Malaria

Background
Malaria vector: Anopheles stephensi mosquito.
Distribution of malaria in the world (2010; see CDC website for current distribution):[1] ♦ Elevated occurrence of chloroquine- or multi-resistant malaria
♦ Occurrence of chloroquine-resistant malaria
♦ No Plasmodium falciparum or chloroquine-resistance
♦ No malaria
The life cycle of malaria parasites.
  • Caused by parasitic protozoa species of the genus Plasmodium (P ovale, P vivax, P malariae, P knowlesi, and P falciparum) carried by the Anopheles mosquito
    • P falciparum most severe
  • Failure to consider for febrile illness following travel, even if seemingly temporally remote, can result in significant morbidity or mortality, especially in children and pregnant or immunocompromised patients
  • Chemoprophylaxsis does not guarantee protection
  • CDC Malaria Hotline: 770-488-7788
  • Malaria is a US nationally notifiable disease and all cases should be reported
  • Malaria vaccine with ~30% efficacy will be piloted in African countries in 2018, study to assess pediatric mortality[2]

Traveler Precautions

The CDC recommends travelers to malaria-endemic regions take the following precautions:[3]

  • Chemoprophylaxis
  • Use of insecticide-treated bed nets
  • Use of DEET-containing insect repellents
  • Wear long-sleeve shirts and pants

Clinical Features
Different fever patterns observed in Plasmodium infections.
Child with malaria.
  • Fever + exposure to endemic country
    • Cyclic fever only after chronic infection
  • Headache, cough, GI symptoms

Classification

Severe

  • Any one of the following:
    • Altered mental status/coma
    • Severe normocytic anemia [hemoglobin < 7]
    • Renal failure
    • ARDS
    • Hypotension
    • DIC
    • Spontaneous bleeding
    • Acidosis
    • Hemoglobinuria
    • Jaundice
    • Hepatomegaly
    • Splenomegaly
    • Repeated generalized seizures
    • Parasitemia >5%

Uncomplicated

  • None of the above

Differential Diagnosis

Fever in traveler

Evaluation
Ring-forms and gametocytes of Plasmodium falciparum in human blood
  • First smear positive in >90% of cases (thick and thin Giemsa stain)
    • If initial negative, must be repeated BID x 2-3 days for proper exclusion of malaria
    • Determines degree of parasitemia and type (e.g. P. falciparum)
  • Additional lab findings

Management
  • Mixed infections involving more than one species of Plasmodium may occur in areas of high endemicity (have a low threshold for including treatment for P falciparum)[4]
  • Hyponatremia in the setting of hypovolemia does not require treatment beyond rehydration
  • Treat hypoglycemia
  • Check HIV status (coinfection can lead to worse clinical outcomes)
  • Exchange transfusion for patients with:
    • P falciparum malaria with a parasitemia greater than 10%
    • Life-threatening complications (ie, coma, respiratory failure, coagulopathy, fulminant kidney failure)
For specific dosing see the CDC Recommendations or call the Malaria CDC Hotline(855) 856-4713

Uncomplicated Malaria
  • Uncomplicated:
    • No evidence of organ dysfunction
    • Parasitemia <5%
    • Able to tolerate PO
  • Hospitalize:
    • Severe clinical manifestations in non-immune host for P. falciparum or P. knowlesi
  • Report to state health department
  • For non-pregnant patients (3 day course)
    • Artemether + lumefantrine
    • Artesunate + amodiaquine
    • Artesunate + mefloquine
    • Dihydroartemisinin + piperaquine
    • Artesunate + sulfadoxine–pyrimethamine (SP)
  • For pregnant (1st trimester)
  • Additional considerations
    • Avoid artesunate + SP in HIV/AIDS patients taking co-trimoxazole
    • Avoid artesunate + amodiaquine in HIV/AIDS patients taking efavirenz or zidovudine

Severe Malaria
  • Do not delay treatment in the unstable patient if strong suspicion for malaria as initial smear may be falsely negative
  • Treatment (IV for ≥24 hours then 3 days PO course)
    • Artesunate (IV)
      • Clears malaria faster than quinine
      • Distributed only through CDC
    • Quinidine (IV) also appropriate choice; more available in US

Cerebral Malaria
  • Insufficient evidence for or against giving antiepileptics
  • For severe cerebral edema, mannitol and steroids have not shown a demonstrable benefit

Disposition

Admit for
  • Patients with suspected or confirmed P falciparum or P knowlesi infection
  • Young children
  • Pregnant women
  • Immunocompromised patients

Admit to ICU for
  • Severe complications (e.g.coagulopathy or end-organ failure)
  • Cerebral malaria (e.g. altered mental status, repeated seizures, coma)
  • Parasitemia
    • >2% in non-immune (i.e. travelers)
    • >5% in semi-immune (i.e. locals)

See Also
  • Travel Medicine
  • Parasitic Diseases

References
  1. "Malaria". US Centers for Disease Control and Prevention. April 15, 2010. Archived from the original on April 16, 2012. Retrieved 2012-05-02.
  2. WHO. Ghana, Kenya and Malawi to take part in WHO malaria vaccine pilot programme. 24 April 2017. http://www.afro.who.int/en/media-centre/pressreleases/item/9533-ghana-kenya-and-malawi-to-take-part-in-who-malaria-vaccine-pilot-programme.html
  3. WHO Malaria Policy Advisory Committee and Secretariat. Malaria Policy Advisory Committee to the WHO: conlusionsions and recommendations of September 2013 meeting. Malar J. 2013;12(1):456
  4. World Health Organization. Guidelines for the treatment of malaria, 3rd ed, WHO, Geneva 2015. http://www.who.int/malaria/publications/atoz/9789241549127/en/
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