# Inflammatory Bowel Disease: Inpatient Management of Flares
## Overview
Inflammatory bowel disease comprises Crohn's disease (CD) and ulcerative colitis (UC), both chronic relapsing-remitting inflammatory conditions of the gastrointestinal tract. UC involves continuous mucosal inflammation extending proximally from the rectum and is limited to the colon. CD features transmural inflammation with skip lesions and can affect any part of the GI tract from mouth to anus, with the terminal ileum being the most common site. It is essential to distinguish IBD flares from infectious colitis (C. difficile, CMV), ischemic colitis, and medication-related colitis (such as checkpoint inhibitor colitis).
## Distinguishing Crohn's from UC in the Acute Setting
| Feature | Ulcerative Colitis | Crohn's Disease |
|---------|-------------------|-----------------|
| Distribution | Continuous, from rectum proximally | Skip lesions, any GI segment |
| Depth | Mucosal | Transmural |
| Bloody diarrhea | Very common | Less common |
| Fistulae/abscesses | Rare | Common |
| Perianal disease | Rare | ~30% |
| Strictures | Uncommon (consider malignancy) | Common |
| Granulomas on biopsy | No | ~30% |
| Smoking effect | Protective | Worsens disease |
| Serologic marker | pANCA (60-70%) | ASCA (60-70%) |
UC presents with continuous distribution from the rectum, mucosal-depth involvement, and very common bloody diarrhea, while fistulae, abscesses, strictures, and perianal disease are rare. Granulomas are not seen on biopsy, smoking appears protective, and pANCA is positive in 60-70%. CD presents with skip lesions that can affect any GI site, transmural involvement, less common bloody diarrhea, and frequent fistulae, abscesses, strictures, and perianal disease (30%). Granulomas are found in 30% of biopsies, smoking worsens the disease, and ASCA is positive in 60-70%.
## Acute Severe Ulcerative Colitis (ASUC)
### Definition -- Truelove and Witts Criteria
ASUC is defined by six or more bloody stools per day plus at least one of the following: heart rate above 90, temperature above 37.8 degrees Celsius, hemoglobin below 10.5 g/dL, or ESR/CRP above 30.
### Initial Assessment and Workup
Stool studies should include C. difficile toxin (PCR plus toxin EIA), stool culture, and ova and parasites. CMV colitis, a reactivation in immunosuppressed patients, should be assessed with CMV PCR and tissue immunohistochemistry on biopsy. Laboratory studies include CBC, CMP, CRP, ESR, albumin, and blood cultures if febrile. An abdominal X-ray assesses for toxic megacolon (transverse colon greater than 6 cm). Flexible sigmoidoscopy (not full colonoscopy) assesses severity and obtains biopsies to rule out CMV, but should be avoided in suspected toxic megacolon. CT abdomen and pelvis is obtained if perforation or abscess is suspected.
### First-Line: IV Corticosteroids
Methylprednisolone 60 mg IV daily (or hydrocortisone 100 mg IV every 8 hours) is initiated, with response assessed at Day 3 using the Oxford Criteria. Day 3 stool frequency greater than 8, or frequency of 3-8 with CRP above 45, carries an 85% chance of failing steroids and requiring colectomy. Additional Day 3 markers of poor prognosis include persistent bloody stools, elevated CRP, and hypoalbuminemia. The overall response rate to IV steroids is approximately 60-70%, with the remainder being steroid-refractory.
### Steroid-Refractory ASUC -- Rescue Therapy
#### Infliximab
Infliximab is administered at 5 mg/kg IV with accelerated induction protocols available (0, approximately 2 weeks, approximately 6 weeks, or even 0, 3 days, approximately 14 days). Higher trough levels are associated with better outcomes. It reduces the colectomy rate from approximately 50% to about 30%. Pre-treatment screening includes hepatitis B serologies, tuberculosis screening, and varicella status. Accelerated dosing with intensified regimens (10 mg/kg or shortened intervals) is used in ASUC for patients with low albumin due to rapid drug clearance, though evidence continues to evolve.
