IBD is an important clinical entity, made up of two idiopathic processes: Crohn Disease (CD) and Ulcerative Colitis (UC). Risk factors involve both genetic (higher incidence in identical twins) and environmental sources. Cigarette smoking = risk factor for CD, protective for UC. Northern populations see higher rates of IBD. Note: may utilize ESR and CRP levels to monitor response to therapy. Finally, patients with chronic colitis ( > 8-10 years in duration) need surveillance colonoscopy q1-2 years to evaluate for colon cancer, as these IBD patients are at increased risk.
Extraintestinal Manifestations of IBD
- Occur in 10% of patients with known IBD, usually present before GI symptoms.
- Top signs/symptoms:
- Oral aphthous ulcers, back pain (AS or sacroiliitis), and joint pain.
- Others include ocular (uveitis, scleritis) and dermatologic (erythema nodosum and pyoderma gangrenosum).
- Liver = primary sclerosing cholangitis (PSC)
Ulcerative Colitis (UC)
- “Bloody UC!”
- Clinically
- Patient complains of bloody diarrhea and abdominal pain; constipation if distal (rectal muscle tone increase).
- Depending of where inflammation is, symptoms may change – typically inflammation arises in distal colon, moves its way up (not always)
- Proctitis – rectal lesions only
- Left-sided colitis – inflammation in the anatomical left colon (to splenic flexure)
- Pancolitis – involving the entire large intestine (colon).
- Physical exam: normal to severe (tachycardia, fever, dehydration, pallor; even hypoactive bowel sounds and rebound tenderness which may suggest bowel perforation or megacolon).
- Labwork: derangements on CBC, low albumin, BMP anomalies (electrolytes).
- Diagnosis
- Colonoscopy with biopsy
- Mucosal lining swelling and erythema, loss of vasculature; fragility, granularity, ulcers, hemorrhage.
- Pathology: abnormal crypt anatomy.
- Inflammation moves in continuous proximal fashion starting at rectum – 50% will have pancolitis at presentation!
- “Back wash ileitis” – pancolitis patients who also have disease in the ileum.
- Colonoscopy with biopsy
- Treatment of UC
- 1st line = 5-ASA drugs
- Used for inducing remission and maintenance therapy
- 5-ASA delivered to colon
- Mesalamine – goes to small and large intestines (prepared specifically for targeted delivery)
- Severe UC = Oral Glucocorticoids
- Prednisone 40-60 mg/day
- Budesonide MMX (high first pass metabolism reduces systemic effects)
- Maintenance therapy:
- If glucocorticoid-responsive, transition to:
- AZA or 6-MP (test for TPMT level – if low level, patient is at risk for toxicity as this inactivates 6-MP.
- If non-responsive to glucocorticoids, transition to:
- Biologics: cyclosporine or anti-TNF antibodies (infliximab, adalimumab, golimumab)
- If glucocorticoid-responsive, transition to:
- 1st line = 5-ASA drugs
Crohn Disease (CD)
- Clinically
- C/C diarrhea, weight loss, abdominal discomfort.
- LESS likely to report bleeding/fever.
- Distribution:
- 30% small-bowel only (belly pain), 40% ileocolonic disease (RLQ pain), 25% colonic disease only (bleeding per rectum, fistula formation), 5% upper GI or perianal (urgency and/or tenesmus)
- Pathophysiology
- Transmural inflammation, leading to fistula formation! More infections.
- Diagnosis
- Colonoscopy with biopsy
- Superficial to deep ulcers, may combine to form “cobblestone” appearance. (Crohn Cobblestone) – rectum is spared.
- Skip lesions (regions of normal tissue)
- Ileum inflammation is typical – required to biopsy this area!
- Pathology: patchy transmural inflammation
- CT or MR enterography, video capsule endoscopy are sometimes useful.
- Colonoscopy with biopsy
- Treatment of Crohn Disease
- Induction is typically with glucocorticoids (prednisone, or budesonide if ileocolonic)
- Maintenance:
- Steroid-responsive – Transition from prednisone to immunomodulator (AZA, 6-MP, or methotrexate)
- Very severe disease – BIOLOGIC anti-TNF, can close fistulas and are pregnancy category B
- Infliximab, adalimumab, certolizumab.
- For test-taking purposes:
- Natalizumab is a mab that can cause PML (JC Virus).
- Vedolizumab – leukocyte trafficking antagonist that does not work in brain.
Bibliography
- ACP MKSAP 17: Gastroenterology and Hepatology, pgs. 37-41
- Image source: https://www.pinterest.com/kimerydavis/ulcerative-colitis/