012015 diarrhea Flashcards Preview

Gastrointes 3 > 012015 diarrhea > Flashcards

Flashcards in 012015 diarrhea Deck (34):
1

diarrhea-malabsorptive vs exudative

malasorptive-inadequate nutrient absorption associated with steatorrhea. relieved by fasting

exudative-due to inflam disease. purulent, blooding stools. continues during fasting

frequent overlap btwn these two

2

malabsorption results from

at least one of four phases of nutrient absorption

3

practical definitions of diarrhea

normal bowel movement: one BM every three days to 3 BMs everyday

diarrhea: more than 3 loose/watery stools per day OR a clear increase in frequency and decrease in consistency over baseline

4

clues to actual diarrhea

consistency
urgency
incontinence (doesn't make it)
nocturnal bowel movements
flatuphobia

5

when diarrhea comes from small bowel as the cause, what is notable?

watery diarrhea, LARGE VOLUME and less frequent
(small bowel fxns to absorb most water, nutrients, minerals, sugars, protein)

abdominal cramping, bloating, gas, weight loss

evidence of MALABSORPTION, VITAMIN, or nutrient deficiencies

fever is rare

rare stool WBCs or occult blood

6

when diarrhea comes from large bowel as the cause, what is notable?

large bowel usually fxns as storage and absorbs some fluids/electrolytes. when it's inflamed/dysfunctional, it can't perform this fxn.

frequent, small, regular stools as opposed to watery

tenesmus (rectal dry heaves)--has to go but nothing comes

painful bowel movement

fever, bloody, mucoid stools

RBCs and WBC on stool smear

7

osmotic diarrhea

unabsorbed ions remain in the lumen and osmotically active ions pull water into lumen of bowel

8

causes of osmotic diarrhea

ingestion of poorly absorbed ions or sugars or sugar alcohols:
--mannitol, sorbitol (in sugar free candy)
--Mg, sulfate, PO4 (in laxatives)

deficiency of enzyme breaking down disaccharide (ex: lactase)

9

symptoms of osmotic diarrhea

disappears w/ cessation of offending substance

10

how does electrolyte absorption fare in osmotic diarrhea?

it's not impaired
electrolyte concentrations in stool water are usually quite low

11

secretory diarrhea

net secretion of anions (Cl or HCO3)
OR inhibition of net sodium absorption

12

most common cause of secretory diarrhea

infection

13

which is more common: secretory or osmotic diarrhea?

secretory

14

acute vs chronic diarrhea

acute: symptoms lasting under 14 days
persistent: 14-28 days
chronic: more than 28 days

15

causes of acute diarrhea

infection (bacteria, parasites, protozoa, viruses)
food allergies
food poisoning
medications
initial presentation of chronic diarrhea

16

causes of chronic diarrhea

fatty diarrhea (causes are malabsorption syndromes, etc)
inflammatory diarrhea (infectious diseases, IBD, Crohn's disease)
watery diarrhea (many causes)

17

waking at night with diarrhea

secretory diarrhea, not osmotic diarrhea

18

what do you want to get in terms of hx from pt presenting with diarrhea

description of diarrhea

past medical history-celiac, IBD
recent travel
pets (turtles)-Salmonella
hobbies (Giardia-drinking from streams)
diet-sorbitol, caffeine, large amt of high fructose corn syrup, alcohol intake

med changes (NSAIDs and Olmesartan cause sprue like illness. antibiotic use or chemo can cause C diff infec)

family hx-celiac, IBD

contacts w/ nursing homes, occupational exposure

19

if diarrhea pt has fever in hx, what should you think of?

invasive bacteria
enteric viruses
cytotoxic organism (C. diff or Entamoeba histolytica)
ischemia
IBD

20

if pt with diarrhea has food history, what should you think of?

if began within 6 hrs--suggests toxin (s aureus or bacillus cereus on rice)

8-14 hours suggests infec w Clostridium perfringens

more than 14 hrs-could be viral or bacterial infection. it's non-specific

21

PE for pt with diarrhea like symptoms should look at

initially focus on VOLUME STATUS
signs of other systemic disease (dermatitis herptiformis in celiac disease, erythema nodosum or arthritis in IBD)

abdominal tenderness/mass

rectal exam (fistula, bloody stool)

22

when should you order stool for pathogens?

when pt is VERY ILL or has RISK FACTORS FOR INFECTION (fever, etc)

23

immune compromised pt can get diarrhea with what infectious organisms?

giardiasis and cryptosporidium (can do ELISA or DFA microscopy)

24

stool electrolytes in secretory vs osmotic diarrhea

secretory: small osmotic gap (under 50 mOsm/kg)

osmotic: high osmotic gap (over 100 mOsm/kg)

25

calculating osmotic gap

serum Osm - est stool Osm

26

stool Osm is

2 * (conc Na + conc K)

27

when osmotic gap is negative, suggests

ingested poorly absorbed multivalent anion, such as phosphate or sulfate

28

stool osmolality's use

not very useful clinically

29

one situation in which stool osmolarity may be useful

surreptitious laxative ingestion

30

chronic diarrhea-the more common causes that should be pursued early in diagnosis

celiac disease
thyroid disease
IBD
IBS

31

when is endoscopy most appropriately used?

peristent and CHRONIC diarrhea
OR pts with significant lab abnormalities

32

when is 72 hr stool collection for fecal fat used?

only for chronic diarrhea

33

tenting of skin/decreased skin turgor

dehydration

34

NPO slows diarrhea some but not by much

suggests it's secretory and NOT osmotic