Gastrointestinal & Hepatic · Topic 18 of 26
Inflammatory Bowel Disease Flare
Gastrointestinal · inflammatory bowel disease
Inflammatory Bowel Disease Flare
Acute severe ulcerative colitis is a medical emergency: exclude infection, start IV steroids, judge response on day 3, then rescue or colectomy.
Key numbers
Severe UC: > 6 bloody stools daily> 6 bloody stools/day
IV methylprednisolone 60 mg dailymethylpred 60 mg/day IV
Day 3 nonresponse: infliximab, cyclosporine or colectomyday 3
Toxic megacolon: transverse colon > 6 cmcolon > 6 cm
No improvement in 24–48 hours: colectomy24–48 h
01 · Defined bySevere UC: > 6 bloody stools daily
Acute severe UC (Truelove–Witts) = more than 6 bloody stools daily plus any of: heart rate > 90, temperature > 37.8 °C, hemoglobin < 10.5 g/dL, or ESR > 30 mm/h. Hospitalize.
02 · GiveIV methylprednisolone 60 mg daily
First-line therapy for acute severe UC is IV corticosteroid: methylprednisolone 60 mg daily (or hydrocortisone 100 mg every 6 hours), typically for 3–7 days.
03 · The ruleDay 3 nonresponse: infliximab, cyclosporine or colectomy
Reassess on day 3 of IV steroids; nonresponders (> 8 stools/day, or 3–8 with CRP > 45 mg/L — about 85% colectomy risk) need rescue with infliximab 5 mg/kg or IV cyclosporine, or colectomy.
01
Diagnosis & monitoring
Work-upToxic megacolon: transverse colon > 6 cm must knowToxic (fulminant) colitis is transmural inflammation with ileus and systemic toxicity; megacolon means transverse colon > 6 cm. Perforation sharply raises mortality.
Screen for TB and hepatitis B before infliximabBefore starting infliximab or another TNF inhibitor, test for latent tuberculosis and hepatitis B; serious infection and HBV reactivation are labeled risks.
02
Do right now
In this orderFirst moves
1
→Severe UC: > 6 bloody stools daily> 6 bloody stools/day
2
→Test for C. difficile; sigmoidoscopy for CMV
3
→IV methylprednisolone 60 mg dailymethylpred 60 mg/day IV
4
→Give VTE prophylaxis to every admitted flare
5
Day 3 nonresponse: infliximab, cyclosporine or colectomyday 3
Why each step
Severe UC: > 6 bloody stools dailyAcute severe UC (Truelove–Witts) = more than 6 bloody stools daily plus any of: heart rate > 90, temperature > 37.8 °C, hemoglobin < 10.5 g/dL, or ESR > 30 mm/h. Hospitalize.
Test for C. difficile; sigmoidoscopy for CMVTest every admitted flare for C. difficile and treat it if positive without delaying IBD therapy; do flexible sigmoidoscopy with biopsies within 48–72 hours to grade severity and exclude CMV colitis.
IV methylprednisolone 60 mg dailyFirst-line therapy for acute severe UC is IV corticosteroid: methylprednisolone 60 mg daily (or hydrocortisone 100 mg every 6 hours), typically for 3–7 days.
Give VTE prophylaxis to every admitted flareHospitalized IBD flares carry high venous thromboembolism risk; give pharmacologic DVT prophylaxis, plus IV fluids and transfusion as needed.
Day 3 nonresponse: infliximab, cyclosporine or colectomyReassess on day 3 of IV steroids; nonresponders (> 8 stools/day, or 3–8 with CRP > 45 mg/L — about 85% colectomy risk) need rescue with infliximab 5 mg/kg or IV cyclosporine, or colectomy.
03
Management
OrdersToxic colitis: NPO, decompress, steroids, antibiotics, surgeonIn toxic colitis stop antidiarrheals, keep NPO with tube decompression, give aggressive IV fluids, potassium and blood, high-dose IV steroids or cyclosporine, and broad antibiotics (eg, metronidazole plus ciprofloxacin); involve surgery early.
Emergency colectomy: hemorrhage, toxic colitis, perforationEmergency colectomy is indicated for massive hemorrhage, fulminant toxic colitis or perforation; the usual operation is subtotal colectomy with ileostomy, leaving a closed rectosigmoid stump for later surgery.
Crohn abscess: drain and treat before immunosuppressionA toxic Crohn patient with fever, rebound or a tender mass needs IV fluids, antibiotics and percutaneous or surgical abscess drainage; give IV steroids or biologics only after infection is excluded or controlled.
Crohn obstruction: NG suction and IV fluidsSmall-bowel obstruction from Crohn disease is treated first with nasogastric suction and IV fluids and usually resolves within days; no prompt response suggests a complication and needs surgery.
Perianal fistula: TNF inhibitor plus antibioticsTreat perianal Crohn fistulas with a TNF inhibitor (infliximab or adalimumab) plus metronidazole and/or ciprofloxacin, and drain any associated abscess.
04
Red flags & don'ts
Avoid harmAvoid opioid and anticholinergic antidiarrheals avoidOpioids and anticholinergic antidiarrheal drugs can precipitate toxic colitis in a severe flare; avoid them.
05
The rules
Know theseNo improvement in 24–48 hours: colectomyIf intensive medical therapy for toxic colitis brings no definite improvement within 24–48 hours, proceed to surgery — delay risks sepsis and perforation.
06
Ulcerative colitis or Crohn disease?
Commonly confused| Distribution | Rectum upward, continuous |
|---|---|
| Depth | Mucosa and submucosa |
| Fistulas and abscesses | Do not occur |
| Typical emergency | Toxic colitis, megacolon > 6 cm |
| Before steroids or biologics | Exclude C. difficile and CMV |
07
More detail
ReferenceShow 6 reference facts
Take flat and upright abdominal radiographs in a severe flare to look for colonic dilation; avoid barium enema, and prefer careful flexible sigmoidoscopy over full colonoscopy because of perforation risk.
IV cyclosporine (2 mg/kg/day in trials) acts fast; responders switch to oral cyclosporine with azathioprine or 6-mercaptopurine for about 3–4 months, with level monitoring and consideration of Pneumocystis prophylaxis.
In a randomized trial of steroid-refractory UC, infliximab and cyclosporine rescue had similar 90-day treatment failure and colectomy rates; JAK inhibitors are emerging rescue options.
About 20–40% of patients hospitalized with ulcerative colitis eventually need colectomy; total proctocolectomy is curative for the colitis.
Patients in a flare who tolerate food should eat; parenteral nutrition supports nutrition but has no value as primary therapy.
Smoking increases Crohn disease recurrence, including after surgery; strongly encourage cessation.
Six bloody stools plus a sick patient: admit, check C. diff and CMV, give IV steroids — and if it is not better by day 3, rescue or call the surgeon.
Sources · Merck Manual Professional — Ulcerative Colitis · Merck Manual Professional — Crohn Disease (Mar 2026; cites ACG 2025 Crohn guideline) · Managing Acute Severe Ulcerative Colitis in 2025 and Beyond. Curr Gastroenterol Rep 2026 (Truelove–Witts, steroid dosing, Oxford day-3 criteria, rescue therapy) · Remicade (infliximab) prescribing information — DailyMed (latent TB and HBV testing) · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).