inpatient / gastroenterology

Inflammatory Bowel Disease (IBD) and Flares

PDF coming soon!

If You Remember Nothing Else

The management of IBD is complex - GI and surgical consultants should be involved from the beginning. Though we tend to think of UC and Crohns in very stark buckets, in reality differentiating between the two (especially when first diagnosed) can be difficult. Classically, UC involves the rectum and colon and is continuous whereas Crohns can involve any part of GI tract from anus to mouth with skip lesions, though typically affects the terminal ileum and colon while sparring the rectum.

In general, the severity of flares is determined based on the number of BMs per day, andpresence of anemia, inflammatory markers, and other symptoms of colitis. Flares are most commonly treated with IV steroids, analgesia (avoid NSAIDs, opioids, anti-motility agents), antibiotics if there is a concern for an intra-abdominal infection, and other supportive care. Complications can include GI bleeding, strictures, fistulae, perforations, and intra-abdominal infections/abscesses. In severe cases, management will include initiating biologics or undergoing surgical management.
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Clinical Pearls

• Stages of IBD include induction, maintenance, endoscopic remission
• Maintenance therapies are numbered and complex - in general they include Anti-TNF-alpha Abs (adalimumab, infliximab, certolizumab), Anti-leukocyte trafficking Abs (vedolizumab), Anti-p40 Abs (ustekinumab), Thiopruine Analogs (azathioprine, 6-mercaptopurine), 5-aminosalicylic acid derivatives (sulfasalazine, mesalamine)
• Take flare very seriously - IV steroids → biologic induction → surgery
• Symptoms do not always correlate with disease severity - look for biomarkers, imaging, and endoscopy to guide the severity of the disease and flare
• UC involves the rectum and colon and is continuous; Crohns can involve any part of GI tract from anus to mouth, though typically is in the terminal ileum and colon, sparring the rectum, with skip lesions
• Crohns has a bimodal distribution - 15-35 and 55-70; high prevalence in northern European and Ashkenazi Jewish descent; UC more commonly 15-35
• Smoking is supposedly protective against UC, but honestly this seems like a dubious retrospective finding
• Fecal calprotectin can take a long time to result and is usually done in the outpatient setting for diagnostic purposes, however, if acute flares can be helpful to trend to assess response to therapy over a long period of time; helps differentiate between inflammatory and functional conditions
• 4% of patients with UC develop PSC
• Microscopic Colitis - inflammatory colitis with a normal appearance on scope but collagenous or lymphocytic infiltrate on biopsy - usually 60+, chronic watery diarrhea, weight loss; stop NSAIDs, give steroids and loperamide
• UC - IL-23-Th17 signaling, usually bloody diarrhea with mucus, tenesmus, crypt abscesses, loss of haustra (lead pipe), PSC, risk of CRC, toxic megacolon, mucosa and submucosa only, no granulomas, curative surgery possible 
• Crohn - Th2 cells, usually non-bloody, watery diarrhea, cobblestone sign, creeping fat, string sign, slip lesions, fistulas, terminal ileum, transmural inflammation, noncaseating granulomas
• Both UC anf Crohns are associated with pyoderma gangrenosum, erythema nodosum, uveitis, apthous stomatitis, arthritis 

Trials and Literature

• SONIC Trial -  in mod-severe Crohns, the combo of azathioprine and infliximab lead to a higher rate of steroid-free remission at week 26 vs either drug alone (30.0% aza vs 44.4% infliximab vs 56.8% combo; infliximab monotherapy > azathioprine; criticism - induction only given to patients receiving infliximab, azathioprine takes 6 months for full effect, combo therapy goes against the typical step-wise approach, no longer term followup, infliximab $$$ (NEJM, 2010)

Other Resources

• Clinical Problem Solvers - Crohns Illness Script