Colouterine fistula mimicking pyometrium--diagnosis established with multi-detector computed tomography.

Fistulae are a recognised complication of severe diverticular disease. The commonest fistulae are from sigmoid colon to bladder and vagina.' Colouterine fistulae, though sporadically reported in the literature, are very rare. Patients often present to gynaecologists with symptoms mimicking a pyometrium. We report a case of a colouterine fistula in a 74 year old lady. A new generation 16 slice multidetector computed tomography (MDCT) scanner with multi-planar reconstruction software was instrumental in establishing the diagnosis, obviating the need for a contrast radiology study. CASE REPORT A 74 year old woman presented with a two week history of increasingly severe left iliac fossa pain associated with pyrexia, nausea, altered bowel habit, anorexia and a more recent history of a foul smelling green vaginal discharge (necessitating changing up to ten pads daily). A speculum examination by the general practitioner revealedpus emanating from the cervical os, and she was sent to the Accident & Emergency department. She denied any previous similar episodes. She was a non-insulin dependent diabetic of seven years' duration (metformin 850 mg tds; gliclazide 80 mg tds) and had hypertension and aloplecia totalis. Four years previously she was investigated for abdominal cramps and a change in bowel habit with a tendency to constipation. She was foundto have diverticulosis on double contrast barium enema. On admission to hospital she had a pyrexia of 380C. There was tenderness in the left iliac fossa on abdominal palpation. Routine blood tests revealed normal renal fimction, a neutrophil leucocytosis and an elevated C-Reactive Protein (275 mg/l, normal <7 mg/l). Vaginal swabs cultured enteric organisms (coliforms) and proteus sp. A limited abdominal ultrasound scan revealed a diffuse pelvic inflammatorymass, and intravenous andoral contrast enhanced abdominal and pelvic multidetector CT was arranged. This revealed a thickened sigmoid colon in keeping with diverticulitis, with a pericolic abscess and surrounding inflammation. A definite communication was seen from the pericolic abscess to the fundus of the uterus, the body of which contained air and fluid (figures 1 & 2). The fluid had tracked into both fallopian tubes resulting in secondary bilateral pyosalpinx. After being informed of the management options, complications and probable need for a stoma she agreed to proceed with surgery. At laparotomy a large pelvic inflammatory mass involvedthe sigmoid colon, small bowel mesentery, uterus, bladder and both fallopian tubes. In the centre of the mass was a moderately sized thick walled abscess containing