Hypoglycaemia in African children with severe malaria

The insulin signaling cascade from nematodes to mammals: insights into innate immunity of Anopheles mosquitoes to malaria parasite infection

As revealed over the past 20 years, the insulin signaling cascade plays a central role in regulating immune and oxidative stress responses that affect the life spans of mammals and two model invertebrates, the nematode Caenorhabitis elegans and the fruit fly Drosophila melanogaster. In mosquitoes, insulin signaling regulates key steps in egg maturation and immunity and likely affects aging, although the latter has yet to be examined in detail. Reproduction, immunity and aging critically influence the capacity of mosquitoes to effectively transmit malaria parasites. Current work has demonstrated that molecules from the invading parasite and the blood meal elicit functional responses in female mosquitoes that are regulated through the insulin signaling pathway or by cross-talk with interacting pathways. Defining the details of these regulatory interactions presents significant challenges for future research, but will increase our understanding of mosquito/malaria parasite transmission and of the conservation of insulin signaling as a key regulatory nexus in animal biology.

The molecular basis of paediatric malarial disease

Severe falciparum malaria is an acute systemic disease that can affect multiple organs, including those in which few parasites are found. The acute disease bears many similarities both clinically and, potentially, mechanistically, to the systemic diseases caused by bacteria, rickettsia, and viruses. Traditionally the morbidity and mortality associated with severe malarial disease has been explained in terms of mechanical obstruction to vascular flow by adherence to endothelium (termed sequestration) of erythrocytes containing mature-stage parasites. However, over the past few decades an alternative ‘cytokine theory of disease’ has also evolved, where malarial pathology is explained in terms of a balance between the pro- and anti-inflammatory cytokines. The final common pathway for this pro-inflammatory imbalance is believed to be a limitation in the supply and mitochondrial utilisation of energy to cells. Different patterns of ensuing energy depletion (both temporal and spatial) throughout the cells in the body present as different clinical syndromes. This chapter draws attention to the over-arching position that inflammatory cytokines are beginning to occupy in the pathogenesis of acute malaria and other acute infections. The influence of inflammatory cytokines on cellular function offers a molecular framework to explain the multiple clinical syndromes that are observed during acute malarial illness, and provides a fresh avenue of investigation for adjunct therapies to ameliorate the malarial disease process.

Human malarial disease: a consequence of inflammatory cytokine release

Malaria causes an acute systemic human disease that bears many similarities, both clinically and mechanistically, to those caused by bacteria, rickettsia, and viruses. Over the past few decades, a literature has emerged that argues for most of the pathology seen in all of these infectious diseases being explained by activation of the inflammatory system, with the balance between the pro and anti-inflammatory cytokines being tipped towards the onset of systemic inflammation. Although not often expressed in energy terms, there is, when reduced to biochemical essentials, wide agreement that infection with falciparum malaria is often fatal because mitochondria are unable to generate enough ATP to maintain normal cellular function. Most, however, would contend that this largely occurs because sequestered parasitized red cells prevent sufficient oxygen getting to where it is needed. This review considers the evidence that an equally or more important way ATP deficiency arises in malaria, as well as these other infectious diseases, is an inability of mitochondria, through the effects of inflammatory cytokines on their function, to utilise available oxygen. This activity of these cytokines, plus their capacity to control the pathways through which oxygen supply to mitochondria are restricted (particularly through directing sequestration and driving anaemia), combine to make falciparum malaria primarily an inflammatory cytokine-driven disease.

Hypoglycemia in falciparum malaria: is fasting an unrecognized and insufficiently emphasized risk factor?

Hypoglycemia is a frequently encountered complication in falciparum malaria that is usually ascribed to increased glucose use and impaired glucose production caused by the inhibition of gluconeogenesis. Here, in light of recent data showing that glucose production and gluconeogenesis are often increased in falciparum malaria, we review the causes and the risk factors leading to hypoglycemia in malaria. Fasting emerges as an important potential risk factor. Length of fasting should be included in studies on hypoglycemia in malaria. Full recognition of this risk factor for hypoglycemia in malaria could change both advice to the population, especially mothers, and treatment guidelines in the health sector.

Sublingual sugar administration as an alternative to intravenous dextrose administration to correct hypoglycemia among children in the tropics

BACKGROUND

Hypoglycemia is a common determining factor of poor prognosis for children with severe malaria in sub-Saharan Africa. Intravenous dextrose administration is rarely available. Oral mucosal delivery may be an alternative to parenteral administration. A randomized, clinical trial was performed in Burkina Faso among moderately hypoglycemic children, comparing sublingual sugar administration with oral water, oral sugar, and dextrose infusion administrations.

METHODS

Sixty-nine children with glucose concentrations of < 0.8 g/L were assigned randomly to 1 of 4 methods of administration, 1 with 3 different doses of sugar, as follows: oral group (OG) (n = 15): 2.5 g of sugar; sublingual group (SG) (n = 27): 2.5 g of sugar under the tongue, with 3 treatment subgroups, ie, 0.1 g/kg, 0.15 g/kg, and 0.2 g/kg; intravenous group (IG) (n = 8): 8 mL of 30% dextrose in a single bolus; water group (n = 11). Eight children received sublingual sugar twice, ie, 0.1 g/kg at baseline and 20 minutes later. Blood glucose concentrations were measured every 20 minutes for 80 minutes. Treatment failures, peak glucose concentrations, times to glucose concentration normalization, and kinetic profiles were evaluated.

RESULTS

No treatment failures were observed in the SG and IG, compared with 8 (53%) and 9 (81.8%) failures in the OG and water group, respectively. SG children exhibited glucose kinetic profiles and bioavailabilities (77%, 99%, and 81% in the 3 SG groups) similar to those of IG children. Bioavailabilities were 84% and 38% in the SG and OG, respectively. Children > 7 years of age required repeated sublingual administrations to maintain normoglycemia.

CONCLUSIONS

The sublingual administration of sugar proved to be effective among moderately hypoglycemic children. It is a simple and promising method to control hypoglycemia among children in both developing and developed countries. This pediatric practice should be investigated in more detail among children with severe malaria.

The relevance of malaria pathophysiology to strategies of clinical management

PURPOSE OF REVIEW

Malaria claims 1-2 million lives a year, mostly children in sub-Saharan Africa. The majority of hospital deaths occur within 24 h of admission despite adequate treatment with antimalarial chemotherapy. Understanding the pathophysiological disturbances of malaria should allow the development of supportive therapy to "buy time" for antimalarial chemotherapy to clear the infection. It is sobering, however, that despite many trials over the last quarter of a century all large trials of adjunctive therapy so far have resulted in either increased morbidity or mortality, or both.

