Two cases of liver cirrhosis with hyperammonemic encephalopathy caused by urease-producing bacteria in the urinary tract

Hyperammonemia is often experienced as a complication of liver cirrhosis, but it is not well known that hyperammonemic encephalopathy is induced by urease-splitting bacteria in the urinary tract. We report two cases of hyperammonemia in two women in their 80s with liver cirrhosis. Both cases were treated as hepatic encephalopathy with usual treatment, but there was no improvement. Urinalysis showed marked alkalinuria and urine culture showed urease-splitting bacteria, which were thought to be related to the pathology. After drainage of urine and administration of antimicrobials, the blood ammonia level decreased and the urine pH level normalized. The mechanism of this is that ammonia is produced by the degradation of urinary urea by urease-producing bacteria in the bladder, and in the presence of dysuria, it is absorbed into the blood circulation from the bladder venous plexus, leading to hyperammonemia. Urine findings should be confirmed when a patient with liver disease develops hyperammonemia or is unresponsive to conventional hepatic encephalopathy treatment.