entamoeba histolytica -amoebiasis
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DIAGNOSIS OF INTESTINAL AMOEBIASIS
STOOL EXAMINATION
MACROSCOPIC EXAMINATION
• Foul smelling, copious and semiliquid.
• Brownish black in colour.
• Intermingled with blood and mucus.
• Not adhere to container.
MICROSCOPIC APPEARANCE
• Cellular exudate scanty.
• Nuclear masses of pus cells, epithelial cells and
macrophages.
• RBCs in clumps with yellow or brown red colour.
• Charcot-Leyden crystals-diamond shaped clear refractile
crystals.
Actively motile trophozoites in fresh stools.
Presence of ingested RBCs
Nucleus not visible.
Cyst has smooth, thin cell wall
Contains round refractile chromatoid bars.
IODINE STAINED PREPARATION• Demonstration of cysts and trophozoites.
• Stains yellow to light brown.
• Nucleus clearly visible with central karyosome.
• Cytoplasm smooth and hyaline appearance.
• Nuclear chromatin- Bright yellow
Glycogen-Golden brown
• Chromatoids-No staining
TRICHROME STAIN is also used to demonstrate trophozoites and cysts.
Microscopy
AB
MUCOSAL SCRAPING
• Scrapings obtained by sigmoidoscopy is examined
• Include:
• Wet mount and iron hemotoxylin and
immunofluoroscent staining.
STOOL CULTURE
Sensitive method in diagnosing chronic and asymptomatic intestinal amoebiasis
Medias used are:
Boeck and Drbohlav media.
NIH polygenic media.
Craig’s medium
Nelson’s medium.
Robinson’s medium
SERODIAGNOSIS
Indirect haemoagglutination(IHA)
Latex agglutination test
ELISA
Positive only in invasive
amoebiasis
MOLECULAR DIAGNOSIS
DNA probes
Radioimmunoassay
It is rapid and specific method
Intestinal Amoebiasis
Stool Examination
1.Microscopy
2.Macroscopy
3. Iodine stained
preperation
4.Trichrome stained
preparation
Stool Culture
Media used:
1.Boeck and Drbohlav
2.NIH polygenic
3.Craig’s
4.Nelson’s
5.Robinson’s
Mucosal Scraping
1. Wet mount stained
preparation
Serodiagnosis
1.IHA
2.ELISA
3.Latex Agglutination test
Molecular diagnosis
DNA probe
DIAGNOSIS OF EXTRAINTESTINAL AMOEBIASIS
MICROSCOPY
• Pus aspirated from liver abscess- demonstrate trophozoites of E.histolytica in less than 20% cases.
• Aspirate from the margin of the abscess show trophozoites.
• Cysts are never seen in extraintestinal amoebiasis.
LIVER BIOPSY
• Trozpozoites of Entamoeba histolytica may be seen in
liver biopsy specimen in case of hepatic amoebiasis or
amoebic hepatitis.
SEROLOGICAL TESTSIt has immense value in diagnosis of hepatic amoebiasis.
1) Complement fixation testing
2) Indirect hemoagglutination(IHA)
3) Latex agglutination
4) Countercurrent immunoelectrophoresis(CIE)
5) Gel diffusion precipitation(GDP)
6) Cellulose acetate membrane precipitation(CAP)
7) ELISA
RADIOLOGICAL EXAMINATION
Radioisotope scan of liver may locate space occupying
lesions.
USG, CT or MRI also found useful in detection of
amoebic liver abscess
AMOEBIC LIVER ABSCESS
Microscopy
Of pus or aspirate
Histopathologicalexamination
Of pus or aspirate
Serodiagnosis
1.IHA
2.ELISA
3.Latex Agglutination
Radiological Examination
1.X-ray
2.USG
3.CT Scan
4. MRI
Stool Examination
TREATMENT
3 classes of drugs:
1) Luminal Amoebicides
2) Tissue amoebicides
3) Both luminal and tissue amoebicides
LUMINAL AMOEBICIDES
Diloxanide Furoate
Paromomicin
Iodoquinol
Tetracycline-Act only in intestinal lumen not in tissues.
TISSUE AMOEBICIDE Emetine
Chloroquine
Effective in systemic infection
Less effective in intestine
Dosage of chloroquine in amoebic liver abscess is 1 g for 2 days followed by 5 g daiily for 3 weeks.
BOTH LUMINAL AND TISSUE AMOEBICIDE
Metronidazole
Tinidazole
Ornidazole
Act on both sites
These are the drugs of choice for amoebic colitis and amoebic liver abscess.
Asymptomatic E.histolytica should be treated.
Oral rehydration and electrolyte replacement should
be done whenever necessary.
PROPHYLAXIS
Generally for all fecal oral infection
Food and water have to be protected from
contamination with excreta.
Detection and treatment of carriers.
Health education
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