Chronic viral hepatitis
Acute Viral Hepatitis
Simply, an infection with a hepatotropic virus, there are five main types responsible:
- Hepatitis A virus (HAV)
- Hepatitis B virus (HBV) and Hepatitis D virus (HDV), which only infects with HBV
- Hepatitis C virus (HCV)
- Hepatitis E virus (HEV)
Other viruses include human cytomegalovirus, epstein-barr virus, herpes simplex, human herpesvirus 6 and Parvovirus B19, which may establish chronic infection, but are not associated with chronic hepatitis.
Generally, we see acute necroinflammation of the liver, mediated by T cell-mediated reaction against infected hepatocytes that express the viral antigen (none of the viruses are actually cytotoxic themselves). Immune elimination may lead to viral clearance, if the immune response fails, we see a chronic infection established.
After infection there is an incubation period of a few days to a few weeks, this period sees leukopenia and lymphocytosis, as well as rash, hives, arthralgia and fever in 10-20% of patients. Once incubation is over, we enter the icteric phase, where symptoms vary from asymptomatic to ictrus, fatigue, anorexia, nausea, dark urine and light coloured stools. Total and direct serum bilirubin and ALT levels are often 10x greater than normal level. The icteric phase lasts 1- 3 weeks, following which we have recovery (ALT and Bilirubin return to normal, symptoms resolve) or chronification (see below).
Laboratory testing for acute viral hepatitis should be:
- Alanine aminotransferase (5-35 iu/L)
- Aspartate aminotransferase (5-35 iu/L)
- Alkaline phosphatase (30-150 iu/L)
- International normalised ratio (<1.2)
- Anti HAV IgM
- HBsAg, Anti-HBc IgM
- Anti-HCV antibodies
- HCV RNA
Chronic Hepatitis B
An insane 4% of the world's population are chronic HBV carriers, in eastern europe (and the asian subcontinent) this jumps to 8%, 1 in 3 of us have been in contact with the virus.
Chronic hepatitis B is usually asymptomatic, where symptoms do occur, they’re usually fatigue, sleep disorders, right upper quadrant pain. ASTs are chronically elevated while ALTs can fluctuate. Incidence of cirrhosis vary form 2-10% of patients, while hepatocellular carcinoma risk is about 1% annually in non-cirrhotic patients, 2-8% annually in cirrhotic patients. Rarely chronic hepatitis can cause the extrahepatic symptoms described above (glomerulonephritis, polyarteritis nodosa, in children and adults respectively).
Diagnosis is based on HBsAg, anti-HBs antibodies, total anti-hepatitis B core antibodies and anti-HBc immunoglobulins. Chronic HBV is on the basis of HBsAg in the serum for more than 6 months after acute episode.