Guidelines for the management of Malaria
Epidemiology
Malaria continues to be one of the most important and devastating infectious
diseases in the developing areas of the world. It is a threat for UK travellers
travelling to malarial areas and immigrants arriving from malarial areas. Every
year, around 2000 cases of malaria are brought into the UK from travellers
returning from countries where there is a risk of contracting malaria. Last year
over 5 million trips from the UK were made to countries that put travellers at risk
of contracting malaria.
Diagnosis
Because malaria cases are relatively rarely seen in the UK, misdiagnosis by
clinicians and laboratories has been a commonly documented problem.
However, malaria is a common illness in areas where it is transmitted and
therefore the diagnosis of malaria should routinely be considered for anyone who
has travelled to an area with known malaria transmission in the past several
months preceding symptom onset. Symptoms of malaria are generally nonspecific and most commonly consist of fever, malaise, weakness, gastrointestinal complaints (nausea, vomiting, diarrhoea), neurological complaints
(dizziness, confusion, disorientation and coma), headache, back pain, myalgia,
chills and or cough. The diagnosis of malaria should also be considered in any
person with fever of unknown origin regardless of travel history. Patients
suspected of having malaria infection should be urgently evaluated. Treatment
for malaria should not be initiated until the diagnosis has been confirmed by
laboratory investigations. Presumptive treatment without the benefit of laboratory
confirmation should be reserved for extreme circumstances (strong clinical
suspicion, severe disease, impossibility of obtaining prompt laboratory
confirmation.
Laboratory diagnosis of malaria can be made through microscopic examination
of thick and thin blood smears. A negative blood smear makes the diagnosis of
malaria unlikely.
However, because non-immune individuals may be
symptomatic at very low parasite densities, that initially may be undetectable by
blood smear, blood smears should be repeated every 12-24 hours for a total of
48 to 72 hours.
After the presence of malaria parasites on a blood smear are detected, the
parasite density should then be estimated, this is done by our laboratory.
Treatment
Once the diagnosis of malaria has been confirmed, appropriate anti-malarial
treatment must be initiated immediately. Treatment should be guided by 3 main
factors; the infecting plasmodium species, the clinical status of the patient, and
the drug susceptibility of the infecting parasites as determined by the geographic
area where the infection was required.
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Determination of the infecting plasmodium species for treatment purposes
is important for 3 main reasons; plasmodium falciparum infections can
cause rapidly progressive severe illness or death while the non-falciparum
(P. vivax, P. Ovale, or P. malariae) species rarely cause severe
manifestations. For plasmodium falciparum infections the urgent initiation
of appropriate therapy is especially critical.
The second factor effecting treatment is the clinical status of the patient.
Patients diagnosed with malaria are generally categorised as having either
uncomplicated or severe malaria. Patients diagnosed with uncomplicated
malaria can be effectively treated with oral anti-malarials. However,
patients who have one or more of the following clinical criteria;
 impaired consciousness – coma, severe normocytic anaemia
 renal failure
 pulmonary oedema
 acute respiratory distress syndrome
 circulatory shock
 disseminated intravascular coagulation
 spontaneous bleeding
 acidosis
 haemoglobinuria
 jaundice
 repeated generalised convulsions
 parasitemia of > 5%
are considered to be manifestations of more severe disease and should be
treated aggressively with parenteral antimalarial therapy.
If the diagnosis of malaria is suspected and cannot be confirmed or if the
diagnosis of malaria is confirmed but the species determination is not possible,
antimalarial treatment effective against plasmodium falciparum must be initiated
immediately.
After initiation of treatment the patients clinical and parasitological status should
be monitored. In infections with P. falciparum, blood smears should be made to
confirm adequate parasitological response to treatment i.e. decrease in parasite
density followed by clearance. Treatment in most parts of the world, falciparum
malaria is resistant to Chloroquine, which is now not given as a treatment.
Oral Treatment
Quinine 10mg/kg (of Quinine salt) 3 times a day for 7 days.
then if Quinine resistance known or suspected
either
Fansidar single dose – up to 4 years half a tablet, 5-6 years 1 tablet, 7-9 years
1.5 tablets and 10-14 year olds 2 tablets
or
Clindamycin (unlicensed indication) 20-40mg/kg daily in 3 divided doses for 5
years and upwards.
Alternatively Malarone or Riamet may be given instead of Quinine.
necessary to give Fansidar after Malarone or Riamet.
It is not
Dosage of Malarone; less than 11kg no suitable dose, 11-20kg 1 standard tablet
daily for 3 days, 21-30kg 2 standard tablets daily for 3 days, 31-40 3 standard
tablets daily for 3 days and over 50kg 4 standard tablets daily for 3 days.
Dosage of Riamet; over 12 years and over 35kg 4 tablets initially followed by 5
further doses of 4 tablets each given at 8,24,36, 48 and 60 hours. Not suitable if
under 12 years or under 35kg.
IV treatment.
IV Quinine; loading dose 20mg/kg (maximum 1.4g) over 4 hours. Then after 8
hours maintenance dose of 10mg/kg (700mg maximum) of Quinine salt infused
over 4 hours every 8 hours until the patient is well enough to take tablets to
complete a 7 day course. This should be followed by Fansidar.
Benign malaria
Plasmodium vivax less common than ovale or malariae. Treatment is with
Chloroquine. Chloroquine 10mg/kg of base (maximum 600mg) then a single
dose of 5mg/kg (maximum 300mg) after 6-8 hours, then 5mg/kg (maximum
300mg) daily for two days. Then for a radical cure for vivax/ ovale; Primaquine
250mcg/kg daily for 14 days (maximum 30mg).
If in doubt about treatment ring the London School of Tropical Medicine, their
switchboard number is 0207 387 9300.
If there is severe malaria but the blood smear is reported as plasmodium vivax,
ovale or malariae, the patient should be treated for plasmodium falciparium in
case of a mixed infection or misdiagnosis.
Treatment should continue with a parasite count every day until the parasite
density is less than 1%.
Parenteral quinine is cardiotoxic and should be administered in an HDU setting
with continuous cardiac and frequent blood pressure monitoring. It may cause
ventricular arrhythmias, decrease in blood pressure, hypoglycaemia and
prolongation of QTc interval. Infusions should be slowed or stopped if there is an
increase in the QRS complex by more than 50% or if the QTc is greater than 0.6
seconds, or if there is hypotension, which is unresponsive to a fluid challenge.
There should be close monitoring of BMs. Exchange transfusion can be
considered for particularly severe malaria, and the American CDC recommends
that exchanged transfusion be strongly considered for persons with a parasite
density of more than 10% or if complications such as cerebral malaria, nonvolume overload pulmonary oedema, or renal complications exist. Always
discuss this with your consultant, and it may be best to discuss it with the London
School of Tropical Medicine.
Ref : CDC treatment guidelines for malaria, 2004
ALS 07/2005
reviewed 2008, next review 2011