All cases of suspected malaria are treated as chloroquine-resistant P. falciparum until proven otherwise. Therefore, the region of travel and malaria species are not initially important. Emergency department therapy is based on stratifying uncomplicated versus severe malaria. Early infectious disease consultation is recommended.

If the clinical picture is consistent with malaria, rapidly obtain a CBC, BMP, thick and thin smears, blood parasite levels, and a type and screen. Blood for smears should be collected in red-top Vacutainer tubes, as lavender-top EDTA or blue-top heparinized tubes preferentially lyse infected RBCs. Many large hospitals employ rapid antigen detection. However, if there is a delay in diagnosis longer than 3 hours and clinical suspicion remains high, empiric therapy with an antimalarial is indicated.

Thin smears are easily prepared and are diagnostic in 95% of cases. The emergency physician should call the pathology department to express the concern for malaria. The presence of intracellular ringed forms (see image) confirms the diagnosis.

However, a single negative smear does not rule out malaria. The CDC recommends obtaining smears every 12-24 hours for 3 consecutive days to rule out malaria.^5,6

Resuscitation should occur with isotonic fluids supplemented with glucose-containing crystalloid (D5NS or D5LR) to maintain euvolemia and euglycemia. Early seizure prophylaxis with benzodiazepines or other anti-epileptics should be considered in cases of suspected severe malaria. In addition, parasitemia above 2% (5% in those who may be partially immune) or signs of severe malaria should mobilize early resources for exchange transfusion and ICU admission.^4,5,7

Antimalarial Drug Treatment Options

Uncomplicated malaria is treated with a course of oral medication. A common regimen consists of four tabs of atovaquone-proguanil 250/100 (Malarone) once daily for

3 days, but antiparasitic regimens are best chosen according to infectious disease consultation. While mild cases of malaria with species other than P. falciparum or P. knowlesi may be safe to discharge home, most physicians would likely admit the patient to assure proper treatment and follow-up.

If the patient cannot tolerate oral medication or severe malaria is suspected, treatment with parenteral medication is indicated. Quinidine gluconate 10 mg/kg IV over 1 hour may be used, followed by infusion at 0.02 mg/kg per minute AND doxycycline 100 mg IV every 12 hours. Quinidine administration requires cardiac monitoring and very frequent (hourly) EKGs to monitor the QT interval, given the risk of torsades des pointes. Because of cardiotoxicity, treatment is recommended in consultation with cardiology in an ICU setting.