Crohns Disease

-1/3 present before the age of 20, 1/5 after the age of 50

-M:F=1:1

-cramping pain , non bloody diarrhea, fever, malaise, anorexia.

-hemorrhage and hematochezia uncommon

-dyspepsia, wt loss, hypoalbuminemia and iron deficiency anemia ( upper GI tract involvement)

-anal and perianal fistulas and fissures

-extraintestinal manifestations  – migratory  polyarthiritis, ankylosing spondylitis, cholngitis, uveitis, erythema nodosum, amyloid.
Etiology and pathogenesis.

-etiology unknown

-chornic inflammatory  relapsing and remitting disease of the GI tract

- strong genetic predisposition -  17-35x the risk in siblings of patients
Gross pathology:

-inflammation anywhere from mouth to anus

creeping fat  subserosal fat contracted over the areas of involvement

-areas of firm, thickened and pipelike bowel

-interloop adhesions

-aphthous erosions

-longitudinal “rake “ ulcers

-cobblestoning

-inflammatory polyps

-Fissures

-fistulas

-rectal sparing
Microscopic:

- biopsy:

-discrete foci of  inflammation and architectural changes adjacent to histologically normal crypts

-basal lymphoplasmacytic infiltrates

-aphthous lesions often associated with underlying lymphoid aggregates

-variability of inflammation within a single bx and among bx fragments from the same anatomic location

-may or may not see granulomata on bx

-panneth cell metaplasia

-resection ( in addition to the above):

-neural hyperplasia

-submucosal fibrosis

-transumural inflammation

-ulcers separated by histological normal mucosa

-lymphoid aggregates in subserosa and submucosa

-fissures, sinuses and fistulas

-granulomata
Differential dianosis

Infectious colitis

-    most common cause of apthous ulcers of small  and large intestine

-    lack of significant chronic inflammation

-    absence of crypt distortion and basal lymphocytosis

-    no epithelial granulomata except for TB and Yersinia, but those have to be teased out on hx
Ischemic colitis

-history is KEY – elderly ppl, atherosclerosis, L-sided distribution of lesions ( more vulnerable to ischemia)

-no granulomata

-LP neutrophillic infiltrate but no crypt abscesses of cryptitis

-intramucosal hyalinization
UC
Medication associated colitis  – ie. NSAIDS, penicillamine, sulfasalazine, and methyldopa

-lack active inflammation

-no mucosal architectural distortion

-may resemble Chron’s because it also has abrupt transition between ulcerated and non ulcerated areas

Diverticular disease associated segmental colitis

-commonly in sigmoid

-diverticula seen on colonoscopy

-foreign body type granulomata, cryptitis and crypt abscesses

-colitis is seen in the distribution of  the diverticula