Clostridium Difficile Colitis in Divergent Colon

INTRODUCTION:
Pseudomembranous colitis describes colitis related to Clostridium difficile infection(CDI). CDI is one of the most common nosocomial infections and associated with substantial morbidity and mortality. Its occurrence typically follows disruption of normal gut microbes usually related to antibiotics. Other factors include advanced age (>65 years), recent hospitalization, gastrointestinal surgery, inflammatory bowel disease, and chemotherapy among others. Symptoms range widely from asymptomatic, to mild diarrhea, to fulminant disease with sepsis and toxic megacolon. Radiological findings are often nonspecific, demonstrating signs of colitis such as liquid stool within the colon, wall thickening, and pericolic stranding. More specific signs such as the "accordion sign" have been described on computed tomagoraphy (CT). This is a highly specific finding in which liquid material becomes trapped between thickened haustral folds, creating alternating bands of attenuation. Diagnosis of C. difficile as the causative agent can be made via positive NAAT followed by toxin enzyme immunoassay. C. difficile enteritis (small bowel) has been well documented in patients following colectomy with ileostomy as have generalized diversion colitis and "pouch-itis". However, infectious colitis of the excluded colon such as in our case has been rarely reported.

CASE INFORMATION:
Patient is a 70-year-old female with a past medical history of diverticulitis and endometrial cancer status post total hysterectomy and bilateral salpingo-oopherectomy in 2019. She initially presented in early 2025 with worsening abdominal pain related to partial small bowel obstruction secondary to intra-abdominal masses. Initial treatment included extended right hemicolectomy with en bloc resection of a small bowel tumor implant and complex abdominal wall hernia repair. Her postoperative course was extremely complicated requiring multiple operative and procedural interventions. Most recently, course was further complicated by cardiogenic shock from massive pulmonary embolism requiring thrombectomy and ICU-level care with subsequent respiratory and urinary tract infections. This culminated in antibiotic treatment with cefepime. However, she developed fever, leukocytosis and hemodynamic instability by day 4 of cefepime. CT imaging was suggestive of colitis involving the oversewn mucous fistula of the residual colon. Her lactic acidosis, altered mental status, and abdominal distension worsened. Stool studies confirmed presence of clostridium and despite broad-spectrum IV and rectal antibiotics, she developed toxic megacolon. Emergent exploratory laparotomy revealed fulminant colitis of the diverted colon, necessitating further resection and additional antibiotics with care still on going.

DISCUSSION/CLINICAL FINDINGS:
CT imaging demonstrated the residual, diverted sigmoid colon and rectum which would typically be relatively decompressed given their lack of inflow. However, in this case, the excluded segment was distended with liquid, showed mild wall thickening, and adjacent stranding suggestive of a nonspecific colitis. The classically described "accordion sign" of pseudomembranous colitis was not evident.

CONCLUSION:
Infectious colitis of an excluded colon is rarely reported, and its clinical presentation, diagnosis, and management are not well established. Available cases also involve patients with history of inflammatory bowel disease or initially underwent colectomy for CDI related colitis. Neither of which were known to be present in this case.