A patient with altered mental status who cannot dorsiflex the wrists due to asterixis most likely has which condition?

• A. Cocaine overdose
• B. Hyperthyroidism
• C. Hepatic encephalopathy
• D. Parkinson's disease

Answer: (C)

Asterixis, the flapping of the hands when the wrists are extended, signals a metabolic encephalopathy, most classically hepatic encephalopathy. In liver failure or portosystemic shunting, toxins like ammonia accumulate and impair brain function, producing altered mental status plus this characteristic motor sign. Cocaine overdose can cause agitation and sympathetic symptoms rather than asterixis. Hyperthyroidism causes a coarse tremor but not the sudden, flapping wrist movement seen with asterixis and encephalopathy. Parkinson's disease features a resting tremor and rigidity rather than asterixis and acute cognitive changes.