Transcript Stool analysis:

Stool analysis:
A stool analysis is a series of tests done on a stool (feces)
sample for differential diagnosis of certain diseases of
digestive system.
Stool analysis procedure is divided into:
1-Physical Examination.
2-Chemical Examination.
3-Microscopic Examination.
Clinical significance of stool analysis:
1-Diagnosis of digestive system infectious diseases:
Bacteria, parasites, virus, and fungi.
2-Diagnosis of pancreas disorders (inflammation); which
associated with malabsorption of nutrients.
3-Primary screening test for some types of digestive
system malignancy such as: Colon cancer.
4-Primary screening test for peptic ulcer disease, and
some types of anemia.
For whom Stool analysis is urgently required?
1-Patients with abdominal pain.
2-Patients with diarrhea.
3-Patients with anemia.
Other situations by which Stool analysis is non-urgently
required:
1-Patients who is too thin or do not grow well.
2-Patient with stool color that is changed to abnormal color.
Stool analysis:
1-Physical Examination:
A-Color: Normal feces has a dark brown color.
(Bilirubin in the presence of bacteria will be
oxidized to urobilinogen which give stool its color).
Abnormal color:
1- Black color indicates blood of upper GIT origin(melena).
2- Red color indicates blood of lower GIT origin.
3- White color indicates yeast fermentation (Candida).
-Very pale color indicates biliary obstruction or barium
enema.
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Physical Examination:
B-Consistency:
-Normal feces is solid to semi-solid depending on diet.
-A ribbon like fecal specimen could indicate irritable bowl
syndrome or GIT obstruction.
-Liquid stool indicates diarrhea (Gastroenteritis).
-80-170 gm/day.
Chemical Examination:
1-The pH: The pH of the stool is 7.0-7.5.
2-Suger contents:
The stool contains less than 0.25 grams per deciliter (g/dL) or
less than 13.9 millimoles per liter (mmol/L) of sugars.
-Elevated Suger indicates (more than 0.5g/dl):
-Lactose intolerance.
3-Fat contents:
The stool contains 2-7 grams of fat per 24 hours (g/24h).
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- High levels of fat(steatorrhea) in the stool may be
caused by diseases such as pancreatitis, celiac
disease(allergy to Gluten protein in wheat) ,or cystic
fibrosis.
4-Occult blood: (The stool guaiac test):
-Occult blood can be detected chemically :
1- Paper surface with phenolic compound alpha-guaiaconic
acid.
2- Stool applied to the paper.
3-Hydrogen peroxide oxidizes alpha-guaiaconic acid to darkblue color within two seconds.
4-Heme is a catalyst of this reaction.
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Patients should be instructed to avoid red meat, horse
raddish, Asprin, Vitamin C as they interfere with the test
by their catalases and peroxidases .
Clinical significance of the test:
1-Diagnosis of Colorectal cancer.
2-Diagnosis of ulcer hemorrhoids.
3-Invasive Gastroenteritis.
Microscopic Examination:
-Fecal leukocytes, especially neutrophils are associated
with dysentery.
-They can be detected by dried smears of the stool stained
with gram stain.
-Wet-mount smear(0.9% Saline) or Iodine stained smear
should be prepared for parasites identification.
1-Wet-mount smear : Show the motility of active
Protozoa.
2-Iodine smear: Show the nucleus and karyosome of
protozoa.
Amoebic dysentery: Entamoeba histolytica (Rhizopoda):
-Offensive stool.
-Faecal matter mixed with blood and mucus.
-RBCs, pus, mucus, and Entamoeba histolytica cyst
or/and trophozoite (central karyosome).
-Trophozoite show motility in one direction.
Giardia intestinalis :
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Gastrointestinal Mastigophora.
Habitat: Small intestine especially in duodenum.
Disease: Fatty diarrhea especially in children.
Morphology: Trophozoite: four pairs of flagella.
Giardia cyst (infective and diagnostic)
Giardia trophozoite (diagnostic stage).
Balantidial dysentery: Balantidium coli:
-Ciliophora.
-Kidney-shaped Macronucleus.
-Small micronucleus.
-Ingestion of Contaminated pork meat.
Helminthes:
Schistosoma mansoni:
- Trematoda.
- Intestinal bilharziasis.
- Diagnosis: finding of ova in stool.
Ova with
Lateral spine
(diagnostic
stage)
Cysticercosis: Taenia (Cestoda) infection:
1- Taenia saginata (beef tapeworm).
2- Taenia solium (pork tapeworm).
Diagnostic stages:
1-Gravid segments.
2-Hexacanthoembryonated ova.
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Ascaris lumbricoides:
-Nematoda.
-Diagnostic stage:
1-Fertilized, un-fertilized ova.
2-Embryonated ova.
3-Adult stage.
N
Hook worms:
- Ancylostoma duodenale.
- Nematoda.
- Diagnostic stage:
4-8 cell stage Embryonated ova.
N
Enterobius vermicularis:
-Nematoda.
-Diagnostic stage:
D-shaped ova.
D-Shaped Ova.
N
• "Scotch tape test"
It is best done at night during the characteristic intense itching or
early in the morning before any bathing or washing.
Wrap a piece of cellophane tape around a tongue depressor, sticky side out, and
press it to the skin around the anus to collect any eggs.
Take the tape to a doctor, who will put it under a microscope to look for
pinworm eggs.
– The doctor may ask the person to use several pieces of tape to increase the
likelihood of seeing the eggs. A single specimen will detect approximately
50% of cases; 90% of cases will be detected if the test is repeated three
times.
– Blood tests are not necessary to establish the diagnosis of pinworm
infection.
• The doctor may decide based upon the patient's symptoms that
pinworms are present and may treat with medication without
doing any tests.
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Strongyloides stercoralis:
-Free-living Nematoda.
-Diagnostic stage:
Rhabditiform larvae in stool.