Pathophys: Small Bowel & Colon Flashcards
What are causes of ischemia in the intestines?
(1) thrombotic or embolic
(2) volvulus or adhesions
(3) vasculitis
(4) hypotension
Where are Peyer’s patches located in the GI tract?
The lamina propia of the terminal ileum.
What layer of the GI tract is most sensitive to ischemia?
The mucosa.
Describe the escalation of injury to the mucosa due to ischemia.
(1) edema and inflammatory infiltrate
(2) ulceration
(3) necrosis
What are Ladd bands?
Bands of fibrosis that “tack down” the gut to wrong locations in the abdominal cavity, possibly leading to obstruction and ischemia.
What are the 2 types of idiopathic inflammatory bowel disease?
(1) ulcerative colitis
(2) Crohn’s disease
What profile has the greatest risk for IBD?
A white, Jewish 20 or 30 something in an urban area.
What segment of the GI tract is affected by Crohn’s disease?
All of them can be, with relative sparing of the rectum.
What are some notable gross features of Crohn’s disease?
(1) fistulae
(2) strictures
(3) serpendigenous ulcers
(4) skip lesions
(5) cobble stone pattern
(6) creeping fat from mesenteries
What are some notable microscopic features of Crohn’s disease?
(1) transmural inflammation
(2) granulomas
(3) fibrosis
(4) cryptitis
(5) knife-like ulcers
(6) neuronal hyperplasia
What are some notable microscopic features of ulcerative colitis?
(1) crypt distortion
(2) muscularis mucosa thickening
(3) cryptitis
What is the primary gene associated with Crohn’s disease?
NOD2.
What are consequences of NOD2 mutations?
(1) abnormal granules in Paneth cells, leading to decreased killing of luminal pathogens.
(2) defective sensing and killing of intracellular bacteria.
(3) decreased synthesis of the anti-inflammatory IL-10.
