Fecalysis Flashcards
<1-2 weeks but it may persist until 4 weeks, most
common cause is toxic ingestion or infection by bacteria,
pathogens, or virus
Acure
last for >4 weeks but is often 8 weeks or longer,
can be inflammatory (intestinal, inflammatory bowel
disease like Crohn’s disease) or noninflammatory (can be
subcategorized by the effect of fasting on the diarrhea).
Chronic
The
third cause is altered motility. This describes the condition
where it is whether enhanced motility or slowed motility
(constipation)
Chronic
Lactose intolerant (those who cannot absorb lactose in the
milk that causes LBM, this caused by the incomplete
breakdown or reabsorption of lactose)
Osmotic diarrhea
an also be caused by celiac sprue, malabsorption of sugar,
amebiasis, and antibiotic administration
Osmotic diarrhea
Fecal fluid pH
> 5.6
Caused by increase secretion of water and electrolytes that is
cased by bacteria that produces enterotoxins.
Secretory diarrhea
Can also be caused by drugs, laxatives, inflammatory bowel
disease, and endocrine disorders
Secretory diarrhea
Electrolytes is increased
Secretory diarrhea
The laboratory tests used to differentiate between them are
fecal electrolytes (fecal sodium, and fecal potassium), fecal
osmolality, and stool pH
Osmotic gap
Fecal sodium
30mmol/ L
Fecal potassium
75 mmol/L
> 50 mOsm/ kg
Osmotic diarrhea
<50 mOsm/kg
Secretory diarrhea
Normal fat/fecal (?) content of stool
6g/day
The clinical significance of___ is for the diagnosis of
pancreatic insufficiency and small bowel disorders that cause
malabsorption
Steatorrhea
used to differentiate malabsorption (low D-
xylose) and maldigestion (normal D-xylose), urine and blood
can be tested
D xylose test
Malabsorption
Low D xylose
Maldigestion
Normal D xylose
Specimen suitable for qualitative testing for blood, and
microscopic examination of leukocytes, muscle fibers, and
fecal fat
Random
Specimen For quantitative twsting
3 day collection
Normal color; this is caused degradation of
urobilinogen to urobilin, and stercobilin
Orange brown
This what
bile duct (post-hepatic obstructions) blockage may cause?
Acholic stool
Upper gastrointestinal bleeding (esophagus,
stomach, duodenum; the blood may take 3 days
before excreted that is why it will exhibit black
color), iron therapy, charcoal, bismuth
Black
Lower gastrointestinal bleeding, beets and food
coloring, rifampin
Red
Bile duct obstruction, barium sulfate
Pale yellow, white, gray
Biliverdin/oral antibiotics, green vegetable
Green
Normal stool appearance
Formed cylindrical masses
Appearance: Bile duct obstruction, pancreatic disorders
Bulky / frothy
Appearance: Intestinal constriction
Ribbon like
Appearance: Colitis, dysentery, malignancy (colon cancer),
constipation
Blood -streaked mucus
_____ in feces indicates irritation of the intestinal
mucosa in ulcerative colitis and bacterial dysentery
Neutrophils
Presence of neutrophils indicates
Invasive bacteria
Absence of neutrophils indicates
Toxin producing bacteria
All smears or slide preparations must be performed on
Fresh specimens
faster to prepare, but more difficult to
interpret; stained with methylene blue
Watery smear
provide permanent slides for evaluation;
stained with either Wright’s or Gram stain
Dry smears
Positive result for neutrophils
3 neutrophils/hpf
Used in the diagnosis and monitoring of patients with
pancreatic insufficiency, biliary obstruction, and gastrocolic
fistulas
Mucus fibers
In mucus fiber test stool is emulsified in what and in how many minutes
10% alcoholic eosin and examine for 5 mins
with visible striations in one direction
Undigested fibers
with striations in one direction
Prtially Digested fibers
no striations
Digested fibers
Significant result of mucus fibers
10 undigested fibers
Screening test for the presence of excess fecal fat
Qualitative Fecal Fat test
Monitoring of patients undergoing treatment for
malabsorption disorders
Qualitative fecal fat test
Lipid dyes
Sudan III
Sudan I V
Oil red O
readily stained by Sudan II and
appear as large orange-red droplets
Neutral fats
Steatorrhea is indicative of
> 60 droplets/hpf
do not stain directly with
Sudan III
Fatty acid salts and fatty acids
For fatty acid salts and fatty acids, specimen must be mixed with?
Acetic acid and heated
stained by Sudan III after heating and
crystallizes during cooling
Cholesterol
Most frequently performed chemical screening test
Occult blood
Bleeding in excess of ____stool is pathologically
significant
2.5mL/150g
Used as a mass screening procedure for the early detection of
colorectal cancer
Occult blood test
Principle of occult blood test
pseudoperoxidase activity of hemoglobin
most sensitive; not preferred because it is
expensive, and detects everything (prone to false (+)
results); ascorbic acid (false (-))
Benzidine
least sensitive; preferred for routine
testing’
Gum guaiac
Occult blood indicator chromogens
Benzidine
Ortho toluidine
Gum guiaic
Used as a confirmatory test for steatorrhea
Quantitative Fecal Fat Testing
Specimen required for quanti fecal fat test
Refrigerated 3 day specimen
Normal valuws for quanti fecal fat twst
1-6g/dL
Methods of Quantitation
Van de kamer titration -gold standard
Gravimetric methos
Distinguishes between fetal blood or maternal blood
Alkali denaturation test
Sample of ADT
infant’s stool or vomitus
Control for ADT
cord blood or adult blood
Reagent for ADT
1%NaOh
Adt: solution remains pink
Fetal hb
Adt: solution turns yellow brown
Maternal hb
X-ray paper is exposed to the stool sample emulsified in water
Trypsin
digestion of gelatin on the x-ray paper = clear
area
Presence of trypsin
inability to digest gelatin = no change
Absence of trypsin
False pos or neg? proteolytic activity of bacterial enzymes
False pos
False pos or neg? intestinal degradation of trypsin; inhibitors in
feces
False neg. Trypsin
More sensitive indicator of less severe cases of pancreatic
insufficiency
Chymotrypsin
More resistant to intestinal degradation
Chymotrypsin
Remains stable in fecal samples for up to 10 days at rom temp
Chymotrypsin
Measured spectrophotometrically
Chymotrypsin
Pancreas specific and a very sensitive indicator of exocrine
pancreatic insufficiency
Elastase I
Easy to perform and requires only a single stool sample
Elastase I
Measured by immunoassay using the ELISA kit
Elastase I
Inability to reabsorb carbohydrates
Celiac diseasw
Lack of digestive enzymes
Lactose intolerance
Detects congenital disaccharidase deficiency and enzyme
deficiencies due to nonspecific mucosal injury
Copper reduction test
Most valuable is assessing cases of infant diarrhea and may
be accompanied by a pH determination
Copper reduction tes
Normal stool ph
7-8
Carbohydrate disorders pH:
<5.5
Result of —— → carbohydrate intolerance
0.5g/dL
Performed after a positive fecal Clinitest
Serum Carbohydrate Intolerance Test