RECENT FINDINGS

Severe malaria may be divided broadly into neurological and metabolic complications. We review recent findings about the pathophysiology of these complications and the implications for future adjunctive therapy of malaria, including the proposed importance of fluid volume depletion and sequestration of parasitized red cells in severe malaria. We also consider other anaemia, hyperparasitaemia and renal failure, which also require urgent treatment in severe malaria.

SUMMARY

We review the important pathophysiological features of severe malaria and promising adjunctive therapies such as dichloroacetate that warrant further larger trials to determine whether they improve the so-far intractable death rate of severe malaria.

Metabolic complications of severe malaria

Metabolic complications of malaria are increasingly recognized as contributing to severe and fatal malaria. Disorders of carbohydrate metabolism, including hypoglycaemia and lactic acidosis, are amongst the most important markers of disease severity both in adults and children infected with Plasmodium falciparum. Amino acid and lipid metabolism are also altered by malaria. In adults, hypoglycaemia is associated with increased glucose turnover and quinine-induced hyperinsulinaemia, which causes increased peripheral uptake of glucose. Hypoglycaemia in children results from a combination of decreased production and/or increased peripheral uptake of glucose, due to increased anaerobic glycolysis. Patients with severe malaria should be monitored frequently for hypoglycaemia and treated rapidly with intravenous glucose if hypoglycaemia is detected. The most common aetiology of hyperlactataemia in severe malaria is probably increased anaerobic glucose metabolism, caused by generalized microvascular sequestration of parasitized erythrocytes that reduces blood flow to tissues. Several potential treatments for hyperlactataemia have been investigated, but their effect on mortality from severe malaria has not been determined.

Unidentified acids of strong prognostic significance in severe malaria*

OBJECTIVE

To calculate, using the Stewart approach to acid-base disorders, the strong anion gap as an estimate for the contribution of unmeasured plasma anions other than lactate to the metabolic acidosis that characterizes severe falciparum malaria and to assess its relative prognostic significance.

DESIGN

Cohort study.

SETTING

The intensive care unit of an infectious diseases hospital in southern Vietnam.

PATIENTS

Consecutive adult patients (n = 268) with severe falciparum malaria.

INTERVENTIONS

The intervention was clinical management in a dedicated unit. We measured baseline venous lactate, electrolytes, biochemical variables, admission arterial blood pH, and gas tensions for calculation of the strong anion gap.

MEASUREMENTS AND MAIN RESULTS

The mean (95% confidence interval) admission strong anion gap was 11.1 (10.4-11.9) mEq/L, compared with lactate (geometric mean, 95% confidence interval) at 2.9 (2.7-3.2) mmol/L. Strong anion gap had a high predictive value for mortality (area under the receiver operating characteristic curve 0.73 (95% confidence interval, 0.65-0.82), which was independent of plasma lactate and creatinine concentrations. Renal failure and hepatic dysfunction were both associated with, but were not the sole determinants of, high levels of strong anion gap.

CONCLUSIONS

In severe malaria, unidentified anions other than lactate are the most important contributors to metabolic acidosis, a major cause of death. The strong anion gap is a powerful prognostic indicator in patients with severe malaria.

Influence of prolonged starvation on glucose kinetics in pregnant patients infected with Plasmodium falciparum

Hypoglycaemia is a recognised complication of malaria in pregnancy, but its pathophysiology is not well understood. We studied the influence of fasting on glucose production and gluconeogenesis by infusion of [6,6-(2)H(2)]glucose and ingestion of (2)H(2)O in 20 female subjects, eight pregnant patients with uncomplicated falciparum malaria, six pregnant controls matched for age and trimester and six non-pregnant controls matched for age. Infection with Plasmodium falciparum induced a significant increase in glucose production (16.7+/-0.3 vs. 12.4+/-0.8 micromol/kg/min; P=0.002) and gluconeogenesis (12.5+/-0.6 vs. 8.2+/-0.7 micromol/kg/min; P=0.001) without a change in the glucoregulatory hormone milieu, compared to the healthy pregnant controls. Extension of the fast from 20.30 to 24.30 h resulted in a rate of decline of glucose production that was similar in patients with malaria and healthy pregnant subjects, a decline that was steeper compared to the non-pregnant subjects (-0.283 and -0.426 vs. -0.065 micromol/kg/min/h; P=0.037). The plasma glucose concentration measured at 20.30 h of fasting in the malaria patients was intermediate between the value found in the pregnant and the non-pregnant controls (4.01+/-0.2 mmol/l) while it was significantly lower in the non-infected pregnant women compared to non-pregnant controls (3.59+/-0.14 vs. 4.70+/-0.29 mmol/l; P=0.009). Plasma glucose concentration declined at a similar rate in patients with malaria and pregnant controls but faster compared to the non-pregnant controls (-0.078 and -0.093 vs. -0.044 mmol/l/h; P < 0.05). We conclude that fasting is a major risk factor for hypoglycaemia in pregnancy. Non-severe Plasmodium falciparum infection in pregnant women results in higher glucose production and higher glucose levels, thereby, compared to healthy pregnant patients, delaying of the occurrence of hypoglycaemia due to fasting. The exact mechanism of hypoglycaemia in fasting pregnant women remains to be elucidated.

A prospective comparison of malaria with other severe diseases in African children: prognosis and optimization of management

The burden of malaria in regions of high endemicity frequently overwhelms hospitals' capacity to provide effective care. A rapid, simple method of identifying children who are at highest risk is vital to reduce mortality among hospitalized children. Multiple regression analysis identified prognostic variables predicting mortality in severely ill children admitted to a Ghanaian teaching hospital. These variables were compared in children with and without malaria. A total of 1492 (90.2%) of 1654 severely ill children referred for assessment had evaluable outcomes. Low Blantyre coma score (BCS), high blood lactate level, and high body mass index were independent predictors of mortality among children with malaria (area under the receiver operating characteristic curve [AUC/ROC], 0.84). In children without malaria, BCS and lactate level also predicted mortality, but the addition of respiratory distress and hematocrit improved the model (AUC/ROC, 0.77). Predictors of mortality in children with malaria differ from those for other severe illnesses and reflect differences in underlying pathophysiological processes.

Case report: Life-threatening hypoglycaemia associated with sulfadoxinepyrimethamine,a commonly used antimalarial drug

Due to chloroquine resistance, several African countries have changed their first-line malaria treatment to sulfadoxine-pyrimethamine (SP). In this report, we present a case of hypoglycaemic coma associated with SP, an adverse reaction that is likely to be underreported and expected to occur with greater frequency as the use of SP increases.

