Inflammatory Bowel Disease

Inflammatory Bowel Disease

Inflammatory Bowel Disease

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IBD Overview - Fiery Bowel Blues

  • Chronic, relapsing idiopathic inflammation of GIT.
  • Two main types: Ulcerative Colitis (UC) & Crohn's Disease (CD).
  • Epidemiology:
    • Peak incidence: 15-30 years & 50-80 years (bimodal).
    • Slight female predominance.
    • Higher in developed nations.
  • Risk factors:
    • Genetics (e.g., NOD2/CARD15 for CD).
    • Smoking (Worsens CD, Protects UC 📌).
    • Diet (Western diet), NSAIDs.
    • Altered gut microbiota.

⭐ Extraintestinal manifestations (EIMs) are common, occurring in up to 50% of IBD patients; arthritis is the most frequent EIM_._

Crohn's vs UC - The Great Divide

FeatureCrohn's Disease (CD)Ulcerative Colitis (UC)
LocationMouth to anus; Skip lesions; Terminal ileum commonRectum (always), continuous proximal spread; Colon only
PathologyTransmural; Non-caseating granulomas (50-60%); Cobblestones, Creeping fatMucosal/Submucosal; Crypt abscesses, Pseudopolyps
ComplicationsFistulae, Strictures, Abscesses; Perianal diseaseToxic megacolon, Hemorrhage; ↑ CRC risk (pancolitis)
SmokingWorsens CDProtective for UC

⭐ Extraintestinal manifestations (EIMs) are common in IBD. Primary Sclerosing Cholangitis (PSC), a significant EIM, has a strong association with Ulcerative Colitis (approx. 70% of PSC patients have UC).

📌 Mnemonic:

  • CD: "GRANny skips on COBBLESTONES from GUM to BUM, but SMOKING makes her FISTulae WORSE."
  • UC: "ULCERS in the COLON are CONTINUOUS from the RECTUM, SMOKING is PROTECTIVE, but watch for CANCER."

Clinical & Diagnosis - Spotting the Signs

  • Common Symptoms:
    • Ulcerative Colitis (UC): Bloody diarrhea (hallmark), tenesmus, urgency, LLQ abdominal pain. Systemic symptoms less prominent.
    • Crohn's Disease (CD): Abdominal pain (RLQ, colicky), weight loss, fatigue, diarrhea (often non-bloody). Perianal disease common.
  • Key Extraintestinal Manifestations (EIMs): (~25-40% IBD patients) 📌 A PIE SAC
    • Arthritis (peripheral/axial), Aphthous stomatitis
    • Pyoderma gangrenosum
    • Iritis/Uveitis
    • Erythema nodosum
    • Sclerosing cholangitis (PSC - UC, ↑cancer risk)
    • Clubbing, Cholelithiasis (CD - ileal)
  • Diagnostic Approach:
    • Labs: CBC (anemia), ↑ESR/CRP, fecal calprotectin. p-ANCA (UC ~60%), ASCA (CD ~60%).
    • Endoscopy + Biopsy (Definitive):
      • UC: Continuous inflammation (rectum proximally), friability, pseudopolyps. Biopsy: cryptitis, crypt abscesses.
      • CD: Skip lesions, aphthous/linear ulcers, cobblestoning, transmural. Biopsy: non-caseating granulomas (pathognomonic, ~30-50%).
    • Imaging (CT/MR Enterography): Small bowel, transmural extent, complications (strictures, fistulae, abscesses).

Endoscopic features: Ulcerative Colitis vs Crohn's

⭐ While crypt abscesses are characteristic of UC, they can also be seen in severe CD; non-caseating granulomas are specific to CD but only found in ~30-50% of biopsies.

Management - Taming the Flames

  • Medical Therapy (Step-Up):
    • Mild: 5-ASA (Mesalamine, Sulfasalazine) for UC; Budesonide for ileocolonic CD.
    • Moderate Flares: Systemic Corticosteroids (Prednisolone $~1mg/kg$, max 40-60mg), taper on remission.
    • Maintenance/Steroid-Sparing: Immunomodulators (Azathioprine, 6-MP, MTX). Monitor side effects.
    • Severe/Refractory: Biologics (📌AIVU: Adalimumab, Infliximab, Vedolizumab, Ustekinumab).

      ⭐ Infliximab requires latent TB screening (reactivation risk).

  • Surgical Therapy:
    • Ulcerative Colitis (UC):
      • Indications: Refractory, dysplasia/cancer, toxic megacolon ($>6cm$ dilation + toxicity), perforation, hemorrhage.
      • Procedure: Total Proctocolectomy with IPAA (curative).
    • Crohn's Disease (CD):
      • Indications: Complications (strictures, fistulas, abscesses, obstruction), refractory disease.
      • Procedures: Conservative resection, stricturoplasty. Not curative.

High‑Yield Points - ⚡ Biggest Takeaways

  • Crohn's Disease: Characterized by transmural inflammation, skip lesions, fistulas, and strictures; smoking is a significant risk factor.
  • Ulcerative Colitis: Features continuous mucosal inflammation typically starting in the rectum, with risk of toxic megacolon; smoking is paradoxically protective.
  • Extraintestinal manifestations like arthritis, uveitis, and skin lesions are common in both.
  • Surgical indications for Crohn's: Primarily for complications (e.g., stricture, fistula, abscess); bowel conservation (e.g., strictureplasty) is paramount.
  • Surgical indications for UC: Includes medically refractory disease, dysplasia/cancer, or acute severe colitis; total proctocolectomy with IPAA is curative.
  • Both IBD types carry an increased colorectal cancer risk, necessitating regular surveillance.
  • Key serological markers: p-ANCA often positive in UC, ASCA often positive in Crohn's Disease.

Practice Questions: Inflammatory Bowel Disease

Test your understanding with these related questions

Which of the following is a type of inflammatory bowel disease primarily affecting the small intestine? a) Coeliac disease b) Tropical sprue c) Regional ileitis d) Cystic fibrosis e) Ulcerative colitis

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Flashcards: Inflammatory Bowel Disease

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Which IBD has appendicectomy as its protective factor?_____

TAP TO REVEAL ANSWER

Which IBD has appendicectomy as its protective factor?_____

Ulcerative colitis

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