Emergent Management of Malaria 

Malaria is the most deadly vector-borne disease in the world. Although typically an illness of tropical regions of the world, more than 1500 cases (nearly all foreign-originating) are diagnosed in the US each year. In some parts of the world, malaria is known as paludism (paludismo). Blackwater fever refers to the dark urine sometimes seen as a result of severe red blood cell (RBC) hemolysis from malaria.^[1]

At least 10 of the more than 200 parasitic protozoa species of the genus Plasmodium can cause human malaria, including P ovale, P vivax, P malariae, P knowlesi, and P falciparum. P falciparum causes the most severe morbidity and mortality.

The emergency physician should have a high index of suspicion if a history of fever is accompanied by suggestive symptoms in a patient with a history of travel to an endemic region. Failure to consider malaria in the differential of a febrile illness following such travel, even if seemingly temporally remote, can result in significant morbidity or mortality, especially in children and pregnant or immunocompromised patients.

Mixed infections involving more than one species of Plasmodium may occur in areas of high endemicity and multiple circulating malarial species. In these cases, clinical differentiation and decision making will be important. However, the clinician should have a low threshold for including treatment for P falciparum, to avoid potentially treating this more dangerous species incompletely or inadequately.

Importantly, although rare, malaria infection should be considered in patients with no history of travel but with otherwise unexplained fever, anemia, central nervous system (CNS) dysfunction, or sepsis.

Go to Malaria and Malaria in Children for complete information on these topics.

Assess the patient’s airway, breathing, and circulation; intervene as necessary. Protective airway may be indicated in cases of severe CNS complications.

If evidence of life-threatening hemolytic anemia is determined, establish large-bore intravenous (IV) lines, initiate fluid resuscitation, and administer transfusion of type-specific packed RBCs.

Hyponatremia probably is associated with continued oral hypotonic fluid intake in the setting of hypovolemia and does not require treatment beyond rehydration.^[2] Overly aggressive treatment of hyponatremia may lead to death.

Monitor and treat hypoglycemia, as needed, and search for any signs of microvascular malarial complications.

Laboratory analysis is helpful, although it is not always readily available to determine the Plasmodium species, level of drug resistance, and degree of parasitemia. Obtain a complete history for the laboratory.

If the infection is caused by an unidentified species or by mixed species, treat it as if it were caused by P falciparum. In the absence of known drug sensitivities, assume that the Plasmodium species in question is chloroquine resistant. If Southeast Asia is the origin of the infection, then assume mefloquine resistance.

If a patient is diagnosed with P falciparum malaria with a parasitemia greater than 10% or if the patient is experiencing life-threatening complications (ie, coma, respiratory failure, coagulopathy, fulminant kidney failure), then investigate exchange transfusion as a treatment option. If transfusion is undertaken, it should continue until the parasitemia falls below 5%, although the mortality benefit of this intervention has not been proven.

Administer parenteral quinidine, quinine, or artemisinin therapy in conjunction with exchange transfusion to eradicate the protozoa from the bloodstream.

Consider human immunodeficiency virus (HIV) testing if indicated. HIV and malaria coinfection is a significant problem across Asia and sub-Saharan Africa, where both diseases may be relatively common. Evidence suggests that malaria and HIV coinfection can lead to worse clinical outcomes in both disease processes, with malarial infections being more severe in HIV-infected patients and HIV replication increasing in malaria infection.

The World Health Organization also has guidelines on the treatment of malaria.^[3]

General hospital admission guidelines are as follows:

• Patients with suspected or confirmed P falciparum or P knowlesi infection
• Children
• Pregnant women
• Immunodeficient individuals

Intensive care unit admission guidelines are as follows:

• Immediate life-threatening complications present, such as coagulopathy or end-organ failure
• Presence of signs and symptoms consistent with cerebral malaria (eg, altered mental status, repeated seizures, coma)
• Patients who are nonimmune with a Pfalciparum parasitemia greater than 2% or who are semi-immune with a P falciparum parasitemia greater than 5%
• Presence of any other severe malarial complications

A reliable, semi-immune, adult patient with a P vivax, P ovale, or P malariae infection may be treated on an outpatient basis. However, special care must be taken if P malariae is diagnosed solely on the basis of a blood smear, as it may be confused with the sometimes fatal P knowlesi, an infection that would require inpatient treatment. Persons treated as outpatients should have adequate follow-up care, including daily blood smears to confirm the treatment’s effectiveness in decreasing parasitemia.

It is recommended that the emergency physician contact an infectious disease clinician or the pathologist when confronted with a possible case of malaria based on history and physical examination, to ensure proper identification and diagnosis. It is particularly recommended that the physician contact the US Centers for Disease Control and Prevention (CDC) directly for any known or suspected case.

To aid in identification of the species of Plasmodium, also notify the pathologist of the patient’s information, including the following:

• Where the patient has traveled and when the patient returned home
• Whether the patient has ever before been diagnosed with malaria, and if so, which species of Plasmodium caused the previous infection
• What medication or prophylaxis the patient has taken and when the last dose was administered
• Whether the patient has a history of blood transfusion or of nonsterile needle usage
• At what date and time the patient's blood sample was drawn and what condition the patient was in at that time (eg, patient was symptomatic, any periodicity of symptoms); also provide an indication of the severity of illness

The CDC has guidelines on the investigation of locally acquired mosquito-transmitted malaria.^[4]