Malaria

Malaria: Excerpt from The 5-Minute Pediatric Consult

Rakesh D. Mistry, MD, MS

Malaria - BASICS

Malaria - description

• Malaria is a febrile illness due to the Plasmodium species of protozoan parasites. Plasmodium falciparum and Plasmodium vivax most commonly infect humans, although Plasmodium malariae, and Plasmodium ovale may also produce malaria infection. The Anopheles mosquito serves as the vector for Plasmodium transmission.
• Malaria was described by the earliest medical writers in China, Assyria, and India, and by the 5th century B.C. Hippocrates was able to describe the characteristic fever patterns and clinical manifestations of the disease.

Malaria - general prevention

• In the hospital setting, universal precautions should be followed.
• Personal protective measures against Anopheles mosquito bites are extremely important:
  • Remain in well-screened areas
  • Protective clothing is advised, including pants and long-sleeved shirts.
  • Insect repellents such as DEET are recommended. However, in children younger than 2 years, concentrations of <10% are recommended; concentrations <35% may be seen in older child.
• Chemoprophylaxis is strongly advised for travelers in endemic areas:
  • Chloroquine is the drug of choice in resistant areas (500 mg once a week or 5 mg/kg once a week)
  • Mefloquine is recommended in chloroquine-resistant areas (250 mg once a week; if weight is <15 kg, 5 mg/kg; if weight is 15–19 kg, 1/4 tablet; if weight is 20–30 kg,1/2 tablet; if weight is 31–45 kg, 3/4 tablet). Contraindications include patients taking beta-blockers or other drugs that alter cardiac conduction, patients with seizure dirsorders or psychosis, and patients requiring fine-motor skill performance.
  • Atovaquone-proguanil (Malarone) is equally effective, with fewer side effects than mefloquine.
  • Doxycycline or chloroquine plus proguanil are also alternatives to mefloquine.
• Chloroquine and mefloquine should begin 1 week before travel, continued during the period of exposure, and 4 weeks after leaving the endemic region. Atovaquone-proguanil is started 2 days prior to travel, and continued 1 week after return.
• Travelers should use pyrimethamine-sulfadoxine (Fansidar) if a febrile illness occurs while on chloroquine and access to medical care is not readily available.

Malaria - epidemiology

• High-risk areas of malaria endemic include parts of Central and South America, Africa, and tropical regions of Asia.
• Malaria is a major cause of infant death in the tropical regions of the world.
• Malaria is the most common cause of fever in travelers returning from foreign countries.

Malaria - incidence

• Worldwide, an estimated 300–500 million cases of malaria occur annually.
• ~1,200–1,400 cases of malaria are imported into the US each year.

Malaria - risk factors

Malaria - genetics

• Sickle cell disease and trait confer protection against malaria by 2 postulated mechanisms: Release of a toxic form of heme that possess antimalarial properties; the hemoglobin S erythrocyte tends to lose potassium required for adenosine triphosphatase (ATPase) activation, thereby depriving the parasites of nutrients.
• Thalassemia and G6PD deficiency may also provide innate resistance to malaria.

Malaria - pathophysiology

• 2 discrete stages of the Plasmodium life cycle: Sexual stage, which develops in the female Anopheles mosquito providing the sporozoites to the host; and asexual stage, which occurs in the human, first in the liver producing merozoites and then in the erythrocytes as trophozoites. Trophozoites cause red cell hemolysis, which releases more merozoites to infect other erythrocytes.
• With the exception of infants with the disease, the cycle is characteristically synchronous and periodic, giving the typical tertian periodicity seen in P. falciparum, P. vivax, and P. ovale and the quartan periodicity seen in P. malariae.
• Symptoms of cerebral malaria are caused by occlusion of the cerebral microvasculature from infected red cells.

Malaria - etiology

• Infection may be acquired throughout the life of the female Anopheles mosquito but can also occur through contaminated blood transfusions or needles or through congenital acquisition.
• The most common infecting species are P. falciparum and P. vivax.
• P. vivax and P. ovale are associated with relapsing disease because of the persistent hepatic stage of the infection.

Malaria - associated conditions

• Severe malaria is usually caused by P. falciparum.
  • Defined as parasitemia >5% with CNS and other end-organ dysfunctions (shock, acidosis, renal failure, and/or hypoglycemia).
• Cerebral malaria is the most serious consequence of malaria infection. Prognosis depends on the management of other complications (e.g., acidosis, renal failure).
• Hemolytic anemia, the most common disease finding, can be severe, especially in P. falciparum; the predominant mechanism is due to IV hemolysis from fragile erythrocytes rather than solely rupture from infected cells.
• Tropical splenomegaly syndrome seen in chronic infections caused by P. malariae produces splenomegaly, hepatomegaly, portal hypertension, and pancytopenia. In P. vivax malaria, acute splenomegaly can induce rupture.
• Blackwater fever is due to acute renal failure caused by accumulation of hemoglobin in the renal tubules resulting in hemoglobinuria with dark urine. This often occurs after repeated attacks of P. falciparum.
• Pulmonary edema, distributive shock, dysentery, and nephrotic syndrome have been described.