The pathophysiology of falciparum malaria

Falciparum malaria is a complex disease with no simple explanation, affecting organs where the parasite is rare as well as those organs where it is more common. We continue to argue that it can best be understood in terms of excessive stimulation of normally useful pathways mediated by inflammatory cytokines, the prototype being tumor necrosis factor (TNF). These pathways involve downstream mediators, such as nitric oxide (NO) that the host normally uses to control parasites, but which, when uncontrolled, have bioenergetic failure of patient tissues as their predictable end point. Falciparum malaria is no different from many other infectious diseases that are clinically confused with it. The sequestration of parasitized red blood cells, prominent in some tissues but absent in others with equal functional loss, exacerbates, but does not change, these overriding principles. Recent opportunities to stain a wide range of tissues from African pediatric cases of falciparum malaria and sepsis for the inducible NO synthase (iNOS) and migration inhibitory factor (MIF) have strengthened these arguments considerably. The recent demonstration of bioenergetic failure in tissue removed from sepsis patients being able to predict a fatal outcome fulfils a prediction of these principles, and it is plausible that this will be demonstrable in severe falciparum malaria. Understanding the disease caused by falciparum malaria at a molecular level requires an appreciation of the universality of poly(ADP-ribose) polymerase-1 (PARP-1) and Na(+)/K(+)-ATPase and the protean effects of activation by inflammation of the former that include inactivation of the latter.

Abnormal blood glucose concentrations on admission to a rural Kenyan district hospital: prevalence and outcome

AIMS

To determine the prevalence, clinical characteristics, and outcome of hypoglycaemia on admission in children at a rural Kenyan district hospital.

METHODS

Observational study of 3742 children (including 280 neonates) in Kilifi District Hospital, Kenya.

MAIN OUTCOME MEASURES

hypoglycaemia (blood glucose <2.2 mmol/l) and hyperglycaemia (blood glucose >10.0 mmol/l).

RESULTS

Non-neonates: the prevalence of hypoglycaemia on admission was 7.3%. Severe illness, malnutrition, last meal >12 hours ago, and a positive malaria slide were independently associated with hypoglycaemia. Overall, mortality in hypoglycaemic children was 20.2% compared to 3.8% in normoglycaemic children (p < 0.001). The brunt of mortality in hypoglycaemic children was borne by those who were severely ill or malnourished (31.8%) as opposed to those who were neither severely ill nor malnourished (9.0%). Neonates: 23.0% of neonates were hypoglycaemic on admission. Inability to breast feed and weight <2500 g were independently associated with hypoglycaemia. Mortality was 45.2% compared to 19.6% in normoglycaemic neonates (p < 0.001). Hyperglycaemia was present in 2.7% of children and was associated with a higher mortality than normoglycaemia, 14.0% versus 3.8% respectively (p < 0.001).

CONCLUSIONS

Hypoglycaemia is common in children admitted to a rural Kenyan district hospital and is associated with an increased mortality. Apart from features of severe illness and poor feeding, clinical signs have a low sensitivity and specificity for hypoglycaemia. Where diagnostic facilities are lacking, presumptive treatment of severely ill children is recommended. For other children, the continuation of feeding (by nasogastric tube if necessary) should be part of standard management.

Plasma glucose and tumour necrosis factor-alpha in adult patients with severe falciparum malaria

Plasma glucose was assessed in 81 patients with severe falciparum malaria at the time of presentation along with tumour necrosis factor-alpha (TNF-alpha). The lowest plasma glucose value was 3.38 mmol/l and none of the patients had hypoglycaemia at admission. Plasma glucose values were not significantly lower in those with multiple organ dysfunction (MOD) than in patients with single organ dysfunction (cerebral malaria only) and in those who died compared with patients who survived. Conversely, TNF-alpha showed a good correlation with depth of coma and was significantly higher in patients who had MOD and those who died. There was no correlation between plasma glucose and TNF-alpha values.

Alanine metabolism in acute falciparum malaria

We investigated the integrity of the gluconeogenic pathway in severe malaria using alanine metabolism as a measure. Alanine disposition and liver blood flow, assessed by indocyanine green (ICG) clearance, were measured simultaneously in 10 patients with falciparum malaria (six severe and four moderately severe malaria). After intravenous infusion of alanine (0.3 g/kg), glucose increments (AUC0-55 min) were lower in patients with severe malaria than in those with moderately severe malaria (median = 508 vs. 808 mmol/min/l; P = 0.055). There were no significant differences in the other metabolite increments (alanine, lactate and pyruvate; P >/= 0.27). The two fatal cases had markedly delayed alanine removal (larger AUC0-55 min), prolonged T(1/2) and slower clearance (P </= 0.007). Overall the increments in blood alanine correlated directly with lactate increments (rs = 0.84; P = 0.002) and inversely with glucose (rs = -0.70; P = 0.025). Between acute and convalescent studies, the increments (AUC0-55 min) of alanine and glucose were not significantly different (P >/= 0.07) but the increments of lactate and pyruvate were lower in convalescence. Thus, the ratio of the increments of alanine to those of lactate and pyruvate were significantly higher in the convalescent study (P </= 0.017). The mean (SD) ICG clearance during acute malaria was not significantly different to that in convalescence (21.6 +/- 9.3 vs. 34.1 +/- 15.5 ml/min/kg; P = 0.25). During the acute study, there was a significant inverse correlation between ICG clearance and the post-infusion increments of lactate (rs = -0.63, P = 0.049) and pyruvate (rs = -0.74, P = 0.014). These data indicate that alanine clearance is impaired in acute falciparum malaria in proportion to the severity of illness and suggest an important role for anaerobic glycolysis in the pathogenesis of hypoglycaemia in severe malaria.

Adult cerebral malaria: prognostic importance of imaging findings and correlation with postmortem findings

PURPOSE

To correlate imaging abnormalities, clinical features, and postmortem findings in patients with proved cerebral malaria.

MATERIALS AND METHODS

Twenty-one patients aged 17-50 years with cerebral malaria consented to undergo transverse nonenhanced (10-mm sections) and contrast material-enhanced (8-mm sections in posterior fossa and 10-mm sections in supratentorial region) CT on admission (n = 21) and on day 10 (n = 6), with thin sections (5 mm) obtained in the area of abnormality. All CT scans were evaluated for diffuse cerebral edema, focal parenchymal abnormalities, and hemorrhage. CT findings were categorized as normal, diffuse cerebral edema, and edema with thalamic hypoattenuation without or with cerebellar hypoattenuation. Spearman rank correlation test was performed.

