Malaria in Children

Most of the 1-3 million who die each year from malaria are children, mainly in Africa, which is hyperendemic for malaria. In older children, malaria has a similar course as in adults. However, in children below the age of 5 years, particularly infants, the disease tends to be atypical and more severe.

In the first two months of life, children may not contract malaria or the manifestations may be mild with low-grade parasitemia, due to the passive immunity offered by the maternal antibodies.

In endemic and hyperendemic areas, the parasite rate increases with age from 0 to 10% during first three months of life to 80 to 90% by one year of age and the rate persists at a high level during early childhood. The mortality rate is highest during the first two years of life. By school age, a considerable degree of immunity would have developed and asymptomatic parasitemia can be as high as 75% in primary school children. In Africa, on an average about 1 in 20 children die from malaria, and in worst affected areas, even 1 in 5 or 6 die from malaria and its related diseases (e.g., anemia).

In areas of low endemicity, where the immunity is low, severe infection occurs in all age groups including adults. The morbidity and mortality due to malaria in children tends to be very high in these areas.

Malnutrition does not increase susceptibility to severe falciparum malaria. In fact, it has been observed that well-nourished children are more likely to develop severe disease than those with malnutrition. However, when severe malaria does occur, malnourished children have a higher morbidity and mortality.

Hemoglobin types in the newborn and the susceptibility to malaria: It has been observed that congenital malaria and malarial parasitemia in newborns are very rare, in spite of significant maternal parasitemia and sequestration of the parasites in the placenta. The reasons for this are not fully understood. Passive immunity due to maternal antibodies, retarded growth of the parasites in erythrocytes containing Hemoglobin F and resistance for parasite growth in old red cells with HbF may be the causes.

Children with heterozygous sickle cell trait have lower parasite rates and less fatal infections compared to normal children (however, homozygous sickle cell disease does not protect against fatal infection). Thalassemias may also confer some protection, may be due to higher levels of HbF. Glucose 6-phosphate dehydrogenase deficiency has been found to have a protective effect against malaria in some studies.

Severe falciparum malaria in children

Severe falciparum malaria is the commonest cause of death in infants and children in areas endemic and hyperendemic for malaria. Inadequate immunity results in rapid increase in the parasite count and development of complications. Delay in diagnosis and treatment also contributes to the mortality.

Clinical features of severe disease should be given utmost priority. History of travel to malarious area, history of previous antimalarial therapy, history of vomiting, diarrhoea, fluid intake, urine output, convulsions etc. should be obtained from parents. Physical examination should include assessment of hydration and of complications of falciparum malaria. Rectal temperature should be measured in infants and small children. All children should be weighed on admission.

Thick and thin films for malaria, haematocrit and hemoglobin, blood glucose (by finger prick) should be done in all cases. If the report is likely to be delayed, presumptive antimalarial treatment should be started. Parasite count should be done in all positive cases of falciparum malaria and a parasite count of >2% indicates impending problems and >5% should be considered as severe infection. All cases with severe falciparum malaria should be managed as medical emergency.

Cerebral malaria:

CNS manifestations are common in children and they can be due to the following causes:

1. Severe infection and cerebral malaria.
2. Severe infection and hypoglycemia.
3. Hypoglycemia induced by quinine.
4. Severe anemia.
5. High grade fever.
6. Drug induced behavioural changes.

Therefore CNS dysfunction may not always indicate cerebral malaria and it is very important to differentiate between the various causes.

Clinical features of cerebral malaria:

The earliest symptoms of cerebral malaria in children include high-grade fever (37.5-41⁰C) and failure to eat and drink. Vomiting and cough are common.Febrile convulsions are common in children aged 6 months to five years and it may be difficult to differentiate from cerebral malaria. If coma persists more than 30 minutes after a convulsion in a child with falciparum malaria, then cerebral malaria should be suspected. Convulsions can continue after the onset of coma and they are associated with higher morbidity and sequelae.

