Parasitic (M-O) Flashcards

1
Q

what is the causing agent of malaria?

A

genus Plasmodium;
Plasmodium falciparum;
P. malariae;
P. ovale;
P. vivax;
P. knowlesi (zoonotic form - Old World monkeys in SE Asia)

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2
Q

how does malaria transmit?

A

female Anopheles mosquito;
blood transfusion, needle sharing, nosocomially, organ transplantation, vertically from mom to fetus

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3
Q

in 2018, how many cases of malaria and death?

A

228 million;
405,000 deaths

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4
Q

what are the symptoms of severe malaria?

A

acute kidney injury, acute respiratory distress syndrome, mental confusion, seizures, coma, and death

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5
Q

incubation time of malaria?

A

7 days to several months or more

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6
Q

which species of malaria is a medical emergency?

A

p. falciparum - very rapid and unpredictable clinical deterioration

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7
Q

if i miss a weekly dose of malaria prevention pill more than 2 days, what to do?

A

take ASAP, then resume at this new day of the week schedule

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8
Q

if i miss 1-2 days of daily malaria prevention pill, what to do?

A

take ASAP, then resume the daily schedule at the new time of day

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9
Q

if a patient has malaria symptoms with travel history of malaria endemic area, what do you need to do?

A

malaria smea or a rapid diagnostic test first;
if test not available, empiric therapy ASAP

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10
Q

what is the most important method for malaria diagnosis and why?

A

blood smear microscopy;
immediate info about the presence of parasites, allow quantification of the density of the infection, allow determination of the species of the malaria parasite

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11
Q

when do you use rapid diagnostic test for malaria and what is the limitation?

A

when microscopy is not available;
RDT cannot distinguish between all Plasmodium species that affect humans, they might be less sensitive than expert microscopy or PCR for diagnosis, they cannot quantify parasitemia, it can be positive for days or weeks after an infection has been treated and cleared, cannot detect mutations (false-negative)

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12
Q

what is the limitation of PCR testing for malaria?

A

it is more sensitive than routine microscopy but results are not usually available as quickly as microscopy results

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13
Q

why does CDC not recommend halofantrine for malaria treatment?

A

adverse cardiac events, including death reported

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14
Q

why is sulfadoxine-pyrimethamine is not recommended for malaria treatment?

A

widespread drug-resistant Plasmodium

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15
Q

what are the self-treatment medicaions for malaria?

A

atovaquone-proguanil;
artemether-lumefantrine

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16
Q

what are the dose of atovaquone-proguanil for malaria treatment?

A

adult - 250/100 - 4 tabs daily single dose for 3 days
kids - 62.5/25
- 5-8kg 2 tabs
- 9-10kg 3 tabs
- 11-20kg 1 adult tabs
- 21-30kg 2 adults tabs
- 31-40kg 3 adult tabs
- >41 kg 4 adult tabs

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17
Q

what are the contraindication of atovaquone-proguanil?

A

with severe renal impairment (creatinine clearnace <30 ml/min)

kids <5kg
pregnancy
breastfeeding infants weighing <5kg

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18
Q

what is the treatment dose for artemether-lumefantrine?

A

artemeter 20mg
lumefantrine 120mg

weight-based for kids and adults;
5-14kg 1 tablet per dose
15kg-24kg 2 tablets per dose
25-34kg 3 tablets per dose
>35kg 4 tablets per dose

0, 8 hour dose; then bid for next 2 days (total 6 doses over 3 days)

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19
Q

what are the contraindication of artemether-lumefantrine?

A

not recommended for people taking mefloquine prophylaxis;
kids <5kg
breastfeeding infants <5kg

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20
Q

who is at the greatest risk for malaria?

A

first- and second-generation immigrants living in nonendemic countries who return to their countries of origin to visit friends and relatives

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21
Q

when does the malaria transmission (mosquito bite) occur primarily?

A

between dusk and dawn (night)

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22
Q

what are the good reasons to take chloroquine for malaria prevention?

A

weekly dosing;
good for long trip;
already taking hydroxychloroquine for rheumatologic conditions;
ok in all trimesters of pregnancy

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23
Q

what is the downside of chloroquine for malaria prevention?

A

chloroquine or mefloquine resistance - cannot be used;
can exacerbate psoriasis;
4 weeks after trip;
need to start 1-2 weeks before travel

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24
Q

what infections can doxycycline prevent other than malaria?

