Gastroenterology emergency

Toxic Megacolon

Toxic megacolon requires immediate recognition of nonobstructive colonic dilation with systemic toxicity, exclusion of mechanical obstruction and superimposed infection, serial reassessment, and early colorectal surgical involvement before perforation, shock, or prolonged unsuccessful medical treatment markedly worsens outcomes.

Clinical question: How should clinicians diagnose, stabilize, evaluate, and escalate treatment for suspected toxic megacolon?

Updated September 16, 20266 minute readGastroenterology

What matters in practice

Treat radiographic right-sided colonic dilation greater than 6 cm plus severe inflammatory systemic toxicity as toxic megacolon; do not wait for perforation to obtain surgical input. Wolters KluwerWolters KluwerClinical Practice Guideline for the Surgical Management of ...
Obtain stool testing for Clostridioides difficile and enteroinvasive bacterial pathogens in new or worsening IBD symptoms; add travel-directed microscopy/culture for amoebic or Shigella dysentery when relevant. BMJBMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut
In acute severe ulcerative colitis, obtain surgical consultation when intravenous corticosteroids are failing at 3–5 days or when rescue therapy is started; toxic megacolon, perforation, uncontrolled hemorrhage, and multiorgan dysfunction are urgent colectomy indications. Wolters KluwerWolters KluwerACG Clinical Guideline: Ulcerative Colitis in Adults - Lippincott
For toxic megacolon with perforation, unstable massive bleeding, shock, or deterioration after 24–48 hours of medical treatment, surgery should not be delayed. PubMedPubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting
When emergency colectomy is required for fulminant ulcerative colitis, subtotal colectomy with end ileostomy and rectal preservation is the preferred initial operation. BMJ+2BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut BMJAdaptations to the British Society of Gastroenterology guidelines on ...BMJBritish Society of Gastroenterology consensus guidelines on ... - Gut

Emergency diagnosis

Identify toxic megacolon and separate it from uncomplicated dilation

Clinical toxicity converts colonic dilation into a surgical-risk emergency.

Diagnose toxic megacolon when imaging shows nonobstructive colonic dilation—classically right-sided dilation greater than 6 cm—together with severe systemic inflammatory toxicity. Jalan criteria include fever, tachycardia, leukocytosis, and anemia, plus at least one of dehydration, altered mental status, electrolyte disturbance, or hypotension. The diagnostic decision is clinical-radiographic: dilation alone is not toxic megacolon. Wiley+1WileyToxic megacolon - Autenrieth - 2012 - Inflammatory Bowel Diseases Wolters KluwerClinical Practice Guideline for the Surgical Management of ...

Escalate immediately for peritoneal findings, shock, clinical deterioration, suspected perforation, or unstable massive hematochezia. These findings mandate urgent operative management rather than continued medical observation. Perforation substantially changes prognosis: reported mortality is 27%–57%, and colectomy in the setting of perforation has been associated with mortality exceeding 40%, compared with 2%–8% when colectomy occurs before perforation. BMJ+1BMJToxic colitis and toxic megacolon - Complications | BMJ Best Practice PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting

Use abdominal radiography or CT to document colonic dilation and assess complications, but actively exclude mechanical obstruction. A mass, volvulus, stricture, hernia, or other obstruction is suggested by a transition point with proximal dilation and decompressed distal bowel; this redirects management away from inflammatory toxic megacolon. PubMedPubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH

Call colorectal surgery at the time toxic megacolon is suspected; operative planning should proceed in parallel with medical stabilization. BMJ+2BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut Wolters KluwerACG Clinical Guideline: Ulcerative Colitis in Adults - Lippincott PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting
Avoid anticholinergic drugs and narcotics during an acute ulcerative colitis flare with colonic dilation because they can worsen colonic hypomotility. Wolters KluwerWolters KluwerClinical Practice Guideline for the Surgical Management of ...
Do not use the absence of an established IBD diagnosis to defer escalation: toxic megacolon can complicate infectious, ischemic, inflammatory, and medication-related colitis. PubMed+2PubMedToxic Megacolon - StatPearls - NCBI Bookshelf PubMedColitis - StatPearls - NCBI Bookshelf PubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH

