Hepatitis A, B, C — Natural History

“Natural History” means the course of untreated disease.

Hepatitis A

Main Risks:  Third World travel, MSM, undercooked shellfish, contact with recent HepA pt / outbreak, daycare

Incubation Period 2-6 weeks

Transaminases rise, to the 1000’s (height is not prognostic)

Symptoms: anorexia, nausea, vomiting, fever, malaise, jaundice

  • Symptoms decline as jaundice appears
  • Many cases asymptomatic, especially in children
  • Uncommon extrahepatic manifestations possible

Lifelong Immunity after infection (100% of persons)

  • Rare cases of relapsing disease

Fulminant HepA: 0.1% of cases (high mortality)

  • Usually persons with other chronic liver disease

Hepatitis B

Main Risks:  Asian immigrant / child of Asian immigrant, MSM, Multiple sexual partners, IDU, partner w/ chronic Hep B

Incubation Period:  2-6 months

Most acute infections are asymptomatic

Most people (90%) clear the virus, remain immune forever (“surface-antibody” positive)

Chronic Hep B: 5-10% of people  —  HBsAg (“surface-antigen”) positive

  • Most of these are just Chronic Carriers (infectious, but don’t get ill)
  • Some get Chronic Active Hepatitis, Dx’d by high viral load [HBV DNA >100,000 copies / 20,000 IU], eventually die from cirrhosis or hepatocellular carcinoma
  • Most vertically-infected persons eventually get Chronic Active Hepatitis

Hepatocellular Carcinoma can occur at any time in course of Chronic Active Hepatitis, even before advent of cirrhosis

Occult Hep B:  screen patients headed for heavy chemotherapy / bone marrow transplant

  • If “core-antibody” positive, some risk of reactivation even if HBsAg negative

Hepatitis C

Main Risks:  Blood transfusion before 1992 (in US), IDU, MSM with multiple sexual partners

Incubation Period:  6-12 weeks

Most acute infections are asymptomatic

Most people (80-85%) remain chronically infected — Dx’d by positive viral load (HCV RNA)

  • 15-20% clear the virus, never get sick, but can get reinfected

Chronic Hep C leads to cirrhosis.  Approximate time frame:

  • 10% of people in 10 yrs.
  • 30% in 30 yrs.
  • 50% in 50 yrs.

Hepatocellular Carcinoma usually only occurs after cirrhosis

Genotype and viral load not prognostic, but do predict response to treatment.