Cologenital Fistula Secondary to Diverticulitis

A78 year-old gravida 3, para 2 with a history of congestive heart failure, chronic obstructive pulmonary disease, and non-insulin-dependent diabetes mellitus presented to an outpatient gynecology clinic with one month of brown vaginal discharge. The patient had had two recent hospitalizations for diverticulitis, diagnosed by computed tomography (CT). On examination, the patient was afebrile with a non-tender, non-distended abdomen. The vagina was atrophic, and the uterus was retroverted with no palpable abnormalities. Ultrasound scanning demonstrated a thickened endometrial stripe, and the patient was admitted to the hospital for further evaluation.

On admission, the patient was stable, with normal vital signs and laboratory values. Abdominal examination was benign. A CT scan with intravenous and oral contrast media demonstrated a low-attenuation tract with several foci of air extending from a perisigmoidal fluid collection toward the cervix and inside the uterus (Fig. 1). Dilation, curettage, and hysteroscopy revealed feculent material emerging from a small communication in the posterior fornix. Sigmoidoscopy uncovered no signs of neoplasm. Endometrial and cervical pathology review likewise found no signs of malignant disease.

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FIG. 1.

Computed tomography demonstrating low-attenuation tract with foci of air extending from perisigmoidal fluid collection toward cervix and inside uterus (thin arrow). Thick arrow points to left ovarian cyst adjacent to uterus.

A poor surgical candidate owing to her multiple medical problems, the patient was treated nonoperatively. Six months later, she still had occasional feculent discharge but had neither demonstrated signs of infection nor need to return to the hospital.

Often having no signs of infection, patients with cologenital communications present with feculent, purulent, or hemorrhagic discharge. Common causes of such fistulae are diverticular disease, cancer, radiation, inflammatory bowel disease, infection, and surgical iatrogenesis. Of patients with diverticulosis, 10–25% will develop diverticulitis, with fistulae complicating as many as 20% of operative cases [1]. Colovesical tracts are most common, being 2- to 3-fold more prevalent in males [2]. The uterine wall presumptively shields the bladder and vagina and is itself resistant to penetration, explaining the association between hysterectomy and colovesical and cologenital fistulae [3]. In 1933, Noecker first reported a colouterine fistula secondary to diverticulitis, but fewer than 20 cases were described before 2004, as reported by Sentilhes et al. [1]. Hysteroscopy, ultrasonography, vaginography, and even charcoal ingestion have limited diagnostic utility, although advances in imaging and contrast media are improving their capabilities [4]. Colonic evaluation, endometrial curettage, and cervical sampling must be included in the initial evaluation to exclude neoplasm. In this case, the CT demonstration of free air in the uterus introduced the possibility of a colouterine fistula. In the context of normal hysteroscopy and the described appearance of the posterior fornix, the final diagnosis was colovaginal fistula, with imaging being complicated by the introduction of gas into the uterus during the preceding physical examination. For surgical candidates, sigmoid resection followed by primary anastomosis achieves satisfactory results in the majority of such cases, although those patients at high risk of dehiscence may be diverted [5]. Otherwise, conservative management may be considered for frail patients with no signs of sepsis.