GI Parasites- Zimmer Flashcards
What is the difference between a protozoan and a helminth?
Protozoan = unicellular eurkaryote
Helminth = multicellular eurkaryote
Most common intestinal parasite in U.S.?
Giardia
What population is most susceptible to Giardia?
Backpackers/Hikers
34 year old male just got back from the boundary waters. Complains of foul-smelling diarrhea, flatulance, and greasy stools that float…… what do you think it is?
Giardia
What are the 3 protozoan parasites?
Giardia
Cryptosporidium
Entamoeba
HIV+ patient presents to clinic with frequent, WATERY, non-bloody stool after a weekend at the Dells (where a storm knocked out their sanitation center)…. what do you think it would be?
Cryptosporidium Parvum
Describe differences between amebic and bacillary dysentery
Amebic = gradual
No fever, chills, pus
Less prostration
Chronic course
Bacillary = sudden
Fever, cills, puss
More prostration
Acute course
A male homosexual patient returns from a trip from the tropics and presents with Bloody, mucus-ey stool….. what do you think it would be?
Entamoeba Histolytic
Treatment for Giardia?
Metronidazole/ Tinidazole
MOA of Metronidazole? Toxicity?
Toxic metabolites generate free radicals and damage DNA
- disulfiram reaction
- disturb normal flora
Do you treat crypto in immunocompotent people?
Not usually
How should you treat an AIDs patient that has cryptosporidium?
- Nitazoxanide
- Viral Therapy
- Loperamide = anti-peristaltic
- Oral rehydration
MOA of nitazoxanide?
Inhibits PFOR that converts pyruvate to acetyl coA
The PFOR enzyme that is inhibited by nitazoxanide is analogous to what enzyme in mammals?
Pyruvate dehydrogenase Complex
What are the two luminal antiparasitics used to treat intestinal protozoa?
Iodoquinol
Paromomycin
MOA of paromomycin?
Aminoglycoside! Targets 30 S ribosome
Why do you not get the classic ototoxicity/nephrotoxicity with paromomycin (aminoglycoside)?
Because it is a LUMINAL antiparasitic!
Minimal absorption after oral administration
Most common helminth infection is US?
Enterobius = pinworm
Will you find enterobius in stool sample?
No!
Need to use “scotch tape” method around peri anal area to retrieve eggs…
What setting is enterobius common in?
Daycare settings
Where are you likely to find soil-transmitted roundworms?
- Where human feces is used for fertilizer
- Warm humid climates
What helminth infection causes a pruritic papular erythematous rash AND iron deficiency anemia?
Ancylostoma/ Necator
What helminth infection can possible autoinfect, especially with immunosuppressed individuals?
Strongyloides
- Barrel-shaped eggs in feces
- Bloody diarrhea causing iron deficiency anemaia
- Could even progress to rectal prolapse
Trichuris Trichiura