RESULTS

Initial scans were normal in seven patients with mild disease (median Acute Physiology and Chronic Health Evaluation [APACHE] II score of 7, median Glasgow Coma Scale [GCS] score of 10), and all survived. Of eight patients with diffuse cerebral edema (GCS > or = 8; median APACHE II, 21), six survived. Cerebral edema with thalamic and cerebellar white matter hypoattenuation was seen in five patients. All had GCS score of 6 or less, median APACHE II score of 26, and multiorgan failure; none survived. One patient (GCS = 6) had thalamic hypoattenuation without cerebellar lesions. He survived with mild residual hemiparesis. Diffuse petechial hemorrhages were seen in the cerebrum and cerebellum at autopsy in all seven patients who died. These petechial hemorrhages were not visualized on CT scans. CT findings did not correlate with degree of parasitemia.

CONCLUSION

CT findings correlate well with level of consciousness and severity of disease but underestimate the extent of disease at pathologic examination. A normal CT scan indicates a favorable outcome, whereas cerebellar hypoattenuation portends a poor outcome.

Malaria and the red cell

Because of the breakdown of malaria control programs, the constant emergence of drug resistant parasites, and, possibly, climatic changes malaria poses a major problem for the developing countries. In addition, because of the speed of international travel it is being seen with increasing frequency as an imported disease in non-tropical countries. This update explores recent information about the pathophysiology of the disease, its protean hematological manifestations, and how carrier frequencies for the common hemoglobin disorders have been maintained by relative resistance to the malarial parasite. In Section I, Dr. Louis Miller and colleagues consider recent information about the pathophysiology of malarial infection, including new information about interactions between the malarial parasite and vascular endothelium. In Section II, Dr. David Roberts discusses what is known about the complex interactions between red cell production and destruction that characterize the anemia of malaria, one of the commonest causes of anemia in tropical countries. In Section III, Dr. David Weatherall reviews recent studies on how the high gene frequencies of the thalassemias and hemoglobin variants have been maintained by heterozygote advantage against malaria and how malaria has shaped the genetic structure of human populations.

The role of tumour necrosis factor-alpha in the pathogenesis of complicated falciparum malaria

Plasmodium falciparum malaria is the most important parasitic infection of humans and is one of the most serious health problems facing the inhabitants of developing countries. It is responsible for about 2 million deaths every year. To date there is no specific treatment for the disease apart from anti-malarials. The declining sensitivity to these drugs is a serious therapeutic problem, while no safe and effective vaccine is likely to be available for general use in the near future. There is now abundant laboratory and clinical evidence to suggest that tumour necrosis factor-alpha (TNF-alpha) plays a major role in the pathogenesis of complicated falciparum malaria. Modulation of TNF-alpha response in combination with the current anti-malarial drugs, may represent a novel approach to the treatment of the serious complications associated with the disease.

Electroencephalographic and clinical features of cerebral malaria

BACKGROUND

Seizures are a prominent feature of childhood cerebral malaria, and are associated with an increased risk of death and neurological sequelae. We present the electroencephalographic (EEG) findings from a detailed clinical and electrophysiological study.

METHODS

Children with cerebral malaria had EEGs recorded within six hours of admission, and at 12 hourly intervals until recovery of consciousness. Ten deeply comatose children underwent intracranial pressure monitoring. Children were not mechanically ventilated, which made it possible to directly correlate the clinical and EEG findings.

RESULTS

Of 65 children aged 9 months and above, 40 had one or more seizures, and 18 had an episode of status epilepticus. Most seizures were partial motor, and spike wave activity consistently arose from the posterior temporo-parietal region, a border zone area lying between territories supplied by the carotid and vertebrobasilar circulations. Fifteen children had seizures that were clinically subtle or electrographic. Clinical seizures were associated with an abrupt rise in intracranial pressure. Fifty children recovered fully, seven died, and eight had persistent neurological sequelae. Initial EEG recordings of very slow frequency, or with background asymmetry, burst suppression, or interictal discharges, were associated with an adverse outcome.

CONCLUSIONS

Serial EEG recording has uncovered a range of clinical, subtle, and electrographic seizures complicating childhood cerebral malaria, and has emphasised their importance in the pathogenesis of coma. Further work is required to determine the most appropriate regimen for the prophylaxis and treatment of seizures in cerebral malaria, in order to improve outcome.

Chloroquine is not a risk factor for seizures in childhood cerebral malaria

OBJECTIVES

There are a number of case reports in the medical literature suggesting an association between the ingestion of chloroquine and subsequent seizure activity. Our study was designed to investigate the relationship between blood levels of chloroquine (CQ), its metabolite desethylchloroquine (DCQ), and seizures in children admitted to hospital with cerebral malaria.

METHODS

Serial blood levels of CQ and DCQ were measured over the first 24 h of hospital admission in children with cerebral malaria. The number and duration of all seizures was recorded, and statistical analysis subsequently performed to determine the relationship between seizure activity and blood concentrations of CQ and DCQ.

RESULTS

Chloroquine was detected in 92% (100/109) of admission blood samples. 54% (59/109) of the patients had one or more seizures after admission, while 8% (9/109) had an episode of status epilepticus. Median (interquartile range) baseline concentrations of CQ and DCQ were, respectively, 169.4 microg/ml (75.1-374.9) and 352.3 microg/ml (81.9-580.1) for those children who had seizures after admission, compared to CQ 227.5 microg/ml (79.4-430.2) and DCQ 364.0 microg/ml (131.3-709.4) for those who did not have seizures (P > 0.5 for all comparisons). Baseline concentrations of CQ and DCQ were not significantly associated with the occurrence of seizures lasting for 5 min or more. The nine children who had an episode of status epilepticus had significantly lower median admission levels of CQ than those without status epilepticus: 75.1 microg/l (7.4-116.5) vs. 227.5 microg/l (85.6-441.2), P = 0.02. Multivariate logistic regression analysis, taking into account factors likely to affect the risk of seizures in hospital, failed to change the significance of these results.

CONCLUSIONS

These findings suggest that chloroquine does not play an important role in the aetiology of seizures in childhood cerebral malaria.

[Severe malaria in children in intensive care. National survey 1990-1995]

BACKGROUND

Severe malaria is a frequent complication of Plasmodium falciparum infections. More than one million children die of malaria each year.

MATERIAL AND METHODS

A French survey was carried out on 15 cases admitted to pediatric intensive care units between 1990 and 1995. The aim of this work was to evaluate the occurrence, mortality, morbidity and treatment of severe malaria in French intensive care units.

RESULTS

All cases were imported from Africa except one case of airport malaria. Diagnosis of many of these cases was delayed. All cases were treated with quinine, and five children received a loading dose. One child died and one has neurological sequelae.

