Viral Hepatitis A B C D E: One-Page Guide to Diagnosis, Treatment, and Mnemonics (CDC & WHO 2024)

A Hepatitis A (HAV)

• Investigate
  • Serum anti-HAV IgM → acute infection.
• Treatment
  • Purely supportive; almost always self-limited.
• Post-exposure / Pre-travel
  • HepA vaccine within 14 days (≥ 12 months old).
  • Add 0.1 mL kg⁻¹ Ig if age < 1 yr, > 40 yr, chronic liver disease, or immunocompromised. cdc.gov

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B Hepatitis B (HBV)

• Investigate
  • Screen: HBsAg, anti-HBs, total anti-HBc ± IgM anti-HBc.
  • If HBsAg + → HBeAg, quantitative HBV-DNA, ALT, APRI/FIB-4 or elastography.
• Start antiviral when any of these present (WHO 2024):
  1. Cirrhosis (clinical or APRI > 2 / FIB-4 > 3.25 / LSM ≥ 11 kPa)
  2. HBV-DNA ≥ 2 000 IU mL⁻¹ + ALT > ULN (30 U/L ♂, 19 U/L ♀)
  3. LSM ≥ 8 kPa and DNA ≥ 2 000 (even if ALT normal)
  4. High-risk host (HIV/HCV/HDV, strong HCC family history, age > 30 y, or planned immunosuppression) and DNA ≥ 2 000
  5. Pregnancy 28-32 wk with DNA ≥ 200 000 or HBeAg +
  6. Severe acute/fulminant hepatitis (INR ≥ 1.5, encephalopathy) who.intcdn.who.intwho.intwho.intcdc.gov
• Give ONE potent NA (life-long in most):DefaultBone/renal sparingeGFR < 15 mL/min or TDF / TAF unavailableTenofovir DF 300 mgTenofovir AF 25 mgEntecavir 0.5 mg (1 mg if 3TC-resistant)No dual therapy needed.
• Monitor ALT + HBV-DNA q3-6 mo; US ± AFP q6 mo once ≥ F3.

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C Hepatitis C (HCV)

• Investigate
  • Screen anti-HCV Ab → reflex HCV RNA on same sample.
  • Stage fibrosis (FIB-4 / elastography).
• Treat when RNA detectable (acute or chronic). hcvguidelines.org
• Pick ONE pan-genotypic DAA course:StatusRegimenDurationNo cirrhosisGlecaprevir 300 mg / Pibrentasvir 120 mg8 wkSofosbuvir 400 mg / Velpatasvir 100 mg12 wkComp. cirrhosisSame; 8 wk (G/P) or 12 wk (SOF/VEL)Decomp. cirrhosisSOF/VEL + Ribavirin12 wk (24 wk if RBV-ineligible)
• Cure check: RNA – at week 12 post-therapy (SVR12).
• HCC surveillance lifelong if baseline F3/F4.

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D Hepatitis D (HDV)

• Investigate (only in HBsAg + individuals)
  • Anti-HDV Ab → confirm with HDV-RNA PCR.
• Treat (specialist):
  • Bulevirtide 2 mg SC daily ± peg-IFN-α 48 wk (higher response with combo). journal-of-hepatology.eujournal-of-hepatology.eu
  • If bulevirtide unavailable/intolerant → peg-IFN-α 52 wk alone. darmzentrum-bern.ch
• Continue/commence HBV NA (TDF/TAF/ETV) in all HDV patients.

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E Hepatitis E (HEV)

• Investigate
  • Anti-HEV IgM or HEV-RNA (serum or stool).
• Treatment
  • Acute immunocompetent: supportive.
  • Chronic (RNA + > 3 mo, usually SOT / chemo):
    1. Lower immunosuppression if possible.
    2. Ribavirin 600-1000 mg day⁻¹ for 12 wk (extend to 24 wk if RNA persists).
    3. Peg-IFN-α alternative in liver-transplant–free cases. sciencedirect.com

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Lightning Mnemonics

• HAV: “IgM + = rest; contact = vax + Ig.”
• HBV: “Cirrhosis OR 2 K + ALT → Tenofovir/Entecavir.”
• HCV: “RNA = Rx; 8/12 wk → cure.”
• HDV: “HDV ≙ bulevirtide ± peg-IFN.”
• HEV: “Chronic HEV? Think ribavirin 3 mo.”