Imaging and clinical findings that distinguish toxic megacolon from other causes of colonic dilation. Wiley+2WileyToxic megacolon - Autenrieth - 2012 - Inflammatory Bowel Diseases Wolters KluwerClinical Practice Guideline for the Surgical Management of ...PubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH
Syndrome	Key discriminator	Immediate implication
Toxic megacolon	Nonobstructive right-sided colonic dilation >6 cm with systemic inflammatory toxicity. Wolters KluwerWolters KluwerClinical Practice Guideline for the Surgical Management of ...	Urgent multidisciplinary management, serial reassessment, and early surgical involvement. Wolters Kluwer+1Wolters KluwerClinical Practice Guideline for the Surgical Management of ...PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting
Mechanical large-bowel obstruction	Transition point with proximally dilated and distally compressed bowel; contrast may show a cutoff. PubMedPubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH	Identify and treat the obstructing lesion rather than presume inflammatory colitis. PubMedPubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH
Acute colonic pseudo-obstruction	Colonic dilation without an anatomic obstruction, often in critically ill or postoperative patients; systemic inflammatory toxicity is less characteristic. PubMedPubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH	Evaluate for pseudo-obstruction after excluding mechanical obstruction and toxic colitis. PubMedPubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH

First hours

Stabilize while defining the inflammatory and infectious driver

Diagnostic sampling and surgical assessment should not delay resuscitation.

Obtain complete blood count, C-reactive protein, erythrocyte sedimentation rate, electrolytes, renal function, liver enzymes, albumin, and—when feasible—fecal calprotectin in suspected severe IBD-associated colitis. These results quantify anemia, leukocytosis, inflammation, electrolyte derangement, renal injury, and nutritional/inflammatory burden for serial assessment and operative risk evaluation. PubMedPubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting

Send Clostridioides difficile testing routinely in an acute severe ulcerative colitis presentation and obtain stool cultures for enteroinvasive bacterial pathogens in new or worsening IBD symptoms. Obtain blood and stool cultures when an urgent IBD presentation raises concern for infection; travel or exposure history should trigger microscopy and culture for amoebic and/or Shigella dysentery. BMJ+2BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut Wolters KluwerClinical Practice Guideline for the Surgical Management of ...PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting

Perform lower endoscopic assessment with flexible sigmoidoscopy or ileocolonoscopy within 24 hours, and no later than 72 hours, in an acute ulcerative colitis flare when clinically feasible; biopsy to evaluate for CMV colitis. CMV is particularly relevant in steroid-refractory IBD, in which it may occur in 10%–30% of patients and is associated with recurrent flares, toxic megacolon, and surgery. BMJ+1BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut Wolters KluwerClinical Practice Guideline for the Surgical Management of ...

Start venous thromboembolism prophylaxis during acute severe ulcerative colitis hospitalization unless a patient-specific contraindication is present. Wolters KluwerWolters KluwerClinical Practice Guideline for the Surgical Management of ...
Encourage oral intake as tolerated in acute ulcerative colitis management while correcting electrolyte abnormalities and monitoring hemodynamics. Wolters KluwerWolters KluwerClinical Practice Guideline for the Surgical Management of ...
Interpret a positive infectious evaluation as a change in the treatment branch, not as a reason to ignore colonic dilation or systemic toxicity; C. difficile and CMV can coexist with or mimic an IBD flare. BMJ+2BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut NatureAcute severe ulcerative colitis: from pathophysiology to clinical management | Nature Reviews Gastroenterology & Hepatology PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting

