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Pseudomembranous colitis: spectrum of imaging findings with clinical and pathologic correlation
S Kawamoto1, K M Horton, E K Fishman
1Department of Radiology, Saitama Medical School, Japan.
Abstract:
Pseudomembranous colitis (PMC) is a potentially life-threatening acute infectious colitis caused by one or more toxins produced by an unopposed proliferation of Clostridium difficile bacteria. PMC is characterized by the presence of elevated, yellow-white plaques forming pseudomembranes on the colonic mucosa. These plaques can be visualized at both pathologic analysis and endoscopy. Plain radiography, contrast enema studies, and computed tomography (CT) are useful in the evaluation of PMC. Plain radiography of the abdomen can demonstrate polypoid mucosal thickening, "thumbprinting" (wide transverse bands associated with haustral fold thickening), or gaseous distention of the colon. A toxic megacolon with distention and occasionally pneumoperitoneum may be seen in the most severe cases of PMC involving perforation. At contrast enema studies, the primary finding in mild cases of PMC is small nodular filling defects representing the mucosal plaques. With more extensive colonic involvement, the plaques are larger and coalesce to form an irregular bowel wall margin. Mural thickening and wide haustral folds caused by intramural edema may also be seen. A contrast enema study is contraindicated in patients with severe PMC due to the danger of perforation. Common CT findings include wall thickening, low-attenuation mural thickening corresponding to mucosal and submucosal edema, the "accordion sign," the "target sign" ("double halo sign"), pericolonic stranding, and ascites. Familiarity with these imaging characteristics may allow early diagnosis and treatment and prevent progression to more serious pathologic conditions.
Insights
Pseudomembranous colitis (PMC), an acute infectious colitis, is caused by Clostridium difficile toxins. Imaging techniques like CT and radiography help diagnose PMC by revealing characteristic mucosal changes and complications.
Area of Science:
- Gastroenterology
- Infectious Diseases
- Radiology
Background:
- Pseudomembranous colitis (PMC) is a severe intestinal inflammation.
- It stems from Clostridium difficile bacterial toxin overgrowth.
- Characterized by pseudomembranes on the colonic mucosa.
Purpose of the Study:
- To review the utility of various imaging modalities in diagnosing PMC.
- To highlight key imaging findings associated with PMC.
- To emphasize the role of imaging in early diagnosis and management.
Main Methods:
- Review of imaging findings from plain radiography, contrast enema, and computed tomography (CT).
- Correlation of imaging findings with pathological and endoscopic observations.
- Analysis of characteristic signs such as 'thumbprinting,' 'accordion sign,' and 'target sign.'
Main Results:
- Plain radiography may show mucosal thickening, 'thumbprinting,' or colonic distention.
- Contrast enema reveals nodular filling defects or irregular bowel margins; contraindicated in severe cases.
- CT findings include wall thickening, edema, 'accordion sign,' 'target sign,' and pericolonic stranding.
Conclusions:
- Familiarity with imaging findings is crucial for early PMC diagnosis.
- Prompt diagnosis aids in timely treatment and prevents disease progression.
- Imaging plays a vital role in identifying complications like toxic megacolon and perforation.