Hepatitis - Causes and Types

Hepatitis - Causes

• Inflammation of the liver
• Can be caused by both infectious and non-infectious agents.
• Infectious causes include bacteria, viruses, and other organisms.
• Non-infectious causes include drug use, alcohol consumption, vascular issues, autoimmune disorders, and metabolic conditions.
• Viral infections included Hepatitis A, B, C, and E.
• Other viral infections include Cytomegalovirus, Epstein-Barr virus, Rubella, and Yellow Fever.

Hepatitis A

• RNA virus that infects the liver
• Transmitted via the fecal-oral route, often through contaminated food or water.
• Incubation period of 30 days (range 15-50).
• Infectious for two weeks before to one week after the onset of symptoms.
• Primarily found in developing countries.
• In developed countries it is most commonly found in travellers to endemic countries, households with confirmed cases, sexual contacts of confirmed cases, and occasional foodborne outbreaks.

Hepatitis B

• DNA virus that infects hepatocytes (liver cells)
• Hepatitis B core, surface, and envelope antigens are produced.
• There are three virus forms: Dane particle, Spherical form, and filaments.
• Dane particles contain the entire viral genome and are the only infectious form.
• Spherical and filamentous forms lack DNA but have the virus envelope that contains the Hepatitis B surface antigen (HBsAg).

Hepatitis C

• RNA virus in the Flaviviridae family.
• At least 6 distinct genotypes (1-6) with no cross-protection.
• Transmission through blood-to-blood contact, primarily via contaminated needles, infected blood products, and sexual intercourse.
• Incubation period of 8 weeks (average).

Hepatitis D

• Incomplete viral particle
• Defective RNA virus.
• Requires Hepatitis B surface antigen (HBsAg) for propagation.

Hepatitis E

• RNA virus with four genotypes.
• Found predominantly in developing countries.
• Transmitted via contaminated water and food.
• Incubation period of 30-40 days.

Hepatitis B Serology

• Antibodies and antigens detected in serum
• Hepatitis B surface antigen (HBsAg): present in acute and chronic infections, indicates infectivity
• Hepatitis B e antigen (HBeAg): present in acute and chronic infections; high levels indicate high viral replication
• Hepatitis B e antibody (HBeAb): indicates the body is controlling infection & viral replication is decreasing
• Anti-Hepatitis B core IgM (HBcAb IgM): appears in acute infection, indicating recent infection
• Anti-Hepatitis B core total (IgG) (HBcAb IgG): usually positive for life, indicating prior exposure to the virus.
• Anti-Hepatitis B surface antibody (Anti-HBs): usually appears after the initial infection has resolved; can indicate vaccination.

Hepatitis B Serology Interpretation

• Patient A: Acute Hepatitis B infection.
• Patient B: Chronic Hepatitis B infection, with declining viral activity.
• Patient C: Resolved Hepatitis B infection.
• Patient D: Resolved Hepatitis B infection with immunity due to vaccination.

Hepatitis C Serology

• Anti-HCV: Indicates prior or current exposure to hepatitis C.
• HCVag: Indicates active infection.
• HCV RNA: Indicates active infection.
• Acute infection (infectious): Anti-HCV may be negative or positive, HCVag is positive, and HCV RNA is positive.
• Chronic infection (infectious): Anti-HCV is positive, HCVag is positive, and HCV RNA is positive.
• Infection cleared (non-infectious): Anti-HCV is positive, HCVag is negative, and HCV RNA is negative.

Hepatitis A Prevention

• Hygiene: Good handwashing practices and sanitation
• Traveller Advice: Educate travellers about potential risks and recommend vaccination or immunoglobulin if needed.
• Vaccination: Inactivated vaccine available
  • Post-exposure: Given to contacts of cases and for outbreak control.
  • Pre-exposure: Recommended for travellers to endemic countries, people with chronic liver disease, injecting drug users, gbMSM, and workers exposed to raw untreated sewage.

Hepatitis A Immunoglobulin (Passive Immunization)

• Given as post-exposure prophylaxis
• Needs to be given within 2 weeks of exposure to be effective.
• Recommended for:
  • Individuals over 60 years old
  • Those at risk of severe complications (e.g., chronic liver disease, chronic hepatitis B or C infection)

Hepatitis B Prevention

• Standard Precautions: Hand hygiene, use of personal protective equipment, safe disposal of sharps.
• Safe Injections: Use of clean needles and disposable syringes.
• Blood Screening: Screen blood products to prevent transmission.
• Safe Sex: Safer sex practices to reduce the risk of transmission.
• Passive Immunization: Immunoglobulin given for post-exposure prophylaxis.
  • Recommended for:
    • Neonates (at birth)
    • Needle stick injuries in unvaccinated individuals or those with inadequate antibodies
    • After high-risk sexual exposure
  • Vaccine is also recommended along with immunoglobulin.

Hepatitis B Vaccination

• Pre-exposure prophylaxis using cloned Hepatitis B surface antigen (HBsAg).
• Vaccine Course: Three doses.
• Antibody Titers: Ideally > 100 IU/mL of anti-HBs.
• High Risk Groups: Healthcare workers, part of national immunisation program.

Hepatitis - Causes

• Hepatitis is inflammation of the liver.
• It can be caused by infectious or non-infectious agents.
• Infectious causes include bacterial, other, and viral agents.
• Viral subtypes include Hepatitis A, B, C, D, and E.
• Non-infectious causes include drugs, alcohol, vascular, autoimmune, and metabolic factors.

