Crohn's disease


  • Can involve any part of the GI tract from the mouth to the anus
  • Bimodal distribution: 15-22yr, 55-60yr
  • Pathology
    • All layers of the bowel are involved
      • Reason why fistulas and abscesses are common complications
    • "Skip lesions" are common

Clinical Features

GI Symptoms

Extraintestinal Symptoms (50%)

  • Arthritis
    • Peripheral arthritis
      • Migratory monoarticular or polyarticular
    • Ankylosing spondylitis
      • Pain/stiffness of spine, hips, neck, rib cage
    • Sacroiliitis
    • Low back pain with morning stiffness
  • Ocular
    • Uveitis
      • Acute blurring of vision, photophobia, pain, perilimbic scleral injection
    • Episcleritis
      • Eye burning or itching with out visual changes or pain; scleral and conj hyperemia
  • Dermatologic
    • Erythema nodosum
      • Painful, red, raised nodules on extensor surfaces of arms/legs
    • Pyoderma gangrenosum
      • Violacious, ulcerative lesions with necrotic center found in pretibial region or trunk
  • Hepatobiliary
  • Vascular

Differential Diagnosis




  • Labs
    • CBC
    • Chemistry
    • ESR/CRP
    • C.diff toxin
    • Type and screen if any bleeding suspicion
  • Imaging:
    • Plain abdominal films - rule out small bowel obstruction, perforation and toxic megacolon
    • CT A/P
      • Most useful diagnostic test in patients with acute symptoms who have known or suspected Crohn
      • Findings: bowel wall thickening, mesenteric edema, local abscess, fistulas


Acute Flare Management

  • IVF
  • Bowel rest
  • Analgesia
  • Electrolyte correction
  • Consider steroid burst

Chronic Treatment

Alterations should be discussed with GI

  • Aminosalicylates (5-ASA) - Mild-to-moderate Crohn's disease. Give with probiotics.
    • Sulfasalazine 3-5gm/day PO (sulfa drug)
    • Mesalamine 4gm/day PO
      • Active moiety of sulfasalazine, and formed from prodrug balsalazide
    • Balsalazide or Olsalazine - Bypasses small intestine to deliver drug into large intestine (better for UC)
  • Anti-diarrheal - Use caution in patients with active inflammation as can precipitate toxic megacolon
    • Loperamide 4-16mg/day
    • Diphenoxylate 5-20mg/day
    • Cholestyramine 4g once to six times daily
  • Glucocorticoids - Symptomatic relief (course not altered)
    • Prednisone - 40-60mg/day with taper once remission induced
    • Methylprednisolone 20mg IV q6hr
    • Hydrocortisone 100mg q8hr
      • Do not start if any suspicion of infection (ie C.diff colitis)
      • Double edge sword: Reduction of bone density in addition to underlying disease process(decreased Ca absorption)
  • Antibiotics - Induce remission
  • Immunomodulators - Steroid-sparing agents used in fistulas and patients with surgical contraindication. Slower onset.
    • 6-Mercaptopurine 1-1.5mg/kg/day → Start at 50mg daily
    • Azathioprine 2-2.5mg/kg/day → Start at 50mg daily
    • Methotrexate IM
  • Anti-TNF - Medically resistant moderate-to-severe Crohn's disease
    • Infliximab (Remicade) 5mg/kg IV
    • Adalimumab (Humira), Natalizumab or certolizumab pegol can also be used


Inpatient Admission

  • Metabolic derangements (ie electrolyte imbalance or severe dehydration)
  • Fulminate colitis
  • Obstruction
  • Peritonitis
  • Significant hemorrhage

Surgical Intervention

Consult EARLY if any of the following suspicions

  • Perforation
  • Abscess/fistula formation
  • Toxic megacolon
  • Significant hemorrhage
  • Perianal disease
  • Failed medical management


  • Obstruction
    • Due to stricture or bowel wall edema
  • Abscess
    • Can be intraperitoneal, retroperitoneal, interloop, or intramesenteric
      • More severe abdominal pain than usual
      • Fever
      • Hip or back pain and difficulty walking (retroperitoneal abscess)
  • Fistula
    • Occurs due to extension of intestinal fissure into adjacent structures
    • Suspect if changes in patient's symptoms (e.g. BM frequency, amt of pain, wt loss)
  • Perianal disease
    • Abscess, fissures, fistulas, rectal prolapse
  • Hemorrhage
    • Erosion into a bowel wall vesel
  • Toxic megacolon
    • Can be associated with massive GI bleeding

Therapy complications

  • Leukopenia /thrombocytopenia
  • Fever / infection
  • Pancreatitis
  • Renal / liver failure

See Also