Etiologic branches in suspected toxic megacolon and the tests that redirect care. BMJ+4BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut NatureAcute severe ulcerative colitis: from pathophysiology to clinical management | Nature Reviews Gastroenterology & Hepatology Wolters KluwerClinical Practice Guideline for the Surgical Management of ...PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting PubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH
Clinical branch	Tests or findings	What the result changes
Ulcerative colitis flare	Assess disease activity with CBC, CRP, ESR, albumin, renal function, electrolytes, and lower endoscopy when feasible. Wolters Kluwer+1Wolters KluwerClinical Practice Guideline for the Surgical Management of ...PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting	Initiate acute severe ulcerative colitis management and reassess response promptly for rescue therapy or colectomy. Wolters KluwerWolters KluwerACG Clinical Guideline: Ulcerative Colitis in Adults - Lippincott
C. difficile or enteroinvasive bacterial colitis	Routine C. difficile testing; stool culture for enteroinvasive bacterial pathogens. BMJ+1BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut Wolters KluwerClinical Practice Guideline for the Surgical Management of ...	Treat the identified infection while maintaining surgical surveillance for toxic megacolon or perforation. PubMed+2PubMedToxic Megacolon - StatPearls - NCBI Bookshelf PubMedClostridioides difficile infection: an update - PMC PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting
CMV colitis complicating IBD	Flexible sigmoidoscopy or ileocolonoscopy with biopsy; prioritize in steroid-refractory or immunocompromised colitis. BMJ+2BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut NatureAcute severe ulcerative colitis: from pathophysiology to clinical management \| Nature Reviews Gastroenterology & Hepatology Wolters KluwerClinical Practice Guideline for the Surgical Management of ...	Reclassify apparent steroid-refractory disease and address superimposed CMV. BMJ+1BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut NatureAcute severe ulcerative colitis: from pathophysiology to clinical management \| Nature Reviews Gastroenterology & Hepatology
Mechanical obstruction or pseudo-obstruction	CT or radiography showing a transition point favors mechanical obstruction; absence of obstruction with dilation may indicate pseudo-obstruction. PubMedPubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH	Avoid labeling all dilation as toxic megacolon; direct management to the structural or functional cause. PubMedPubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH

When CMV testing changes management

Prioritize CMV evaluation in severe steroid-refractory colitis and in patients receiving purine analogues, which are an independent risk factor for CMV reactivation. CMV colitis can mimic active ulcerative colitis and has been reported to account for treatment failure in up to 10% of patients labeled steroid refractory. BMJ+1BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut NatureAcute severe ulcerative colitis: from pathophysiology to clinical management | Nature Reviews Gastroenterology & Hepatology

Parallel treatment

Use a short, explicit reassessment window

Medical therapy is a bridge only while the patient is stable and improving.

In acute severe ulcerative colitis, initial multidisciplinary treatment includes intravenous corticosteroids, venous thromboembolism prophylaxis, avoidance of anticholinergics and narcotics, and repeat CT or CT enterography as clinically needed. Reassess clinical status, abdominal examination, inflammatory markers, and imaging trajectory frequently enough to detect loss of response or evolving perforation. Wolters KluwerWolters KluwerClinical Practice Guideline for the Surgical Management of ...

If acute severe ulcerative colitis does not adequately improve after 3–5 days of corticosteroids, obtain surgical consultation and move to a rescue-versus-colectomy decision. Infliximab and cyclosporine are rescue options; select between them according to clinician experience, prior immunomodulator or anti-TNF failure, and serum albumin. Wolters KluwerWolters KluwerACG Clinical Guideline: Ulcerative Colitis in Adults - Lippincott

For toxic megacolon specifically, a lack of clinical improvement with biological deterioration after 24–48 hours of medical treatment is an indication for mandatory surgery. Do not extend a medical trial in a critically ill patient simply because rescue therapy has been initiated. PubMedPubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting

Escalate to urgent surgery before 24–48 hours if shock, perforation, unstable massive bleeding, or clinical deterioration develops. PubMedPubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting
After rescue therapy for acute severe ulcerative colitis, proceed to subtotal colectomy and ileostomy if there is no response within 7 days, or sooner if toxic megacolon, perforation, or severe hemorrhage occurs. BMJBMJAdaptations to the British Society of Gastroenterology guidelines on ...
Do not defer indicated colectomy for complete biologic or JAK inhibitor washout; operative timing should prioritize severity, nutritional status, corticosteroid exposure, and clinical stability. Wolters Kluwer+1Wolters KluwerClinical Practice Guideline for the Surgical Management of ...Wolters KluwerACG Clinical Guideline: Ulcerative Colitis in Adults - Lippincott

