Crohn disease

From IDWiki

Clinical Manifestations

  • Diarrhea frequency, consistency, bloody, steatorrhea
  • Ileitis and Colitis: diarrhea, abdominal pain, weight loss, fever
  • Crampy abdominal pain
  • Bleeding less common than UC
  • Fistulae: enteroenteric, enterovesicular, fistulae to psoas abscess
  • Associated symptoms: aphthous ulcers, dysphagia, odynophagia, gastric outlet obstruction, fat malabsorption and steatorrhea, perianal disease


  • Consider other causes
    • Food poisoning: restaurant, foods
    • Infectious: travel history, contacts, HIV risk factors, Yersinia, TB
    • Ischemic: CAD and cardiac risk factors
    • Drug induced: recent antibiotics
  • Complications of IBD
    • General: fever/chills/weight loss
    • HEENT: eye for uveitis, episcleritis
    • Chest: pulmonary fibrosis
    • GI: PSC with elevated ALP, steatorrhea causing malnutrition, Vit D deficiency
      • Massive hemorrhage, acute perforation, fistula, abscess, toxic megacolon
    • Renal: oxalate stones due to increased oxalate absorption (Ca bound to free fatty acids)
    • MSK: arthritis (large joints, ank spondylitis), osteoporosis
    • Skin: erythema nodosum, pyoderma gangrenosum
    • Heme: venous thromboembolism, vit B12 deficiency (ileal disease)
  • PMH, Meds, Allergies, Smoking, Alcohol
  • Family history of IBD


  • Vitals: may be volume depleted or febrile
  • H&N: uveitis, episcleritis, oral ulcers, lymphadenopathy
  • Resp: pulmonary fibrosis
  • GI: abdo pain, liver, jaundice, spleen, masses, acute abdomen
  • MSK: arthritis, osteoporosis
  • Skin: erythema nodosum, pyoderma gangrenosum

Differential Diagnosis

Comparison to Ulcerative Colitis

Feature Crohn UC
Symptoms Abdo pain/cramping, diarrhea +/- blood Tenesmus, bloody stool, mucous
Distribution Discontinuous with skip lesions; 80% TI, 50% ileocolonic, 30% isolated ileal, 20% isolated colonic Continuous; 30% pancolitis, 50% proctosigmoiditis
Muscosa Transmural inflammation Mucosal inflammation
Extraintestinal manifestations More skin (pyoderma, EN), arthritis, osteopenia, fistulas, strictures More PSC, more ophtho, arthritis, osteopenia


  • Mild
    • Colonic: sulfasalazine
    • Ileocolic: controlled-release budesonide
    • Azathioprine or methotrexate for maintenance
  • Fistulas
    • Infliximab or other anti-TNF-alpha biologic
      • Add antibiotics for perianal fistulas
    • May be able to use antibiotics alone for simple fistulas
  • Active
    • Oral corticosteroids for remission followed by azathioprine for maintenance
      • Can also consider methotrexate for maintenance
    • If refractory, use infliximab

Further Reading


  1. ^  Steven DiLauro, Nancy F. Crum-Cianflone. Ileitis: When It is Not Crohn’s Disease. Current Gastroenterology Reports. 2010;12(4):249-258. doi:10.1007/s11894-010-0112-5.