GIT

Indications for stool examination:

1. To evaluate the function and integrity of the GI tract.
2. To rule out the presence of WBCs and RBCs.
3. To find ova or parasites.
4. To see the presence of fat for malabsorption syndrome.
5. For screening for colon cancer.
6. For asymptomatic ulceration of GI tract.
7. Evaluate diseases in the presence of diarrhea and constipation.
8. Summary of stool studies are done to evaluate:
   1. Intestinal bleeding.
   2. Infestation.
   3. Inflammatory diseases.
   4. Malabsorption.
   5. Different causes of diarrhea.

Gross Stool examination includes:

1. Color.
2. Consistency.
3. Quantity.
4. Odor.
5. Mucous.
6. Helminths.
7. Concretions (gallbladder stones rarely may be found).

Undigested food particles like:

1. Vegetable cells.
   1. Vegetable fibers.
   2. Plant hairs.
   3. Amorphous vegetable material.

Stool physical character and possible causes:

Presence of Fat:

1.  The fat in the stool shows the possibility of :
   1. Malabsorption.
   2. Deficiency of pancreatic digestive enzyme.
   3. Deficiency of Bile.

Presence of Leukocytes:

1. Normally, there are no WBCs.
2. WBCs only appear in infection or inflammation.
3. Their presence is important in case of diarrhea or dysentery.
4. >3 WBCs /high fields are seen in ulcerative colitis and bacterial infection.
5. Greater numbers of WBCs indicate invasive pathogens.
6. Viruses and parasites don’t cause the presence of  WBCs in the stool.
7. Increased number of WBCs seen in the stool:
   1. Bacillary dysentery.
   2. Chronic ulcerative colitis.
   3. Shigellosis.
   4. Salmonella infection.
   5. Yersinia infection.
   6. Invasive E.coli diarrhea.
   7. Fistula of anus or rectum.
   8. Localized abscess.
8. Few WBCs are seen in amoebiasis.
   1. Also, WBCs are seen in typhoid.

The absence of WBCs seen in some of the diarrhoeal conditions alike:

1. Cholera.
2. Viral diarrhea.
3. Drug-induced diarrhea.
4. Amoebic colitis.
5. Non-invasive E.coli diarrhoea.
6. Parasitic infestation.
7. Toxigenic bacterial infection.

Presence of Red Blood Cells in the stool:

1. Normally RBCs are absent.
2. Epithelial cells are present, and these are increased with GI tract irritation.
3. Few WBCs are seen, which may be increased due to GI tract inflammation.
4. Blood in the stool can be:
   1. Bright red from the bleeding in the lower GI tract.
   2. Maroon in color.
   3. Black and tarry from bleeding from the upper GI tract.
   4. Occult blood (not visible to the naked eye).
5. Causes of blood in stool:
   1. Hemorrhoids.
   2. Cancer.
   3. Dysentery.
6. Make a smear from the mucus area or the blood-colored area from the watery or semiformed stool.

Ova and parasites:

1.  Normally there are no parasites or eggs in the stool sample.
2. Multiple stool samples are needed to rule out the parasitic infestation for at least three consecutive days.
3. An abnormal result means parasites or eggs are present in the stool. Such infections include:
4. Roundworms: Ascaris lumbricoides.
5. Hookworms: Necator americanus.
6. Pinworms: Enterobius vermicularis.
7. Whipworm: Trichuris trichiura.
8. Tapeworms: Diphyllobothrium latum, Taenia saginata, and Taenia solium.
9. Protozoa: Entamoeba histolytica (an amoeba) and Giardia lamblia (a flagellate)
10. Strongyloidiasis.

Normal

• Occult blood normally is negative.

Causes of positive OB test seen in:

1. Gastrointestinal tumors.
   1. Rectal carcinoma.
   2. Gastric carcinoma.
2. Inflammatory bowel disease.
3. Diverticulosis.
4. Varices.
5. Ischemic bowel disease.
6. Arteriovenous malformations of the GI tract.
7. Hemorrhoids.
8. Blood is swallowed from the oral cavity or nasopharynx.
9. Adenoma.
10. Peptic ulcer.
11. Gastritis.
12. Amyloidosis.
13. Kaposi’s sarcoma.