Escalation thresholds for acute severe ulcerative colitis complicated by toxic megacolon. BMJ+2BMJAdaptations to the British Society of Gastroenterology guidelines on ...Wolters KluwerACG Clinical Guideline: Ulcerative Colitis in Adults - Lippincott PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting
Time point or event	Action	Rationale
At suspected toxic megacolon	Begin medical stabilization and involve colorectal surgery immediately. Wolters Kluwer+1Wolters KluwerClinical Practice Guideline for the Surgical Management of ...PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting	Perforation and shock require mandatory surgery; preoperative planning should not await failed prolonged medical therapy. PubMedPubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting
After 24–48 hours of medical treatment	Operate if there is no clinical improvement with biological deterioration. PubMedPubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting	Continued deterioration is a mandatory surgical trigger. PubMedPubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting
After 3–5 days of IV corticosteroids for acute severe ulcerative colitis	Obtain surgical consultation and determine rescue therapy versus colectomy. Wolters KluwerWolters KluwerACG Clinical Guideline: Ulcerative Colitis in Adults - Lippincott	Failure to progress predicts need for escalation; delayed surgery increases postoperative complications. Wolters KluwerWolters KluwerACG Clinical Guideline: Ulcerative Colitis in Adults - Lippincott
Within 7 days after infliximab or cyclosporine rescue	Perform subtotal colectomy with ileostomy if no response, or sooner for deterioration, toxic megacolon, hemorrhage, or perforation. BMJBMJAdaptations to the British Society of Gastroenterology guidelines on ...	A defined endpoint prevents harmful delay after rescue therapy. BMJBMJAdaptations to the British Society of Gastroenterology guidelines on ...

Definitive control

Choose prompt staged colectomy when surgery is indicated

Emergency surgery controls the diseased colon while avoiding a high-risk restorative procedure during critical illness.

Use subtotal colectomy with end ileostomy and preservation of a long rectal stump as the preferred operation for acute severe ulcerative colitis requiring emergency surgery, including medically refractory disease, toxic megacolon, perforation, or life-threatening hemorrhage. BMJ+3BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut BMJAdaptations to the British Society of Gastroenterology guidelines on ...BMJBritish Society of Gastroenterology consensus guidelines on ... - Gut PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting

Surgery is indicated in acute severe ulcerative colitis for medical nonresponse, intolerable medication adverse effects, life-threatening hemorrhage, toxic megacolon, or perforation. Absolute operative indications include toxic megacolon, colonic perforation, uncontrolled severe hematochezia, and multiorgan dysfunction. BMJ+1BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut Wolters KluwerACG Clinical Guideline: Ulcerative Colitis in Adults - Lippincott

Frame colectomy as time-sensitive source control rather than therapeutic failure. Delays after failed corticosteroids or rescue therapy are associated with increased postoperative complications, whereas biologic exposure alone should not be used to postpone necessary surgery. Wolters Kluwer+1Wolters KluwerClinical Practice Guideline for the Surgical Management of ...Wolters KluwerACG Clinical Guideline: Ulcerative Colitis in Adults - Lippincott

Involve surgery early enough to discuss the likelihood of subtotal colectomy and end ileostomy before hemodynamic collapse or perforation occurs. BMJ+1BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut Wolters KluwerACG Clinical Guideline: Ulcerative Colitis in Adults - Lippincott
If the retained rectal stump leaks postoperatively, management may include percutaneous drainage of a resulting collection and antibiotics; occasional cases require reoperation. BMJBMJToxic colitis and toxic megacolon - Complications | BMJ Best Practice
Maintain heightened postoperative surveillance in patients operated on after perforation because mortality rises markedly once perforation has occurred. BMJBMJToxic colitis and toxic megacolon - Complications | BMJ Best Practice

Operative triggers and the recommended emergency procedure in toxic megacolon associated with ulcerative colitis. BMJ+4BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut BMJAdaptations to the British Society of Gastroenterology guidelines on ...BMJBritish Society of Gastroenterology consensus guidelines on ... - Gut Wolters KluwerACG Clinical Guideline: Ulcerative Colitis in Adults - Lippincott PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting
Trigger	Timing	Operative approach
Perforation, shock, unstable massive bleeding, or deterioration	Immediate; surgery is mandatory. PubMedPubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting	Subtotal colectomy with end ileostomy and rectal preservation. BMJ+3BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut BMJAdaptations to the British Society of Gastroenterology guidelines on ...BMJBritish Society of Gastroenterology consensus guidelines on ... - Gut PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting
No improvement with biological deterioration after medical treatment	Within 24–48 hours. PubMedPubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting	Do not prolong medical management; proceed to colectomy. PubMedPubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting
No response after infliximab or cyclosporine rescue	Within 7 days, or earlier for complications. BMJBMJAdaptations to the British Society of Gastroenterology guidelines on ...	Subtotal colectomy and ileostomy with rectal preservation. BMJ+1BMJAdaptations to the British Society of Gastroenterology guidelines on ...BMJBritish Society of Gastroenterology consensus guidelines on ... - Gut

Etiology

Maintain disease-specific treatment while prioritizing source control

The etiology guides adjunctive therapy, but instability overrides prolonged diagnostic refinement.

