In a patient with a history of intravenous drug use presenting with signs of chronic liver disease, which virus is most commonly associated with chronic infection and progression to cirrhosis?

• A. Hepatitis A
• B. Hepatitis B
• C. Hepatitis C
• D. Hepatitis D

Answer: (C)

Chronic infection that steadily progresses to cirrhosis in adults with a history of intravenous drug use is most commonly due to hepatitis C. This virus has a high tendency to persist for life after exposure, and over years or decades it can cause ongoing liver inflammation and fibrosis, culminating in cirrhosis and its complications. In contrast, hepatitis A usually causes an acute, self-limited illness with no long-term liver damage, so it’s not a source of chronic infection. Hepatitis B can become chronic, especially with perinatal transmission, but in adults the rate of chronicity is lower than that seen with hepatitis C, and it’s less consistently linked to progression to cirrhosis in this context. Hepatitis D requires hepatitis B to infect and does not represent the most common cause of chronic liver disease in this setting. Therefore, hepatitis C best explains both chronic infection and progression to cirrhosis in an IV drug user with signs of chronic liver disease.