Fluid Management of Severefalciparum Malaria in African Children

Nitric oxide for the adjunctive treatment of severe malaria: hypothesis and rationale

We hypothesize that supplemental inhaled nitric oxide (iNO) will improve outcomes in children with severe malaria receiving standard antimalarial therapy. The rationale for the hypothesized efficacy of iNO rests on: (1) biological plausibility, based on known actions of NO in modulating endothelial activation; (2) pre-clinical efficacy data from animal models of experimental cerebral malaria; and (3) a human trial of the NO precursor l-arginine, which improved endothelial function in adults with severe malaria. iNO is an attractive new candidate for the adjunctive treatment of severe malaria, given its proven therapeutic efficacy in animal studies, track record of safety in clinical practice and numerous clinical trials, inexpensive manufacturing costs, and ease of administration in settings with limited healthcare infrastructure. We plan to test this hypothesis in a randomized controlled trial (ClinicalTrials.gov Identifier: NCT01255215).

Altered fluid, electrolyte and mineral status in tropical disease, with an emphasis on malaria and leptospirosis

Fluid, electrolyte and mineral perturbations are prevalent features of tropical disease. Hemodynamic alterations, fever, nitrogen wasting, and changes in membrane transport and acid-base balance contribute to these perturbations. Models of malaria and leptospirosis have been used to show that common hemodynamic changes in tropical disease include decreased systemic vascular resistance, increased cardiac output and increased renal vascular resistance. Blood volume is initially increased, but it decreases as disease progresses. Response to fluid loading is decreased. Diabetes insipidus is occasionally observed in malaria. Hyponatremia occurs frequently in tropical diseases, as a result of increased levels of antidiuretic hormone (vasopressin), entry of sodium into cells, sodium loss and resetting of osmoreceptors. Natriuresis and kaliuresis are observed in patients with leptospirosis. Large amounts of sodium and potassium are lost in stool as a result of diarrhea. Hypernatremia is uncommon, whereas hypokalemia caused by hyperventilation is often observed (more frequently in patients with leptospirosis and kaliuresis). During severe tropical infective episodes, hyperkalemia results from intravascular hemolysis or rhabdomyolysis, and occasionally from decreased activity of Na+,K+-ATPase. Hypocalcemia, hypomagnesemia and hypophosphatemia are common features of both malaria and leptospirosis. Loss of magnesium in the urine is uniquely associated with leptospiral nephropathy. Hypozincemia and hypocupremia can also develop during tropical infection, and might interfere with a patient's immune response. These electrolyte and mineral perturbations are transient and quickly resolve when the disease is controlled.

Falciparum Malaria

Malaria is one of the most common infectious diseases in the world today, being the most important parasitic infection, and Plasmodium falciparum is the organism responsible for most of the mortality [1]. It has been estimated that approximately 300–500 million people contract malaria every year, with approximately 1–2 million deaths, most of these occurring in children [1–5]. Plasmodium falciparum, Mycobacterium tuberculosis and measles currently compete for the title of the single most important pathogen causing human morbidity and mortality [2, 3]. Infection with Plasmodium falciparum has a wide variety of potential clinical consequences [4, 6, 7].

Perturbations in Electrolyte Levels in Kenyan Children with Severe Malaria Complicated by Acidosis

BACKGROUND

To date, information about the frequency of electrolyte disturbances among children with severe falciparum malaria is limited.

METHODS

We describe changes in potassium, calcium, magnesium, and phosphate levels in 56 Kenyan children (42 who survived and 14 who died) admitted to the hospital with clinical features of severe malaria (impaired consciousness or deep breathing) complicated by acidosis (base deficit, >8 mmol/L).

RESULTS

Mild-to-moderate hypercalcemia was common at admission, particularly among children with severe anemia. Severe hyperkalemia complicated falciparum malaria in 9 children (16%), of whom 7 (78%) died, generally soon after admission. Hypokalemia, hypomagnesemia, and hypophosphatemia were uncommon (<7% of children) at admission but developed in >30% of children within 24 h. Hypocalcemia was infrequent (<5% of children) at any time point. Apart from administration of potassium, electrolyte deficiencies were not corrected and were not associated with an adverse outcome.

CONCLUSIONS

At admission to the hospital, hyperkalemia may complicate cases of acidosis due to severe malaria and is associated with high, early mortality. After admission, mild asymptomatic deficiencies in magnesium and phosphate levels were common but were not associated with any deleterious effect. Thus, routine correction when serial measurement of electrolyte levels cannot be performed is unwarranted. Asymptomatic potassium deficiency developed despite provision of this electrolyte at maintenance doses. Further studies are justified but are unlikely to be a major research priority because, as these data suggest, the impact on mortality would at most be limited.