Some children may have noisy and laboured breathing. Deep breathing due to acidosis may be seen in some. Cold, clammy skin with a core-to-skin temperature difference of >10⁰C may be seen. Some children may have associated shock, with the systolic pressure below 50 mm Hg. Some children may present with extreme opisthotonus (‘bent-like-a-bow’) posture, mimicking either tetanus or meningitis.

Neurological signs include features of symmetrical upper motor neuron and brain stem disturbances including disconjugate gaze, decerebrate and decorticate postures. In children with profound coma, corneal reflex and ‘Doll’s eye’ movements may be absent. Retinal haemorrhages and exudates are rarer than in adults.

In all comatose children, CSF examination must be done to rule out other diseases. CSF examination in cerebral malaria is usually normal; however in some, increase in pressure, protein level and cell-count (mostly lymphocytes, 50cells/ml) may be seen.

Leukocytosis may be present in severe disease and may not necessarily indicate bacterial infection.

Treatment: The management of cerebral malaria in children is same as in adults.

A single intramuscular injection of phenobarbitone sodium, 10-15mg/kg of body weight can be given prophylactically to prevent convulsions in all cases of severe falciparum malaria. When convulsions do occur, they can be controlled immediately with diazepam or paraldehyde.

Bronchopneumonia is a common complication in children with cerebral malaria. Comatose children should be nursed in either lateral or semi-prone position and turned frequently to prevent aspiration as well as bedsores.

With effective antimalarial chemotherapy, children generally regain consciousness in 2-3 days; however, sometimes the coma may last as long as one week despite the reduction in fever and parasitemia. Prolonged coma may necessitate nasogastric feeding. About 10% of children who survive may have neurological sequelae in the form of hemiparesis, cerebellar ataxia, cortical blindness, hypotonia, spasticity or aphasia.

Severe anemia: Anemia is the commonest complication of malaria in children. The rate of development and degree of anemia depend on the severity and duration of parasitemia. In some children, repeated untreated episodes of malaria can result in normocytic anemia. In these cases, bone marrow shows changes of dyserythropoeisis and peripheral blood shows low-grade parasitemia, sometimes with pigmented monocytes. In patients with high parasitemia, anemia may develop rapidly due to hemolysis of the parasitized red cells and this may worsen even after completion of antimalarial therapy. It can present with serious problems in children with pre-existing anaemia.

Children with severe anemia may present with symptoms and signs of cardiac failure- dyspnoea, tachycardia, gallop rhythm, basal crackles, hepatomegaly, raised jugular pressure etc. Severe anemia can also cause confusion, restlessness, retinal haemorrhages and even coma.

Treatment: Furoscemide, 1-2 mg/kg up to a maximum of 20 mg can be given in children with signs of cardiac failure. Children with a hematocrit of less than 15% (Hemoglobin less than 5g%) should be given blood transfusion. 10ml/kg of packed cells or 20 ml/kg of whole blood can be given by slow transfusion. Whenever possible, parents should be encouraged to donate blood to minimize the risk of other blood borne infections. Hemoglobin concentration should ideally be maintained above 7g/dL (hematocrit above 20%).

Renal failure: Renal failure is uncommon in children. A slight increase in urea and creatinine may sometimes occur due to dehydration and it returns to normal with rehydration.

Treatment: In older children with renal dysfunction, the management consists of careful assessment and monitoring, initial conservative management and if needed, dialysis.

Commonest cause of oliguria in children with malaria is dehydration. Such patients have signs of dehydration, lower blood pressure, high urine specific gravity with low urinary sodium, and normal urine microscopy. Such patients should be carefully rehydrated. If the urine output fails to improve to about 4ml/kg in the first eight hours despite adequate rehydration, then furoscemide can be given, starting at 2mg/kg, then doubled at hourly intervals to a maximum of 8mg/kg. If this fails to improve the urine output, injection dopamine can be infused at 2-5mg/kg/min through a central venous catheter or a free flowing peripheral vein. If the child fails to produce more than 4 ml urine/kg body weight at the end of 16 hours, then further fluid load should be withheld. If the conservative measures fail, dialysis should be considered.

