Appendicovesical fistula presenting as hypokalaemic hyperchloraemic metabolic acidosis: a case report

A 52-year-old man was admitted with diarrhoea and faecaluria and referred recurrent urinary tract infections for over 20 years. He also reported a two-week hospital admission more than 20 years ago for right iliac fossa pain, which was managed conservatively. Computed tomography showed a fistulous tract extending from the bladder with an unclear connection to the bowel. Cystoscopy confirmed the presence of a vesical fistula and biopsy of the tract confirmed colonic mucosa. Flexible sigmoidoscopy was negative. A cystogram was requested as an outpatient procedure and the patient was discharged after antibiotic treatment. A few days after discharge the patient was readmitted as an emergency to critical care for severe hyperchloraemic hypokalaemic acidosis and a Glasgow Coma Score of 6/15. He was intubated and ventilated and his metabolic derangement was treated. As soon as his conditions improved, he underwent emergency laparotomy, which revealed the presence of a fistula between the caecal fundus and the bladder. The fistula was repaired and the patient recovered swiftly and completely and was discharged on postoperative day 5. At 12-month follow up the patient was completely symptoms-free, his bowel habits were normal and he has not had any urinary infection. Appendicovesical fistula is a rare and potentially lethal condition due to its metabolic consequences. Past history of right iliac fossa pain treated conservatively, diarrhoea and recurrent urinary tract infection must raise suspicion.