Parasitology

Question 1

Protozoa GI infection

Answer 1

giardia lamblia, E. histolytica, cyrptosporidium

Question 2

What disease is caused by giardia infection? Transmission? treatment?

Answer 2

giardiasis: bloating, flatulance, foul-smelling fatty diarrhea. often seen in campers and hikers.
transmitted by cysts in water
tx: metronidazole

Question 3

What disease is caused by E. histolytica? transmission? treatment?

Answer 3

amebiasis: bloody diarrhea, liver abscesses (anchovy paste), RUQ pain with flash shaped ulcer if submucosal abscesses of colon rupture.
transmitted by cysts in water. tx: metronidazole. iodoquinol for asymptomatic cyst passers

Question 4

Dx of Giardia

Answer 4

trophozoites or cysts in stool

Question 5

Dx of E. histolytica

Answer 5

serology and/or trophozoites with RBCs in the cytopmaslm or cysts with up to 4 nuclei in the stool

Question 6

What disease is caused by cryptosporidium? transmission? treatment?

Answer 6

severe diarrhea in AIDS. mild disease in immunocompetent. transmitted by oocysts in water. tx: prevention, nitazoxanide in immunocompetent

Question 7

What are the CNS protozoa parasites?

Answer 7

toxoplasma gondii, naegleria fowleri, trypansoma brucei

Question 8

Toxoplasma gondii: diseases

Answer 8

brain abscesses in HIV (ring enhancing). or, congenital infection: chorioretinitis, hydrocephalus, intracranial calcifications

Question 9

transmission, dx, and tx of toxoplasma

Answer 9

cysts in meat or oocytes in cat feces. crosses placenta.
dx: serology or biopsy showing tachyzoite.
Tx: Sulfadiazine (folate inhibitor) with pyrimethamine

Question 10

Naegleria fowleri: disease

Answer 10

rapidly fatal meningoencephalitis

Question 11

Naegleria fowleri: transmission, diagonsis, and treatment

Answer 11

swimming in freshwater lakes. enters via cribiform plate
Dx: amoebas in spinal fluid
Tx: very few survivors, but try amphotericin B

Question 12

Trypanosoma brucei disease

Answer 12

African sleeping sickness. casues relapsing/remitting fever d/t antigenic variation, LAD, somnolence, coma

Question 13

Transmission of brucei disease

Answer 13

tsetse fly

dx: blood smear
tx: Suramin for blood-borne disease or melarsoprol for CNS penetration

Question 14

Characteristics of malaria

Answer 14

fever, headache, anemia, splenomegaly

Question 15

Differentiating btw P. vivax, ovale, falciparum, malariae

Answer 15

P. vivax/ovale: 48 hr cycle with dormant form in liver
P. falciparum- severe, irregluar fever patterns with parasitized RBCs occluding capallaries in the brain, kidneys, and lungs
P malariae: 72 hr cycle

Question 16

Dx of malaria

Answer 16

blood smear showing trophozoite ring form within RBCs or schizont containing merozoites

Question 17

Treamtnet for malaria

Answer 17

chloroquine, which blockes heme polymerase. if resistant, use mefloquine or atovaquone/proguanil
if life threatening, use qunidine after testing for G6PD deficiency
vivax and ovale: ad primaquine for the hypnozoite. test for G6PD deficiency

Question 18

Babesia disease

Answer 18

fever and hemolytic anemia in NE US. Asplenia is a risk for severe disease

Question 19

Babesia transmission

Answer 19

Ixodes tick (just like for lyme disease).

Question 20

Dx and Tx for babesia

Answer 20

blood smear, ring forms or maltese cross. PCR. treat with atovaquone and azitrhomycin