A

rickettsial infections;
leptospirosis;
good if camping, hiking, swimming in fresh water where risk is high

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25
what is the downside for taking doxycycline for malaria prevention?
pregnancy or breastfeeding; kids <8 years; prone to get vaginal yeast infections; sun sensitivity; stomach upset
26
when can you not do mefloquine for malaria prevention?
if mefloquine-resistant Plasmodium spp; patients with psychiatric conditions; seizures; not recommended if cardiac conduction abnormalities; need to start 2 weeks before, weekly dosing; need to continue 4 weeks after
27
when can you use primaquine for malaria prevention?
if P. vivax - if area is >90% P. vivax; good for last minute travelers - 1-2 days before, 7 days after; daily taken
28
who cannot take primaquine?
with G6PD deficiency; cossts and delays associated with getting a quantitative G6PD test might prohibit testing; pregnant & breastfeeding (unless the infant has also been tested for G6PD); upset stomach
29
when can you use tafenoquine?
area with P. vivax, but also P. falciparum; good choice for shorter trip - take one dose 1 week after the trip; last-minute trip- start 3 days before travel
30
when cam you not do tafenoquine?
pt with G6PD deficiency; cannot be used by kids, pregnancy, breastfeeding (unless infant is not G6PD def), psychotic disorder
31
if you travel longer than 6 months, what do you need to consider for malaria prevention?
same!!
32
what is drug interaction between proguanil and warfarin?
increase the effect of warfarin
33
what is the dose of chloroquine for malaria prevention?
adult - 300mg base (500mg salt) once weekly; kids - 5mg/kg base (8.3mg/kg salt); 1-2 weeks before, 4 weeks after
34
what is the dose of doxycycline for malaria prevention?
100mg qd; 8 years and up - 2.2mg/kg; 1-2 days before, 4 weeks after
35
what is the dose of hydroxychloroquine for malaria prevention?
310mg (400mg salt) once weekly; 5mg/kg (6.5mg/kg salt) once weekly; 1-2 weeks before, 4 weeks after
36
what is the dose of mefloquine for malaria prevention?
228mg (250mg salt) once weekly; 1-9kg: 4.6mg/kg base (5mg/kg salt) 10-19kg: 1/4 tablet 20-30kg: 1/2 tablet 31-45kg: 3/4 tablet >45kg: 1 tabet 2 weeks before, 4 weeks after
37
who should not take mefloquine?
allergic to mefloquine or related compounds (quinidine, quinine); active depression, hx of depression, generalized anxiety disorder, psychosis, schizophrenia, other major psychiatric disorders, seizures; ppl with cardiac conduction abnormalities;
38
what is the dose of primaquine for malaria prevention?
adult: 30mg base (52.6mg salt) daily kids: 0.5mg/kg base (0.8mg/kg salt) 1-2 days before, 7 days after;
39
what are the side effects of chloroquine and hydroxychloroquine?
blurred vision, dizziness, GI disturbance, headache, insomnia, pruritus - do not require to discontinue drug high dose chloroquine - retinopathy (serious very rare) take with meals
40
when patient received Ty21a vaccine, when can you start doxycycline for malaria prevention?
Ty21a completion, then after 24 hours, start doxycycline
41
what can happen if you take primaquine when you have G6PD deficiency?
life-threatening hemolysis!
42
what is terminal prophylaxis?
presumptive antirelapse therapy - indicated for long-term travelers with prolonged exposure to P. ovale or P. vivax malaria. take primaquine toward the end of the exposure period for the presumptive purpose of eliminating hypnozoites (dormnt liver stages) of P. ovale or P. vivax, thereby preventing relapses or delayed -onset clinical presentations of malaria.
43
how many days of primaquine for terminal prophylaxis?
take for 14 days after leaving a malaria-endemic area, concurrently with their primary prophylaxis medication. -chloroquine, doxycycline, mefloquine: prescribe primaquine to take during the last 2 weeks of postexposure prophylaxis -atovaquone-proguanil: take primaquine during the final 7 days of atovaquone-proguanil, and then for an additional 7 days.
44
what is the dose of tafenoquine for primary prophylaxis?
100mg daily for 3 days before leaving; then weekly while in the malaria-endemic area; final dose in the week after leaving the malaria-endemic area
45
what is the contraindication of tafenoquine?
pregnancy & breastfeeding; psychotic disorder;
46
what malaria prophylaxis is recommended for pregnancy?
chloroquine or hydroxychloroquine; mefloquine
47
what malaria prophylaxis is recommended for infants & breastfeeding moms?
chloroquine and mefloquine
48
which malaria causing species is chloroquine-resistant?
P. falciparum - all parts of the world except the Caribbean and countries west of the Panama Canal
