Chapter 248 MALARIA

Question 1

Responsible for nearly all deaths of malaria

Answer 1

Plasmodium falciparum

Question 2

merozoites then invade the red blood cells (RBCs) and multiply

Answer 2

six- to twentyfold every 48 h

(P. knowlesi, 24 h; P. malariae, 72 h).

Question 3

When the parasites reach densities of ~50/μL of blood or ____ the symptomatic stage of the infection begins.

Answer 3

(~100 million parasites in the blood of an adult),

Question 4

In ____ infec- tions, a proportion of the intrahepatic forms do not divide immediately but remain inert for a period ranging from 3 weeks to ≥1 year before reproduction begins.

Answer 4

P. vivax and P. ovale

Question 5

____, are the cause of the relapses that characterize infection with these two species.

Answer 5

hypnozoites

Question 6

The swollen infected liver cells eventually burst, discharging motile _____ into the bloodstream.

Answer 6

merozoites

Question 7

After entry into the bloodstream, merozoites rapidly invade erythrocytes and become ____.

Answer 7

trophozoites

Question 8

By the end of the intraerythrocytic life cycle, the para- site has consumed two-thirds of the RBC’s hemoglobin and has grown to occupy most of the cell. It is now called a ______.

Answer 8

schizont

Question 9

This zygote matures into an _____, which penetrates and encysts in the mosquito’s gut wall.

Answer 9

ookinete

Question 10

to transmit malaria, the mosquito must survive for___

Answer 10

> 7 days.

Question 11

potentially toxic heme is detoxified by lipid-mediated crystallization to biologically inert

Answer 11

hemozoin (malaria pigment)

Question 12

The processes of cytoadherence, rosetting, and agglutination are central to the pathogenesis of

Answer 12

falciparum malaria.

Question 13

Manifestation of severe falciparum malaria:

Answer 13

1. Unarousable coma or severe malaria
2. Acidemia or acidosis
3. Anemia
4. Renal failure
5. ARDS
   6: hypoglycemia
6. Hypotension
7. Bleeding
8. Convulsions

Question 14

Coma is a characteristic and ominous feature of falciparum malaria and, despite treatment, is associated with death rates of ~20% among adults and 15% among children.

Answer 14

Cerebral Malaria

Question 15

Most common funduscopic abnormalities include discrete spots of

Answer 15

retinal opacification (30–60%)

Question 16

Approximately ____% of children surviving cerebral malaria—especially those with hypoglycemia, severe anemia, repeated seizures, and deep coma—have residual neu- rologic deficits when they regain consciousness;

Answer 16

10%

Question 17

Chronic or repeated infections with P. malariae (and possibly with other malarial species) may cause soluble immune complex injury to the renal glomeruli, resulting in the nephrotic syndrome.

Answer 17

QuARTAN MALARIAL NEPHROPATHY

Question 18

The diagnosis of malaria rests on the demonstration of asexual forms of the parasite in stained

Answer 18

peripheral-blood smears.

Question 19

Repeat blood smears should be performed at least _____ for 2 days if the first smears are negative and malaria is strongly suspected.

Answer 19

every 12–24 h

Question 20

Treatment Known chloroquine- sensitive strains of Plasmodium vivax,
P. malariae, P. ovale, P. knowlesi,
P. falciparumb

Answer 20

Chloroquine (10 mg of base/kg stat followed by 5 mg/ kg at 12, 24, and 36 h or by 10 mg/kg at 24 h and
5 mg/kg at 48 h)

or

Amodiaquine (10–12 mg of base/kg qd for 3 days)

Question 21

Radical treatment for P. vivax or P. ovale infection

Answer 21

In addition to chloroquine or amodiaquine as detailed above,

primaquine (0.5 mg of base/kg qd in tropical regions and 0.25 mg/kg for temperate-origin P. vivax) should be given for 14 days to prevent relapse.
or
Artesunated (4 mg/kg qd for 3 days) plus amodiaquine (10 mg of base/kg qd for 3 days)e

Question 22

Sensitive
P. falciparum malaria treatment

Answer 22

Artesunated (4 mg/kg qd for 3 days) plus sulfadoxine (25 mg/kg)/pyrimethamine (1.25 mg/kg) as a single dose
Or
Artesunated (4 mg/kg qd for 3 days) plus amodiaquine (10 mg of base/kg qd for 3 days)

Question 23

Treatment for Multidrug-resistant P. falciparum malaria

Answer 23

Either artemether-lumefantrined (1.5/9 mg/kg bid for 3 days with food)
or
Artesunated (4 mg/kg qd for 3 days) plus mefloquine (24–25 mg of base/kg—either 8 mg/kg qd for 3 days or 15 mg/kg on day 2 and then 10 mg/kg on day 3)e
or
Dihydroartemisinin-piperaquined (2.5/20 mg/kg qd for 3 days)

Question 24

Second-line treat- ment/treatment of imported malaria

Answer 24

Either artesunated (2 mg/kg qd for 7 days) or quinine (10 mg of salt/kg tid for 7 days) plus 1 of the following 3:
1. Tetracyclinef (4 mg/kg qid for 7 days)
2. Doxycyclinef (3 mg/kg qd for 7 days)
3. Clindamycin (10 mg/kg bid for 7 days)
or
Atovaquone-proguanil (20/8 mg/kg qd for 3 days with food)

Question 25

Severe falciparum malaria

Answer 25

Artesunated (2.4 mg/kg stat IV followed by 2.4 mg/kg at 12 and 24 h and then daily if necessary)h

Question 26

remains a first-line treatment for the non-falciparum malarias (P. vivax, P. ovale, P. malariae, P. knowlesi) except in Indonesia and Papua New Guinea, where high levels of resistance in P. vivax are prevalent.

