Colonic volvulus is a life-threatening condition that occurs when a part of the colon twists upon its mesentery resulting in colonic obstruction or vascular compromise. Delaying treatment is associated with high morbidity and mortality. Twisting can occur in any position of the large bowel but most commonly involves the sigmoid colon due to the mesenteric anatomy. Common predisposing factors include chronic constipation, presence of a pelvic or ovarian mass, and pregnancy. Patients with volvulus are likely to be elderly, debilitated, and bedridden, as well as have associated dementia or psychiatric impairment. Postoperative adhesions, hernias, carcinoma, and intussusception are less common risk factors. Those who have had volvulus are likely to have a history of acute episodes in the past that have spontaneously resolved. Patients will present with acute onset of colicky abdominal pain, cramping, abdominal distension, obstipation, and constipation. As the condition progresses, nausea and vomiting will occur. Persistent abdominal pain is a sign that there is development of colonic obstruction, which can lead to ischemia, gangrene, and bowel perforation. Physical exam will reveal a largely distended, tympanitic abdomen. Patients who have rebound tenderness should be suspected to have peritonitis due to a perforated bowel. A complete blood count with differential may reveal an elevated white blood cell count, which would point to bowel ischemia, peritoneal infection, or sepsis. An abdominal radiograph can confirm diagnosis by revealing U-shaped, distended sigmoid colon (“bent inner tube” sign). Other studies such as computed tomography scan, barium enema, and colonoscopy or sigmoidoscopy may be helpful but not necessary if the radiograph is sufficient for diagnosis. Definitive treatment includes decompression via sigmoidoscopy and surgical resection. Patients who have peritonitis or ischemic bowel will require fluid resuscitation and broad-spectrum antibiotic treatment with emergency surgery to follow.
An ileus (B) occurs when there is hypomotility of the gastrointestinal tract and most commonly occurs after an abdominal surgery, which is not part of the patient’s history. Ischemic colitis (C) is characterized by insufficient blood supply to the intestines, so abdominal radiograph findings would most likely be normal. Toxic megacolon (D) is also characterized by colonic distension, but this diagnosis also requires other symptoms (e.g., fever, tachycardia, leukocytosis, etc.).