1. Crohn Disease (Regional Enteritis)
Sammy Termanini
1490

2. Overview Life long inflammatory bowel disease
Lumen becomes swollen and develops ulcers
Idiopathic cause

3. Morphology
Most common sites of presentation, terminal ileum, ileocecal valve and cecum
Skip lesions from apththous ulcers
Cobblestone appearance from fissures between mucosal folds
Intestinal wall is thickened
Creeping fat

5. Microscopic Features Active infection
Abundant neutrophils that infiltrate and damage crypt epithelium or crypt abscess
Distortion of of mucosal architecture
Epithelial metaplasia consequence of chronic relapsing infection (pseudopyloric metaplasia)
Paneth cell metaplasia in left colon, normally absent
Non-caseating granulomas
Absence of granulomas does not preclude diagnosis of Crohn’s Disease

6. Non-caseating Granuloma

7. Clinical Features Extremely variable
Usually begins with intermittent attacks of mild diarrhea, fever and abdominal pain
20% of cases present with right lower quadrant, fever and bloody diarrhea mimicking acute appendicitis or bowel perforation
Periods of active disease interrupted by asymptomatic intervals
Reactivated by physical or emotional stress, specific dietary items and cigarette smoking

8. Clinical Features Iron deficiency anemia may develop
Serum protein loss and hypoalbuminemia, generalized nutrient malabsorption, or malabsorption of vitamin B12 and bile salts.
Fibrosing strictures of the terminal ileum, require surgical resection.
Recurs at the site of anastomosis, and almost half require additional resections within 10 years.
Fistulas develop between loops of bowel and may also involve the urinary bladder, vagina, and abdominal or perianal skin.
Perforations and peritoneal abscesses are common.

9. Extraintestinal Manifestations
Uveitis, migratory polyarthritis, sacroiliitis, ankylosing spondylitis, erythema nodosum, and clubbing of the fingertips,
Pericholangitis and primary sclerosing cholangitis also occur but are more common in ulcerative colitis.
Risk of colonic adenocarcinoma increased in patients with long-standing Crohn disease

10. Diagnosis
Medical history, physical examination, imaging tests to look at intestines and lab tests
May go years without diagnosis
Colonoscopy or flexible sigmoidoscopy
Abdominal X-ray
Upper gastrointestinal series or endoscopy
CT scan
MRI

11. Treatment
Manage mild symptoms with antidiarrheal medicine (loperamide)
Moderate symptoms use aminosalicylates ,antibiotics to control inflammation
Severe symptoms treated with corticosteroids, immunomodulator medicines, or biologics.
First step is to control the disease. When your symptoms are gone, your doctor will plan your treatment to keep you symptom-free (in remission).
After symptoms are controlled, treatment focuses on medicine or a combination of medicines that keeps disease in remission
Some severe cases of Crohn's disease need to be treated in the hospital.

12. References
Kumar,Vinay; Abbas, Abul K.; Aster, Jon C.; Basic Pathology, Robbins; Philadelphia; Elservier Saunders;2013. Print.