42. HEPATITIS

Introduction

Hepatitis means inflammation and injury of the liver cells. It can occur due to toxins, alcohol, drugs, autoimmune diseases, and infections. Most commonly, hepatitis refers to viral infections of the liver caused by Hepatitis A, B, C, D, E and G. In India and Asia, Hepatitis A, B and C are most frequent.

Types of Viral Hepatitis

Hepatitis viruses (A, B, C, D, E, G) are responsible for most liver inflammation worldwide. Other viruses like herpes simplex, cytomegalovirus, Epstein–Barr virus, yellow fever virus and adenovirus can also cause hepatitis.

General Etiology

  • Use of infected needles or syringes
  • Intravenous drug use
  • Transfusion of infected blood/blood products
  • Unprotected sexual contact with infected person

Hepatitis A Virus (HAV)

Spread through contaminated food and drinking water, especially raw shellfish. Common in areas with poor sanitation. Mostly self-limiting and does not cause chronic hepatitis.

Pathophysiology

After ingestion, HAV crosses intestine, enters liver through blood, replicates inside hepatocytes, and causes cell damage by immune response and direct cell injury. Microscopically, spotty necrosis and inflammation are seen.

Hepatitis B Virus (HBV)

HBV infection ranges from mild, short-term illness to chronic liver disease, cirrhosis and liver cancer. Many adults recover fully, but infants and children have higher risk of chronic infection.

HBV Structure

  • Partially double-stranded DNA virus (Hepadnavirus)
  • Outer coat — HBsAg; excess production used for diagnostic tests
  • Nucleocapsid contains DNA + DNA polymerase with reverse-transcriptase activity
  • HBcAg present in hepatocytes; HBeAg in blood indicates infectivity

Pathophysiology

HBV itself does not kill liver cells. The immune system (cytotoxic T cells) attacks HBV-infected hepatocytes causing inflammation and liver injury. Acute cases show strong immune response and clearance; chronic cases show weak T-cell response leading to persistence. Long-term DNA integration increases risk of hepatocellular carcinoma.

Hepatitis C Virus (HCV)

Spread mainly through infected blood, unsafe needle use, and from mother to baby. Often asymptomatic until advanced liver disease develops.

Pathophysiology

HCV infects hepatocytes and sometimes B cells. Viral clearance happens only with strong immune response. Persistent infection leads to inflammation, fibrosis, cirrhosis and liver cancer in some patients.

Hepatitis D Virus (HDV)

Occurs only in people already infected with hepatitis B (requires HBsAg for replication). Infection can be co-infection (HBV + HDV together) or superinfection (HDV infects existing HBV carrier).

  • Co-infection: Often self-limiting but can cause acute liver failure.
  • Superinfection: More severe, rapid progression to cirrhosis, chronic hepatitis and liver cancer.

Hepatitis E Virus (HEV)

Spread mainly through contaminated water in endemic areas. Usually causes acute, self-limiting infection. Severe disease may occur in pregnant women or immunocompromised persons.

Pathophysiology

HEV is a non-enveloped RNA virus. Genotypes 1 and 2 infect humans; genotypes 3 and 4 infect both humans and animals. It replicates in the liver and causes acute inflammation.

Hepatitis G / GB Virus C

RNA virus belonging to pegivirus family. It infects humans but does not cause liver disease. Virus may be found in liver and blood cells.

Symptoms of Viral Hepatitis

  • Nausea and vomiting
  • Loss of appetite
  • Weakness and fatigue
  • Fever
  • Dark urine
  • Pale stool
  • Jaundice
  • Abdominal pain

Special Symptoms

  • HAV: Rare acute liver failure
  • HBV: May be asymptomatic in infants; chronic cases → cirrhosis, kidney issues
  • HCV: Chronic fatigue, weight loss, joint pain, cirrhosis, encephalopathy
  • HDV: Makes HBV symptoms more severe
  • HEV: Neurologic issues like neuropathy, GBS, confusion in rare cases

Diagnosis

1. Blood Tests

Detect antibodies and viral antigens.

  • IgM Anti-HAV — early infection
  • HBsAg — early infection or chronic carrier
  • IgM Anti-HBc — acute HBV
  • Anti-HCV — exposure (need follow-up tests)
  • HDV antibodies and HDV RNA for HDV diagnosis
  • Anti-HEV IgM — acute HEV
  • GBV-C RNA — research-level diagnosis

2. Liver Function Tests

ALT, AST, ALP and GGT rise due to hepatocyte injury.

3. Liver Biopsy

Used to estimate damage, grade/stage hepatitis, or guide treatment.

Treatment

Hepatitis A

  • No specific antiviral treatment
  • Supportive care
  • Milk thistle sometimes used as alternative therapy (not proven clinically)

Hepatitis B

  • Acute HBV: Usually no treatment required
  • Chronic HBV: Antivirals like lamivudine, adefovir, entecavir, telbivudine
  • Interferon therapy (peg-IFN)
  • Liver transplant for end-stage disease
  • Vaccination is highly effective

Hepatitis C

  • Modern treatment aims for cure
  • Drugs: Sofosbuvir, Ledipasvir, Simeprevir, Ribavirin, Peginterferon
  • No vaccine available
  • HCV patients should be vaccinated against HAV and HBV

Hepatitis D

  • High-dose interferon therapy (48 weeks)
  • Liver transplant for severe cases
  • HBV vaccination prevents HDV (no separate HDV vaccine)

Hepatitis E

  • Usually supportive treatment
  • Ribavirin may be used for severe disease
  • Interferon therapy in chronic HEV (rare cases)

Prevention

  • Safe drinking water and proper sanitation
  • Personal hygiene
  • Avoid raw/undercooked shellfish
  • Safe sex practices
  • Screening of blood donors
  • HBV vaccination for all newborns, children and adults at risk
  • Avoid sharing razors, toothbrushes, needles, nail tools

Detailed Notes:

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