#### Cyclosporine
Cyclosporine is administered at 2 mg/kg IV continuous infusion (the older 4 mg/kg dose was shown by the CYAS trial to be equivalent to 2 mg/kg). Trough levels, renal function, blood pressure, magnesium, and cholesterol require monitoring. It has effective short-term rescue (approximately 60-80% initial response) but requires transition to thiopurine maintenance. Side effects include nephrotoxicity, seizures (especially with low cholesterol or magnesium), infections, and hypertension. Direct bridging to infliximab is not possible because sequential immunosuppression increases infection risk.
#### Infliximab vs. Cyclosporine
The CONSTRUCT trial showed no significant difference in colectomy-free survival at 3 years. Infliximab is preferred in many centers because it is easier to administer and can continue as maintenance therapy. Cyclosporine may be used when infliximab has already failed or is contraindicated. The choice often depends on institutional expertise.
### Adjunctive Management in ASUC
Thromboprophylaxis is essential because IBD is a major VTE risk factor; subcutaneous LMWH should be started even with rectal bleeding unless hemorrhage is life-threatening. Enteral nutrition is preferred, with TPN reserved only when bowel rest is mandatory. Opioids (which mask symptoms and can precipitate toxic megacolon), anticholinergics, NSAIDs, and loperamide should all be avoided. Antibiotics are not routinely recommended unless concurrent infection or toxic megacolon is suspected. Surgical consultation should be obtained early, as colectomy is life-saving for toxic megacolon, perforation, uncontrolled hemorrhage, or failure of rescue therapy.
### Toxic Megacolon
Toxic megacolon is defined by transverse colon dilation exceeding 6 cm with systemic toxicity (fever, tachycardia, leukocytosis). It represents a medical emergency with high perforation risk. Management includes IV steroids, IV antibiotics covering gut flora, nasogastric tube decompression, and serial abdominal X-rays every 12 hours. Colectomy is indicated if there is no improvement in 24-72 hours or any sign of perforation.
### Surgical Management
Subtotal colectomy with end ileostomy is the procedure of choice in the acute setting. Proctectomy and ileal pouch-anal anastomosis (IPAA or J-pouch) is performed later as a staged procedure. Long-term outcomes of IPAA are good, though pouchitis occurs in up to 50% of patients and is treated with antibiotics.
## Acute Crohn's Disease Flares
### Assessment
Assessment includes determining disease location (ileal, colonic, ileocolonic, upper GI, perianal), behavior (inflammatory, stricturing, penetrating), and severity. The CDAI or Harvey-Bradshaw Index quantifies severity. CRP and fecal calprotectin correlate with mucosal inflammation. CT enterography or MR enterography assesses for complications including abscess, stricture, and fistula.
### Inpatient Management
IV corticosteroids (methylprednisolone 40-60 mg daily) are administered for moderate-severe flares. Abscesses require percutaneous drainage plus antibiotics (ciprofloxacin plus metronidazole), and immunosuppression should not be started until the abscess is drained. Stricturing disease requires determination of the inflammatory versus fibrotic component: inflammatory strictures may respond to steroids and biologics, while fibrotic strictures require endoscopic balloon dilation or surgical resection. Bowel obstruction is managed with NPO, IV fluids, NG tube decompression, and IV steroids if an inflammatory component is present, along with surgical consultation. Fistulizing disease requires MRI pelvis for perianal fistulae, seton placement, and infliximab (the best-studied biologic for fistulizing CD).
### Biologic and Advanced Therapies for CD
Anti-TNF agents (infliximab, adalimumab, certolizumab) are effective for induction and maintenance, with infliximab being best for fistulizing disease. Vedolizumab (anti-integrin) is gut-selective with lower infection risk but slower onset. Ustekinumab (anti-IL-12/23) has effective induction and maintenance with a good safety profile. Risankizumab and guselkumab (anti-IL-23) are emerging with strong efficacy data. Upadacitinib (JAK inhibitor) is approved for CD, while tofacitinib is approved for UC only. S1P receptor modulators ozanimod and etrasimod are approved for UC.
