Entamoeba Histolytica: Diagnosis and Treatment
Diagnosis of amoebiasis
Diagnosis is made by:
1. Stool examination
- For amoebic colitis definitive diagnosis is made by:
- The demonstration of hematophagous trophozoites
- Erythrophagocytosis
- Fecal findings are:-
- Positive test for heme.
- Paucity (lack) of neutrophils (pus cells).
- Presence of amebic cysts or trophozoites
- Charcot-leyden crystals.
- Charcot-Leyden crystals are also seen in whipworm , Ascaris pneumonia, and bronchial asthma.
2. Serological tests
- Most useful for invasive amaebiasis (e.g. amaebic hepatitis/liver abscess).
- Most commonly used test is indirect hemagglutination (IHA).
- But ELISA is best (sensitive and specific) test and now replacing IHA.
- Ultrasonography is the preferable initial diagnostic test.
- Exploratory technique
- Most practical methods for confirming the diagnosis of amboebic liver abscess.
- The aspirated pus may be examined for the demonstration of trophic forms (trophozoites) of E. histolytica.
- Aspirations from the center of amoebic liver abscess do not show trophozoites
- Aspirates from the margins show trophozoites.
Treatment:
Drug therapy for Amoebiasis
1. Asymptomatic carrier (asymptomatic cyst passers)
- Diloxamide furoate is the DOC.
2. Luminal amoebicides:
- Diloxamide furoate, iodoquinol, paromomycin.
- Effective in amoebic colitis.
3. Tissue Amoebicides:
- Emetine, chloroquine, effective in extraintestinal amoebiasis
- Metronidazole is effective in both conditions.
Prophylaxis:
Personal prophylaxis:
- Avoidance of use of raw fruits and vegetables.
- Use of boiled drinking water.
- Protection of food and drink from contamination through flies and cockroaches.
- Obeying the elementary hygienic conditions.
- Personal cleanliness.
Community prophylaxis:
- Safe and effective disposal of human excreta coupled with sanitary practices like washing hands after defecation.
- Cysts are resistant to readily attainable levels of chlorine, disinfection by iodination (Tetraglycine hyperiodide).
- Protection of water supplies against faecal contamination.
- Avoidance of fresh human faces as fertilizer.
- Health education and public awareness about the parasite and its mode of transmission.
Exam Question
- Amoebic liver abscess can be diagnosed by demonstrating trophozoites in the pus.
- Ultrasonography is the preferable initial diagnostic test for liver abscess
- Invasive amoebiasis can be best diagnosed by ELISA
- The presence of red blood cells in the cytoplasm (erythrophagocytosis) is diagnostic of E. histolytica as it is the only intestinal amoeba to exhibit this characteristic.
- cysts are resistant to readily attainable levels of chlorine, disinfection by iodination (Tetraglycine hyperiodide) is recommended.
Drug therapy for Amoebiasis
1. Asymptomatic carrier (asymptomatic cyst passers)
- Diloxamide furoate is the DOC.
2. Luminal amoebicides:
- Diloxamide furoate, iodoquinol, paromomycin.
- Effective in amoebic colitis.
3. Tissue Amoebicides:
- Emetine, chloroquine, effective in extraintestinal amoebiasis
- Metronidazole is effective in both conditions
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