CHAPTER 16: FECAL ANALYSIS Flashcards
Primary site for the final breakdown and reabsorption of proteins, carbohydrates, and fats
small intestine
Digestive enzymes secreted into the small intestine by the pancreas
Trpysin
Chymotrypsin
Amino Peptidase
Lipase
Produced by the liver that aid in the digestion of fats
Bile salts
Note:
9000 mL ingested fluid enter DT
500-1500 mL reach Large Intestine
150 mL excreted in feces
The large intestine is capable of absorbing approximately 3,000 mL of water. What results to excess amount of water?
Diarrhea
Provides time for additional
water to be reabsorbed from the fecal material, producing small, hard stools
Constipation
Defined as an increase in daily stool weight above 200 g, increased liquidity of stools, and frequency of more than three times per day
Diarrhea
Diarrhea classification is based on
four factors, what are these?
Illness duration
Mechanism
Severity
Stool Characteristics
1) Diarrhea lasting more than 4 weeks
2) Diarrhea lasting less than 4 weeks
a. acute
b. chronic
1) Diarrhea lasting more than 4 weeks
- chronic
2) Diarrhea lasting less than 4 weeks
- acute
Major mechanisms that cause diarrhea
Secretory
Osmotic
Intestinal hypermotility
Bacterial, viral, and protozoan infections produce increased secretion of water and electrolytes, which override the reabsorptive ability of the large intestine, leading to ______________.
secretory diarrhea
What organisms can stimulate secretions of water and electrolytes?
Enterotoxin-producing organisms
a. E. coli
b. Clotridium
c. Vibrio chlorae
d. Salmonella & Shigella
e. Staphylococcus
f. Campylobacter
Protozoa
Parasites
a. Cryptosporidium
Caused by poor absorption whereby there is incomplete breakdown or reabsorption of food presents increased fecal material to the large intestine, resulting in retention of water and electrolytes in the large intestine.
Excessively watery stool
Osmotic diarrhea
These contribute to osmotic diarrhea (2)
Maldigestion
Malabsorption
A functional disorder in which the nerves and muscles of the bowel are extra sensitive, causing cramping, bloating, flatus, diarrhea, and constipation
Irritable bowel syndrome
Increased fecal fat that is useful in diagnosing pancretic insufficiency and small-bowel disorders that cause malabsorption
Steatorrhea
Its absence produces an increase in stool fat
Bile salts
A sugar that does not need to be digested but does need to be absorbed to be present in the urine.
D-xylose
1) Low urine D-xylose
2) Normal D-xylose test
a. malabsorption
b. pancreatitis
1) Low urine D-xylose
- malabsorption
2) Normal D-xylose test
- pancreatitis
What intestinal infection is caused by malabsorption
G. lamblia
Often the first indication of GI disturbances
Changes in brown color and formed consistency
The brown color of the feces results from intestinal oxidation of _____________ to _____________.
stercobilinogen to urobilin
Significance of pale (acholic) stools
Blockage of bile duct
Diagnostic procedures that use barium sulfate
In question: COLOR
Blood that originates from the esophagus, stomach, or duodenum takes approximately 3 days to appear in the stool; during this time, degradation of hemoglobin produces the characteristic _________ stool
black, tarry stool
In question: COLOR
Blood from the lower GI tract requires less time to appear and retains its _________ stool color.
Red
In question: COLOR
Observed in patients taking oral antibiotics because of the oxidation of fecal bilirubin to biliverdin.
Green stool
Indication of ribbon-like stools
obstruction of normal passage of material through the intestine
Indication of pale stolls that appear bulky and frothy
Biliary obstruction
Steatorrhea
Indication of the presence of mucos-coated stools
Intestinal inflammation or irritation
1) Presence of leukocytes
2) Presence of undigested muscle fibers
a. microbial diarrhea
b. steatorrhea
1) Presence of leukocytes
- microbial diarrhea
2) Presence of undigested muscle fibers
- steatorrhea
Neutrophil infiltration into the intestinal mucosa is a characteristic of
Ulcerative colitis
bacterial dysentery
Bacteria that cause diarrhea by toxin production
Staphylococcus aurues
Vibrio spp.
Stain for wet preparations known as a faster procedure
Methylene blue
Used to stain dried smears
Wright’s; or
Gram stain
A component of granulocyte secondary granules that indicates an invasive bacterial pathogen
lactoferrin
A black tarry stool is indicative of:
Upper GI bleeding
Stool specimens that appear ribbon-like are indicative of which condition?
Bile duc obstruction
Routine stain for lipids
ORO and Sudan III
Neutral fats are readily stained by Sudan III and appear as
large orange-red droplets
This test has a high positive predictive value for detecting colorectal cancer in the early stages
Testing for occult blood
The screening test used most frequently for fecal blood is the
_________________ based on detecting
the pseudoperoxidase activity of hemoglobin
Guaiac-Based Fecal Occult Blood (gFOBT)
How many samples should be testeed before a negative result is confirmed?
2 samples
Specific for the globin portion of human hemoglobin and uses polyclonal antihuman hemoglobin antibodies
Immunochemical Fecal Occult Blood Test (iFOBT)
It is more sensitive to lower GI bleeding that could be an indicator of colon cancer
Immunochemical Fecal Occult Blood Test (iFOBT)
The test measures both intact hemoglobin and the hemoglobin that has been converted to porphyrins
Porphyrin-Based Fecal Occult Blood Test
Confirmatory test for steatorrhea
Quantitative Fecal Fat Testing
The method used routinely for fecal fat measurement
Van de Kamer titration
A test to distinguish between the presence of fetal blood or maternal blood in an infant’s stool or vomitus
APT Test (Fetal hgb)
Carbohydrates are seen in patients with this disease
celiac disease
Normal stool pH
between 7 and 8
A test on stools that can distinguish between diarrhea caused by abnormal excretion of reducing sugars and those caused by various viruses and parasites.
Clinitest
Sugar not detecte by cliitest because it is not a reducing sugar
sucrose
