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Flashcards in micro: protozoa Deck (13):
1

entamoaba histolytica

-> amebiasis: bloody diarrhea (dysentery), liver abscess (anchovy-paste exudate), RUQ pain, histology shows flask-shaped ulcer. transmission: cysts in water. Dx: serology and/or trophozoites (w/RBCs in cytoplasm) or cysts (up to 4 nuclei) in stool. Tx: flagyl; iodoquinol for ASx cyst passers

2

cryptosporidium

-> severe diarrhea in AIDS. mild dz in immunocompetent. transmission: oocysts in water. Dx: oocysts on acid-fast stain. PPx: filter city water; nitazoxanide for immunocompetent hosts

3

toxoplasma

congenital: classic triad: chorioretinitis, hydrocephalus, intracranial calcifications; reactivation in AIDS -> brain abscess = ring-enhancing lesions. transmission: cysts in meat, cat feces, crosses placenta. Dx: serology, Bx: tachyzoite. Tx: sulfadiazine + pyrimethamine

4

naegleria fowleri

-> rapidly fatal meningoencephalitis. transmission: swimming in freshwater lakes (think nalgene), enters via cribriform plate. Dx: amoebas in spinal fluid. Tx: ampho B (most die).

5

trypanosoma brucei

-> african sleeping sickness: LAD, recurring fever, somnolence, coma. transmission: tsetse fly: painful bite. Dx: blood smear. Tx: suramin for blood-borne, melarsoprol for CNS penetration. "it sure is nice when melatonin helps me sleep."

6

plasmodium

-> malaria: fever, h/a, anemia, splenomegaly. transmission: anopheles mosquito. Dx: blood smear: trophozoite ring form w/in RBC, schizont containing merozoites. Tx: chloroquine (blocks plasmodium heme polymerase). if resistant, use mefloquine or atovaquone/proguanil. if life-threatening, IV quinidine or artesunate (test for G6PD first).

7

P. vivax/ovale

48hr cycle (tertian; includes fever on 1st and 3rd days (48 hrs apart)), dormant form (hypnozoite) in liver so add Tx w/primaquine after testing for G6PD.
red granules (schuffner stippling) throughout RBC

8

P. falciparum

-> severe, irregular fever patterns; parasitized RBCs occlude capillaries in brain (cerebral malaria), kidneys, lungs

9

P. malariae

72hr cycle (quartan)

10

babesia

-> fever + hemolytic anemia, predominantly in NE US; asplenia -> inc. risk of dz. transmission: ixodes tick (same as borrelia), may often coinfect humans. Dx: blood smear: ring form, maltese cross, PCR. Tx: atovaquone + azithro

11

trypanosoma cruzi

chagas dz: dilated CM w/apical atrophy, megacolon, mesaesophagus, predominantly in SA. unilateral periorbital swelling (romana sign) characteristic of acute stage. transmission: reduviid bug = kissing bug feces, deposited in a painless bite. Dx: blood smear. Tx: benznidazole or nifurtimox

12

leishmania

-> visceral leishmaniasis (kala-azar): spiking fevers, HSM, pancytopenia. transmission: sandfly. Dx: macrophages containing amastigotes. Tx: ampho B, NA stibogluconate

13

trichomonas

cannot exist outside human b/c it cannot form cysts.