F3: Fecalysis (Part 3: Osmotic Gap-Secretory vs. Osmotic)

Question 1

OSMOTIC GAP

Formula for computing osmotic gap?

Answer 1

290 - {2 (fecal Na + fecal K)}

Question 2

OSMOTIC GAP

Osmotic or Secretory Diarrhea?

Greater than 50 mOsm/kg

Answer 2

Osmotic diarrhea

Question 3

OSMOTIC GAP

Osmotic or Secretory Diarrhea?

Less than 50mOsm/kg

Answer 3

Secretory Diarrhea

Question 4

OSMOTIC GAP

In secretory diarrhea, osmotic is lower due to?

Answer 4

Increase in electrolyte (NA, CL)

Question 5

TESTS TO DIFFERENTIATE THE MECHANISMS OF DIARRHEA

Identify reference value according to test:

Total fecal osmolarity

Answer 5

290 mOsm/kg

Question 6

TESTS TO DIFFERENTIATE THE MECHANISMS OF DIARRHEA

Identify reference value according to test:

Normal fecal sodium

Answer 6

30 mmol/L

Question 7

TESTS TO DIFFERENTIATE THE MECHANISMS OF DIARRHEA

Identify reference value according to test:

Normal fecal potassium

Answer 7

75 mmol/L

Question 8

TESTS TO DIFFERENTIATE THE MECHANISMS OF DIARRHEA

Identify reference value according to test:

pH

Answer 8

7-9

Question 9

TESTS TO DIFFERENTIATE THE MECHANISMS OF DIARRHEA

Answer 9

< 5.6 (malabsorption of sugars)

Question 10

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic

MECHANISM: Increased secretion of water and electrolytes

Answer 10

Secretory

Question 11

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:

Increased quantities of osmotically active solutes (undigested food in the lumen)

Answer 11

Osmotic

Question 12

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:

COMMON CAUSES: Enterotoxin-producing organisms, V. cholera, Salmonella, Shigella, E. coli, Clostridium, Staphylococcus Protozoa, Virus

Answer 12

Secretory

Question 13

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:

COMMON CAUSES: Maldigestion (pancreatic insufficiency) Lactose intolerance, Malabsorption, Celiac disease, Tropical sprue

Answer 13

Identify if Secretory or Osmotic:

Question 14

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:
LABORATORY TEST: S

Answer 14

Secretory

Question 15

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:
LABORATORY TEST: O

Answer 15

Osmotic

Question 16

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:
OSMOTIC GAP: Less than 50 mOsm/kg

Answer 16

Secretory

Question 17

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:
OSMOTIC GAP: Greater than 50 mOsm/kg

>75 Osm/kg for strasinger

Answer 17

Osmotic

Question 18

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:
PH: > 5.6

Answer 18

Secretory

Question 19

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:
PH: < 5.3

Answer 19

Osmotic

Question 20

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:
REDUCING SUBSTANCES: Negative

Answer 20

Secretory

Question 21

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:
REDUCING SUBSTANCES: Positive

Answer 21

Osmotic

there are sugars present in the stool

Question 22

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:
FECALYSIS FINDINGS: RBC, WBC, mucus

Answer 22

Secretory

Question 23

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:
FECALYSIS FINDINGS: Meat fiber, fats, lactose watery and Gaseous (Partially/undigested food, gas)

Answer 23

Osmotic

Question 24

DIFFERENTIAL FEATURES FOR DIARRHEA

Identify if Secretory or Osmotic:
STOOL NA (SODIUM): > 90 mmol/L

Answer 24

Secretory

Question 25

# DIFFERENTIAL FEATURES FOR DIARRHEA Identify if Secretory or Osmotic: STOOL NA (SODIUM): < 60 mmol/L

Answer 25

Osmotic

Question 26

# DIFFERENTIAL FEATURES FOR DIARRHEA Identify if Secretory or Osmotic: STOOL OUTPUT IN 24 HOURS: > more than 200 g

Answer 26

Secretory

Question 27

# DIFFERENTIAL FEATURES FOR DIARRHEA Identify if Secretory or Osmotic: STOOL OUTPUT IN 24 HOURS: less than 200 g

Answer 27

Osmotic

Question 28

# COMMON FECAL TESTS FOR DIARRHEA Identify if Secretory or Osmotic: * Stool culture * Parasite examination * Rotavirus immunoassay * Fecal leukocytes

Answer 28

Secretory

Question 29

# COMMON FECAL TESTS FOR DIARRHEA Identify if Secretory or Osmotic: * Fecal fats * Muscle fiber * Trypsin * Clinitest * D xylose tolerance Lactose tolerance Fecal electrolytes, pH, osmolality

Answer 29

Osmotic

Question 30

# COMMON FECAL TESTS FOR DIARRHEA Identify if Secretory or Osmotic: Fecal tests are more on identifying different toxin producing microorganisms

Answer 30

Secretory ## Footnote again, these are causes of secretory diarrhea

Question 31

# COMMON FECAL TESTS FOR DIARRHEA Identify if Secretory or Osmotic: More on identifying reducing substances, electrolytes, osmolality, etc.

Answer 31

Osmotic