The most appropriate treatment is cefotaxime and albumin. This patient has been hospitalized with overt hepatic encephalopathy, which in many instances may be the sole presenting feature of spontaneous bacterial peritonitis (SBP). It is important to perform a diagnostic paracentesis in patients with ascites who are admitted to the hospital, especially those with overt hepatic encephalopathy. This patient's ascitic fluid analysis demonstrates a polymorphonuclear cell count of 574/µL, which exceeds the diagnostic threshold for SBP of 250/µL. The most important therapeutic intervention at this time is treatment of SBP, which precipitated this patient's hepatic encephalopathy. Appropriate treatment of SBP consists of a systemic antibiotic and intravenous albumin. For patients without nosocomial SBP or recent exposure to β-lactams, intravenous cefotaxime is the drug of choice. Patients with a serum creatinine level greater than 1 mg/dL (88.4 µmol/L), a serum bilirubin level greater than 4 mg/dL (68.4 µmol/L), or a blood urea nitrogen level greater than 30 mg/dL (10.7 mmol/L) should receive 1.5 g/kg of intravenous albumin (25%) on the day of diagnosis and 1 g/kg of albumin on day 3; this practice has demonstrated a survival benefit.

Cefotaxime and normal saline are not appropriate because this patient's survival will be improved with the use of intravenous albumin, whereas use of normal saline may result in worsening ascites.

Norfloxacin (or ciprofloxacin) is effective for secondary prevention of SBP and should be given to this patient indefinitely after completion of intravenous cefotaxime. However, norfloxacin is a poorly absorbed second-generation fluoroquinolone that is not appropriate for treatment of newly diagnosed SBP.

Treatment of overt hepatic encephalopathy is aimed at treating the underlying precipitant, in this case SBP. In these cases treatment consists of administering lactulose to achieve two to three, soft, formed bowel movements per day. Rifaximin is FDA approved for maintenance of remission in patients with previous episodes of overt hepatic encephalopathy, but it is not approved for initial treatment of overt hepatic encephalopathy or as treatment for SBP.