Malaria - DIAGNOSIS

Malaria - signs & symptoms

• Upon return from a malaria endemic zone, high fevers, headache, chills, sweating, and rigors are common presenting findings.
  • Periodicity of fever is dependent on the plasmodium species and is less commonly seen in young children and travelers.
• Cough, irritability, anorexia, vomiting, abdominal pain, back pain, and arthralgias may be present.
• Dark urine
• Cerebral malaria will manifest with signs of increased intracranial pressure, encephalopathy, and seizures.

Malaria - history

• Travel to malaria endemic region
• Pattern of fevers
• Poor compliance with malaria prophylaxis

• Failure to obtain a thorough travel history to determine exposure risk to developing malaria can delay the diagnosis and appropriate therapy.
• Delay in the diagnosis of malaria has been shown to increase the morbidity and mortality up to 20-fold compared with diagnosis and treatment within 24 hours of presentation.

Malaria - physical exam

• Ill-appearance during fever, with relatively well appearance in between
• Jaundice or pallor
• Hepatosplenomegaly may be present and is more likely observed in chronic infections due to P. falciparum.
• There is no rash present in malaria; presence of rash should elicit consideration of alternative diagnoses.

Malaria - tests

Malaria - lab

• Hemoglobin:
  • Hemolytic anemia is present initially as mild then more severe, depending on the Plasmodium species.
• WBC:
  • Leukocyte counts are usually normal or low; there is no eosinophilia.
  • Thrombocytopenia due to liver and splenic sequestration occurs in the more severe cases.
• Peripheral smear:
  • Thick and thin peripheral blood smears are required for definitive diagnosis (thick smears enable better sensitivity if the parasitemia is low; thin smears provide for species identification).
  • If initial smears are negative, repeated specimens should be obtained q8–12h during a 72-hour period to confirm a truly negative result.
  • The percent of red cells involved is an important risk factor for severe disease.
  • A parasitemia >5% of red cells, signs of CNS (mental status changes), or other organ involvement are indications for more intensive therapy.
• Quantitative buffy coat (QBC) analysis:
  • Available as a rapid screening test, but confirmation by blood smears is still necessary.
• Serologic tests:
  • Using indirect immunofluorescent assays may be helpful, but they have a low sensitivity in the early phases of acute infections.
• Polymerase chain reaction (PCR):
  • To date, other tests, including rapid detection kits and PCR techniques have demonstrated variable sensitivity and specificity but may be of use in the future.

Malaria - differencial diagnosis

Because of its potential for severe disease, malaria must be ruled out in any febrile traveler returning from an endemic zone.

• Other causes of fever in travelers should be considered, based on the region of travel.
  • Typhoid fever
  • Dengue fever
  • Yellow fever
  • Hepatitis
  • Hemolytic-uremic syndrome
  • Leptospirosis
• Common etiologies of fever, such as sinusitis, pneumonia, and influenza should alsobe considered

Malaria - TREATMENT

Malaria - medication

• For all Plasmodium species except chloroquine-resistant P. falciparum and chloroquine-resistant P. vivax, chloroquine phosphate is recommended at a dose of 10 mg/kg PO (maximum, 600 mg), then 5 mg/kg PO in 6 hours (maximum, 300 mg), then 5 mg/kg PO at 24 and 48 hours (maximum, 300 mg).
• If parenteral therapy is necessary, treatment with quinidine gluconate, 10 mg/kg IV initial dose (maximum, 600 mg) over 2 hours followed by 0.02-mg/kg/min infusion until oral therapy can be started.
• For chloroquine-resistant P. falciparum or chloroquine-resistant P. vivax; quinine sulfate, 25 mg/kg/d PO in 3 doses for 3–7 days plus doxycycline, 2 mg/kg/d PO b.i.d. for 7 days (maximum, 1 g/d) is recommended. Instead of doxycycline, clindamycin 20–40 mg/kg/d PO in 3 doses for 5 days.
• A safe alternative for children is mefloquine, 15 mg/kg PO followed by 10 mg/kg PO 8–12 hours later.
• Other alternatives include pyrimethamine–sulfadoxine (Fansidar), quinine sulfate plus doxycycline, or atovaquone plus proguanil.
• Primaquine phosphate is used for the prevention of P. vivax and P. ovale relapses but should not be used in patients with G6PD deficiency or in pregnancy.

Malaria - FOLLOW UP

Malaria - disposition

Malaria - admission criteria

Travelers diagnosed with malaria infection should be managed as inpatients.

