Case of the Week: October 10-October 17, 2002

11 year old with 2 year history of vague abdominal pain,

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Case Details

Answer

Diagnosis: DIAGNOSIS: CROHN'S DISEASE

DEFINITION:

A transmural granulomatous inflammatory disease that may affect any part of the GI tract from mouth to anus. 

EPIDEMIOLOGY:

  • incidence: 5-11/100,000 

  • age of onset: 

    • peak age of onset in 2nd and 3rd decades 

    • less than 5% present before 5 years of age : 

  • M = F 

  • whites > blacks 

PATHOGENESIS:

1. Etiology

  • the exact etiology is unknown, infection or an autoimmune process has been suggested. Up to 10% of patients with Crohn's Disease have a family history of Irritable Bowel Disease. 

2. Anatomic Involvement

  • terminal ileum + variable segments of the colon (particularly the ascending colon) - 50-60% 

  • small bowel involvement only (most in terminal ileum) - 30-35% 

  • large bowel only - 10-15% 

  • the esophagus, stomach, or duodenum is involved in 30-40% of patients 

CLINICAL FEATURES:

1. Gastrointestinal Manifestations

  • abdominal pain (75%) 

  • diarrhea (65%) 

  • weight loss (65%) 

  • fever (50%) 

  • growth retardation (25%) 

  • nausea/vomiting (25%) 

  • rectal bleeding (20%) 

  • perirectal disease (15%) 

  • extraintestinal manifestations (25%) 

2. Gastrointestinal Complications

1. Hemorrhage

2. Obstruction

3. Perforation

4. Abscess

5. Fistula Formation

6. Others

  • toxic megacolon (3.7%) - increases to 11% if disease confined to colon 

  • carcinoma - 20x greater risk than in general population

Imaging Studies:

1. Barium Enema

A. Single Contrast

  • to identify colonic fissures 

  • contraindicated in suspected cases of severe colitis 

B. Double Contrast (Air-Barium)

  • to define mucosal defects - narrowing, stenotic areas, cobblestoning, filling defects 

2. Upper GI Series with Small Bowel Follow-through

  • particularly to visualize the terminal ileum: 

  • cobblestone appearance 

  • deep ulcers 

  • fistula 

  • nodularity 

  • stenotic areas (string sign) 

  • thickened bowel wall 

3. Abdominal Ultrasound/CT

  • bowel wall thickening 

  • abscesses 

  • fistula

  • focal fat proliferation

Endoscopy/Colonoscopy:

1. Macroscopic

  • focal or segmental inflammation with skip areas of normal mucosa 

  • complications of inflammation: 

  • cobblestone pattern (ulceration with regeneration and hyperplasia) 

  • wall thickening with stricture formation 

  • fissures, sinuses, ulcerations, fistulas, phlegmon (inflammatory masses) 

  • matted adjacent loops of bowel 

2. Microscopic

A. Early Changes

  • superfical aphtoid lesions of mucosa overlying lymphoid follicles; granulomas 

B. Later changes

1. Transmural Enterocolitis

  • diagnostic with histopathology of intestinal lesions showing extensive infiltration with inflammatory cells 

  • lymphocytes, histiocytes, plasma cells found throughout the bowel wall but extensively in the submucosa 

  • collagen deposition within the submucosa leading to strictures +/- obstruction 

  • deep fissuring ulceration into the muscularis propria 

  • crypt abscesses and goblet cell depletion 

2. Granulomas

  • may be absent in 60-70% of biopsies 

Goals of Therapy:

  • therapy (pharmacolgic, nutritional, or surgery) is not curative 

  • no prophylactic role of therapy 

  • goal is to control symptoms, prevent complications, improve growth, and to induce remission during an acute episode by either pharmacologic, nutritional and/or surgical strategies 

Prognosis:

  • Crohn's Disease at this time is a chronic incurable disease of the bowel marked by periods of exacerbation and remission (99% suffer at least one relapse) 

  • triggers of acute exacerbations are unknown but viral illnesses (EBV, adenovirus) may play a role 

  • unable to predict the extent and severity of the disease over time (except those with ileocolitis have greater morbidity) thus while morbidity is very high, mortality is essentially zero 

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VCU Department of Pediatric Radiology Virginia Commonwealth University VCU Medical Center