9: SI And Colon Flashcards
Most common site of GI neoplasm in America
Colon
When the SI and LI are rapidly growing during weeks 4-5 in fetus, what happens?
Entire midgut herniates into the umbilical cord forming a loop + NCCs enter the foregut and hindgut
Organ most commonly involved in GI obstruction + why
SI - bc of relatively small lumen
Ileus
Temporary disturbance of peristalsis in absence of mechanical obstruction
Most. Common cause of intestinal obstruction worldwide vs in US
Worldwide: Hernias
US: adhesions
How do SI and colon tolerate slowly progressive blood supply loss from one artery
Thanks to interconnections between arcades + collateral vessels from prox celiac and distal pudendal and iliac circulations
Mechanisms of reperfusion injury after ischemia in the gut
- Leakage of gut lumen bacterial products into circulation
- free radicals produced
- Neutrophil infiltrate
- Release of inflammatory mediators
In bowel ischemia, what is the artery associated with the worst outcome
Superior mesenteric artery
Three of the most common malapsorption disorders in the US
- Pancreatic insufficiency
- Celiac dz
- Crohn’s disease
Dysentery
Painful, bloody, small volume diarrhea
Four categories of diarrhea + explain
- Secretory: isotonic stool
- Osmotic: excess osmotic forces from unabsorbed luminal solutes
- Malabsorptive: failure of nutrient absorption
- Exudative: due to inflammatory disease, is purulent and bloody
Which two types of diarrhea are relieved by fasting and which two will continue despite fasting?
- Relieved b fasting: osmotic and malapsorptive diarrhea
2. Continue during fasting: secretory, exudative
What condition is dermatitis herpetiformis associated with?
Celiac dz
What GI disorder comes with IPEX?
Autoimmune enteropathy
Guillain-Barre symptoms
Demyelinating polyneuropathy -> parasthesias in hands and feet, respiratory and muscle weakness, absent/depressed DTRs
Describe erythema nodosum
Reddish, painful nodules on legs
Treatment for Shigella and what tx makes it worse
- Tx: Abx
2. Anti-diarrheal meds: prolong sx and delay Shigella clearance
Five type of E. Coli and what they stand for
- ETEC: enterotoxigenic
- EPEC: enteropathogenic
- EHEC: enterohemorrhagic
- EIEC: enteroinvasive
- EAEC: enteroaggregative
Two Abx that are typically effective against C. Diff
- Metronidazole
2. Vancomycin
What stains are positive for mycobacterium?
Acid fast stain
Mechanism of vibrio cholerae
Toxin -> massive Cl secretion -> water follows -> secretory diarrhea
Three major functions of the colon
- Fluid absorption
- Mucin secretions
- Digestion by colonic bacteria
Histo of GI tract in graft vs host dz
Crypts may be completely destroyed in severe cases