DISCUSSION

Despite improvement in management, the prognosis of severe malaria remains poor. With reference to the literature, we propose management of severe malaria, emphasizing the necessity of a rapid effect with a loading dose of quinine.

Hypoglycemia in infants and children

Hypoglycemia is more common in the pediatric patient than in adults. This article discusses the many diagnoses that can be associated with hypoglycemia in infancy and childhood. A guide to help practitioners evaluate such patients and suggested treatments for many of these disorders are provided. As genetic diagnosis continues to develop, it is anticipated that the list of specific disorders associated with hypoglycemia in infancy and childhood will increase.

Drug-induced hypoglycemia

Therapeutically administered antidiabetic drugs, notably insulin and the sulfonylureas, are undoubtedly the most common cause of hypoglycemia encountered in clinical practice. Nevertheless, an impressive list of other drugs can produce hypoglycemia unpredictably in seemingly healthy individuals in whom it may masquerade as spontaneous hypoglycemia. Unless the true cause is identified when the patient is first seen, fruitless and expensive overinvestigation may ensue. The most important drugs are discussed herein and brief mention made of those for which coincidence has not been eliminated.

Recent developments in the management of malaria

The last decade has seen in increase in our understanding of the pathophysiology of severe malaria in both adults and children. However, this increased knowledge has yet to be matched by progress in the clinical management of this medical emergency. In the last few years a wide variety of measures have been advocated to lessen the mortality due to severe malaria, but none have shown a significant benefit in terms of mortality or morbidity. In this review we concentrate on aspects of the pathophysiology of malaria which are amenable to intervention at present or in the near future. In the field of uncomplicated malaria problems remain mostly related to the continued spread of drug-resistance and the limited array of available drugs. Outlined are a number of important advances in antimalarial pharmacology and parasite biology that may lead to future improvement in the care of patients with malaria.

[Severe malaria in children in Togo]

BACKGROUND

The definition of severe malaria is no longer limited to cerebral malaria, but is as well extended to other clinical forms of the disease. This work analyses epidemiological, clinical and evolutive aspects of severe malaria in Togo.

PATIENTS AND METHODS

This study included 549 children, aged from 0 to 15 years, hospitalized in 1994-5 in the pediatric department of the Lome-Tokoin University Teaching Hospital for severe malaria as defined by World Health Organization (WHO) criteria.

RESULTS

The hospitalization frequency was 7.44%; the maximum frequency was from 1 to 5 years of age, but 6.56% of patients were more than 10 years old. The most frequent clinical form was that of severe anemia, followed by cerebral complications, as seen in many African countries. The death rate was 18.94% and the proportional mortality was 8.21%; 2.73% of the patients had neurological sequelae (behaviour disturbances in five cases, aphasia in four, hemiplegia in three, mumbling in one, oculomotor paralysis in one, and cerebellar ataxia in one). Hypoglycemia was fairly frequent (11.6%) and was associated with a poor prognosis.

CONCLUSION

It is possible to improve severe malaria prognosis in Africa by insisting not only on better equipment in intensive care wards, but also on improved and early management of hypoglycemia.

Non-radioisotopic glucose turnover in children with falciparum malaria and enteric fever

To determine whether glucose turnover is increased in acute falciparum malaria compared to enteric fever in children, steady-state 6,6-D2-glucose turnover was measured in 9 Malaysian children with uncomplicated malaria (6 males and 3 females; median age 10 years, body weight 22 kg) and in 12 with uncomplicated enteric fever (8 males and 4 females; median age 10 years, body weight 24 kg) in acute illness, after quinine (5 malaria patients) and in convalescence. Baseline plasma glucose concentrations in malaria and enteric fever were similar (all values are medians [ranges in brackets]) 5.6 [3.2-11.3] vs. 5.5 [4.2-8.0] mmol/L), as were serum insulin levels (5.6 [0.4-26.5] vs. 6.8 [1.1-22.5] milliunits/L; P > 0.4). Glucose turnover in the malaria patients was higher than in patients with enteric fever (6.27 [2.71-6.87] vs. 5.20 [4.50-6.08] mg/kg.min; P = 0.02) and in convalescence (4.74 [3.35-6.79] mg/kg.min; P = 0.05 vs. acute malaria study), and fell after quinine together with a rise in serum insulin (P = 0.03). Basal plasma lactate concentrations were higher in enteric fever than in malaria (3.4 [1.8-6.4] vs. 0.8 [0.3-3.8] mmol/L; P < 0.0001) and correlated inversely with glucose turnover in this group (rs = -0.60; n = 12; P = 0.02). These data suggest that glucose turnover is 20% greater in malaria than in enteric fever. This might reflect increased non-insulin-mediated glucose uptake in falciparum malaria and/or impaired gluconeogenesis in enteric fever, and may have implications for metabolic complications and their clinical management in both infections.

ATP-dependent desensitization of insulin binding and tyrosine kinase activity of the insulin receptor kinase. The role of endosomal acidification

Incubating endosomes with ATP decreased binding of 125I-insulin but not 125I-labeled human growth hormone. Increasing ATP concentrations from 0.1 to 1 mM increased beta-subunit tyrosine phosphorylation and insulin receptor kinase (IRK) activity assayed after partial purification. At higher (5 mM) ATP concentrations beta-subunit tyrosine phosphorylation and IRK activity were markedly decreased. This was not observed with nonhydrolyzable analogs of ATP, nor with plasma membrane IRK, nor with endosomal epidermal growth factor receptor kinase autophosphorylation. The inhibition of endosomal IRK tyrosine phosphorylation and activity was completely reversed by bafilomycin A1, indicating a role for endosomal proton pump(s). The inhibition of IRK was not due to serine/threonine phosphorylation nor was it influenced by the inhibition of phosphotyrosyl phosphatase using bisperoxo(1,10-phenanthroline)oxovanadate anion. Prior phosphorylation of the beta-subunit with 1 mM ATP did not prevent the inhibition of IRK activity on incubating with 5 mM ATP. To evaluate conformational change we incubated endosomes with dithiothreitol (DTT) followed by SDS-polyacrylamide gel electrophoresis under nonreducing conditions. Without DTT the predominant species of IRK observed was alpha2 beta2. With DTT the alpha beta dimer predominated but on co-incubation with 5 mM ATP the alpha2 beta2 form predominated. Thus, ATP-dependent endosomal acidification contributes to the termination of transmembrane signaling by, among other processes, effecting a deactivating conformational change of the IRK.