Malaria - issues for referral

Any patient with suspected malaria infection

Malaria - prognosis

The prognosis is dependent on the Plasmodium species, relapsing nature of the disease, chloroquine resistance, and age of the patient.

• Infants with P. falciparum infection account for most of the mortality due to malaria with case-fatality rates between 0.6% and 3.8%.
• If treated promptly, even P. falciparum malaria will respond well to current treatment options.

Malaria - complications

• P. falciparum tends to cause more severe disease, and morbidity is significantly increased due to multiorgan system involvement.
• Chronic relapses occur from P. vivax and P. ovale infections and can occur during periods ranging from every few weeks to a few months.
• In the pregnant patient, increased perinatal mortality has not been reported with malaria in stable, endemic regions. However, for semiimmune or nonimmune mothers, transplacental antibodies may be lacking, and the risk of congenital infection may be higher in this subgroup.

Malaria - bibliography

1. Agarwal D, Teach SJ. Evaluation and management of a child with suspected malaria. Pediatr Emerg Care. 2006;22(2):127–133.
2. Franco-Paredes C, Santos-Preciado SI. Problem pathogens: Prevention of malaria in travelers. Lancet Infect Dis. 2006;6:139–149.
3. Kramer MH, Lobel HO. Antimalarial chemoprophylaxis in infants and children. Paediatr Drugs. 2001;3:113–121.
4. Maitland K, Bejon P, Newton CR. Malaria. Curr Opin Infect Dis. 2003;16:389–395.
5. Newton CR, Hien TT, White N. Cerebral malaria. J Neurol Neurosurg Psych. 2000;69:433–441.
6. Skarbinski J, James EM, Causer LM, et al. Malaria surveillance-United States, 2004. MMWR. 2006;55(4):23–27.
7. White NJ. Antimalarial drug resistance. J Clin Invest. 2004;113:1084–1092.

Malaria - CODES

Malaria - icd9

084.6 Malaria

Malaria - PATIENT TEACHING-MED

Malaria - prevent

• Consultation with a travel clinic is advisable when traveling into a malaria endemic zone
• Chemoprophylaxis is not 100% effective; therefore, prevention measures against mosquito bites is equally important

Malaria - FAQ

• Q: What is the optimal drug regimen for the young infant or child or the lactating or pregnant female?
• A: The only drug not contraindicated in any of these patients is chloroquine. In chloroquine-resistant areas, mefloquine has been shown to be safe in the 2nd and 3rd trimesters. Limited data suggest safety in the 1st trimester also. Mefloquine is excreted in breast milk; however, limited data suggest safety for young infants. Atovaquone-proguanil is not recommended in pregnant or breast-feeding women, or in children <11 kg.
• Q: Is there a vaccine available to prevent malaria?
• A: No adequate vaccination is currently available, however, recent advances in the technology for introducing malarial DNA coding into bacteria may lead to an effective vaccine in the future.
• Q: How can I determine if the area my patient is traveling to has chloroquine-resistant malaria?
• A: The Centers for Disease Control (CDC) has an automated traveler’s hotline accessible from a touch-tone phone 24 hours a day, 7 days a week: (404) 332-4559. Questions can also be faxed to (404) 332-4565. The Internet address for information is www.cdc.gov.

Book Source Details

• Book Title: The 5-Minute Pediatric Consult
• Author(s): M. William Schwartz MD; et al.
• Year of Publication: 2008
• Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.

More About Malaria

• Back to disease: Malaria: Introduction
• Next Book Extract About Malaria: Surveys relating to Malaria
• More Book Extracts: All Online Books for Malaria

More Medical Textbooks Online about Malaria

Review other book chapters online related to Malaria:

Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.

More About This Book: Title: The 5-Minute Pediatric Consult Authors: M. William Schwartz MD; et al. Publisher: Lippincott Williams & Wilkins Copyright: 2008 ISBN: 0-7817-7577-9

Rate This Website

What do you think about the features of this website? Take our user survey and have your say:

Website User Survey

Medical Tools & Articles:

Next articles:

• Surveys relating to Malaria
• Ask Question about Malaria

Tools & Services:

• Bookmark this page
• Symptom Search
• Symptom Checker
• Medical Dictionary
• Give your feedback

Medical Articles:

• Disease & Treatments Search
• Misdiagnosis Center
• Full list of interesting articles

Forums & Message Boards

• Ask or answer a question at the Boards:
• I cannot get a diagnosis. Please help.
• Tell us your medical story.
• Share your misdiagnosis story.
• What is the best treatment for my condition?
• See all the Boards.

Enter your search terms Submit search form
Search The Web Search wrongdiagnosis.com

Common Health Mistakes

Symptom
Checker

Search Specialists by State and City