Makindo Medical Notes

Related Subjects: |Colorectal cancer |Colorectal polyps |Ulcerative Colitis |Acute Severe Colitis |Crohn's disease

Anti-TNF agents have significantly improved outcomes by enhancing the ability to achieve and maintain remission in Crohn’s disease.

About

• Crohn's disease is a chronic, relapsing inflammatory granulomatous condition.
• It can affect any part of the gastrointestinal tract, from the mouth to the anus.
• UK incidence: 5-8 per 100,000 per year; prevalence: 50-80 per 100,000.

Aetiology

• More common in Caucasian and Jewish populations, with a 3-4 times higher risk among smokers.
• Familial forms are linked to polymorphisms in the NOD2/CARD15 gene on chromosome 16, often correlating with ileal disease.
• Environmental factors, including exposure to specific antigens and oral contraceptive use, may increase risk.

Pathology

• Characterized by granulomatous, transmural inflammation that is often oedematous.
• Granulomas may be deep and sometimes absent in biopsy samples; deep ulcers may form.
• Distinctive “skip lesions” are present, with inflamed areas interspersed with healthy segments.
• Fistulas can form between affected areas, potentially involving the bladder, uterus, or vagina.

Disease Location - Discontinuous Skip Lesions

• Terminal ileum involvement: ~90%.
• Ileocolonic disease: 40%.
• Small intestine: 40%.
• Crohn’s colitis: 20%.
• Perianal disease: <10%, with rectal sparing in most cases.

Clinical Presentation

• Proximal Small Bowel Disease: Crampy abdominal pain, partial bowel obstruction, weight loss, anorexia.
• Terminal Ileal Disease: Right lower quadrant pain (mimics appendicitis), malabsorption, steatorrhea, and inflammatory mass in the right lower quadrant.
• Colonic Disease: Diarrhea, which may contain blood and mucus (Crohn's colitis).
• Perianal Disease: Skin tags, fistulas, abscesses, often requiring surgical or pharmacological intervention.
• Systemic features: Finger clubbing, anaemia, fever, malaise, and mouth ulcers.

Complications

• Eye: Uveitis, episcleritis, conjunctivitis.
• Renal: Kidney stones due to increased urinary oxalate.
• Musculoskeletal: Arthropathy, sacroiliitis, ankylosing spondylitis.
• Skin: Erythema nodosum, pyoderma gangrenosum, amyloidosis.
• Increased risk of colonic malignancy with long-standing Crohn’s colitis.
• Increased risk of venous thromboembolism.

Investigations

• Blood tests: Check hemoglobin, B12, folate, ferritin, WCC, platelets, ESR, and CRP levels, which correlate with disease activity.
• LFTs and bone profile.
• Stool tests for ova, cysts, and parasites to exclude infectious causes.
• Capsule endoscopy for small bowel disease staging.
• Imaging:
• AXR: Look for bowel obstruction.
• Small Bowel Barium Follow-Through: "String sign of Kantor," deep ulcers, and cobblestone appearance.
• CT with contrast: High sensitivity for active disease areas.
• MRI: Ideal for assessing perianal disease.
• Endoscopy (OGD and Colonoscopy) with biopsies.
• Positive antibody to Saccharomyces cerevisiae (ASCA) in about 60% of cases.

Differential Diagnosis

• Tuberculosis.
• Yersinia infection.

Management

• Mild Disease: Initial treatment with reducing doses of Prednisolone over a month. 5-ASA drugs like Sulfasalazine or Mesalazine are useful for Crohn’s colitis to induce remission, administered orally or rectally.
• Moderate Disease: Prolonged oral Prednisolone course, with steroid enemas for proctosigmoid involvement. Budesonide may be used due to fewer side effects. Obstruction episodes may require hospitalization, IV fluids, and nasogastric decompression. Immunosuppressants like azathioprine or methotrexate may be introduced.
• Severe Disease: Includes toxic megacolon or acute abdomen. Life-threatening colitis requires joint gastroenterology and surgical care, with IV methylprednisolone, antibiotics, VTE prophylaxis, and possible IV Ciclosporin or anti-TNF therapy (e.g., Infliximab, Adalimumab) if steroid-resistant. Surgery may be necessary.
• Fistulating Disease: Treat asymptomatic perianal disease conservatively. Symptomatic cases may require antibiotics (Metronidazole, Ciprofloxacin), immunosuppressants, and sometimes surgery. MRI is preferred for imaging.
• Surgery: Colectomy for severe colitis/toxic megacolon, stricture management, and abscess drainage. Approximately two-thirds of Crohn's patients will require surgery.

Additional Therapeutic Agents

• Azathioprine as a steroid-sparing agent.
• Methotrexate in steroid-resistant disease, dosed weekly.
• Infliximab/Adalimumab for severe Crohn’s and fistulating disease, given as an infusion every 8 weeks.
• Metronidazole for perianal disease, with antibacterial and immunosuppressive properties.
• Dietitian support to optimize nutrition.
• Specialist nurse assistance for patient education and care coordination.