Snapshot A 45-year-old male presents with an acute change in mental status. He has had waxing and waning attention span and currently is mumbling his words and making no sense. The patient has a past medical history of intravenous drug use and unprotected sexual intercourse with over 75 different partners in his lifetime. On physical exam you note a nearly obtunded gentleman with yellowing of his skin and a shaking of his hands when he holds them in an outstretched position. Serology for this patient is positive for IgM against hepatitis C as well as core antibody positivity against hepatitis B. Introduction Seen in cirrhosis patients Due to brain toxicity from excess ammonia and other toxins not degraded by failing liver Precipitated by alkalosis hypokalemia CNS drugs GI bleeding infection hypovolemia Presentation Symptoms dementia seizures obtundation / coma Physical exam hyperreflexia asterixis (flapping of extended wrists) Treatment Treat precipitating cause (e.g., give K+ if hypokalemic) Lactulose metabolized to lactic acid by colonic flora, converts NH3 to NH4+ which can be absorbed Neomycin replaced with rifamixin, neomycin no longer routinely used antibiotics kill colonic flora leading to decreased NH3 production