Abstract
Drug-induced nodular regenerative hyperplasia is an uncommon injury with unique pathophysiology,
clinical, and diagnostic considerations. This injury is characteristically asymptomatic
in its early phases with only mild elevations in transaminases (< 3× upper limit of
normal [ULN]). The latency period is typically more than 6 months. Once clinically
apparent, it is marked by complications of portal hypertension, including hypersplenism,
ascites, and variceal bleeding, with little or no hepatic dysfunction. Hence, it is
an important cause of noncirrhotic portal hypertension. The most commonly associated
drugs include thiopurines, chemotherapeutic agents, and antiretroviral agents. Diagnosis
is aided by the recognition of noncirrhotic portal hypertension, a detailed history
of prior drug exposure, and exclusion of the other causes of nodular regenerative
hyperplasia. Clinical history, abdominal imaging, and hepatic hemodynamic studies
provide important diagnostic clues, but histologic examination remains the diagnostic
gold standard. Therapeutic intervention is aimed at earliest discontinuation of the
offending agent and of portal hypertension complications. The natural history varies
widely, and portal hypertension can progresses despite drug discontinuation.
Keywords
nodular regenerative hyperplasia - drug-induced liver injury
