Answer for BIR CoW 09 Aug 2026
Pseudomembranous colitis
Findings
Diffuse smooth enhancing bowel wall thickening from rectum to ileocaecal junction showing pericolic fat stranding and surrounding mesentric subcentimetric lymph nodes. bowel wall showing mural stratification, submucosal edema with hyperemic mucosa in large bowel loops reflecting Accordion sign. - Suggestive of Psuedomembranous cholitis.
Discussion
Pseudomembranous colitis is a toxin-mediated colitis caused by Clostridioides difficile, usually following broad-spectrum antibiotic use.Predisposing factors include prolonged hospitalization, advanced age, immunosuppression, inflammatory bowel disease, chemotherapy, and proton pump inhibitor use.Contrast-enhanced CT is the imaging modality of choice for evaluating severe disease, extent, and complications.The characteristic CT finding is diffuse or segmental circumferential colonic wall thickening with submucosal edema producing a target (double-halo) sign.The accordion sign—oral contrast trapped between markedly thickened haustral folds—is highly suggestive of pseudomembranous colitis but is not pathognomonic.Thumbprinting may be seen due to marked submucosal edema or hemorrhage.A useful imaging clue is marked bowel wall thickening with relatively mild pericolonic fat stranding.The disease most commonly involves the rectosigmoid colon but may progress to pancolitis.Additional CT findings include mucosal hyperenhancement, haustral thickening, luminal fluid, and variable colonic dilatation.Major complications include toxic megacolon, perforation, ischemia, pneumoperitoneum, septic shock, and abscess formation.Important differentials include ischemic colitis, ulcerative colitis, Crohn disease, other infectious colitides, neutropenic enterocolitis, CMV colitis, and graft-versus-host disease.Compared with ulcerative colitis, pseudomembranous colitis typically demonstrates greater mural thickening with less prominent pericolonic inflammatory change.Diagnosis is confirmed by stool toxin or nucleic acid amplification tests, while CT assesses disease severity and complications.Colonoscopy shows characteristic yellow-white pseudomembranes, but should be avoided in fulminant disease because of the risk of perforation.Early recognition of the target sign, accordion sign, and disproportionate mural thickening on CT facilitates prompt treatment and improves patient outcomes.
Referrences- Grainger & Allison's Diagnostic Radiology (7th edition), Gastrointestinal Imaging. Diagnostic Imaging: Gastrointestinal (Elsevier, latest edition). Radiographics: CT evaluation of infectious colitis and pseudomembranous colitis. American Journal of Roentgenology (AJR): CT features of Clostridioides difficile colitis. ACR Appropriateness Criteria: Acute Nonlocalized Abdominal Pain and suspected colitis.
Findings
Diffuse smooth enhancing bowel wall thickening from rectum to ileocaecal junction showing pericolic fat stranding and surrounding mesentric subcentimetric lymph nodes. bowel wall showing mural stratification, submucosal edema with hyperemic mucosa in large bowel loops reflecting Accordion sign. - Suggestive of Psuedomembranous cholitis.
Discussion
Pseudomembranous colitis is a toxin-mediated colitis caused by Clostridioides difficile, usually following broad-spectrum antibiotic use.Predisposing factors include prolonged hospitalization, advanced age, immunosuppression, inflammatory bowel disease, chemotherapy, and proton pump inhibitor use.Contrast-enhanced CT is the imaging modality of choice for evaluating severe disease, extent, and complications.The characteristic CT finding is diffuse or segmental circumferential colonic wall thickening with submucosal edema producing a target (double-halo) sign.The accordion sign—oral contrast trapped between markedly thickened haustral folds—is highly suggestive of pseudomembranous colitis but is not pathognomonic.Thumbprinting may be seen due to marked submucosal edema or hemorrhage.A useful imaging clue is marked bowel wall thickening with relatively mild pericolonic fat stranding.The disease most commonly involves the rectosigmoid colon but may progress to pancolitis.Additional CT findings include mucosal hyperenhancement, haustral thickening, luminal fluid, and variable colonic dilatation.Major complications include toxic megacolon, perforation, ischemia, pneumoperitoneum, septic shock, and abscess formation.Important differentials include ischemic colitis, ulcerative colitis, Crohn disease, other infectious colitides, neutropenic enterocolitis, CMV colitis, and graft-versus-host disease.Compared with ulcerative colitis, pseudomembranous colitis typically demonstrates greater mural thickening with less prominent pericolonic inflammatory change.Diagnosis is confirmed by stool toxin or nucleic acid amplification tests, while CT assesses disease severity and complications.Colonoscopy shows characteristic yellow-white pseudomembranes, but should be avoided in fulminant disease because of the risk of perforation.Early recognition of the target sign, accordion sign, and disproportionate mural thickening on CT facilitates prompt treatment and improves patient outcomes.
Referrences- Grainger & Allison's Diagnostic Radiology (7th edition), Gastrointestinal Imaging. Diagnostic Imaging: Gastrointestinal (Elsevier, latest edition). Radiographics: CT evaluation of infectious colitis and pseudomembranous colitis. American Journal of Roentgenology (AJR): CT features of Clostridioides difficile colitis. ACR Appropriateness Criteria: Acute Nonlocalized Abdominal Pain and suspected colitis.
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!