Reactive nitrogen intermediates and outcome in severe adult malaria

The role of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) in the pathophysiology of severe falciparum malaria remains unclear. We conducted a retrospective case-control study of Vietnamese adults with severe malaria to determine the relationship between outcome and admission plasma reactive nitrogen intermediates (RNI), the stable metabolites of NO. The study was designed to take into account the potential confounders of recent dietary nitrogen intake and renal function. Seventy-six patients who died from severe malaria were matched for age and sex with 76 survivors from a prospectively studied series of 560 patients. Median untransformed unadjusted plasma RNI levels were slightly higher in fatal cases (45 mumol/L, range 0-482) than in survivors (24.1 mumol/L, range 1.4-466) (P = 0.031, Wilcoxon signed-rank). There was a significant positive correlation between RNI levels and plasma creatinine (Spearman's rho = 0.35, P < 0.0001), and the addition of plasma creatinine as a covariate in a multivariate analysis abolished the trend towards higher RNI levels in fatal cases (P for the coefficient for RNI = 0.96). There was no association between RNI levels and either depth of coma on admission or time to regain consciousness. These findings do not support a pivotal role for systemic generation of NO in the pathogenesis of severe malaria in general, or cerebral malaria in particular.

The biological basis of malarial disease

In this review we summarise the arguments that inflammatory cytokines, triggered by material released from the parasite at schizogony (malarial toxin), might induce the illness and pathology seen in malaria. These pro-inflammatory cytokines can generate inducible nitric oxide synthase and cause nitric oxide to be released, as can low concentrations of malarial toxin itself provided interferon-gamma, which has only low activity in the absence of malarial toxin, is present. We suggest here that recently described hypermetabolic functions of these mediators provide a much more plausible explanation for malarial hyperlactataemia and hypoglycaemia, the chief prognostic indicators in falciparum malaria, than does hypoxia secondary to mechanical blockage of vessels by sequestering parasites, which is the dominant current theory. We also review the arguments that rationalise, through these mediators, the reversibility of the coma of cerebral malaria. Although not yet tested at a cellular level, the proposal that nitric oxide generated in cerebral vascular walls contributes to this coma continues to gather indirect support. In addition, new evidence incriminating nitric oxide in the mechanism of tolerance to endotoxin rationalises the raised nitric oxide generation seen in malarial tolerance.

Glucose homeostasis in children with falciparum malaria: precursor supply limits gluconeogenesis and glucose production

To evaluate glucose kinetics in children with falciparum malaria, basal glucose production and gluconeogenesis and an estimate of the flux of the gluconeogenic precursors were measured in Kenyan children with uncomplicated falciparum malaria before (n = 11) and during infusion of alanine (1.5 mg/kg.min; n = 6). Glucose production was measured by [6,6-2H2]glucose, gluconeogenesis by mass isotopomer distribution analysis of glucose labeled by [2-13C]glycerol. Basal plasma glucose concentration ranged from 2.1-5.5 mmol/L, and basal glucose production ranged from 3.3-7.3 mg/kg.min. Glucose production was largely derived from gluconeogenesis (73 +/- 4%; range, 52-93%). During alanine infusion, plasma glucose increased by 0.4 mmol/L (P = 0.03), glucose production increased by 0.8 mg/kg.min (P = 0.02), and gluconeogenesis increased by 0.8 mg/kg.min (P = 0.04). We conclude that glucose production in children with uncomplicated falciparum malaria is largely dependent on gluconeogenesis. However, gluconeogenesis is potentially limited by insufficient precursor supply. These data indicate that in children with falciparum malaria, gluconeogenesis fails to compensate in the presence of decreased glycogen flux to glucose, increasing the risk of hypoglycemia.

Residual neurologic sequelae after childhood cerebral malaria

BACKGROUND

Cerebral malaria is an important cause of pediatric hospital admissions in the tropics. It commonly leads to neurologic sequelae, but the risk factors for this remain unclear and the long-term outcome unknown.

OBJECTIVE

The purpose of this study was to identify the common forms of neurologic sequelae that occur after cerebral malaria, their evolution over time, and the major clinical risk factors for residual disability.

STUDY DESIGN

Prospective study in 624 children admitted with cerebral malaria to two hospitals in The Gambia, West Africa.

RESULTS

We found that 23.3% of survivors had neurologic sequelae on discharge from the hospital. By 1 month the proportion had decreased to 8.6%, and at 6 months only 4.4% of survivors were found to have residual neurologic sequelae. The most common forms of neurologic sequelae were paresis and ataxia, often found in combination with other neurologic abnormalities. In a multiple logistic regression analysis, depth of coma on admission, multiple convulsions, and duration of unconsciousness were the only three independent risk factors. Hypoglycemia and lactate acidosis were not predictive of sequelae, although they are important risk factors for fatality.

CONCLUSION

This finding raises the possibility that fatal outcome and neurologic sequelae arise from separate pathologic processes.

Comparison of artemisinin suppositories, intramuscular artesunate and intravenous quinine for the treatment of severe childhood malaria

Severe malaria remains a major cause of mortality and morbidity for children living in many tropical regions. With the emergence of strains of Plasmodium falciparum resistant to both chloroquine and quinine, alternative antimalarial agents are required. The artemisinin group of compounds are rapidly effective in severe disease when given by intramuscular or intravenous injection. However, these routes of administration are not always available in rural areas. In an open, randomized comparison 109 Vietnamese children, aged between 3 months and 14 years, with severe P.falciparum malaria, were allocated at random to receive artemisinin suppositories followed by mefloquine (n = 37), intramuscular artesunate followed by mefloquine (n = 37), or intravenous quinine followed by pyrimethamine/sulfadoxine (n = 35). There were 9 deaths: 2 artemisinin, 4 artesunate and 5 quinine-treated children. There was no difference in fever clearance time, coma recovery, or length of hospital stay among the 3 groups. However, parasite clearance times were significantly faster in artemisinin and artesunate-treated patients than in those who received quinine (P < 0.0001). Both artemisinin and artesunate were very well tolerated, but children receiving these drugs had lower peripheral reticulocyte counts by day 5 of treatment than those in the quinine group (P = 0.011). No other adverse effect or toxicity was found. There was no treatment failure in these 2 groups, but 4 patients in the quinine group failed to clear their parasites within 7 d of starting treatment and required alternative antimalarial therapy. Artemisinin suppositories are easy to administer, cheap, and very effective for treating children with severe malaria. In rural areas where medical facilities are lacking these drugs will allow antimalarial therapy to be instituted earlier in the course of the disease and may therefore save lives.

Falciparum malaria

Falciparum malaria is one of the most common infectious illnesses in the world and can progress rapidly to coma and death in the nonimmune patient. The presentation is nonspecific, so blood smears must be made and read quickly. Proper therapy requires taking into account drug resistance, recognizing the signs of severe malaria, and proper treatment for complications. Long-sleeved clothing, bed nets, insecticides, and chemoprophylaxis can help prevent malaria, but the infection must be suspected in any traveler returning from an endemic area. This article reviews epidemiology, diagnosis, treatment, and prevention of falciparum malaria in the temperate zone.

