Necrotic stercoral colitis: importance of computed tomography findings

Abstract

Aim: To study the computed tomography (CT) signs in facilitating early diagnosis of necrotic stercoral colitis (NSC).

Methods: Ten patients with surgically and pathologically confirmed NSC were recruited from the Clinico-Pathologic-Radiologic conference at Chang Gung Memorial Hospital, Taoyuan, Taiwan. Their CT images and medical records were reviewed retrospectively to correlate CT findings with clinical presentation.

Results: All these ten elderly patients with a mean age of 77.1 years presented with acute abdomen at our Emergency Room. Nine of them were with systemic medical disease and 8 with chronic constipation. Seven were with leukocytosis, two with low-grade fever, two with peritoneal sign, and three with hypotensive shock. Only one patient was with radiographic detected abnormal gas. Except the crux of fecal impaction, the frequency of the CT signs of NSC were, proximal colon dilatation (20%), colon wall thickening (60%), dense mucosa (62.5%), mucosal sloughing (10%), perfusion defect (70%), pericolonic stranding (80%), abnormal gas (50%) with pneumo-mesocolon (40%) in them, pericolonic abscess (20%). The most sensitive signs in decreasing order were pericolonic stranding, perfusion defect, dense mucosal, detecting about 80%, 70%, and 62.5% of the cases, respectively.

Conclusion: Awareness of NSC and familiarity with the CT diagnostic signs enable the differential diagnosis between NSC and benign stool impaction.

Keywords: Computed tomography; Dense mucosa; Fecal impaction; Pericolonic stranding; Stercoral colitis.

Figure 1

A 70-year-old woman (patient 6) with necrotic stercoral colitis. The computed tomography scan revealed stool impaction and distension of the recto-sigmoid colon with asymmetrical wall thickening at the posterior aspect (arrow).

Figure 2

An 80-year-old woman (patient 5) with perforation of the necrotic stercoral colitis at the sigmoid colon. A: An unenhanced computed tomography (CT) scan reveals dense mucosa (arrow) conforming to the colon wall; B: An enhanced abdominal CT scan reveals discontinuation of the colonic mucosa (arrow) suggesting perfusion defect; C: A small air bubble abutting the damaged colon (arrow) and increased pericolonic infiltration (arrowhead) can be seen.

Figure 3

An 88-year-old women (patient 7) with perforation of the necrotic stercoral colitis at the sigmoid colon. A: An enhanced abdominal computed tomography scan reveals mucosal flap (arrow) slough into the lumen of the colon indicating mucosal sloughing; B: Air pockets (arrow) abutting the colonic wall and pericolonic loculated fluid indicative of abscess formation (arrowhead).

Figure 4

An 87-year-old man (patient 4) with perforated stercoral colitis at the proximal end of co-existing rectosigmoid colon cancer. An enhanced abdominal computed tomography scan at lung-window setting reveals air confined inside the mesocolon indicating pneumo-mesocolon (arrow).