Answer 26

chloroquine

Question 27

World Health Organization (WHO) now recommends _____ as first-line treatment for uncomplicated falciparum malaria

Answer 27

artemisinin-based combinations (ACTs)

Question 28

has therefore become the drug of choice for all patients with severe malaria everywhere.

Answer 28

Artesunate

Question 29

total plasma concentrations of ___ for quinine and ____ for quinidine are effective and do not cause serious toxicity.

Answer 29

Quinine 8–15 mg/L

Quijidine 3.5–8.0 mg/L

Question 30

Infections due to sensitive strains of P. vivax, P. knowlesi, P. malariae, and P. ovale should be treated with

Answer 30

oral chloroquine (total dose, 25 mg of base/kg) or with an ATC known to be efficacious for UNCOMPLICATED MALARIA

Question 31

In areas with multidrug-resistant falciparum malaria (parts of Asia and South America, including those with mefloquine-resistant parasites; these regimens provide cure rates of >90%.

Answer 31

artemether-lumefantrine, artesunate-mefloquine, or dihydroartemisinin-piperaquine should be used;

Question 32

is the only drug advised for pregnant women traveling to areas with drug-resistant malaria; this drug is generally considered safe in the sec- ond and third trimesters of pregnancy, and the data on first-trimester exposure, although limited, are reassuring.

Answer 32

MEFLOQUINE

Question 33

Used for presumptive antirelapse therapy (terminal prophylaxis) to decrease risk of relapses of P. vivax and P. ovale

Answer 33

PRIMAQUINE

Question 34

For prevention of malaria in areas with mainly
P. vivax

Answer 34

PRIMAQUINE

Question 35

Prophylaxis in areas with chloroquine-resistant
P. falciparum

Answer 35

MEFLOQUINE

Question 36

An alternative to chloroquine for primary prophylaxis only in areas with chloroquine-sensitive P. falciparumc or areas with P. vivax only

Answer 36

Hydroxychloroquine sulfate (PLAQUENIL)

Question 37

Prophylaxis in areas with chloroquine- or mefloquine-resistant
P. falciparum

Answer 37

DOXYCYCLINE

Question 38

Prophylaxis only in areas with chloroquine-sensitive P. falciparumc or areas with P. vivax only

Answer 38

Chloroquine phosphate (Aralen and generic)

Question 39

Prophylaxis in areas with chloroquine- or mefloquine-resistant Plasmodium falciparum

Answer 39

Atovaquone- proguanil (Malarone)

Question 40

is a fixed-combination, once-daily prophylactic agent that is very well tolerated by adults and children, with fewer adverse gastrointestinal effects than chloroquine-proguanil and fewer adverse central nervous system effects than mefloquine.

Answer 40

Atovaquone-proguanil (Malarone; 3.75/1.5 mg/kg or 250/100 mg, daily adult dose)

Question 41

has been widely used for malarial prophylaxis because it is usually effective against multi- drug-resistant falciparum malaria and is reasonably well tolerated

Answer 41

Mefloquine (250 mg of salt weekly, adult dose)

Question 42

Daily administration of ____ is an effective alternative to atovaquone-proguanil or mefloquine and is generally well tolerated but may cause vulvovaginal thrush, diarrhea, and photosensitivity and cannot be used by children <8 years old or by pregnant women.

Answer 42

doxycycline (100 mg daily, adult dose)

Question 43

_____ taken with food), an 8-aminoquinoline compound, has proved safe and effective in the prevention of drug-resistant falciparum and vivax

Answer 43

Primaquine (daily adult dose, 0.5 mg of base/kg or 30 mg

Question 44

True or false

Children born to nonimmune mothers in endemic areas (usually expatriates moving to malaria-endemic areas) should receive prophylaxis from birth.

Answer 44

TRUE

Question 45

Travelers should start taking antimalarial drugs ____ before departure so that any untoward reactions can be detected and so that therapeutic antimalarial blood concentrations will be present when needed

Answer 45

2 days to 2 weeks

Question 46

Antimalarial prophylaxis should continue for 4 weeks after the traveler has left the endemic area, except if ____ has been taken; these drugs have significant activities against the liver stage of the infection

Answer 46

atovaquone-proguanil or primaquine

Question 47

chloroquine (a 4-aminoquinoline) act on the ____ stage of parasitic develop- ment

Answer 47

erythrocyte

Question 48

inhibitors also inhibit preerythro- cytic growth in the liver (causal prophylaxis) and development in the mosquito (sporontocidal activity).

Answer 48

dihydrofolate reductase

DHR

Question 49

Lumbar tap mean opening pressure

Answer 49

Approximately 180mmhg