Amebiasis Flashcards
Describe the lifecycle of Amebiasis parasite
- ingests cysts
- trophs have tropism for and invade liver, lung, large intestine, etc.
- Cysts and trophs shed in feces. Cysts can survive.
For which organs to Amebiasis trophs have a tropism?
liver, lung, large intestine
Clinical: What are the asymptomatic concerns with amebiasis? (3)
- Stools will have cysts but no evidence of tissue invasion
- Negative serum Ab, normal colonoscopy
- generally found by accident
Clinical: What are the clinical manifestations of amebiasis via diarrhea?
Amebic colitis (diarrhea) or amebic dysentery
- onset over several days, mucoid diarrhea, gross or occult blood
- abdominal discomfort +/- fever
- *almost always Occult blood**
Clinical: What are the clinical manifestations of amebiasis via liver abcess?
Liver abcess (most common extraintenstinal disease)
- fever, RUQ pain, tenderness over liver
- Remote history of diarrhea but not generally during this stage
- patient will report travel history and iarrhea, fever, malaise, RUQ discomfort weeks to months go
- CT reveals liver abcess
Approximately how many deaths occur from Amebiasis annually?
70,000-100,000 deaths annually
3rd leading cause of parasitic death globally
In which countries is amebiasis most common?
Central or South America, Africa, Asia
In US mainly due to traveler’s
In which populations does amebiasis most often present?
Generally see it in travelers. Prevalence is low
- institutionalize patients (poor hygiene)
- men having sex with men
- recent immigrants
- migrant works from endemic areas
Amebiasis is the only parasite that causes _____ disease?
microvascular disease
How do you diagnose Ambiasis?
Diagnosis is very problematic because:
- stool exams for cysts generally negative – may need multiple samples
- non-pathgenetic cysts look the same, including E. coli
- Extra-intestinal disease (hepatic abscess)
- not many will have cysts in stool
- CT may reveal an abscess but hard to tell
- Index of suspicion with travel hx and general hx
- Serum Ab tests are important
- indirect hemagglutination previously
- now ELISA
- Microscopic stool exam in lab
- RBC within cytoplasm of trophs this is suggestive of E. histolytica
- Fecal WBC = active amebic colitis with bowel inflammation Probably not overwhelming amounts b/c they use lyse neutrophils
- EIS on stool – fresh or frozen
Which diagnostic tests are most important with Ambiasis? (6)
- CT to reveal abscess + hx
- Serum Ab tests
- ELISA
- Microscopic stool exam (RBC within cytoplasm of trophs is suggestive of E. histolytica
- Fecal WBC = active amebic colitis with bowl inflammation (but probably not a lot)
- EIA on stool, fresh or frozen
- Basic Stool exam often negative 3 amebas look the same & cysts are not usually present!
How do you treat Ambiasis?
- Look up!
- Treat asymptomatic to decrease risk for invasive
How do you prevent Ambiasis? (4)
- proper waste disposal and water purification
- boil contaminated water - iodine/chlorine WON’T kill!
- Assume fruits and veggies to be contaminated
- avoid fecal/oral contact
