Viral hepatitis

Introduction

Viral hepatitis refers to inflammation of the liver caused by infection with one of the five major hepatitis viruses: Hepatitis A, B, C, D, and E. These viruses target liver cells, leading to varying degrees of liver inflammation, hepatocyte injury, and potential long-term complications such as cirrhosis and hepatocellular carcinoma (HCC).

Hepatitis A

• Definition:
  • Acute viral hepatitis caused by the Hepatitis A virus (HAV).
  • Transmitted via the faecal-oral route (contaminated food/water).
• Course:
  • Incubation: 2–6 weeks
  • Symptoms:
    • Fatigue, nausea, vomiting, abdominal pain
    • Jaundice
  • Resolution:
    • Self-limiting; most cases resolve without complications.
    • No chronic infection.
• Diagnosis
  • Positive anti-HAV IgM (acute infection)
  • Positive anti-HAV IgG (past infection or immunity)
• Management:
  • Supportive care (hydration, rest).
  • Post-exposure prophylaxis:
    • HAV vaccine and/or immune globulin within 2 weeks of exposure.
• Prevention:
  • HAV vaccine available
    • recommended for travellers and at-risk populations such as men who have sex with men.

Hepatitis B

• Definition
  • Hepatitis B is a viral infection caused by the Hepatitis B virus (HBV).
  • Transmitted via blood and body fluids (e.g., sexual contact, IVDU, vertical transmission).
• Course
  1. Acute Infection
     • Incubation: 1–6 months
     • Symptoms: Often asymptomatic; may cause fatigue, nausea, jaundice, and right upper quadrant pain.
     • Severe Cases: Can lead to fulminant hepatitis (rare but life-threatening).
     • Resolution: Most adults recover completely, developing anti-HBs antibodies (immunity).
  2. Chronic Infection
     • More common in infants (90%) than adults (5%).
     • Two types:
       • Inactive carrier state: Low viral replication, minimal liver damage.
       • Chronic active hepatitis: Persistent liver inflammation, increased risk of cirrhosis & hepatocellular carcinoma (HCC).
• Investigations
  • Hepatitis B serology
  • Screen for other blood-borne viruses (HCV, HIV) and other STIs
• Complications
  • Chronic hepatitis → “Ground-glass” hepatocytes on biopsy.
  • Hepatocellular carcinoma (HCC).
  • Cirrhosis & Liver failure.
  • Extrahepatic: Glomerulonephritis, polyarteritis nodosa, cryoglobulinemia.
• Management
  • Acute HBV:
    • Supportive care (fluids, rest)
    • Most cases resolve spontaneously
  • Chronic HBV:
    • First-line antiviral: Pegylated interferon-alpha.
    • Other options: Tenofovir, Entecavir (used long-term to suppress virus).
    • Screen for HCC (liver cancer) with ultrasound & FibroScan.
    • Liver transplant for end stage liver disease
  • Additional management
    • Lifestyle changes: Avoid alcohol, stop smoking.
    • Have a low threshold for screening patients who are are risk of developing hepatitis B
    • Notify public health England as it a notifiable disease
    • Educate the patient about reducing transmission and informing potential risk contacts
• Screening and diagnosis
  • All pregnant women screened for HBV
  • Screen high-risk individuals (e.g., IVDU, MSM, healthcare workers)
• Vaccination
  • Part of UK routine schedule (6-in-1 vaccine) at 2, 3, and 4 months.
  • At-risk groups (HCWs, IVDUs, sex workers, CKD, liver disease, prisoners) should be vaccinated.
  • Booster at 5 years for at-risk individuals if anti-HBs < 100 mlU/ml.
• Pregnancy and newborns
  • All pregnant women are screened.
  • If mother is HBV-positive,
    • Newborns gets vaccine
    • HBIG at birth
    • extra doses at 1 & 12 months.
  • Breastfeeding is safe if infant is vaccinated.

Hepatitis C

• Definition:
  • Viral hepatitis caused by HCV, a single-stranded RNA virus.
  • Transmitted through blood contact (IVDU, transfusion, sexual)
• Course:
  • Acute:
    • Incubation: 2–12 weeks
    • Often asymptomatic
    • 80% progress to chronic infection
  • Chronic:
    • Progressive liver damage → cirrhosis (20–30%)
    • Increased risk of HCC
• Diagnosis
  • HCV RNA – Confirms active infection
  • Anti-HCV antibodies – Confirms past or current infection
• Management:
  • Direct-acting antivirals (e.g., sofosbuvir, ledipasvir)

    • 95% cure rate

  • Screen for HCC and liver fibrosis regularly

Hepatitis D

• Definition:
  • Caused by the Hepatitis D virus (HDV), a defective RNA virus that requires HBV to replicate.
• Course:
  • Co-infection:
    • Acute HBV and HDV infection leading to severe hepatitis
  • Superinfection:
    • Chronic HBV + HDV leading to rapid progression to cirrhosis
• Diagnosis
  • Positive HDV RNA
  • Positive anti-HDV antibodies
• Management:
  • Pegylated interferon-alpha (poor response)
  • HBV suppression reduces HDV activity
  • Liver transplant if severe cirrhosis

Hepatitis E

• Definition:
  • Caused by Hepatitis E virus (HEV)
  • Faecal-oral transmission (contaminated food/water)
• Course:
  • Acute:
    • Incubation: 2–8 weeks
    • Self-limiting in most cases
  • Severe in Pregnancy:
    • Risk of fulminant hepatitis and liver failure (especially in 3rd trimester)
• Diagnosis
  • Anti-HEV IgM – Acute infection
  • HEV RNA – Confirms active infection
• Management:
  • Supportive care
  • Avoid immunosuppressive drugs if chronic infection in immunocompromised
• Prevention
  • Improve sanitation and water quality
  • HEV vaccine available in some countries (not globally licensed)