Chapter 248 MALARIA Flashcards
Responsible for nearly all deaths of malaria
Plasmodium falciparum
merozoites then invade the red blood cells (RBCs) and multiply
six- to twentyfold every 48 h
(P. knowlesi, 24 h; P. malariae, 72 h).
When the parasites reach densities of ~50/μL of blood or ____ the symptomatic stage of the infection begins.
(~100 million parasites in the blood of an adult),
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.
P. vivax and P. ovale
____, are the cause of the relapses that characterize infection with these two species.
hypnozoites
The swollen infected liver cells eventually burst, discharging motile _____ into the bloodstream.
merozoites
After entry into the bloodstream, merozoites rapidly invade erythrocytes and become ____.
trophozoites
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 ______.
schizont
This zygote matures into an _____, which penetrates and encysts in the mosquito’s gut wall.
ookinete
to transmit malaria, the mosquito must survive for___
> 7 days.
potentially toxic heme is detoxified by lipid-mediated crystallization to biologically inert
hemozoin (malaria pigment)
The processes of cytoadherence, rosetting, and agglutination are central to the pathogenesis of
falciparum malaria.
Manifestation of severe falciparum malaria:
- Unarousable coma or severe malaria
- Acidemia or acidosis
- Anemia
- Renal failure
- ARDS
6: hypoglycemia - Hypotension
- Bleeding
- Convulsions
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.
Cerebral Malaria
Most common funduscopic abnormalities include discrete spots of
retinal opacification (30–60%)
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;
10%
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.
QuARTAN MALARIAL NEPHROPATHY
The diagnosis of malaria rests on the demonstration of asexual forms of the parasite in stained
peripheral-blood smears.
Repeat blood smears should be performed at least _____ for 2 days if the first smears are negative and malaria is strongly suspected.
every 12–24 h
Treatment Known chloroquine- sensitive strains of Plasmodium vivax,
P. malariae, P. ovale, P. knowlesi,
P. falciparumb
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)
Radical treatment for P. vivax or P. ovale infection
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
Sensitive
P. falciparum malaria treatment
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)
Treatment for Multidrug-resistant P. falciparum malaria
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)
Second-line treat- ment/treatment of imported malaria
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)
