Urinary Tract Infection as a Cause of Hyperammonemic Encephalopathy

We report on a case of the altered mental status from hyperammonemia due to a urinary tract infection of ureaseproducing (urea-splitting) bacteria. A 98-year-old Japanese woman, who had no history of liver cirrhosis or portal hypertension, presented with altered mental status. The cause of the altered mental status was attributed to an elevation of ammonia in her blood. The urine culture grew Proteus vulgaris. Complete recovery occurred with the use of an antibiotic for the urinary tract infection. Among patients with urinary tract infections, but without liver cirrhosis or portal hypertension, production by urea-splitting bacteria and the subsequent tubular reabsorption of ammonia, may result in hyperammonemic encephalopathy.