SUPERStudy: Hepatitis B 

By usmlevideoss

SUPERStudy: Hepatitis B 

Introduction

Hepatitis B is a liver infection caused by the Hepatitis B virus (HBV), a partially double-stranded DNA virus of the Hepadnaviridae family. It can cause both acute and chronic liver disease, leading to complications such as cirrhosis, liver failure, and hepatocellular carcinoma (HCC).

Etiology

  • Causative agent: Hepatitis B virus (HBV).
  • Transmission routes:
  • Blood (e.g., needle sharing, transfusions).
  • Sexual contact.
  • Perinatal (mother-to-child during childbirth).
  • Other body fluids (e.g., saliva, semen).

Epidemiology

  • Global prevalence:
  • High in sub-Saharan Africa and East Asia.
  • Intermediate in parts of the Middle East and Eastern Europe.
  • High-risk groups:
  • Healthcare workers.
  • People who inject drugs.
  • Infants born to HBV-positive mothers.
  • Vaccination:
  • Effective in preventing HBV infection.

Pathophysiology

  1. HBV entry and replication:
  • HBV infects hepatocytes and replicates using reverse transcriptase.
  1. Immune response:
  • Acute HBV: Strong immune response clears the infection.
  • Chronic HBV: Weak immune response leads to viral persistence and ongoing liver damage.
  1. Liver injury:
  • Mediated by immune-mediated destruction of infected hepatocytes.
  1. Complications:
  • Fibrosis → Cirrhosis → Hepatocellular carcinoma (HCC).

Clinical Manifestations

  1. Acute Hepatitis B:
  • Incubation period: 1–4 months.
  • Symptoms: Fever, fatigue, nausea, vomiting, abdominal pain, jaundice, dark urine, and pale stools.
  • Can progress to acute liver failure in rare cases.
  1. Chronic Hepatitis B:
  • Often asymptomatic or presents with fatigue and mild liver dysfunction.
  • Long-term complications: Cirrhosis and hepatocellular carcinoma.

Diagnosis

  1. Serologic markers:
  • HBsAg (Hepatitis B surface antigen): Indicates active infection.
  • Anti-HBs (Hepatitis B surface antibody): Indicates immunity (resolved infection or vaccination).
  • Anti-HBc (Hepatitis B core antibody): Indicates past or ongoing infection.
  • HBeAg (Hepatitis B e antigen): Marker of high viral replication.
  1. Viral DNA (HBV DNA): Determines viral load and guides treatment.
  2. Liver function tests (LFTs): Elevated ALT and AST levels in active disease.

Treatment

  1. Acute Hepatitis B:
  • Supportive care; antiviral therapy is rarely needed.
  1. Chronic Hepatitis B:
  • Antivirals (first-line):
  • Tenofovir (TDF/TAF).
  • Entecavir.
  • Immune modulation:
  • Pegylated interferon-alpha (Peg-IFN-α).
  • Goals of treatment: Suppress viral replication, reduce liver inflammation, and prevent progression to cirrhosis or HCC.

Prognosis

  • Acute Hepatitis B:
  • Most immunocompetent individuals clear the infection spontaneously.
  • Rarely progresses to fulminant liver failure.
  • Chronic Hepatitis B:
  • Risk of progression to cirrhosis (15–40%) and HCC.
  • Prognosis improves with effective antiviral therapy and regular monitoring.

SUPERPoint

Hepatitis B can cause both acute and chronic liver disease. Chronic infection is preventable with vaccination and manageable with antiviral therapy to prevent complications like cirrhosis and hepatocellular carcinoma.

SUPERFormula

Patient presents with fever, fatigue, nausea, vomiting, abdominal pain, jaundice, dark urine, and pale stools + HBsAg positive, Anti-HBc IgM positive, HBeAg positive + preventable with vaccination = Acute hepatitis B.