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Flashcards in Diarrhea Deck (31):
1

What constitutes diarrhea?

>200 grams or 200 mL per 24 hour period

2

Malabsorptive diarrhea

Inadequate nutrient absorption
Associated with steatorrhea
Relieved by fasting

3

Exudative diarrhea

Due to inflammatory disease
Purulent, bloody stools
Continue during fasting

4

What constitutes a normal bowel movement?

One BM every 3 days to 3 BM every day

5

What are some history clues to investigate with diarrhea?

1. Consistency
2. Urgency
3. Incontinence
4. Nocturnal BM
5. Flatuphobia

6

Diarrhea due to small bowel disease

Watery diarrhea, large volume, less frequent
Abdominal cramping, bloating, gas and weight loss
Evidence of malabsorption, vitamin or nutrient deficiencies
Fever is rare
Rare stool WBCs or occult blood

7

Diarrhea due to large bowel disease

Inflamed dysfunctional colon/rectum cannot perform this function
Frequent, small, regular stools
Tenesmus (rectal "dry heaves")
Painful BM
Fever, bloody, mucoid stools
RBCs and WBC on stool smear

8

Osmotic diarrhea

Small intestine and colon cannot maintain an osmotic gradient against serum
Unabsorbed ions remain in the lumen --> pull water into the lumen of bowel
Maintain intraluminal osmolality = 290 mOsm/kg

9

What are some things that may cause osmotic diarrhea?

Ingestion of poorly absorbed ions or sugars or sugar alcohols -- Mannitol, sorbitol, magnesium, sulfate and phosphate

Monosaccharides but not disaccharides can be absorbed

10

Disappears with fasting

Osmotic diarrhea

11

Secretory diarrhea

Many causes --> net secretion of anions (chloride/bicarb) or inhibition of net sodium absorption
Most common cause is infection
Enterotoxins
Endocrine tumors

12

What constitutes acute, persistent and chronic diarrhea?

Acute: 28 days

13

What are some causes of acute diarrhea?

Infection -- bacteria, parasites, protozoa, viruses
Food allergies
Food poisoning
Medications
Initial presentation of chronic diarrhea

14

What are some causes of chronic fatty diarrhea?

Malabsorption syndromes
Mesenteric ischemia
Mucosal diseases (celiac, Whipple's)
Short bowel syndrome
Small intestinal bacterial overgrowth
Maldigestion

15

What are some causes of inflammatory chronic diarrhea?

Diverticulitis
Infectious disease
Invasive bacterial/parasitic infections
Pseudomembranous colitis
IBD
Crohn's
Ulcerative colitis
Neoplasia
Lymphoma
Radiation colitis

16

What are some main things you must address during the history in a patient who presents with diarrhea?

Assess volume status (symptomatic, orthostatis, fluid intake)
Try to assess constancy
Frequency
Abdominal Pain
Tenesmus
Nocturnal waking
Blood in stool (never normal)
Flatuphobia

17

What are some medications that may cause diarrhea?

NSAIDs and Olmesartan (anti-htn) -- sprue like illness

18

What are some possible causes if diarrhea presents with a fever?

Invasive bacteria
Enteric viruses
Cytotoxic organism (C. diff or Entamoeba histolytica)
Ischemia
IBD

19

What are some causes if diarrhea begins w/i six hours?

Suggests ingestion of toxin
Staph aureus or Bacillus cereus

20

What are some of the causes of diarrhea if it began within 8-15 hours?

Suggests infection with Clostridium perfringens

21

What are some of the possible causes of diarrhea if it began more than 14 hours?

Result of viral or bacterial infection, non-specific

22

How should you focus your physical exam with a patient who is presenting with diarrhea?

Initially focus on volume status
Check for signs of other systemic disease -- DH in Celiac disease or EN in arthritis/IBD
Abdominal tenderness/mass
Rectal exam for (fistula, blood stool)

23

When do you order a stool sample for pathogens?

When a patient is very ill or has risk factors for infection

24

When do you use ELISAs or DFA microscopy on stool samples?

To test for Giardiasis and Cryptosporidium
-Sensitivities greater than 90%
-Specificities approaching 100%
Useful if proper history or immune compromised

25

What is the osmotic gap?

Osmotic gap = Serum Osm - Est Stool Osm (290)

The osmolality of colonic fluid contents is in equilibrium with body fluids (290 mOsm/kg)

26

What is the osmotic gap like in secretory vs osmotic diarrhea?

In secretory diarrhea -- the osmotic gap is small (100 mOsm/kg)

27

What does it mean if the osmotic gap is negative?

There is a poorly absorbed multivalent anion, such as phosphate or sulfate

The measured stool osmolality is of little value -- stool osmolality tends to rise once the stool has been collected b/c of continuing bacterial fermentation in vitro.

28

How can you test for surreptitious laxative ingestion?

There will be a large osmotic gap -- suggesting magnesium ingestion
Or a negative osmotic gap
Stool can be analyzed for laxatives by chemical or chromatographic methods

29

What are some common causes of chronic diarrhea that should be pursued early?

Celiac disease (caucasians)
Thyroid disease
IBD
IBS

30

When is it appropriate to pursue endoscopy for chronic diarrhea?

Persistent and chronic with significant lab abnormalities -- obtain biopsies of even normal appearing mucosa is essential

31

What does a 72 hour stool collection for fecal fat determine?

7-14 grams considered abnormal but not diagnostic
>14 grams considered indicative of fat malabsorption