Protozoa Flashcards
cryptosporidium
causes chronic, watery diarrhea in AIDS patients
transmitted by oocysts in water or person-to-person
filtration removes oocysts from water
diagnose with acid fast stain of stool
giardia lamblia
hikers get this from drinking stream water.
ingested cysts turn into trophozoites that interfere with fat absorption, leading to
- acute, fatty, foul- smelling diarrhea
- flatulence
- abdominal bloating
look for pear-shaped trophozoites (owl’s eye) or cysts in stool
treat with metronidazole
entameoba histolytica
amebiasis leading to bloody diarrhea "amoebic dysentery" invades colon -tissue damage can perforate the colon -you may see flask- shaped ulcers
liver abscesses lead to RUQ pain
fecal- oral tranmission
Dx: serology
or, trophozoites (with RBC in cytoplasm) or cysts (up to 4 nuclei each) in stool
Treat:
metronidazole or tinidazole for trophozoites
iodoquinol and paromomycin for cysts
GET GAP on the Metro
Giardia Entamoeba Trichomonas Gardnerella vaginalis Anaerobic bacteria Pylori (H. pylori)
Trichomoas vaginalis
Foul- smelling discharge
Flagella
Flagyl (metronidazole)
most common protozoal infection in US.
vaginitis, foul- smelling greenish vaginal discharge
increases pH of the vagina
- sexually transmitted
- trophozoites with flagella can be seen on wet mount (strawberry cervix)
metronidazole (Flagyl)
Toxoplasma gondii
common protozoal infection, with cats as the primary host
handling cat feces or litter
cysts in infected meat
brain abcess in HIV- infected patients
congenital infection:
chorioretinitis
hydrocephalus
intracranial calcifications
dx: serology
biopsy (ddx: primary CNS lymphoma)
treatment: sulfadiazine + pyrimethamine +folinic acid
triad of symptoms in congenital toxoplasma gondii infection
chorioretinitis
hydrocephalus
intracranial calcifications
avoid cleaning litter boxes while pregnant
naegleria fowleri
causes rapidly fatal meningoencephalitis, rapidly fatal
transmission is usually from swimming in freshwater lakes
enters brain from cribriform plate
treatment: amphotericin B, but usually the patient dies before treatment is possible
Trypanosoma brucei rhodesiense (Zimbabwe)
trypanosoma brucei gambiense (W Africa)
African sleeping sickness
transmitted through tsetse fly (painful fly bite)
bloodstream infection:
- fever
- enlarged lymph nodes
- somnolence
late stage infection involves the CNS and causes encephalitis, coma, death
dx: blood smear
Treatment: Suramin for blood-borne disease
Melarsoprol for CNS penetration (it Sure is nice to go to sleep; melatonin helps with sleep)
Trypanosoma cruzi
causes Chagas South America reduviid bug -painless bite -feces scratched into skin
symptoms:
- dilated cardiomyopathy
- megaesophagus
- megacolon
diagnosis:
blood smear
treatment:
benznidazole
nifurtimox
Leishmania donovani
visceral leishmaniasis
cutaneous leishmaniasis
-ulcerating papules that are slow to heal
Treatment: sodium stiboglyconate
transmitted via sandfly
dogs and mammals can be reservoirs
clinical features:
spiking fevers
hepatosplenomegaly
pancytopenia
dx:
amastigotes inside macrophages
tx: liposomal amphotericin B
Malaria
pasmodium
p. vivax/ovale (48 hr cycle)
p. falciparum
p. malariae (72 hr cycle)
anopheles mosquito cyclic symptoms (eg fever), occur when RBCs rupture and release merozoites
fever
HA
anemia
splenomegaly
dx: trophozoites, merozoites, gametocytes
p.vivax/ovale (48 hr cycle)
dormant infection in liver
tx. primaquine
p.falciparum
most severe form
no dormant form
can cause sequestration of RBCs leading to occlusion of small vessels
cause of malaria
plasmodium species
