Non-infectious Diarrhea Flashcards
(28 cards)
Difference btwn acute & chronic non-infectious diarrhea?
acute: < 4 weeks, chronic > 4 wks
If non-infectious diarrhea is large volume where is the damage likely coming from & why?
What kind of bowel movements would these patients have?
SI b/c it does most of the water absorption
they’d have large, painless diarrhea
Which would improve with fasting, osmotic or secretory non-infectious diarrhea?
osmotic improves w/ fasting
what’st he mechanism for secretory diarrhea?
there’s a net secretion of anions (chloride or bicarb) or net inhibition of sodium absorption
What’s the MC cause of secretory diarrhea? specifics about that?
Enterotoxins produced by bacteria like cholera, E coli and shigella
Other than enterotoxins, what 3 other things can cause secretory diarrhea?
- peptides like gastrin, VIP & 5-hydroxytrytamine (5-HT)
- Loss of absorptive surface like in short bowel syndrome, celiac sprue or IBD
- Rapid intestinal motlility like in IBS or hyperthyroidism
what’s VIP and how’s it involved in secretory diarrhea?
Vasoactive Intestinal Peptide
NT in peripheral & central NS that causes secretion of Cl and bicarb by intestinal epithelia
What’s VIPoma? what’s another name for it? what’s the common SE?
tumor that secretes VIP leads to loss of bicarb (decreasing pH) in stool water leading to metabolic acidosis, assoc w/ 1-3 L stools/day w/ dehydration
Aka Watery diarrhea hypokalemia achlorhydria (WDHA) syndrome
S/S: Hypokalemia: colon preserves sodium (to try and compensate for fluid loss from SI) but loses K in exchange
What can cause non-infectious osmotic diarrhea? (4 things)
ingestion of :
- cations
- anions
- sugars (like dissacharides like lactose)
- sugar alcohols like sorbitol that’s in sugar free foods
what’s the MOA of non-infectious osmotic diarrhea?
ions overwhelm the system & saturate their transporters so draws water out to equalize
what kind of saccharides can and can’t be absorbed?
Monosaccharides can be aborbed
Diassacharides cannot so need disaccharidases to break them down
where is lactase located? what happens w/ its deficiency?
brush border of SI cells
can’t break lactose into glucose and galactose so can’t absorb lactose leading to osmotic diarrhea
Which would have electrolyte imbalance, osmotic or secretory non-infectious diarrhea?
secretory diarrhea
whats the stool osmotic gap and what do you use it for?
290 mOsm/kg - 2(Na+K) (stool levels)
use it to determine secretory vs osmotic diarrhea
Small osmotic gap < 50: secretory diarrhea (b/c large secretion of Na & K in stool)
large osmotic gap > 100: osmotic diarrhea
what’s the difference btwn maldigestion and malabsorption? what could they lead to?
Maldigestion: pancreatic exocrine insufficiency and lack of bile (like in chronic pancreatitis or CF) lead to inability to breakdown food
Malabsorption: mucosal diseases (like Celiac) likes to inability to absorb nutrients
they could lead to steatorrhea
what’s the MC cause of steatorrhea & when would it occur? what else might you see with it?
pancreatic insufficiency but not until only 10% or < of pancreas function is left
might also see weight loss (malabsorption of fat) and fat soluble vit deficiency (vit A, D, E & K)
what are 3 ways to test for pancreatic insufficiency?
- stool test - qualitative or quantitative fecal fat
- secretin stimulation test - secretin stimulates pancreas, aspirate duodenal contents & measure bicarb output (rarely performed b/c complex)
- fecal elastase activity
what’s Celiac sprue?
what would it lead to?
what would an endoscopy & histo loop like?
autoimmune disorder occurs w/ ingestion of gluten (Ab against gliadin and tissue transglutaminase)
Leads to SI inflammation, vili atrophy and malabsorption
Scope would see scaloped duodenal folds; histo: inflammation, decreased pili & hyperplastic crypts
how would celiac present in childhood?
failure to thrive, hypotonia, abd distension
how would celiac present in adulthood?
diarrhea, bloating, dermititis herpetaformis (vesicular lesions, puritic), iron def anemia (b/c prox SI), osteopenia
when would bile acid induce diarrhea?
w/ ileal resection or disease b/c of loss of transporters leads to increased bile acid in colon > 3-5 mmol/L which can inhibit electrolyte absorption and stimulate secretion
what’s microscopic colitis and what are the 2 main types?
histologic chronic mucosal inflammation w/ gross healthy looking colonic mucosa
2 types: collagenous colitis and lymphocytic colitis
What’s collagenous colitis? what can cause it?
what would histo look like?
type of microscopic colitis
Cause: NSAIDs, SSRIs
Histo: irregularly thickened subepithelial collagen bands & mixed inflam cells (lymph, plasma & eosinophils) in lamina propria
what’s lymphocytic colitis? what can cause it?
what would histo look like?
type of microscopic colitis
Cause: SSRIs, BBs, bisphosphonates, statins
Histo: increased intraepithelial lymphocytes w/ no mucosal architectural distortion
