An alternative path to the cecum: nicorandil-associated diverticular sigmoido-cecal fistula

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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

Competing interests: None

References

• 1 Wong S K, Ho Y H, Leong A P, Seow-Choen F. Clinical behavior of complicated right-sided and left-sided diverticulosis.  Dis Colon Rectum. 1997;  40 344-348
• 2 Woods R J, Lavery I C, Fazio V W et al. Internal fistulas in diverticular disease.  Dis Colon Rectum. 1988;  31 591
• 3 Goh C, Wong S C, Borland C. Persistent orocutaneous and anal fistulae induced by nicorandil: a case report.  J Med Case Rep. 2009;  3 119
• 4 McDaid J, Reichl C, Hamzah I et al. Diverticular fistulation is associated with nicorandil usage.  Ann R Coll Surg Engl. 2010;  92 (6) 463-465