Crohn's disease

Background

• 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

• Abdominal pain
• Diarrhea
• Weight loss
• Perianal fissures or fistulas

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
    • Violaceous, ulcerative lesions with necrotic center found in pretibial region or trunk
• Hepatobiliary
  • Cholelithiasis (33%)
  • Fatty liver
  • Autoimmune hepatitis
  • Primary sclerosing cholangitis
  • Cholangiocarcinoma
• Renal
  • Increased risk for calcium oxalate stones due to hyperoxaluria
• Vascular
  • Thromboembolism

Differential Diagnosis

Colitis

• Viral gastroenteritis
• Bacterial gastroenteritis
• Campylobacter infections
• Clostridium difficile colitis
• Colon cancer
• Crohn disease
• Cryptosporidiosis
• Mycobacterium Avium-Intracellulare
• Toxic megacolon
• Ulcerative colitis
• Ischemic bowel disease (e.g. mesenteric ischemia, strangulated hernia)
• Pseudomembranous enterocolitis
• Lymphoma
• Ileocecal amebiasis
• Sarcoidosis
• Yersinia
• Campylobacter

Other

• Appendicitis

Evaluation

Work-Up

• Rule out alternate etiologies for symptoms
• Evaluate for complications (e.g. fistulae, abscess, obstruction)
• Labs
  • CBC
  • Chemistry
  • ESR/CRP
  • Fecal calprotectin (sensitive indicator of intestinal inflammation, unreliable in select Crohn's patients)
  • C.diff toxin
  • Type and screen if any bleeding suspicion
• Consider 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

Management

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)
    • Caution: Can cause folate deficiency so give with folic acid, and can cause hemolytic anemia in G6PD patients
  • 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
  • Ciprofloxacin 500mg q8-12hr OR
  • Metronidazole 500mg q6hr OR
  • Rifaximin 800mg BID
• 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

Disposition

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

Complications

• Bowel 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

• Ulcerative Colitis
• Colitis