The relationship between glucose production and plasma glucose concentration in children with falciparum malaria

The pathophysiology of hypoglycaemia in children with acute falciparum malaria, a frequent and serious complication, is unknown due to absence of data on glucose kinetics. We investigated the correlation between basal glucose production and plasma glucose concentration in 20 children (8 girls) with acute, uncomplicated falciparum malaria by infusion of [6,6-2H2]glucose. Median plasma glucose concentration was 4.5 (range 2.1-6.5) mmol/L and the median glucose production 5.0 (range 4.1-8.4) mg/kg/min. There was a positive correlation between basal glucose production and plasma glucose concentration (r = 0.53, P = 0.016). There was no correlation between the rate of glucose production and the plasma concentrations of alanine, lactate, counter-regulatory hormones or cytokines. It was concluded that, in children with acute uncomplicated falciparum malaria, endogenous glucose production is an important determinant of plasma glucose concentration, contrary to previous findings in adults with malaria, in whom peripheral uptake seems to be more important than glucose production in determining plasma glucose concentration.

Post-malaria neurological syndrome

BACKGROUND

Neurological signs and symptoms are common in malaria, but observations in Vietnam and Thailand have pointed to a discrete transient neurological syndrome after recovery from severe infections.

METHODS

A prospective study of the post-malaria neurological syndrome (PMNS) was conducted at two centres in Vietnam over four years. Criteria for inclusion were recent symptomatic malaria infection with parasites cleared from blood (and in cases of cerebral malaria full recovery of consciousness), and development of neurological or psychiatric symptoms within two months after the acute illness. Half of the patients with severe falciparum malaria had been taking part in a randomised trial of antimalarials.

FINDINGS

Of 18,124 patients with falciparum malaria treated (1176 of whom had severe infections) 19 adults and three children had subsequent PMNS; in one patient it followed uncomplicated malaria and in 21 it followed severe malaria. The overall incidence (95% confidence interval) of PMNS after falciparum malaria at the main study centre was 1.2 per 1000 (0.7 to 1.8 per 1000) and relative risk (95% CI) for developing PMNS after severe versus uncomplicated falciparum malaria was 299 (40 to 2223). 13 patients had an acute confusional state or psychosis, six had one or more generalised convulsions, two had generalised convulsions followed by a long period of acute confusion, and one developed a fine tremor. At the time of PMNS diagnosis all patients were aparasitaemic. The syndrome was self-limiting, median duration 60 h (range 24-240). PMNS was associated with the use of oral mefloquine. In the randomised trial 4.4% (10/228) of patients with severe malaria who received mefloquine after parenteral treatment developed PMNS compared with 0.5% (1/210) of those who received quinine; relative risk 9.2 (95% CI 1.2 to 71.3, p = 0.012).

INTERPRETATION

Mefloquine is not the only risk factor for PMNS but it is a strong one. Where an effective alternative drug is available, mefloquine should not be used after treatment of severe malaria.

A trial of artemether or quinine in children with cerebral malaria

BACKGROUND

Cerebral malaria has a mortality rate of 10 to 30 percent despite treatment with parenteral quinine, a situation that may worsen with the spread of quinine resistance. Artemether is a new antimalarial agent that clears parasites from the circulation more rapidly than quinine, but its effect on mortality is unclear.

METHODS

We conducted a randomized, unblinded comparison of intramuscular artemether and intramuscular quinine in 576 Gambian children with cerebral malaria. The primary end points of the study were mortality and residual neurologic sequelae.

RESULTS

Fifty-nine of the 288 children treated with artemether died in the hospital (20.5 percent), as compared with 62 of the 288 treated with quinine (21.5 percent). Among the 418 children analyzed at approximately five months for neurologic disease, residual neurologic sequelae were detected in 7 of 209 survivors treated with artemether (3.3 percent) and 11 of 209 survivors treated with quinine (5.3 percent, P = 0.5). After adjustment for potential confounders, the odds ratio for death was 0.84 (95 percent confidence interval, 0.53 to 1.32) in the artemether group, and for residual neurologic sequelae, 0.51 (95 percent confidence interval, 0.17 to 1.47). There were fewer local reactions at the injection site with artemether than with quinine (0.7 percent vs. 5.9 percent, P = 0.001).

CONCLUSIONS

Artemether is as effective as quinine in the treatment of cerebral malaria in children.

The disposition and effects of two doses of dichloroacetate in adults with severe falciparum malaria

1 Dichloroacetate (DCA) is a promising treatment for lactic acidosis complicating severe malaria. The pharmacokinetics, pharmacodynamics and toxicity of dichloroacetate were evaluated in 11 patients with severe malaria, and their lactate responses compared with nine control patients in an open-label prospective study. 2 Intravenous DCA (46 mg kg-1 infused in 30 min) or saline placebo was given on admission to the study, and 12 h later, as an adjunct to standard quinine treatment. 3 An open one-compartment model with the following parameters described the pharmacokinetics of DCA after one dose (mean [s.d.]): V = 0.44(0.2) 1 kg-1; CL = 0.13 [0.027] 1 h-1 kg-1; Cmax = 106[28] mg1-1; t1/2 = 3.4(2.2) h. After two doses of DCA (n = 9) the pharmacokinetic parameters were similar to those after the first dose. 4 DCA decreased venous plasma lactate concentrations by 42% of baseline values 8 h after admission, normalized arterial pH from a mean(s.d.) of 7.367(0.063) to 7.39(0.1), and decreased the calculated base deficit from 9.2(7.3) mEq 1-1 to 6.4(10.4) mEq 1-1. In control patients lactate concentrations fell by approximately 14% of baseline concentrations (P < 0.02 compared with DCA recipients). Venous lactate concentrations fell a further 16% from baseline values after the second dose of DCA but this change was not significantly different from controls. There was no electrocardiographic or other evidence of toxicity associated with DCA. 5 These data suggest that a single intravenous infusion of DCA rapidly reduces hyperlactataemia in patients severely ill with malaria, and that DCA should be evaluated further as an adjunct to conventional antimalarial and supportive measures for such patients with lactic acidosis.

