micr 10 protozoa

Question 1

Toxoplasma gondii

Protozoa—CNS infections

Answer 1

😗Immunocompetent: mononucleosis-like symptoms, ⊝ heterophile antibody test.
😗Reactivation in AIDS Ž brain abscesses usually seen as multiple ring-enhancing lesions on MRI ,
😗Congenital toxoplasmosis: classic triad of chorioretinitis, hydrocephalus, and intracranial calcifications.
Transmission,,
Cysts in meat (most common); oocysts in cat feces; crosses placenta (pregnant women should avoid cats)
treatmeN t,,Sulfadiazine + pyrimethamine

Question 2

Naegleria fowleri

Protozoa—CNS infections

Answer 2

Rapidly fatal meningoencephalitis
🌼 Swimming in warm freshwater enters via cribriform plate
Amoebas in CSF
Tx,, Amphotericin B has been effective for a few survivors

Question 3

Trypanosoma brucei

Protozoa—CNS infections

Answer 3

🌼 African sleeping sickness—enlarged lymph nodes, recurring fever (due to antigenic variation), somnolence, coma
🌼 Tsetse fly, a painful bite
🌼 Trypomastigote in blood smear D
🌼 Suramin for blood-borne disease or melarsoprol for CNS penetration (“I sure am mellow when I’m sleeping”; remember melatonin helps with sleep)

Question 4

Plasmodium

P vivax/ovale P falciparum P malariae
Disease🌞
Protozoa—hematologic infections

Answer 4

Malaria—fever, headache, anemia, splenomegaly
🤓P vivax/ovale—48-hr cycle (tertian; includes fever on first day and third day, thus fevers are actually 48 hr apart);
🤓dormant form (hypnozoite) in liver
🤓P falciparum—severe; irregular fever patterns; parasitized RBCs occlude capillaries in brain (cerebral malaria), kidneys, lungs
🤓P malariae—72-hr cycle (quartan)

Question 5

Plasmodium

P vivax/ovale P falciparum P malariae
Transmission,dx,tx

Answer 5

🦋Anopheles mosquito

🦋Blood smear: trophozoite ring form within RBC A , schizont containing merozoites; red granules (Schüffner stippling) B throughout RBC cytoplasm seen with P vivax/ovale

🦋Chloroquine (for sensitive species), which blocks Plasmodium heme polymerase; if resistant, use mefloquine or atovaquone/ proguanil If life-threatening, use intravenous quinidine or artesunate (test for G6PD deficiency) For P vivax/ovale, add primaquine for hypnozoite (test for G6PD deficiency)

Question 6

Babesia

Protozoa—hematologic infections

Answer 6

🍁Babesiosis—fever and hemolytic anemia; predominantly in northeastern United States; asplenia  risk of severe disease

🍁 transmission,,Ixodes tick (same as Borrelia burgdorferi of Lyme disease; may often coinfect humans)

Dx,,Blood smear:

Tx,,Atovaquone + azithromycin

Question 7

T. cruzi

Answer 7

Chagas disease—dilated cardiomyopathy with apical atrophy, megacolon, megaesophagus;
😲predominantly in South America Unilateral
😲periorbital swelling (Romaña sign) characteristic of acute stage
. Transmission,,Triatomine (“kissing”) bug, a type of reduviid bug, deposits feces in a painless bite (much like a kiss)

Dx,,Trypomastigote in blood smear A

Tx,,Benznidazole or nifurtimox; cruzing in my Benz, with a fur coat on

Question 8

Leishmania donovani

Answer 8

😗Visceral leishmaniasis (kala-azar)—spiking fevers, hepatosplenomegaly, pancytopenia
😗Cutaneous leishmaniasis—skin ulcers

Transmission,,Sandfly

Dx,,Macrophages containing amastigotes
Tx,,Amphotericin B, sodium stibogluconate

Question 9

Trichomonas vaginalis

Answer 9

😉Vaginitis—foul-smelling, greenish discharge; itching and burning;
😉do not confuse with Gardnerella vaginalis, a gram-variable bacterium associated with bacterial vaginosis

Transmission,, Sexual (cannot exist outside human because it cannot form cysts)

Dx,,Trophozoites (motile) D on wet mount; “strawberry cervix”
Tx,, Metronidazole for

patient and partner (prophylaxis)