49
where is P. falciparum predominates?
in Africa; but also found in South America and Asia
50
where is chloroquine-resistant P. vivax has been confirmed in?
Papua New Guinea and Indonesia
51
where are the areas with choloroquine-sensitive Plasmodium spp?
many Latin American countries where malaria predominantly is caused by P. vivax; chloroquine sensitive P. falciparum is present in the Caribbean and Central American countries west of the Panama Canal.
52
where is mefloquine-resitant P. falciparum has been confirmed in?
Southeast Asia on the borders of Thailand with Burma (Myanmar) and Cambodia, in the western provices of Cambodia, in the eastern states of Burma on the obrder between Burma and china, along the borders of Burma and Laos, and in southern Vietnam.
53
if you need to stop atovaquone-proguanil due to side effect, what are other options?
doxycycline; primaquine (only if normal G6PD); note - choloroquine, mefloquine, tafenoquine not recommended.
54
if you need to stop chloroquine due to side effect and there are 3 more weeks left to departure from a malaria-risk area, and want to switch to Atov-prog, how to do that?
take AP once daily and 7 days after leaving the area
55
if you need to stop chloroquine due to side effect and there are less than 3 weeks left to departure from a malaria-risk area, and want to switch to Atov-prog, how to do that?
take AP once daiy at least 4 weeks more after the switch.
56
if you need to stop chloroquine due to side effect and you already left the risky area, and want to switch to Atov-prog, how to do that?
take AP once daily for 4 weeks after leaving the area
57
can you swith chloroquine to doxycyline?
yes
58
can you switch chloroquine to mefloquine?
no
59
can you switch chloroquine to primaquine?
yes only if they are G6PD normal. and areas with mainly P. vivax. once daily and additional 7 days after leaving the area
60
can you switch chloroquine to tafenoquine?
yes only if they are G6PD normal. tafenoquine once daily for 3 days, then once weekly while still in the area. 1 final dose during the week after leaving the endemic area
61
which one can you switch from doxycycline if there is side effect for malaria prevention?
AP (same protocol as chloroquine switch); primaquine
62
if mefloquine is needed to stop due to side effect, what other drugs can you do for malaria prevention?
AP; doxycyline; primaquine; fafenoquine
63
if primaquine is needed to stop due to side effect, what other drugs can you do for malaria prevention?
AP (once daily then 7 days after) ; doxycycline
64
if tafenoquine is needed to stop due to side effect, what other drugs can you do for malaria prevention?
AP(once daily then 7 days after); doxycycline
65
how long do you need to wait to donate blood after traveling to malaria enedmic areas?
3 months
66
how long do you need to wait to donate blood if you are former resident of malaria-endemic areas or if you are diagnosed with malaria?
3 years
67
waht causes onchocerciasis (river blindness)?
Onchocerca volvulus - filarial nematode
68
how does river blindness, or onchocerciasis, transmit?
female blackfly (genus Simulium) bites - bite during the day and breed near rapidly flowing rivers and streams
69
where is onchocerciasis endemic to?
sub-Saharan Africa; Arabian Peninsula (Yemen) and in Americas (Brazil and Venezuela); mostly rural, near rapidly flowing water
70
what are the symptoms of onchocerciasis?
highly pruritic, papular dermatitis; subcutaneous nodules; lymphadenitis; ocular lesions - lead to vision loss and blindness
71
how to diagnose onchocerciasis?
skin snip biopsy; by identifying adult worms in histologic sections of excised nodules or characteristic eye lesions; serologic testing; serum filarial antibody
72
how to treat onchocerciasis?
ivermectin - only kills the microfilariae but not the adult worms - might require repeated annual or semiannual doses
73
some experts recommend treating onchocerciasis with 1 dose of ivermectin, then 6 weeks of doxycycline. why?
to kill Wolbachia, and endosymbiotic rickettsia-like bacterium that appears to be required for the survival of the O. volvulus adult worm and for embryogenesis.
74
when you treat someone with ivermectin, what do you need to consider as the risk?
risk for co-infection with Loa loa - due to risk of loa loa-related fatal post-treatment reactions associated with ivermectin
75
what is contraindicated as a treatment for onchocerciasis?
diethylcarbamazine - leads to microfilarial death and, in some cases, systemic reactions associated with an increased risk for causing blindness in some patients with eye disease.
76