Hepatitis C

Definition

Hepatitis C is a viral infection caused by the Hepatitis C virus (HCV), leading to acute or chronic liver disease, which may progress to cirrhosis, liver failure, and hepatocellular carcinoma.

Epidemiology

• Global prevalence: ~58 million people chronically infected
• Higher prevalence in Egypt, Pakistan, and parts of Africa and Asia
• Most infections occur via blood transfusion, unsafe injections, or intravenous drug use
• Chronic infection develops in 75–85% of acutely infected adults
• Peak incidence in adults aged 30–50 years

Etiology

• Hepatitis C virus (HCV), an enveloped single-stranded RNA virus of the Flaviviridae family
• Transmission: parenteral exposure to infected blood, intravenous drug use, unsafe medical practices, blood transfusions (before screening)
• Sexual transmission is less common but possible
• Vertical transmission from mother to child (~5% risk)
• No vaccine currently available

Pathophysiology

• HCV infects hepatocytes and replicates using host machinery
• Immune-mediated hepatocyte injury leads to inflammation and fibrosis
• Chronic infection results from inadequate immune clearance
• Progressive fibrosis may lead to cirrhosis, portal hypertension, and liver failure
• HCV induces oxidative stress, cytokine production, and altered lipid metabolism
• Extrahepatic manifestations: cryoglobulinemia, renal disease, lymphoproliferative disorders