Upload
aisyahmayangwulan
View
221
Download
1
Embed Size (px)
Citation preview
Powerpoint Templates Page 1Powerpoint Templates
Gastro-intestinal tract
Entamoeba histolytica
Isna Indrawati
Powerpoint Templates Page 2
Class Rhizopoda
8 species live in GI tract : Entamoeba histolytica Entamoeba dispar Entamoeba coli Entamoeba gingivalis Entamoeba hartmani Endolimax nana Dientamoeba fragilis Iodamoeba butschlii
Powerpoint Templates Page 3
• HOST : human amebiasis
•DISTRIBUTION:• cosmopolite, occurs worldwide
•>>> in tropic and sub tropic• strong correlation with personal hygiene
• high prevalence in countries where poor socioeconomic and sanitary conditions
Powerpoint Templates Page 4
Prevalence of amebiasis• ± 50 million cases of invasive E.
histolytica disease occur each year (up to 100,000 deaths)
• Only an estimated 10%–20% of individuals infected with E. histolytica become symptomatic.
• Prevalence of symptomatic amebiasis vary geographically
Powerpoint Templates Page 5
Prevalence (cont’d)
• Prevalence vary ranging from 1% to 21% in developing countries
• Indonesia : 10 – 18 %
Powerpoint Templates Page 6
Morphology & Life cycle
Powerpoint Templates Page 7
Pathogenesis
• the triad of Gal-lectin, cysteine proteinases and amoebapores of the parasite were thought to be responsible for invasive process
• Typical intestinal amebic ulcers : flask shape ulcer with slightly elevated areas of the mucosa
Powerpoint Templates Page 8
Pathogenesis
Predilection site
Powerpoint Templates Page 9
Clinical symptoms
• Incubation period : 2–4 weeks (but ranges from a few days to years)
• Most infections (≥90%) remain asymptomatic
• characterized classically by abdominal pain and bloody diarrhea.
Powerpoint Templates Page 10
Clinical symptoms: Intestinal Amebiasis• Acute amebiasis ( 1 month):
– amebic dysentery, with frequent, urgent, small bloody stools, tenesmus
• Chronic amebiasis ( > 1 month):–alternating diarrhea and
constipation every few days– Fatigue, weight loss.
Powerpoint Templates Page 11
Complications• Complications of intestinal
disease : spread through percontinuitatum):
rectovaginal fistulas, perianal skin ulceration, perforation, peritonitis, shock, and death.
hematogenous : extra intestinal amebiasis
Powerpoint Templates Page 12
Extra intestinal amebiasis
• 1-3 monts after first attack : 5 % of intestinal amebiasis developed extra instestinal amebiasis
• trophozoites enter the bloodstream and disseminate to other body sites
• most common site: the liver (amebic liver abscess= ALA).
Powerpoint Templates Page 13
• Amebic liver abscess presents with fever and right upper quadrant abdominal pain, hepatomegaly
• usually in the absence of diarrhea.
Powerpoint Templates Page 14
Formation of ameboma
• Granulomatous reactions are pseudotumoural lesions, whose formation is associated with : necrosis, inflammation and oedema of the mucosa and submucosa of the colon.
• These granulomatous masses may obstruct the bowel (stricture)
Powerpoint Templates Page 16
Diagnosis :• Detection of amoebic
trophozoites containing ingested red blood cells in the fresh faecal specimen
• Biopsy : identification of trophozoites within the tissues
• Detection of cysts ( light microscopy): should be reported as E. histolytica / E. dispar two species are indistinguishable
Powerpoint Templates Page 17
trophozoites:
Trichrome stain
Powerpoint Templates Page 18
E.hist/E.dispar in iodine
Chromatoid body with blunt rounded end
Trichrome stain
Powerpoint Templates Page 19
Diagnostic support
• Colonoscopy • Aspiration of liver abscess • USG• Rx. Serology : high titres of
specific antibody is strongly correlated with the presence of invasive amoebiasis
Powerpoint Templates Page 20
Diagnosis (cont’d)
• E. histolytica and E.dispar can be differentiated by :– Isoenzyme patterns : particularly
hexokinase.– Antigen detection: specific epitopes,
recognized by reaction with several monoclonal antibodies.
– DNA blotting : sequence differences in the rDNA
Powerpoint Templates Page 21
Histopathology
Colon biopsy
Colonoscopy
Powerpoint Templates Page 22
Epidemiology:• Transmission occurs through
ingestion of cysts from food or water contaminated by feces
• “Silent carrier” :–have the ameba in their
intestines and excrete amebic cysts, but have no symptoms.
– important as a source of infection
Powerpoint Templates Page 23
Prevention :• drink purified or boiled water• Wash and peel all raw
vegetables and fruits before eating
• Protecting food from fly contamination
• Washing hands after defecation and before preparing or eating food
• using the toilet