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

Crohn's disease vs. ulcerative colitis

Crohn's disease vs. ulcerative colitis

Finding	Crohn's disease	Ulcerative colitis
Depth of inflammation	May be transmural, deep into tissues	Shallow, mucosal
Distribution of disease	Patchy areas of inflammation (skip lesions)	Continuous area of inflammation
Terminal ileum involvement	Commonly	Seldom
Colon involvement	Usually	Always
Rectum involvement	Seldom	Usually (95%)
Involvement around anus	Common	Seldom
Stenosis	Common	Seldom

Clinical Features

An aphthous mouth ulcer (aphthous stomatitis) on seen with Crohn's disease.

A single lesion of erythema nodosum.

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
  • LFTs/lipase
  • May additionally consider:
    • ESR/CRP
    • Type and screen (if concern for significant bleeding)
    • Fecal calprotectin (sensitive indicator of intestinal inflammation, unreliable in select Crohn's patients)
    • C.diff toxin

• Consider imaging:
  • CT A/P if concern for small bowel obstruction, perforation, or toxic megacolon
    • 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

CT scan showing Crohn's disease in the fundus of the stomach.

Acute Flare Management

• IVF
• Bowel rest
• Analgesia
• Electrolyte correction
• Consider steroid burst
  • Methylprednisolone (e.g., 30mg IV bid) or prednisone (e.g., 60 mg day 1, then 40 mg daily x 4 days), OR
  • Budesonide for mild to moderate disease due to fewer systemic side effects
• Antidiarrheals are contraindicated

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

• Significant metabolic derangements (i.e. 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

References

1. Thomas N, Wu AW. Large intestine. In: Walls RM, Hockberger RS, Gausche-Hill M, et al., eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 10th ed. Elsevier; 2023.