Inflammatory Bowel Disease

Inflammatory Bowel Disease: Overview - Gut Feeling Gone Wrong

• Inflammatory Bowel Disease (IBD): Chronic, immune-mediated inflammation of the GI tract.
• Two main forms: Crohn's Disease (CD) and Ulcerative Colitis (UC).
• Pediatric peak incidence: 10-19 years.
• Key Differentiators:
  • CD: Any part of GIT (mouth to anus); transmural inflammation; skip lesions; "cobblestone" appearance; fistulas/strictures common.
  • UC: Limited to colon (starts in rectum, extends proximally); mucosal/submucosal inflammation; continuous lesions; crypt abscesses.

⭐ Smoking is a risk factor for Crohn's Disease but is paradoxically protective for Ulcerative Colitis.

Inflammatory Bowel Disease: Etiopathogenesis - The Inside Story

• Genetic Factors: Key genes include NOD2/CARD15 (Crohn's), IL23R, ATG16L1.
• Immune Dysregulation:
  • Crohn's Disease (CD): Driven by Th1/Th17 pathways.
  • Ulcerative Colitis (UC): Involves atypical Th2 response.
• Gut Microbiome: Dysbiosis (imbalance of gut bacteria) is a significant contributor.
• Environmental Triggers: Smoking (↑CD risk, ↓UC risk), diet, infections, NSAIDs.

⭐ NOD2/CARD15 gene mutations are the strongest genetic risk factor for Crohn's disease, particularly ileal involvement.

Inflammatory Bowel Disease: Clinical Features - Spotting the Signs

• Pediatric Hallmarks: Insidious onset common. Abdominal pain, chronic/nocturnal diarrhea (± blood), weight loss/poor gain, profound growth failure (key!). Unexplained fever, fatigue.
• CD vs. UC Comparison:

  Feature	Crohn's Disease (CD)	Ulcerative Colitis (UC)
  Diarrhea	Often non-bloody	Usually bloody, urgent
  Abd. Pain	RLQ, crampy	LLQ, tenesmus
  Growth Failure	Frequent, severe	Less frequent
  Perianal Lesions	Common (tags, fistulae)	Rare
  Rectal Bleeding	Less common	Hallmark

• Common Extraintestinal Manifestations (EIMs):
  • Arthritis (peripheral > axial)
  • Uveitis, episcleritis
  • Erythema nodosum
  • PSC (esp. with UC)
  • Aphthous stomatitis

⭐ Growth failure may be the only sign of pediatric Crohn's Disease, often preceding GI symptoms.

Inflammatory Bowel Disease: Diagnosis - Unmasking IBD

• Key Labs: ↑ Fecal Calprotectin (FC >250 µg/g indicative), ↑CRP, ↑ESR. Anemia, hypoalbuminemia.
• Serology: ASCA (+ve CD), pANCA (+ve UC) - supportive; limited standalone utility.
• Endoscopy (Ileocolonoscopy + Upper GI) & Biopsy:
  • CD: Skip lesions, aphthous ulcers, cobblestoning. Histo: Transmural inflammation, non-caseating granulomas.
  • UC: Continuous inflammation (rectum proximally), superficial erosions. Histo: Crypt abscesses, cryptitis.
• Pediatric Activity: PCDAI (CD), PUCAI (UC) for severity.

⭐ Non-caseating granulomas on biopsy are highly specific for Crohn's Disease, though found in only ~30% of cases, guiding diagnosis.

vs Ulcerative Colitis (continuous inflammation, crypt abscess))

Inflammatory Bowel Disease: Management - Managing the Mayhem

Goals: Achieve clinical remission, mucosal healing, normal growth & Quality of Life (QoL).

• Nutrition: Crucial. EEN for CD induction. Nutritional support vital for growth & healing.
• 5-ASA (Mesalamine): Key in UC (induction/maintenance); limited role in pediatric CD.
• Surgery: For complications (e.g., strictures, fistulae, perforation) or failed medical Rx.
• Complications: Growth failure, delayed puberty, malnutrition, ↓bone health, ↑malignancy risk.

⭐ Exclusive Enteral Nutrition (EEN) is first-line for induction in pediatric Crohn's Disease, promoting mucosal healing & better nutrition.

High‑Yield Points - ⚡ Biggest Takeaways

• Crohn's Disease: Transmural inflammation, skip lesions, non-caseating granulomas; terminal ileum commonest site. ASCA positive. Complications: fistulas, strictures.
• Ulcerative Colitis: Mucosal inflammation, continuous lesions starting from rectum; bloody diarrhea is hallmark. p-ANCA positive. Risk: toxic megacolon, colorectal cancer.
• Pediatric IBD: Growth failure and delayed puberty are key presentations, often preceding GI symptoms.
• Diagnosis: Endoscopy with biopsy is gold standard. Fecal calprotectin indicates intestinal inflammation.
• EIMs: Common include arthritis, uveitis, skin manifestations (erythema nodosum, pyoderma gangrenosum), and PSC (esp. with UC).
• Treatment: Exclusive Enteral Nutrition (EEN) is first-line for pediatric CD induction. Others: 5-ASA, corticosteroids, immunomodulators, biologics.