Malaria/Plasmodium

Question 1

life cycle of plasmodium spp.

Answer 1

1. female anopheles mosquito transmits sporozoites during blood meal
2. sporozoites invade hepatocytes/develop into merozoites(1-4wks)
3. merozoites invade individual erythrocytes and mature into ring form(trophozoite)
4. trophozoites divide into schizonts(multi-nuclei)
5. schizonts burst, releasing several merozoites to infect more erythrocytes
   
   1. some diff. into male/female gametocytes
   2. p. ovale/p. vivax form hypnozoites that go hang in the liver

Question 2

var genes

Answer 2

large gene family encoding variable cytoadherence proteins on plasmodium infected RBC surface

bind endothelium; cause inflammation; sequestration

exclusive to p. falciparum

Question 3

differentiate blood/liver stage of malaria

Answer 3

liver stage is asymptomatic

blood stage (every 48hrs; 72 for p. malariae)

• destruction of RBC
• toxin mediated stimulation of TNF, cytokines, nitric oxide
• sequestration clogging up endothelials to brain, organs

Question 4

most susceptible population to malaria

Answer 4

children because they dont have mom’s immunity anymore and are naive to the disease

Question 5

presentation of uncomplicated malaria

Answer 5

• HA, myalgia, cough, diarrhea, ab pain,anorexia
• paroxysmal fever w/shaking chills
  
  • every 48hr; 72 for p. malariae
• anemai, hepatomegaly, jaundice

Question 6

presentation of severe malaria(p. falciparum)

Answer 6

severe anemia= Hgb < 5 mg/dl

cerebral malaria = AMS, seizures, rapid onset/recovery, brain swelling

other symptoms(sequestration):

Respiratory distress
Renal, hepatic, cardiac dysfunction, shock, DIC
Hypoglycemia, acidosis, fever

Question 7

complicationsof p. vivax/ p. ovale infection

Answer 7

can cause splenic rupture/chronic anemia

intermittent/prolonged illness

NO SEQUESTRATION

Question 8

diagnosis of malaria

Answer 8

Thick smear: blood cells are lysed; looking for plasmodium. answers “does this person have malaria?”

Thin smear: blood cells intact, very thin layer; answers “what species is this and how bad?”

Question 9

treatment of uncomplicated p. falciparum malaria

what to add if p. vivax(or ovale) is the spp.?

Answer 9

DONT USE SAME DRUG AS PROPHYLAXIS

ChloroquineArtemether-lumefantrine (CoArtem) is best option

add primaquine to kill hypnozoites after blood is treated with CoArtem if p. vivax spp.

Question 10

special considerations for primaquine use?

Answer 10

G6PD activity must be normal in liver

Question 11

treatment for SEVERE malaria(p. falciparum)

Answer 11

IV quinine or quinidine in intensive care setting

IV artesunate is superior, but only CDC available. it is used for quinine allergies/lack of reactivity