Colonic fistulas are rare and, in patients without inflammatory
bowel disease or neoplasia, are usually related to complicated appendicitis or
diverticulitis. We report a case of sigmoido-cecal fistula with no known
history of ileocolonic disease.
A 76-year-old caucasian man was referred for colonoscopy due to
change in bowel habits (recurrent bouts of mild diarrhea) for the previous 6
months. The patient denied having fever, abdominal pain, gastrointestinal
bleeding, prior abdominal trauma, or surgery. He had a history of hypertension
and ischemic heart disease; his usual medication consisted of nicorandil,
carvedilol, candesartan, acetylsalicylic acid, pravastatin, and pantoprazole.
Colonoscopy revealed multiple large diverticula on the sigmoid colon and,
adjacent to the appendix, a smooth round orifice wide enough to allow the
colonoscope to pass (11 mm wide), leading to what appeared to be the
sigmoid colon, with the distal portion of the colonoscope in view ([Video 1]; [Fig. 1]).
Fig. 1 Passage through the
fistula from the cecum to the sigmoid.
Video
1 View from the cecal side of
the fistula showing the moving colonoscope in the sigmoid colon.
A barium enema confirmed a wide sigmoido-cecal fistula ([Fig. 2]).
Fig. 2 Barium enema showing the
large-caliber fistula between the cecum and sigmoid colon.
Intra-abdominal fistulas are a known complication of diverticular
disease, but patients usually have a long history of symptoms and previous
episodes of diverticulitis [1]. Fistulization occurs
mostly to the bladder (65 %) or vagina (25 %);
colo-colonic fistulas are rare [2]. Nicorandil, a
potassium channel opener with a nitrate component, has been used for over 20
years in the management of angina. Recognized side effects of this drug include
oral, gastrointestinal, and genital ulceration, as well as fistula formation in
rare cases [3]. A recent case-control study by McDaid et
al, involving 153 patients with diverticular disease [4],
suggests that nicorandil may be associated with fistula formation in such
patients, with an odds ratio of 7.8. The pathogenesis and natural history of
nicorandil-induced ulceration and fistulization are still not clear.
In the present case, the authors believe that the use of nicorandil
could explain the paucisymptomatic presentation and large caliber of what
seemed to be a diverticular fistula.
Endoscopy_UCTN_Code_CCL_1AD_2AG