Bleeding disorders: Bleeding tendencies with prolonged clotting time, thrombocytopenia and decreased coagulation factors may occur in falciparum malaria. Spontaneous bleeding from various sites, including the upper GI tract may occur.

Pulmonary oedema: Children with cerebral malaria, severe anemia and high parasitemia may develop acute pulmonary oedema. It may also be due to fluid overload. Tachypnoea is the earliest sign of impending pulmonary oedema.

Treatment: Pulmonary oedema is managed with stringent fluid management, propped up position, oxygen inhalation, diuretics and venesection and letting of blood. If needed, patient has to be started on mechanical ventilation with positive end expiratory pressure.

Hypoglycemia: This is also less common in children compared to the adults. It may be associated with lactic acidosis in severe falciparum infections. It may present with convulsions, or impairment in the level of consciousness.

Treatment: Intravenous 50% dextrose, 1 ml/kg, should be given followed by intravenous infusion of 10% dextrose. Recurrent hypoglycemia may occur even during administration of 10% dextrose. Further episodes of drug induced, hyperinsulinemic hypoglycemia can be prevented by administration of somatostatin analogue octreotide. However, it is very expensive.

Fever: In children, high-grade fever itself can cause various problems and hence should be managed energetically. Fanning and tepid sponging should be used regularly. Paracetamol injection can be used in hyperpyrexia.

Antimalarial drugs: In cases of severe falciparum malaria, the child should be admitted. Oral antimalarials should be avoided. Chloroquine or quinine injections should be used, depending on the sensitivity. Chloroquine can be given by intravenous, intramuscular or subcutaneous injections while quinine can be given by intravenous or intramuscular injections. All intravenous infusions should be carefully titrated with infusion pumps.

Dose of antimalarials for severe malaria in children
Drug	Dose
Chloroquine	Intravenous: 5 mg base/kg diluted with normal saline or 5% dextrose 10 ml/kg, infused over 4 hours. The dose can be repeated every 12 hours to obtain a total dose of 25 mg base/kg. Rapid I.V. bolus may cause fatal hypotension. Subcutaneous: 2.5 mg/kg, followed by another 2.5 mg/kg after one hour; repeated every 12 hours to attain a dose of 25 mg/kg.
Quinine	Intravenous: 24mg salt/kg or 20 mg base/kg in normal saline or 5% dextrose, infused over 4 hours as a bolus, followed by 12 mg salt/kg or 10 mg base/kg infused every eight hours. (Bolus dose should be skipped in children who have already received quinine in the previous two days). Note that the dose is slightly higher in children (24 mg of salt per kg as against 20 mg of salt per kg in adults). Intramuscular: 10 mg base/kg every eight hours by deep I.M. injections to the anterior thigh. The total duration of treatment is 7-10 days. In children with protracted severe malaria, the dose of quinine may have to be reduced by one third or one half after the third day until the clinical condition improves, to avoid cumulative toxicity.
Arteether	3mg / kg IM for 3 days
Artemether	3.2mg / kg IM followed by 1.6 mg / kg for 5 days or 9.6 mg/kg max.
Artesunate	2.4 mg/kg at 0, 12, 24, 48 and once a day later, if required

Severe Malaria: Differences between Adults and Children
Clinical manifestation	Adults	Children
Duration of illness prior to complications	5-7 days	1-2 days
Convulsions	Common	Very common; can be due to severe infection, hypoglycemia, febrile seizures, severe anemia etc.
Abnormal brain stem reflexes (oculovestibular, oculocervical)	Rare	More common
C.S.F. pressure	Usually normal	Variable, often raised
Resolution of coma	2-4 days	1-2 days
Neurological sequelae	<5%	>10%
Cough	Uncommon	Common
Anemia	Common	More common and more severe; may be the presenting feature
Jaundice	Common	Uncommon
Pre-treatment hypoglycemia	Uncommon	Common
Pulmonary oedema	Common	Rare
Renal failure	Common	Rare
Bleeding/clotting disturbances	Up to 10%	Rare

 

©malariasite.com ©BS Kakkilaya | Last Updated: Mar 11, 2015