Protozoa

Question 1

Giardia lamblia

Answer 1

Ingest Cysts, trophozoites mature and decrease absorption

Foul smelling, bloating, burping, flatulence, fatty diarrhea.

Dx: O&P of stool

Tx: Metronidazole

Question 2

Entamoeba histolytica

Answer 2

Amebiasis: Bloody diarrhea, liver abscess "anchovy paste"
RUQ pain (flask shaped ulcer if submucosal abscess ruptures in colon)

Dx: Serology and/or RBCs in the cytoplasm or cysts (up to 4 nuclei) in stool

Tx: Metronidazole

Idoquinol for asymptomatic cyst passers

Transmitted by cysts in water

Question 3

Flask shaped ulcer

Answer 3

Entamoeba histolytica

Question 4

Anchovy paste abscess

Answer 4

Entamoeba histolytica

Question 5

Perforated colon

Answer 5

Entamoeba histolytica

Question 6

Cryptosporidium

Answer 6

Severe diarrhea in aids. Mild/water diarrhea in immunocompetent (self limited)

Oocysts in water = Transmission

Dx: oocyst on acid fast stain of stool

Prevent w filtering.

Nitazoxanide in immmunocompetent

Chlorine won’t work, but filtering does

Question 7

Toxoplasma gondii

Answer 7

#1 protozoal infection in US
TORCH, crosses placenta

Brain abscess in HIV
RING ENHANCING BRAIN LESIONS

Congenital Toxo: Triad: Chorioretinitis, hydrocephalus, intracranial calcifications.

Transmitted by cysts in meat, or oocysts in cats
Cats are reservoir.

Pregnant women should avoid. Crosses placenta

Dx; Serology and Biopsy

Tx: Sulfadiazine and pyrimethamine

Question 8

Prevent w/ filtering, but not chlorination

Answer 8

Cryptosporidium

Question 9

Chorioretinitis, hydrocephalus and intracranial califications

Answer 9

Congenital Toxo

Question 10

Ring enhancing brain lesions

Answer 10

Toxo in HIV

Question 11

Oocysts from cats and cysts for meat

Answer 11

Toxo

Question 12

Naegleria fowleri

Answer 12

Rapidly fatal meningoencephalitis

Freshwater. Via Cribiform plate

Dx: amoebas in CSF

Tx: AMphotericin B

Question 13

Trypansoma brucei

Answer 13

African sleeping sickness

Enlarged lymph nodes
Recurring fever (antigenic variation), somnolence, coma

Tstse fly. painful bight

Dx: long whispy blood smear

Suramin for blood borne disease/early

Melarsoprol for CNS penetration

Question 14

Plasmodium vivax/ovale

Answer 14

Malaria: Fever, headache, anemia, splenomegaly

Transmitted by Anopheles

Vivax/ovale: 48hr cycle fever.

Hypnozoites in liver –> Primaquine

DX: Blood smear: trophozoite ring withing RBC

Shizont w/ merozoites

Tx: Chloroquine (blocks heme polymerase)

Mefloquine or Atovaquone/proguanil if resistant

QUinidine if severe

Artemisinin and Lumefantrine (CoArtem)

Question 15

P. falciparum

Answer 15

Malaria: Fever, headache, anemia, splenomegaly.

Severe irregular fever. Parasitized RBCs, occlude capillaries in brain, kidney, lungs

Severe. more likely to require quinidine

Banana (gamete) is Diagnostic

Artemisinin and Lumefantrine (CoArtem)

Question 16

P. malariae

Answer 16

Malaria: Fever, headache, anemia, splenomegaly

Chloroquine –> Mefloquine or Atovaquone/proguanil.

Qunidine if severe

Artemisinin and Lumefantrine (CoArtem)

Question 17

Babesia

Answer 17

Transmitted by Ixodes

Fever, hemolytic anemia

INcrease severity w/ asplenia

Maltese cross is Dx. also can have ring form

Tx: atovaquone and azithromycin

Clinda and quinine if severe

Question 18

Tsetse Fly

Answer 18

Trypansoma brucei,

painfull bight

Question 19

Reduviid bug

Answer 19

Trypansoma cruzi

Painless bight

Question 20

Trypansoma cruzi

Answer 20

Chagas: Cardiomyopathy, megacolon, megaesophagues

Reduviid bug, painless. Transmitted when scratched in

Dx: blood smear

Tx; Benzidazole or nifurtimox (from CDC)

Question 21

Leshmania donvani

Answer 21

Visceral Leishmaniasis: Spiking fevers, hepatosplenmegaly, pancytopenia

Or Cutaneous

Visceral if immunocompromized usually

Transmitted by sanflies

Macrophages contain amastigotes

Tx: Amphotericin B (visceral)
Sodium stibogluconate (cutaneous)

Question 22

Trchomonas vaginalis

Answer 22

Vaginitis: foul-smelling, greenish, itching, burning.

Transmitted sexually. only found in humans, no cysts

Trophozoites on wet mount and strawberry cervix

tx: Metronidazole, and for partner

Increase pH

Flagella