012015 diarrhea

Question 1

diarrhea-malabsorptive vs exudative

Answer 1

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

Question 2

malabsorption results from

Answer 2

at least one of four phases of nutrient absorption

Question 3

practical definitions of diarrhea

Answer 3

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

Question 4

clues to actual diarrhea

Answer 4

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

Question 5

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

Answer 5

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

Question 6

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

Answer 6

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

Question 7

osmotic diarrhea

Answer 7

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

Question 8

causes of osmotic diarrhea

Answer 8

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)

Question 9

symptoms of osmotic diarrhea

Answer 9

disappears w/ cessation of offending substance

Question 10

how does electrolyte absorption fare in osmotic diarrhea?

Answer 10

it’s not impaired

electrolyte concentrations in stool water are usually quite low

Question 11

secretory diarrhea

Answer 11

net secretion of anions (Cl or HCO3)

OR inhibition of net sodium absorption

Question 12

most common cause of secretory diarrhea

Answer 12

infection

Question 13

which is more common: secretory or osmotic diarrhea?

Answer 13

secretory

Question 14

acute vs chronic diarrhea

Answer 14

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

Question 15

causes of acute diarrhea

Answer 15

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

Question 16

causes of chronic diarrhea

Answer 16

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

Question 17

waking at night with diarrhea

Answer 17

secretory diarrhea, not osmotic diarrhea

Question 18

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

Answer 18

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

Question 19

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

Answer 19

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

Question 20

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

Answer 20

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

Question 21

PE for pt with diarrhea like symptoms should look at

Answer 21

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)

Question 22

when should you order stool for pathogens?

Answer 22

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

Question 23

immune compromised pt can get diarrhea with what infectious organisms?

Answer 23

giardiasis and cryptosporidium (can do ELISA or DFA microscopy)

Question 24

stool electrolytes in secretory vs osmotic diarrhea

Answer 24

secretory: small osmotic gap (under 50 mOsm/kg)
osmotic: high osmotic gap (over 100 mOsm/kg)

Question 25

calculating osmotic gap

Answer 25

serum Osm - est stool Osm

Question 26

stool Osm is

Answer 26

2 * (conc Na + conc K)

Question 27

when osmotic gap is negative, suggests

Answer 27

ingested poorly absorbed multivalent anion, such as phosphate or sulfate

Question 28

stool osmolality’s use

Answer 28

not very useful clinically

Question 29

one situation in which stool osmolarity may be useful

Answer 29

surreptitious laxative ingestion

Question 30

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

Answer 30

celiac disease
thyroid disease
IBD
IBS

Question 31

when is endoscopy most appropriately used?

Answer 31

peristent and CHRONIC diarrhea

OR pts with significant lab abnormalities

Question 32

when is 72 hr stool collection for fecal fat used?

Answer 32

only for chronic diarrhea

Question 33

tenting of skin/decreased skin turgor

Answer 33

dehydration

Question 34

NPO slows diarrhea some but not by much

Answer 34

suggests it’s secretory and NOT osmotic