Pediatric emergency medicine trisk 2308 2308
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ovale may show symptoms several months to years after exposure. Seventy percent of P. vivax infections are
acquired in Asia or Latin America.
Chloroquine-sensitive malaria exists in Central America as well as the Caribbean and limited parts of South
America. There are regions that have developed chloroquine and mefloquine (Lariam) resistance, specifically in
Southeast Asia. It is vital for the clinician to ask about not only if malaria prophylaxis was taken but also the
medication and how it was administered. Both chloroquine and mefloquine kill the parasite only in the
hematogenous phase; it is thus vital to take these medications for 4 weeks upon leaving the endemic region. Early
termination of these medications could result in malaria even in someone who was “taking prophylaxis.” Bed nets
are effective as the mosquito vector is a night-time feeder.
Goals of Treatment
The goal of treatment is for the clinician to rapidly recognize that the febrile child returning from a malariaendemic region should be evaluated for plasmodial infection and that empiric antimalarial therapy, even in the
absence of a positive blood smear, should be initiated for the toxic-appearing child.
Clinical Considerations
Clinical recognition: The most common symptoms of malaria are fever, malaise, headache, myalgia, vomiting, and
diarrhea. Signs include pyrexia, tachycardia, tachypnea, dehydration, pallor, splenomegaly, and icterus. While the
frequency and spectrum of complications differ among the plasmodial species ( e-Table 94.15 ), signs and
symptoms cannot differentiate between species. The malaria species and degree of parasitemia will affect the types
and degree of symptoms that are displayed. Severe malaria is defined as shock, acidosis, hypoglycemia, end-organ
involvement (e.g., CNS, renal), and/or parasitemia exceeding 5% of erythrocytes.
Triage considerations: Given the constellation of symptoms, malaria should be considered in all febrile travelers
almost regardless of their clinical presentation.
Clinical assessment: The blood smear is considered the diagnostic reference standard. Both thick and thin
smears should be obtained. Thick smears allow for a much larger volume of blood to be examined and thus for the
detection of smaller numbers of parasites (leading to increased sensitivity), while the thin smear will allow for the
identification of the species and the percentage of affected red blood cells. If the initial blood films are negative for
malaria and the disease is still clinically suspected, examination of the thick and thin smears should be repeated at
least once within 12 to 24 hours after the initial evaluation. One negative blood smear should not cause the
clinician to exclude malaria from the differential diagnosis. In malaria-endemic areas, many children have lowlevel parasitemia. It is therefore important to consider other pathogens when children are found to have low-grade
parasitemia on blood smear. Thrombocytopenia without leukocytosis is a characteristic feature of malaria, as is
splenomegaly. Rapid assays for malaria are also available. In laboratories where personnel may be less familiar
with performing blood smears, these rapid assays may be far superior to blood smears.
Management: Malaria is a reportable disease to the U.S. CDC. Empiric treatment should be decided upon in
consultation with an ID specialist. Most children with malaria treated in the United States are admitted for
treatment. Empiric therapy is based upon the disease severity, the species, and data regarding drug resistance in
different geographic regions. Children with severe malaria should be admitted to an intensive care unit for
monitoring and because some children will require exchange transfusion (if parasitemia exceeds 10% or there is
evidence of cerebral or renal involvement). These children should receive parenteral therapy (clindamycin with
either IV quinine or quinidine; artesunate is a newer parenteral regimen and is likely to be used more frequently as
IV quinidine becomes less available). Blood smears should be repeated after therapy is initiated to evaluate
response to therapy and need for additional interventions. Primaquine is needed to kill the dormant phase seen in P.
vivax and P. ovale infections to prevent relapse. Prior to use of primaquine, patients need to be screened for
glucose-6-phosphate dehydrogenase (G6PD) deficiency (primaquine can cause hemolytic anemia in patients with
G6PD); women of child-bearing age also need to be screened for pregnancy (primaquine is a potential teratogen).
Both chloroquine and quinidine are available in intravenous preparations from the CDC. Standard precautions are
used for patients with malaria.
Tuberculosis
CLINICAL PEARLS AND PITFALLS