Inflammatory bowel disease and C. difficile infection account for most toxic megacolon presentations, but infectious, ischemic, inflammatory, and medication-related colitides are recognized precipitants. In a patient with colonic dilation and systemic toxicity, identify the cause in parallel with surgical evaluation because the common endpoint—perforation, sepsis, and multiorgan failure—requires the same urgency. PubMedPubMedToxic Megacolon - StatPearls - NCBI Bookshelf

For fulminant C. difficile infection with toxic megacolon or suspected perforation, early resuscitation and surgical consultation are essential. A cited regimen is vancomycin administered via nasogastric tube four times daily plus intravenous metronidazole 500 mg every 8 hours; this regimen should be integrated with urgent reassessment for operative source control rather than used to delay it. PubMedPubMedClostridioides difficile Infection in Special Populations: Focus on Inflammatory Bowel Disease—A Narrative Review from Pathogenesis to Management

In IBD with severe refractory colitis, distinguish active inflammatory disease from C. difficile, CMV, and other enteric pathogens before intensifying immunosuppression. Superimposed infections increase the risk of toxic megacolon, perforation, and mortality if untreated. BMJ+1BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut NatureAcute severe ulcerative colitis: from pathophysiology to clinical management | Nature Reviews Gastroenterology & Hepatology

Consider amoebic and Shigella-directed testing only when travel or contact history supports that branch. BMJBMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut
Use the presence of a transition point to favor a structural obstruction rather than toxic megacolon. PubMedPubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH
For all etiologies, clinical decline, shock, perforation, or unstable hemorrhage ends the medical trial and requires operative management. PubMedPubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting

Cause-specific actions that accompany emergency management of toxic megacolon. BMJ+5BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut NatureAcute severe ulcerative colitis: from pathophysiology to clinical management | Nature Reviews Gastroenterology & Hepatology PubMedToxic Megacolon - StatPearls - NCBI Bookshelf PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting PubMedClostridioides difficile Infection in Special Populations: Focus on Inflammatory Bowel Disease—A Narrative Review from Pathogenesis to Management PubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH
Likely cause	Diagnostic priority	Cause-directed action supported here
Acute severe ulcerative colitis	C. difficile testing; lower endoscopy with biopsy for CMV when feasible. Wolters KluwerWolters KluwerClinical Practice Guideline for the Surgical Management of ...	IV corticosteroids, then rescue therapy or colectomy on the defined reassessment timeline. Wolters KluwerWolters KluwerACG Clinical Guideline: Ulcerative Colitis in Adults - Lippincott
Fulminant C. difficile infection	C. difficile assay and assessment for toxic megacolon or perforation. PubMed+1PubMedClostridioides difficile infection: an update - PMC PubMedClostridioides difficile Infection in Special Populations: Focus on Inflammatory Bowel Disease—A Narrative Review from Pathogenesis to Management	Vancomycin via nasogastric tube four times daily plus IV metronidazole 500 mg every 8 hours; early surgical consultation. PubMedPubMedClostridioides difficile Infection in Special Populations: Focus on Inflammatory Bowel Disease—A Narrative Review from Pathogenesis to Management
CMV complicating refractory IBD	Endoscopic biopsy, especially in steroid-refractory or immunocompromised colitis. BMJ+2BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut NatureAcute severe ulcerative colitis: from pathophysiology to clinical management \| Nature Reviews Gastroenterology & Hepatology Wolters KluwerClinical Practice Guideline for the Surgical Management of ...	Address CMV as a contributor to apparent steroid failure while monitoring for surgical triggers. BMJ+2BMJBritish Society of Gastroenterology guidelines on inflammatory ... - Gut NatureAcute severe ulcerative colitis: from pathophysiology to clinical management \| Nature Reviews Gastroenterology & Hepatology PubMedWSES-AAST guidelines: management of inflammatory bowel disease in the emergency setting
Structural obstruction	CT or contrast evaluation for a transition point or cutoff. PubMedPubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH	Treat the obstructive lesion; do not apply an inflammatory toxic-megacolon pathway without systemic toxic colitis. PubMedPubMedIntestinal Pseudo-Obstruction - StatPearls - NCBI Bookshelf - NIH