Drug-induced nodular regenerative hyperplasia.

Area of Science:

• Hepatology
• Toxicology
• Pathology

Background:

• Drug-induced nodular regenerative hyperplasia (NRH) is an uncommon liver injury.
• It is characterized by unique pathophysiology and diagnostic challenges.
• Early stages are often asymptomatic with mild transaminase elevations.

Purpose of the Study:

• To review the pathophysiology, clinical presentation, diagnosis, and management of drug-induced NRH.
• To highlight its role as a cause of noncirrhotic portal hypertension.
• To discuss commonly associated drug classes.

Main Methods:

• Review of literature on drug-induced NRH.
• Analysis of clinical, diagnostic, and histological features.
• Identification of causative agents and management strategies.

Main Results:

• Drug-induced NRH presents with mild transaminase elevations (< 3× ULN) and a latency period > 6 months.
• Clinical manifestations include portal hypertension complications (hypersplenism, ascites, variceal bleeding) with minimal hepatic dysfunction.
• Commonly associated drugs include thiopurines, chemotherapy, and antiretroviral agents.
• Diagnosis relies on recognizing noncirrhotic portal hypertension, drug history, and excluding other causes.
• Histologic examination is the gold standard, though imaging and hemodynamic studies are valuable.
• Discontinuation of the offending agent is the primary treatment, but portal hypertension can persist.

Conclusions:

• Drug-induced NRH is a significant cause of noncirrhotic portal hypertension.
• Early recognition and drug cessation are crucial for management.
• Prognosis varies, and portal hypertension may progress despite treatment.