The infection is caused by a virus of hepatitis D (HDV virus). This is quite a special virus, which can not exist individually, but only in coexistence with virus of infectious hepatitis B (HBV). Hepatitis D virus is transmitted by body fluids, i.e. during sexual intercourse or by sharing needles among intravenous drug addicts. Relatively common is also transmission from a sick pregnant woman to the fetus. It is possible to get infected by contaminated blood transfusion or by dialysis, but this is extremely rare in developed countries.
The incubation period is relatively long and it may last for 1-2 months. When the patient has been infected by a co-infection of both HBV and HDV, the disease usually manifests with acute symptoms including nausea, vomiting and anorexia. Jaundice may or may be not present. This acute stage is in the majority of cases followed by full recovery, only in few people the disease turns to chronic liver inflammation.
The situation is worse when HDV infection occurs in patient with already ongoing viral hepatitis B. In such case, the infection leads to a significant deterioration of the liver inflammation, which may relatively quickly progress into liver cirrhosis with all its complications, or it may be followed with acute liver failure, which is often fatal.
Clinical symptoms may be suspicious, especially inpatients with risky behavior (promiscuous sexual behavior, unprotected sex, intravenous drug abuse, etc.). Blood tests show elevation of liver tests marking the liver damage. Serology can confirm the diagnosis by finding specific antibodies directed against the virus in the patient’s blood. Signs of liver cirrhosis and its complications can be found by abdominal ultrasound.
The therapy of chronic hepatitis D equals the therapy of hepatitis B. Special antivirotics are used, probably the best is called pegylated interferon. Cases that have progressed into liver cirrhosis are treated symptomatically and liver transplant may be indicated in the most severe cases of liver failure.