Cecal bascule with concurrent acute appendicitis
The average age of patients at presentation with cecal volvulus is 53 years.4 Symptoms include colicky pain of sudden onset, vomiting, borborygmus, and often dehydration with electrolyte disturbance. Leukocytosis may also be present. Early diagnosis is essential to reduce the reported high mortality rate. Volvulus is essentially a closed-loop obstruction that may lead to vascular compromise with gangrene and perforation.
Cecal volvulus occurs in patients with a mobile, defectively fixed right colon, often while they are asleep. The volvulus occurs in the ascending colon, above the ileocecal valve, and takes one of 2 forms. Axial torsion, the more common form, is a twist of 180-360 degrees along the longitudinal axis of the ascending colon. This form has a high mortality rate, with immediate vascular occlusion occurring along with the obstructive process. The second type (making up as much as 30% of cases), illustrated by this case, is the bascule type, where the cecum folds anteriorly and cephalad to the ascending colon, with the production of a flap-valve occlusion at the site of flexion.
Defective peritoneal fixation permitting abnormal mobility of the ascending colon and cecum occurs in 10% to 25% of the population.2 Any sudden colonic distention may precipitate volvulus in these individuals.5 Associations include trauma, constipation, distal colonic obstruction (ie, colonic carcinoma or diverticulitis), atony (colonic ileus/pseudo-obstruction), colonoscopy, postpartum abdomen, and postoperative abdomen. Traction due to a diseased appendix is also implicated.2
In this case, colonic atony due to appendicitis with traction of the diseased appendix seemed probable. At surgery there was a non-ischemic, mobile ascending colon with the cecum twisted around it in the epigastrium. The appendix was inflamed.
In practice, differentiating between the 2 types of cecal volvulus is not clinically important as their presentation and treatment are the same. However, recognition of different radiographic appearances is important for early diagnosis. Delay increases complications; these include 20% mortality with perforation, and 45% mortality with gangrene. Distention occurs in up to 65% of cases, with distention of more than 10 to 12 cm placing patients at high risk for perforation. It has been suggested that the duration of distention is as significant as the absolute size.2
In diagnosis, bowel gas patterns may not be characteristic as the right colon/cecum may be displaced to any part of the abdominal cavity.The distended cecal loop may be confused with a sigmoid volvulus or even a distended stomach. In fact, in one large review with abdominal radiographs alone, cecal volvulus was suggested in 46% of patients, but diagnostic in only 17%.4 If the positive diagnosis is not made on the abdominal series, follow-up films, contrast enema, or CT exam is required.
In most patients, obstruction is almost complete; thus, the distal colon is usually empty and the small bowel is frequently distended.Occasionally, the folded, bascule-type volvulus may be associated with signs of incomplete obstruction. The ileocecal valve may be identified, and occasionally the point of torsion may be outlined by intraluminal gas as an area of cone-like narrowing, or the so-called “beak” sign.
In the cecal bascule form of volvulus, the distended, air-filled cecum is located more centrally. The ileum may passively twist with the cecum such that the small bowel is not obstructed. If the appendix is gas filled and attached to a distended cecum in an unusual location, the diagnosis can be made readily. In our case, care was taken not to mistake the CT appearance of the inflamed appendix for a displaced ileal loop.
On CT, the axial twist volvulus demonstrates a U-shaped, distended bowel segment and signs of ischemia (antimesenteric border),including mural thickening, infiltration of the mesenteric fat, and pneumatosis intestinalis. A whirl sign may be apparent with a tight torsiono of the mesentery caused by the twist between the afferent and efferent loops.
Single-contrast barium enema (BE) examination is used for the evaluation of cecal volvulus. As little barium as possible should be allowed to flow proximal to the site of obstruction as flooding proximal to the obstruction site might precipitate complete obstruction. An attempt should be made to reduce the volvulus. Reduction may be achieved during colonic filling by barium, yet reduction occasionally occurs during barium evacuation.
In the presence of a double obstruction of the colon (left colon obstruction associated with a cecal volvulus), evaluation of the right colon may not be possible with BE, and the diagnosis may need to be made by plain radiographic findings or CT.
Definitive treatment is surgical, particularly if reduction by barium enema fails. Colonoscopy is unlikely to reduce the volvulus and risks colonic perforation. Surgery is urgent when peritoneal tenderness or leukocytosis develops to suggest ischemia. Cecopexy, cecostomy, and resection are all surgical options. The highest rates of recurrence and complication are associated with cecostomy. Cecal resection is favored in most patients due to improvements in perioperative care and modern surgical techniques. Ileocecectomy can be performed with low morbidity.4
Volvulus is not a rare condition. The various imaging appearances must be recognized and considered immediately on plain film exams. High morbidity can be reduced by early treatment. CT scans and barium enema examinations are useful in diagnosis. Cecal resection is suggested surgically.