order an HCV RNA level. If the RNA is negative, this indicates a previous infection that is now cleared, and the patient is no longer infected. A positive HCV RNA level indicates ongoing infection, and these patients should be referred for evaluation of treatment. Identifying those patients who are no longer infected is of vital importance, as it prevents patients from needless worry about a possible infection.
Hepatitis D can only exist in patients who are already infected with Hepatitis B. Risk factors for the transmission for Hepatitis D are the same as those for Hepatitis B. In patients with hepatitis B, a sudden increase in liver enzymes, or a deterioration in liver function may be secondary to either a flare of the hepatitis B, or may be a sign of a superimposed Hepatitis D infection.