NBME 22 Reduviid bug (NBME Answers)

Retired NBME 22 Answers

nbme22/Block 2/Question#23 (reveal difficulty score)
A 32-year-old woman comes to the physician ...
Reduviid bug 🔍 / 📺 / 🌳 / 📖
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submitted by ∗usmleuser007(464)

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Arthropod infections

a. Trypansoma cruzi = reduviid bug

b. Trypanosoma brucei = Tsetse fly

c. Malaria = Anopheles mosquito

d. Flavivirus Group (West Nile Virus, Dengue) = Aedes mosquito

e. Microfilariae = black fly

f. Leishmania braziliensis = sand fly

g. Borrelia & Babesia =Ixodes tick

h. Rickebsia rickebsii & Francisella tularensis = Dermacentor tick

i. Rikebsia prowazekii = lice

j. Loa loa (African eye worm) = deer fly

k. Wuchereria bancrofti = mosquitoes

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zoek816 West Nile Virus = Culex +1

imgdoc Add anaplasma to Ixodes tick. Loa Loa is also mango fly, horse fly. +

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submitted by biliarytree220(13)

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Chagas disease, trypomastigote on blood smear; cardiomyopathy, predominantly found in South America

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submitted by ∗pg32(218)

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How did anyone get this as T cruzi? That was literally the first answer I ruled out. She has swelling of the eye, but that is the only sx that fits. Chagas presents 10-20 years after initial infection, not two weeks later. It also doesn't present with recurrent fever, muscle aches and joint pain. I mostly ruled it out because of the time course.

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castlblack I made the same mistake. Tsetse flies only exist in africa. African sleeping sickness is named well. Chagas is only in south america/central. Leishmaniasis is found on both continents. +

medjay7 The clinical presentation confused as hell, but I could recognize that Trypomastigote anywhere and definitely was not African sleeping sickness. +2

usmleboy She has the swelling of the eye, edema, and chest pain. T cruzi causes dilated cardiomyopathy (chest pain and edema), and the eye swelling (Romana sign) is pretty buzzwordy for Chagas. Also it looks like a trypanosome. +1

an1 -Acute: nonspecific S/S (fever, malaise, anorexia), inflammataion/ swelling at site of innoculation (chagoma), swelling around eye (Ramona) +

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submitted by ∗asharm10(37)

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Unilateral periorbital swelling acute stage of chagas disease

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ankigravity Known as Romaña sign +

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submitted by drbravojose(7)

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FA 2019 p156 Does anyone know how to differentiate the picture labeled Trypanosoma brucei and cruzi?

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footballa This question is likely not important for two reason: They're both Trypansomastigotes, so of course they look almost the same. You can differentiate these two species clinically as they have very little clinical similarity in patient presentation. For these reasons there's little to no reason you would be expected to differentiate these two species by histology alone +2

snripper Does Chagas have recurrent fever? Because that's what pointed me to African Sleeping Sickness. +

baja_blast The history of travel to the Amazon is what pointed me to Cruzi over Brucei but agree it's a tough distinction to make here. In the absence of that detail I would have probably picked Tsetse fly. +1

ankigravity The trypamastigote on blood smear eliminates all answers except Reduviid bug and Tsetse fly. The fact that she has a cardiomyopathy with recent travel makes Reduviid bug the winner. If she had neuro issues and slipped into a coma following travel to Africa, I would've chosen Tsetse fly. +

-3 upvote downvote
submitted by ∗usmleuser007(464)

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16. Arthropod infections 
    a. Trypansoma cruzi = reduviid bug
    b. Trypanosoma brucei = Tsetse fly
    c. Malaria = Anopheles mosquito
    d. Flavivirus Group (West Nile Virus, Dengue) = Aedes mosquito
    e. Microfilariae = black fly
    f. Leishmania braziliensis = sand fly 
    g. Borrelia & Babesia =Ixodes tick 
    h. Rickebsia rickebsii & Francisella tularensis = Dermacentor tick 
    i. Rikebsia prowazekii = lice 
    j. Loa loa (African eye worm) = deer fly 
    k. Wuchereria bancrofti = mosquitoes

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