Abstract
Summary
We report an unusual case of a male patient with a colovesical fistula secondary to diverticulitis presenting in the genitourinary medicine clinic as non-gonococcal urethritis.
INTRODUCTION
A fistula is an abnormal passage usually between two internal organs or leading from an internal organ to the surface of the body. 1 Enterovesical fistulae occur between the bowel and the bladder. Colovesical fistulae are the most common type, usually involving the sigmoid colon and the dome of the bladder.
CASE REPORT
A 46-year-old man presented to genitourinary (GU) medicine with a four-week history of dysuria, brown penile discharge and red urine. He denied any abdominal or testicular pain, rectal bleeding or change in bowel habits. He had no past history of inflammatory bowel diverticulitis or bowel surgery. He had a history of gout for which he took Diclofenac as required. He was heterosexual with only one partner over the previous seven years.
On genital examination, there was a clear penile discharge but nothing else of note. The two-glass test showed the presence of threads and debris and on microscopy there were 5–10 pus cells per high field. Urethral swabs were taken for gonorrhoea and chlamydia together with a mid-stream sample of urine (MSSU). He was given a diagnosis of non-gonococcal urethritis (NGU), treated with a week's course of doxycycline 100 mg twice daily and asked to return in two weeks. The tests for gonorrhoea and chlamydia were negative, but the MSSU grew mixed faecal organisms for which he was treated with Cefalexin. When reviewed after treatment his symptoms had improved. However, he still had brown spots in his urine and noticed bubbles at the end of micturition. The latter specifically occurred at the time of defaecation. Abdominal palpation was normal and rectal examination revealed no masses but a ballooning posterior rectal wall. A colovesical fistula was suspected and a surgical referral made.
The patient underwent a colonoscopy. This revealed multiple diverticula with associated muscle hypertrophy and a provisional diagnosis of diverticulitis was given. However, during anterior resection of the left colon, the fistula became evident. Histology confirmed diverticulitis with features consistent with fistula formation.
DISCUSSION
The presenting symptoms of enterovesical fistulae occur primarily in the urinary tract. They include dysuria, pneumaturia (40% of patients), faecaluria (60% of patients) and recurrent urinary tract infections due to Escherichia coli, coliform, mixed growth or enterococcus. 2,3 Our patient experienced all of these symptoms.
Acquired enterovesical fistulae occur, among other things, as a result of diverticulitis, malignancy, Crohn's disease and iatrogenic causes such as radiation burn injury.
Diverticulitis was responsible for the patient's fistula. It is the most recurrent cause of colovesical fistula and has an overall incidence of 2%. 2,4 It is more common in men than in women with a ratio of 3:1. This is because of the protective presence of the uterus in women. 4
Cystoscopy is the most useful diagnostic tool. It has been reported to confirm a diagnosis of colovesical fistula in 60–75% of cases. 4
Other helpful diagnostic tools include radiological studies such as computed tomography (which is the most sensitive), cystography and barium enema. 5 Fistulae may be missed when any of these methods are used, but they are useful because they often demonstrate other intra-abdominal or pelvic pathology.
Colonoscopy and flexible sigmoidoscopy are of limited use in diagnosing fistulae but are able to exclude other pathology in the colon. 2 When our patient underwent a colonoscopy, the fistula was missed but diverticulitis was diagnosed. The fistula was subsequently diagnosed during surgery.
Our patient underwent an anterior repair, which is the treatment of choice for uncomplicated colovesical fistula secondary to diverticulitis.
CONCLUSION
We report an unusual case of NGU in a male patient due to a colovesical fistula secondary to diverticulitis.
We suggest that there should be a high index of suspicion for a colovesical fistula in a patient presenting to GU medicine with a low risk of sexually transmitted disease who complains of a discoloured penile discharge, passes bubbles in his urine and has mixed organisms in a MSSU.