Predictors of severity of illness on presentation in children with cerebral malaria

The presenting features of 195 children with cerebral malaria were analysed to determine which correlated with severity of coma and anaemia. The children, who came from a single community in southern Zambia, were enrolled in an ongoing blinded drug trial in 1992 and 1993. Children with deep coma (scoring 0-2) had significantly longer duration of coma before presentation (P = 0.019) and were more likely to have been treated with chloroquine (P = 0.022) than children with light coma (scoring 3 or 4 on the Blantyre coma scale). Children with severe anaemia (haematocrit < 18%) were younger (P = 0.005), had been febrile longer (P = 0.005), had splenomegaly (P < 0.005) and hypoglycaemia (P < 0.008) more often and were more likely to have been treated with chloroquine (P < 0.005) than those without severe anaemia. The counts of asexual parasites in the peripheral blood were not significantly correlated with depth of coma or severity of anaemia. The observed widespread and uncontrolled use of chloroquine has probably led to the development of resistant malaria and of many severe complications despite early consultation. While early treatment of febrile illnesses in young children and immediate medical attention for altered consciousness must be emphasized in the community approach to severe malaria, our data indicate that effective public health measures will be difficult to develop in the face of a high prevalence of chloroquine resistance.

Prevalence of malaria and its relationship to anemia, blood glucose levels, and serum somatomedin c (IGF-1) levels in the Solomon Islands

As part of establishing effective methods for malaria control, the malaria-associated nutritional status was surveyed on Guadalcanal Island in the Solomon Islands in 1993. A total of 506 residents participated in this study. The slide positive rate for malaria was 54% (275/506) in all ages, with a high of 79% for children aged 4-6 years. Plasmodium falciparum was the most common species (52%), followed by P. vivax (29%). Splenomegaly in children from infants to age 15 was detected at the rate of 30% (104/343) by the palpation method. Body mass index was lower in Solomon Islanders than for the Japanese population up to 15 years old in both genders. Mean values for serum insulin-like growth factor-1 (IGF-1) were also lower in Solomon Islanders in children under 18 years old. The hemoglobin distribution curves were almost identical in the malaria-positive (P(+)) and -negative (P(-)) groups. The percentage of cases with less than 80 mg/dl of blood glucose and those with less than 50 ng/ml of IGF-1 were higher in the P(+) group than for the anti-malaria drug-untreated malaria-negative (P(-)D(-)) group. It is suggested that low blood glucose and low IGF-1 levels may have some relationship with the malaria infection.

Dichloroacetate for lactic acidosis in severe malaria: a pharmacokinetic and pharmacodynamic assessment

Lactic acidosis and hypoglycemia are potentially lethal complications of falciparum malaria. We have evaluated the pharmacokinetics and pharmacodynamics of dichloroacetate ([DCA], 46 mg/kg infused over 30 minutes), a stimulant of pyruvate dehydrogenase and a potential treatment for lactic acidosis, in 13 patients with severe malaria and compared the physiological and metabolic responses with those of a control group of patients (n = 32) of equivalent disease severity. The mean +/- SD peak postinfusion level of DCA was 78 +/- 23 mg/L, the total apparent volume of distribution was 0.75 +/- 0.35 L/kg, and systemic clearance was 0.32 +/- 0.16 L/kg/h. Geometric mean (range) venous lactate concentrations in control and DCA recipients before treatment were 4.5 (2.1 to 19.5) and 5.5 (2 to 15.4) mmol/L, respectively (P > .1). A single DCA infusion decreased lactate concentrations from baseline by a mean of 27% after 2 hours, 40% after 4 hours, and 41% after 8 hours, compared with decreases of 5%, 6%, and 16%, respectively, in controls (P = .032). These changes were preceded by rapid and marked decreases in pyruvate concentrations. Arterial pH increased from 7.328 to 7.374 (n = 10, P < .02) 2 hours after the infusion. Hypoglycemia was prevented by infusing glucose at 3 mg/kg/min. There was no clinical, electrocardiographic, or laboratory evidence of toxicity. These results suggest that DCA should be investigated further as an adjunctive therapy for severe malaria.

Glycerol metabolism in severe falciparum malaria

Gluconeogenesis and liver blood flow (LBF) in severe falciparum malaria were assessed from the clearance and metabolic response to intravenously administered glycerol (0.3 g/kg) and Indocyanine Green ([ICG] 0.4 mg/kg), respectively. Fasting baseline blood glycerol concentrations (mean +/- SD) were significantly higher in acute malaria (133 +/- 65 mumol/L, n = 14), than in convalescence (65 +/- 31 mumol/L, n = 9, P = .01), but basal triacylglycerol concentrations were similar. Estimated glycerol turnover was also more than twice as high in acute malaria compared with convalescence (1.36 +/- 0.87 v 0.54 +/- 0.15 mumol.min-1.kg-1, P = .015). The increment in plasma glucose (AUC0-55 min) following glycerol infusion was greater during acute malaria compared with convalescence (median [range], +31.6 [-0.9 to +107.6] v +14.5 [-103 to +27.1] mmol.min-L-1, P < .05), but the insulin increments were similar (P = .9), indicating reduced tissue insulin sensitivity. The increment in venous lactate (AUC0-55 min) was higher in severely ill patients (17.2 [-7.8 to +53.4] mmol.min.L-1, n = 10) compared with patients with moderately severe malaria (-3.1 [-8.7 to 3.2] mmol.min-L-1, n = 4, P = .01). LBF estimated from ICG clearance was lower during acute illness than in convalescence (mean +/- SD, 15.5 +/- 2.3 v 18.6 +/- 2.9 mL.min-1.kg-1, P = .007) and correlated inversely with the basal venous lactate concentration (rs = .53, P < .05). LBFs less than 15 mL.min-1.kg-1 were associated with hyperlactatemia, and all four fatal cases had LBFs of less than 12 mL.min-1.kg-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Convulsions in childhood malaria

A retrospective survey was conducted of all 2911 children admitted with malaria to 4 provincial hospitals in eastern Thailand between 1977 and 1987. 96 (3.3%) had cerebral malaria of whom 21 (22%) died, 225 (7.7%) had convulsions but were not comatose (4 died), and 2590 were conscious and had no fits (5 died). Thus the relative risk of a fatal outcome associated with convulsions, in the absence of cerebral malaria, was 9.2 (95% confidence interval [CI] = 2.5-34.1), P = 0.004. Overall, Plasmodium falciparum caused 81% of infections, P. vivax 16%, and 3% were mixed. Convulsions without cerebral malaria were more common in children under 3 years old (16%) compared with older children (3%): relative risk 5.6 (95% CI = 4.2-7.5), and were significantly associated with falciparum malaria (8.3%) compared with vivax malaria (4.7%): relative risk 1.7 (95% CI = 1.1-2.7). Convulsions are an important complication of malaria in young children, and are associated specifically with P. falciparum infection, even in otherwise uncomplicated malaria.