Hepatitis A

• It is an RNA virus, an enterovirus (picornavirus).
• It is not cytopathic in itself; cellular immunity is thought to cause liver damage.
• It is transmitted primarily person-to-person via the fecal-oral route.
• Transmission can also occur through contaminated food and water.
• The incubation period is 30 days (range 15-50).
• Period of infectiousness is 2 weeks before to 1 week after onset of symptoms.

Hepatitis B

• It is a DNA virus that infects hepatocytes.
• Viral proteins are expressed on the surface, triggering the cellular immune response.
• There are three virus forms: Dane particle, spherical form, and filaments.
• The Dane particle is the infectious particle.

Hepatitis C

• It is an RNA virus (flavivirus).
• There are at least six distinct genotypes (1-6).
• There is no cross-protection; individuals can be reinfected with another genotype.

Hepatitis D

• It is a defective RNA virus.
• Uses hepatitis B surface antigen for propagation.

Hepatitis E

• It infects both animals and humans.
• There are four genotypes with different geographic distributions and epidemiology.
• Genotypes 1 and 2 are transmitted via fecally-contaminated water in developing countries.
• Genotypes 3 and 4 are found in humans, pigs, and other mammals.
• Transmission to humans occurs through undercooked or raw pig and game meat, processed pork, shellfish (genotype 3), handling animals (particularly pigs), and contaminated water.
• Incubation period is 30-40 days post exposure.

Hepatitis B and C

• Hepatitis B is vaccine-preventable, while Hepatitis C is not.
• The incubation period for Hepatitis B is 1-6 months, compared to 8 weeks (average) for Hepatitis C.
• Transmission to humans for both Hepatitis B and C includes perinatal, sexual, and parenteral routes.

Hepatitis B - Epidemiology:

• In low prevalence areas, acute infection is sporadic in adults.
• Spread is primarily through sex and parenteral routes.
• In high prevalence areas, acute infection is found in infants and young children.
• Spread is through intrapartum and close household contact.

Clinical Presentation of Viral Hepatitis

• Patients may be asymptomatic or symptomatic.
• Symptomatic infections are often preceded by prodromal symptoms (fever, loss of appetite, nausea, fatigue, right upper quadrant abdominal pain).
• Other symptoms include dark urine, pale greasy stools, and jaundice (build-up of bilirubin).
• Abnormal liver function tests (LFTs) are seen in cases of viral hepatitis.

Hepatitis A Clinical Course

• Acute infection is generally asymptomatic in children.
• Risk of symptomatic infection increases with age and coinfection (e.g., hepatitis B).
• Fulminant disease (acute hepatitis failure) is unusual.
• It takes 6 months for chronic infection to develop.

Hepatitis B - Laboratory Diagnosis

• HBsAg (surface antigen) is positive in acute and chronic infection.
• Hep BeAg (e antigen) is detectable when the virus is actively reproducing.
• Hep Be Ab (e antibody) and anti Hep B core IgM are positive in current hepatitis B infection.
• Anti Hep B core total (IgG) and anti HBs (surface antibody) are positive in cleared infection.

Hepatitis C - Laboratory Diagnosis

• Hepatitis C antibody (Anti-HCV) is positive 2-6 months after exposure to hepatitis C.
• It remains positive even if infection has cleared.
• Hepatitis C antigen (HCV ag) is positive in acute and chronic infection.
• Hepatitis C virus (HCV) RNA is positive in acute and chronic infection.

Hepatitis A Treatment and Prevention

• Treatment is supportive care.
• Prevention includes hygiene, advice to travelers, sanitation, and vaccination.

Hepatitis A Vaccination

• It is an inactivated (not live) vaccine.
• Post-exposure: It is used for management of contacts of cases and outbreak control.
• Pre-exposure: It is recommended for travelers to endemic countries, at-risk individuals (chronic liver disease, injecting drug users, men who have sex with men, workers exposed to raw untreated sewage), and those over 60 years of age.
• Passive immunization (immunoglobulin) is a post-exposure prophylaxis option.

Hepatitis E Management and Prevention

• Acute infection is usually self-limiting; treatment is symptomatic.
• Chronic infection in transplant patients may require reducing immunosuppression and using antivirals.

Hepatitis B Treatment

• Acute infection requires supportive therapy.
• Chronic infection management includes patient education, vaccination, and antiviral therapy.
• Antiviral therapy aims to prevent progression to cirrhosis, liver failure, and cancer but cannot eradicate the virus.
• Goal of antiviral therapy is to reduce hepatitis B DNA below detectable levels and achieve seroconversion of e antigen to e antibody.
• Liver cancer monitoring (ultrasound, Alpha Feta Protein) is important.
• Transplantation is considered for fulminant hepatitis and end-stage chronic hepatitis.

Hepatitis B Prevention

• Strategies vary based on high and low prevalence areas.
• Prevention includes standard precautions (safe sex, screening blood products, clean needles/disposable equipment, hand hygiene, gloves, goggles, aprons, safe disposal of sharps), avoiding risk factors, and passive immunization (immunoglobulin) for post-exposure prophylaxis.
• Pre-exposure prophylaxis includes vaccination.
• Hepatitis B vaccine uses a cloned surface antigen (HBsAg) and induces antibodies to HBsAg (Anti-HBs).

Hepatitis C Management

• There is no post-exposure prophylaxis for acute infection.