GI Lumen Pathologies Flashcards
2 pathophys mechanisms of constipation
Transit times
Muscular function
Failure of pelvic floor muscles or anal sphincter to relax with defecation
Dyssynergic defecation or ANISMUS
Impaired colonic motor activity with infrequent bowel movements and straining
Slow-transit constipation
Normal rate of stool passage but difficulty with stool evacuation from low-residue, low-fiber diet
Normal transit, or FUNCTIONAL constipation
Nonabsorbable substance in the intestine draws water into the lumen by osmosis - causing large volume diarrhea
Osmotic Diarrhea
seen in dumping syndrome, lactose intolerance
Form of large volume diarrhea caused by excessive mucosal secretion of chloride of bicarb-rich fluid (like what??) or inhibition of net sodium absorption
Secretory Diarrhea
can cause metabolic acidosis
Excessive motility which decreases transit time, mucosal surface contact, and opportunities for fluid absorption
Motility diarrhea
What metabolic effect can secretory diarrhea have, on account of excessive secretion of bicarb fluid?
Metabolic acidosis
Antimotility treatments
loperamide (opiate)
atropine (lomotil)
Acetylcholine antagonist
How do adsorbents work for diarrhea?
Attapulbite or Polycarbophil
Bind toxins and bacteria in the colon
Also bind water, to make poo more solid
Usual etiology of maldigestion issues
Enzyme deficiency (lactose intolerance)
Pancreatic insufficiency (cystic fibrosis*** or any other pancreatic disease)
Usual etiology of malabsorption issues
Intestinal mucosa - can’t absorb and transport nutrients into bloodstream
Inflammation of intestine or colon
Crohns or UC
Salmonella / Shigella infection
Pancreatic enzymes
Lipase
Amylase
Trypsin
Chymotrypsin
Pathophys of lactose intolerance
Inability to break down LACTOSE (disaccharide) into GLUCOSE and GALACTOSE
Lactose goes to colon, fermented by bacteria > causes gas, cramping, and osmotic diarrhea
What does lactose break down into, in the presence of lactase?
GLUCOSE and GALACTOSE
Causes of bile salt deficiency?
Liver disease
Bile duct obstruction
Gallbladder removal
Result of bile salt deficiency
Maldigestion
Steatorrhea, fat-soluble vitamin deficiency (A D E K)
What digestion problem might happen after a pyloroplasty or a partial gastrectomy?
Dumping syndrome - hypertonic chyme rapidly empties from stomach into small intestine, (15-30mins after eating) causing
osmotic diarrhea cramping nausea hypotension diaphoresis tachycardia
Pharm tx for dumping syndrome that would slow intestinal transit time and inhibit insulin release
Somatostatin
IBD most commonly diagnosed in
Ages 20-40, Jewish decent
Pathophys of IBD can include
Altered epithelial barrier function
Immune response to intestinal flora
Abnormal T cell responses
Autoantibodies
Key pathophys characteristics of UC
Lesions are Continuous and limited to the mucosal layer
Lesions are NOT transmural
Key pathophys characteristics of Crohns
Can affect any part of the tract, from mouth to anus
Granulomatous mucosa
Lesions have “cobblestoned” appearance, because they pass through many layers of mucosa - ENTIRE INTESTINAL WALL - making bowel thicker
Lesions are NOT continuous, and OFTEN transmural (opposite of UC)
Why do lesions in Crohns have a cobblestone appearance?
Because they pass through many layers of mucosa, making bowl thicker
