Hyperammonemic encephalopathy associated with post-radiotherapy vesicointestinal fistula following cervical cancer

The majority of hyperammonemic encephalopathy is due to liver cirrhosis. However, urinary tract infection caused by urease-producing bacteria increases ammonia in urine and can lead to hyperammonemic encephalopathy, especially in cases with obstructive uropathy and vesicointestinal fistula. This is the first case report of hyperammonemic encephalopathy in a cervical cancer patient associated with postradiotherapy vesicointestinal fistula. A 52-year-old woman developed diarrhea due to vesicosigmoidal fistula 14 years after radical hysterectomy and radiotherapy to treat cervical cancer. She refused urinary and/or fecal diversion. Twelve months after the diagnosis of fistula, she was admitted due to somnolence. Blood examination showed hyperammonemia without liver dysfunction. Urine culture showed Proteus rettgeri and Klebsiella pneumoniae. She recovered after intravenous antibiotics. Eight months after recovery, she was readmitted due to somnolence reoccurring with failed intravenous, but successful oral antibiotic treatment. She finally agreed to undergo percutaneous nephrostomy and hyperammonemia never recurred during 7 years of follow-up.