Inflammatory Bowel Disease (IBD)
Markers for Intestinal Inflammation
- Fecal lactoferrin.
- Fecal calprotectin.
Hygiene Hypothesis
- Increased intake of preservative-rich foods
- ↓↓ mucosal immunity → IBD.
Genetic Factors
- NILA
- NOD2 gene polymorphism (Chromosome 16)
- ↑↑ activation of NF-kB (Growth signaling) pathway
- Increased cell proliferation → IBD.
- → Defective Innate immunity
- → Overactive Adaptive Immunity (Th1 mediated).
- IRGM gene (Immunity Related GTPase m).
- IL-23 gene polymorphism
- ATG16L1 (Autophagy related).
- ↓↓ Fecalibacterium → due to alteration in gut flora.
Age:
- Bimodal distribution.
- 1st peak → 15-20 years.
- 2nd peak → elderly.
- Note: Bimodal age distribution also seen in Hodgkin's lymphoma.
Oral contraceptive pills
- Associated with increased risk of CD
- NOT UC
Feature | Crohn's Disease | Ulcerative Colitis (UC) |
Age | • Bimodal peak ↳ (20-40 years, >70 years) | • 25-40 years |
Gender | • F > M | • M > F |
Gene | • NOD2/CARD15 | ㅤ |
Clinical Feature | • Skip lesions • Transmural (full thickness) • fissures, fistulas • Any GI tract part, • Ileum most common ↳ Large volume diarrhea. • Rectum spared (never affected) | • Bloody diarrhea (hallmark), • Toxic megacolon • Continuous lesions • Mucosal and submucosal • Starts from Rectum (always involved) • spreads retrograde |
Smoking | Risk factor (increases risk) | • Protective/Preventive ↳ (may relieve symptoms) |
Gross findings | • Creeping fat, • Cobblestone appearance, • Aphthous ulcers ↳ → serpiginous ulcers | • Ulcers, Pseudopolyps • (regenerating mucosa) |
Microscopy | • Non-caseating granulomas | • Crypt abscesses |
Associated fungus/bug | • Saccharomyces cerevisiae | None |
Antibodies | • ASCA positive (Anti-Saccharomyces cerevisiae) • P-ANCA in ~11% cases | • P-ANCA positive (also in Primary Sclerosing Cholangitis) |
Cytokine | • Increased TNF alpha | ㅤ |
Radiology | • String sign (barium study) | • Lead pipe appearance (barium study: straight, rigid) |
Radiological Sign | • String sign of Kantor ↳ terminal ileum stricture ↳ also seen in TB | • Toxic Megacolon (diameter >6 cm) • with high risk of perforation |
Complications | • Skin nodules, Fissures, Fistulas • Calcium oxalate stones | • Toxic megacolon, Backwash ileitis • PSC →Also dont respond to Rx |
Cancer risk | • Yes (less than UC) | • Increased risk of cancer |
Treatment | • Infliximab (anti-TNF alpha) • Steroids + 5-ASA derivatives (Aminosalicylates) | • Medical Rx: Conservative • 5-aminosalicylic acid (5-ASA), • 6-mercaptopurine (6-MP) • Total proctocolectomy + Ileal Pouch-Anal Anastomosis (IPAA) (curative) |
Smoking protective for
- PIH
- UC
Indications of Aspirin:
- APLA
- Past h/o PIH/chronic Hytn
- Multifetal pregnancy
- Overt DM
- CKD
Radiology
Very very important PIC
- Garden hose or hose pipe appearance:
- Thickening of bowel wall, fissures, fistula, and abscess.
- Leads to fibrosis and strictures.
- Fissure ulcers: Rose thorn appearance.
- String Sign of Kantor: Fibrosis in terminal ileum.
- Creeping mesenteric fat:
- Thickened mesentery encasing bowel wall.
- Atrophic, featureless, short, and narrow colon in UC
- Lead pipe or pipestem colon (with no haustrations).
- Loss of Crypt Architecture.
- Cryptitis and crypt abscess:
- non-specific
- UC>CD
Endoscopy of Ulcerative Colitis
Indications for Surgery (for IBD)
- Failure to respond to medical management
- Steroid toxicity
- Complications of IBD (e.g., perforation, stricture, fistula)
- Unremitting extraintestinal manifestations (those responsive to bowel disease control)
- Dysplasia/cancer development
Extra-Intestinal Manifestations of IBD
Mnemonic:
- So (Psoriasis) So (Spondylitis) So (Sacroilitis) U (Uveitis)
- UV () Sar () Gange () nodu Sorry (psoriasis) paranju ()
- CD > UC
- Two exceptions: UC > CD
- Pyoderma Gangrenosum.
- Primary Sclerosing Cholangitis (PSC) → Risk factor for Cholangiocarcinoma.
Other General Manifestations
- Stones:
- Kidney Stones (e.g., Calcium oxalate).
- Increased risk for Thromboembolism.
Systemic Manifestations
- Skin:
- Erythema Nodosum.
- Pyoderma Gangrenosum.
- Eye:
ㅤ | ㅤ |
Episcleritis | • Crohn’s |
Uveitis | • Crohn’s and UC |
- Arthritis:
- Ankylosing Spondylitis.
- Large Joint - Migratory Asymmetric pauci articular arthritis (LMAP).
- Hematologic:
- Anemia of chronic disease
- Iron deficiency anemia
- Thrombocytosis
EIMs Correlating with IBD Relapse
- Erythema Nodosum.
- Episcleritis.
- LMAP (Migratory Asymmetric pauci articular arthritis).
Genetic Disorders associated with IBD
- Turners syndrome: Associated with both Ulcerative Colitis and Crohn’s Disease.
- Associated with Granulomatous Colitis:
- Glycogen storage disease Type I (von – Gierke’s disease)
- Hermansky Pudlak Syndrome
- Wiskott-Aldrich Syndrome: → Non – granulomatous involvement.
- IL-10 deficiency or IL – 10 receptor dysfunction:
- IL-10 is a powerful anti-inflammatory cytokine.
- Leads to early onset refractory IBD.
Different Clinical, Endoscopic, and Radiographic Features
Feature | Ulcerative Colitis | Crohn's Disease |
Clinical Features | ㅤ | ㅤ |
Gross blood in stool | Yes | Occasionally |
Mucus | Yes | Occasionally |
Systemic symptoms | Occasionally | Frequently |
Pain | Occasionally | Frequently |
Abdominal mass | Rarely | Yes |
Significant perineal disease | No | Frequently |
Fistulas | No | Yes |
Small intestinal obstruction | No | Yes |
Colonic obstruction | Rarely | Frequently |
Response to antibiotics | No | Yes |
Recurrence after surgery | No | Yes |
ANCA - positive (Mnemonic: ANU) | Frequently | Rarely |
ASCA - positive | Rarely | Frequently |
Endoscopic features | ㅤ | ㅤ |
Rectal sparing | Rarely | Frequently |
Continuous disease | Yes | Occasionally |
Cobblestoning | No | Yes |
Granuloma on biopsy | No | Occasionally |
Radiographic features | ㅤ | ㅤ |
Small bowel significantly abnormal | No | Yes |
Abnormal terminal ileum | No | Yes |
Segmental colitis | No | Yes |
Asymmetric colitis | No | Yes |
Stricture | Occasionally | Frequently |
Risk for Malignancies
Malignancy | Comparison |
Colorectal Ca | UC > CD |
Cholangiocarcinoma | UC only |
Non – Hodgkin Lymphoma | CD > UC |
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