Inflammatory Bowel Disease

• Core 1 (Pre-Clerkship)
  • Gastroenterology
    • IBD pathology
    • Pathology of Inflammatory Bowel Disease in the Small Bowel and Colon
    • Small Groups: pathology - inflammatory state of the small bowel and colon
    • Pediatric tutorial cases
• Core 2 (Clerkship)
• Core 3 (Post Clerkship) Electives that may further knowledge - Peds GI

History

• Diarrhea 

• Abdominal pain 

• Bloody stools, rectal bleeding 

• Increased stool frequency/urgency, nocturnal stooling 

• Weight loss, loss of appetite 

Physical exam

• Decreased linear growth 

• Perianal pain/drainage 

Complications

• Strictures (intestinal obstruction, distention, decreased bowel sounds) 

• Perforation (abdominal rigidity, pain, decreased bowel sounds) 

• Intra-abdominal abscess (abdominal pain, fevers) 

• Malabsorption (iron deficiency anemia, vitamin D deficiency, decreased bone health, growth problems) 

• Toxic megacolon (in ulcerative colitis) 

• Thromboembolism 

• Colon cancer 

• Infection (viral, bacterial, parasitic, tuberculosis) 

• Vasculitis such as Bechet’s, IgA vasculitis, among others 

• Lymphoma 

• Primary immunodeficiencies, chronic granulomatous disease 

• Drug induced colitis 

Evaluation

• Labs
  • Microcytic anemia (due to iron deficiency) 
  • Hypoalbuminemia (malabsorption) 
  • Elevated inflammatory markers (ESR/CRP)
  • Elevated white count/thrombocytosis (inflammation)
  • Elevated fecal calprotectin
  • Elevated liver enzymes
• Endoscopy
  • Visual and pathology findings on upper endoscopy and colonoscopy
  • Evaluates esophagus, stomach, proximal duodenum, terminal ileum, and colon
  • Does not evaluate much of the small bowel
  • Findings: erythema, ulcerations, mucopurulent exudate, and friability of the mucosa
• Pathology
  • Inflammatory infiltrate, cryptitis, crypt abscesses
  • Pathologic features of chronic inflammation: mainly architectural distortion of the crypts – required for the diagnosis of IBD
• Imaging
  • MR Enterography is typically used to assess the small bowel not assessed by endoscopy and complications such as fistulae, strictures, and abscesses
  • CT Enterography and bowel ultrasound may also be used 

Management

• Depends on severity, disease location, and complications (intestinal strictures, fistulae, or abscesses) 

• Improved outcomes with step-down approach with early introduction of biologics 

• Biologic medications – most often first line 

• • Antibodies created using mammalian cells that target specific parts of the immune system to suppress autoimmune inflammatory response 

• • Formulation is IV or subcutaneous injection 

• • Infliximab and adalimumab (anti-TNF-alpha) are the only two biologics FDA approved for use in pediatrics 

• • Other classes are available and are often used off-label in pediatrics 

• • Side effects can vary, but in general are immunosuppressive and can potentially increase risk of cancers 

• Non-biologic medications 

• • Aminosalicylates (mesalamine, sulfasalazine) 

• • Can be used in mild cases of ulcerative colitis, no evidence in Crohn’s 

• Immunomodulators (6-MP, Azathioprine, methotrexate) 

• • Often not used any more due to worse side effect profile and decreased efficacy compared to biologics 

• Steroids/Antibiotics 

• • Often used as adjuncts to biologic therapy in severe disease 

• Diet 

• • Exclusive enteral nutrition 

• • Formula makes up the majority of calories (80-90%) 

• • Can induce remission in Crohn’s disease, hard to continue for maintenance 

• • Other specialized diets: CD-ED, SCD 

• • Mixed evidence for induction and maintenance of Crohn’s and UC 

• Surgery 

• Bowel resection may be indicated in patients with refractory disease or complications such as strictures, abscesses, fistulae 

• Colectomy is curative in ulcerative colitis 

• Autoimmune condition that causes inflammation and injury to the bowel. Crohn’s disease causes transmural inflammation and can involve the whole GI tract whereas ulcerative colitis causes surface mucosal inflammation and only involves the colon
• IBD can cause symptoms outside of the GI tract
• Biologics are commonly used as first line in treatment of IBD
• Likely caused by a combination of genetic predisposition, environmental/dietary triggers, immune system dysregulation, and the microbiome 
• Very-Early Onset (VEO) IBD is defined as IBD with onset < 6 years old
  • Higher likelihood of monogenic cause of underlying disease (especially if onset < 1-2 years old)
  • Often associated with immune system dysregulation
  • Can have more severe phenotype or refractory disease
• Separated into two main categories: Crohn’s disease and ulcerative colitis 

Comparison of Crohn’s Disease and Ulcerative Colitis 

Answers

Q1. 6 years old.

Q2. Under 2 years old.

Q3. Features of chronic inflammation, such as architectural distortion of the crypts, are required for the diagnosis of IBD.

Q4. Biologic therapy—specifically anti-TNF agents (infliximab or adalimumab)—which are the only two FDA-approved biologics in pediatrics. There is evidence supporting improved outcomes with early biologic use (step-down approach).

Q5. Crohn’s disease. Ulcerative colitis has continuous inflammation starting at the rectum, so rectal sparing is not consistent with UC.

Q6. Crohn’s disease. Transmural inflammation leads to complications such as strictures, fistulae, and abscesses, which are rare in ulcerative colitis.

Q7. Crohn’s disease. Granulomas are a histologic feature seen in Crohn’s disease, not ulcerative colitis.

Q8. Extra-intestinal manifestations include:

Q9. Most of the small bowel is not evaluated during standard endoscopy (except for the proximal duodenum and terminal ileum). Evaluation of the rest requires imaging such as MR enterography (MRE) or CT enterography (CTE).

Q10. Fecal calprotectin.

• JAMA Pediatrics IBD Review 

• NAPSGHAN IBD Papers/Resources 

• UpToDate Clinical Presentation and Diagnosis of IBD