## General Principles for IBD Inpatient Care
Screening for C. difficile and CMV is required in all flares, especially if the patient is immunosuppressed. VTE prophylaxis is mandatory because IBD patients have 2-3 times higher VTE risk. Opioids should be avoided when possible due to the risk of ileus and masking of symptoms. Nutritional support should be enteral when possible, as there is no role for bowel rest in most IBD flares. Smoking cessation should be discussed in Crohn's disease because it worsens the disease course and surgical recurrence. A multidisciplinary approach involving gastroenterology, surgery (with early involvement), nutrition, and pharmacy produces the best outcomes.
A clinical decision algorithm for acute severe ulcerative colitis management. Start with Truelove-Witts criteria assessment, then IV corticosteroids with Day 3 reassessment using Oxford criteria. Branch into steroid-responsive (transition to oral taper + maintenance therapy) vs. steroid-refractory (rescue therapy with infliximab or cyclosporine). Show surgical pathway for toxic megacolon, perforation, or rescue therapy failure. Include VTE prophylaxis and infection screening as parallel mandatory steps.
A comparison table infographic of rescue therapies for steroid-refractory ASUC. Two columns for infliximab and cyclosporine showing: mechanism, dosing (standard vs. accelerated), response rates, key side effects, monitoring requirements, transition to maintenance, and key trial evidence (CONSTRUCT trial). Include a decision aid showing when to favor each agent based on patient factors.
A visual guide to complications of Crohn's disease requiring inpatient management. Show a cross-sectional diagram of bowel wall with four panels: (1) inflammatory disease with mucosal ulceration and transmural inflammation, (2) stricturing disease with luminal narrowing, (3) penetrating disease with fistula formation (enteroenteric, enterocutaneous, enterovesical), and (4) perianal disease with abscess and fistula. Each panel includes imaging modality of choice and management approach.
## Clinical Pearls
All hospitalized IBD patients need VTE prophylaxis because IBD is an independent risk factor for VTE and immobilization during flares compounds this risk. C. difficile and CMV superinfection must always be ruled out before escalating immunosuppression in an IBD flare, as treating the wrong cause with more immunosuppression is dangerous. Steroid response should be assessed at Day 3 in ASUC using the Oxford criteria, because early identification of steroid failure allows timely rescue therapy and reduces emergency colectomy rates. Opioids should be avoided in IBD flares because they mask symptoms, promote ileus, and can precipitate toxic megacolon. In Crohn's disease with abscess, the abscess must be drained first before starting immunosuppression, as starting biologics with an undrained abscess risks sepsis. Infliximab is the best-studied biologic for fistulizing Crohn's disease, and accelerated dosing should be considered in ASUC with low albumin due to rapid drug clearance. Early surgical consultation is not a failure of medical therapy but rather a standard component of ASUC management.
## References
- Truelove SC, Witts LJ. Cortisone in Ulcerative Colitis. BMJ. 1955.
- Travis SP, et al. Predicting Outcome in Severe Ulcerative Colitis. Gut. 1996.
- Williams JG, et al. CONSTRUCT Trial: Infliximab vs. Cyclosporine in Steroid-Refractory ASUC. Health Technology Assessment. 2016.
- Feuerstein JD, et al. AGA Clinical Practice Guidelines on the Management of Moderate to Severe Ulcerative Colitis. Gastroenterology. 2020.
- Lichtenstein GR, et al. ACG Clinical Guideline: Management of Crohn's Disease in Adults. Am J Gastroenterol. 2018.
- Harbord M, et al. ECCO Consensus: Third European Guideline on the Diagnosis and Management of IBD. J Crohn's Colitis. 2017.
- Rutgeerts P, et al. Infliximab for Fistulizing Crohn's Disease (ACCENT II). NEJM. 2004.