A Twisted Case of Severe Megacolon Complicated by Recurrent Volvulus

Abstract

Purpose: A 69-year-old male with morbid obesity and 10 years of progressive abdominal distension presented with decreased stool output and mild abdominal pain over one week. His last bowel movement was two days prior and mostly mucous. His weight was 345 lbs and he appeared comfortable with massive abdominal distension that was diffusely tympanic and non-tender. A rectal exam was without stool impaction. His labs showed new iron deficiency anemia. CT scan revealed marked dilatation (>20 cm) of the colon without a transition point. A water-soluble contrast enema was unable to reach the splenic flexure. Colonoscopy was limited by inadvertent retroflexions in the dilated sigmoid but did reveal severe erythema, edema, and ulcerations with significant narrowing of the distal sigmoid. The patient was subsequently admitted to the hospital for small volume hematochezia and hypotension. He underwent emergent surgery, with removal of a massively dilated colon with a sigmoid volvulus. Pathology did not reveal Hirschsprung's disease or neoplasm. His clinical status improved daily and he was discharged 80 lbs lighter at 265 lbs. Megacolon has been defined as a luminal diameter of >6.5 cm when applied to the rectosigmoid or descending colon. Its etiologies include aganglionosis (Hirschsprung's), medications, chronic constipation, infection, acquired colonic dysmotility, or true mechanical obstruction. Megacolon is a predisposing factor to sigmoid volvulus. There have been a few cases of megacolon presenting as sigmoid volvulus in the literature. This is a case of chronic megacolon from chronic constipation leading to a sigmoid volvulus. Notably, sigmoid volvulus is a rare cause of obstruction in the United States and this diagnosis can be made even more difficult with imaging limitations in the obese population. In this case, the iron deficiency anemia raised the possibility that he was bleeding from ischemic ulcers. If such as suspicions exist, a patient should not be given a colonoscopy prep as this can worsen the obstruction. Additionally, endoscopy should be performed with caution given the difficulties of safely advancing in dilated colons. Ultimately, in cases where chronic constipation and megacolon co-exist, an abrupt clinical change warrants consideration for colonic volvulus.Figure: [1230]