Protozoal infections Flashcards
protozoa causing bloody diarrhea
- Entamoeba
- Balantidium
symptoms caused by entamoeba histolytic
- bloody diarrhea
- ulcers
- liver abscesses
epidemiology of entamoeba
- associated with camping/hikers
- fecal oral transmission - cysts are passed in stool
lifecycle of entamoeba
- only cyst form is infectious
- ingest cyst, stomach acid erodes cyst leading to growth and invasion
- trophozoites are the actively replicating form and indicates parasitic infection
pathogenesis of entamoeba
- gastric acid stimulates excystation
- local necrosis of large intestine
- destruction of epithelial cells
clinical disease of entamoeba
- ab pain and cramps, colitis, bloody diarrhea
- weight loss and anorexia
- liver abscess - flask shaped ulcer, fever, RUQ pain, tenderness
treatment of entamoeba
- non-invasive: paramomycin
- invasive: metronidazole followed by paramomycin
MOA of metronidazole
- destabilizes DNA
epidemiology of balantidium coli
- ciliate: only spp that infects humans
- fecal oral transmission
- pigs are reservoirs
- infection from ingested cysts
clinical disease of balantidium coli
- watery diarrhea WITH blood and pus
- ab pain, nausea, anorexia
- secondary bacterial infections of GI mucosa
treatment for balantidium coli
- tetracycline
- metronidazole and iodoquinol are alternatives
epidemiology of giardia
- fecal oral via cysts
- beavers and muskrats are reservoirs
- more common in campers and hikers and also in daycares
- most often transmitted from contaminated water
clinical disease of giardia
- explosive watery diarrhea
- foul smelling stools
- ab cramps
- can progress to malabsorption syndrome - steatorrhea (foul smelling (malodorous), mushy, greasy stool)
diagnosis of giardia
- microscopic examination of stool
- bilobed nuclei, looks like a horseshoe crab
- has flagellum
- falling leaf motility
treatment and prevention of giardia
- treat with metronidazole
- boil water and treat carriers
- cysts can survive in chlorinated water
epidemiology of cryptosporidium
- mainly affects children (peak age around 5)
- can be severe in IC patients - lethal in AIDS, #1 cause of AIDS associated diarrhea
pathogenesis of cryptosporidium
- oocyst is infectious form
- stains acid fast
- resistant to chlorination
- water born disease
lifecycle of cryptosporidium
- infects intestinal epithelial cells
- oocyst is infectious and diagnostic form
clinical disease of cryptosporidium
- asymptomatic to severe disease
- self limited (1-2 wk) enterocolitis
- watery diarrhea, dehydration, weight loss, ab pain, fever, N/V
- in AIDS pts, can shit up to 50 times a day
diagnosis of cryptosporidium
- acid fast staining
- pink is positive and green is negative
treatment of cryptosporidium
- replace fluids and electrolytes
- nitazoxanide for immunoCOMPETENT patients
- HAART therapy for AIDS patients
epidemiology of isospora belli
- humans are only known reservoir
- more prevalent in AIDS pts
- outbreaks are commonly seen in day cares and mental institutions
- fecal oral: mature oocysts ingested and reside in epithelium
clinical disease of isospora belli
- mimics giardiasis with malabsorption syndrome
- steatorrhea
diagnosis of isospora belli
- oocyst found in feces is elliptical
- cryptosporidium is round
- microscopic examination of iodine-stained stool smears
triad for isospora belli diagnosis
- acid fast staining
- malabsorption
- watery diarrhea
treatment for isospora belli
- TMP-SMX
characteristics of cyclospora cayetanensis
- resembles cryptosporidium excepts infects immunoCOMPETENT patients
- explosive watery diarrhea
- fecal contaminated water or food (raspberries or basil)
clinical disease of cyclospora cayetanensis
- low grade fever, fatigue, anorexia, abdominal pain, N/V
diagnosis of cyclospora cayetanensis
- stains acid-fast
- fluoresces blue under UV light
treatment of cyclospora cayetanensis
- TMP-SMX
latin name for pinworms
- enterobius vermicularis
common name for enterobius vermicularis
- pinworm
transmission of enterobius vermicularis (pinworm)
- fecal oral
- eggs are “sticky”
- eggs can be transmitted on fomites
- autoinfection occurs
- common in children 5-9 years old
clinical disease of enterobius vermicularis (pinworm)
- intense perianal itching at night
- prickling pain
- diarrhea during acute infection
- migrating worms may get lost: vaginal itching and granuloma formation
diagnosis of enterobius vermicularis (pinworm)
- cellophane (scotch) tape method
- only used for this type of worm
treatment for enterobius vermicularis (pinworm)
- mebendazole
latin name for roundworms
- ascaris lumbricoides
common name for ascaris lumbricoides
- roundworm
transmission of ascaris lumbricoides (roundworm)
- fecal oral
- contaminated food or water
- eggs can survive for months
lifecycle of ascaris lumbricoides (roundworm)
- ingest egg
- egg hatches and travels to liver, heart, lungs, etc.
clinical disease for ascaris lumbricoides (roundworm)
- dependent on number of eggs
- few eggs - asymptomatic
- early phase: large migrate to lungs producing fever, nonproductive cough, dyspnea, wheezing
- late phase: diffuse or epigastric pain, N/V, bolus can obstruct and perforate bowel
- can be lethal
diagnosis of ascaris lumbricoides (roundworm)
- CBC may show eosinophilia
- sputum may show larvae
- eggs in stool: knobby coated, oval shaped, bile stained
treatment for ascaris lumbricoides (roundworm)
- albendazole
- if pregnant then use pyrantel pamoate
toxocariasis (roundworm)
- dog and cat roundworms