The most appropriate treatment for acute kidney injury in this patient is 25% albumin. This patient has acute kidney injury (AKI) and hepatic encephalopathy, most likely precipitated by dehydration from lactulose-induced diarrhea. AKI is common and occurs in approximately 20% of hospitalized patients with cirrhosis. In approximately 70% of patients with cirrhosis and AKI, the precipitant is prerenal, from sources such as infection, gastrointestinal bleeding, excessive diuresis, or diarrhea. This patient has dry mucous membranes, diarrhea, and no obvious signs of infection or bleeding and has been treated with diuretics. Approximately two thirds of patients with prerenal AKI are fluid responsive. After stopping diuretics and lactulose, the best initial treatment is intravenous colloid administration, usually in the form of 25% albumin, administered at 1 g/kg body weight per day in divided doses.

The other third of patients who are not fluid responsive generally have type 1 or type 2 hepatorenal syndrome (HRS). HRS diagnostic criteria consist of (1) an increase in the serum creatinine level to greater than 1.5 g/dL (132.6 µmol/L) over days to weeks, (2) lack of response to an albumin challenge of 1 g/kg/d for 2 days, and (3) the absence of shock, nephrotoxic drugs, active urine sediment, proteinuria greater than 500 mg/d, and ultrasound evidence of parenchymal kidney disease or obstruction. Although this patient could have evolving HRS, this cannot be diagnosed until fluid responsiveness has been evaluated. If she is not fluid responsive and does not have evidence of acute tubular necrosis on urinalysis, then treatment for type 1 HRS could begin. Norepinephrine with albumin infusion is effective for patients with type 1 HRS who are in the ICU. Midodrine, octreotide, and albumin are the appropriate treatments for type 1 HRS in patients outside of the ICU. Terlipressin is effective for type 1 HRS but is not available in the United States.