Emergency Central is a collection of disease, drug, and test information including 5-Minute Emergency Medicine Consult, Davis’s Drug, McGraw-Hill Medical’s Diagnosaurus®, Pocket Guide to Diagnostic Tests, and MEDLINE Journals created for emergency medicine professionals. Explore these free sample topics:
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- Protozoan infection transmitted through the Anopheles mosquito
- Incubation period 8–16 days
- Periodicity of the disease is due to the life cycle of the protozoan:
- Exoerythrocytic phase: Immature sporozoites migrate to liver, where they rapidly multiply into mature parasites (merozoites).
- Erythrocytic phase: Mature parasites are released into circulation and invade RBCs.
- Replication within RBCs followed 48–72 hr later by RBC lysis and release of merozoites into circulation, repeating cycle
- Fever corresponds to RBC lysis.
- Plasmodium falciparum:
- Cause of most cases and almost all deaths
- Usually presents as an acute, overwhelming infection
- Able to infect red cells of all ages:
- Results in greater degree of hemolysis and anemia
- Causes widespread capillary obstruction:
- Results in end-organ hypoxia and dysfunction
- More moderate infection in people who are on or who have recently stopped prophylaxis with an agent to which the P. falciparum is resistant
- Post-traumatic immunosuppression may cause relapse of malaria in patients who have lived in endemic areas.
- Plasmodium vivax and Plasmodium ovale:
- May present with an acute febrile illness
- Dormant liver stages (hypnozoites) that may cause relapse 6–11 mo after initial infection
- Plasmodium malariae:
- May persist in the bloodstream at low levels up to 30 yr
- Transmission usually occurs from the bite of infected female Anopheles mosquito.
- North American transmission possible:
- Anopheles mosquitoes on east and west coasts of US.
- Transmission may also occur through infected blood products and shared needles.
- Sickle cell trait protective
- Cerebral malaria more common in children
- In highly endemic areas with minimal lab capability, all children presenting with febrile illness may be treated.
Pregnant patients, especially primigravida, at higher risk