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

Admission Point-of-Care Testing for the Clinical Care of Children with Cerebral Malaria

Point-of-care testing (PoCT), an alternative to laboratory-based testing, may be useful in the clinical care of critically ill children in resource-limited settings. We evaluated the clinical utility of PoCT in the care of 193 Malawian children treated for World Health Organization-defined cerebral malaria (CM) between March 2019 and May 2023. We assessed the frequency of abnormal PoCT results and the clinical interventions performed in response to these abnormalities. We determined the association between abnormal PoCT results and patient outcomes. Overall, 52.1% of all PoCT results were abnormal. Of the children with abnormal results, clinical interventions occurred in 16.9%. Interventions most commonly followed abnormal results for PoCT glucose (100.0% of the patients had treatment for hypoglycemia), potassium (32.1%), lactate (22.0%), and creatinine (16.3%). Patients with hypoglycemia, hyperlactatemia, and hypocalcemia had a higher mortality risk than children with normal values. Future studies are needed to determine whether obtaining laboratory values using PoCT and the clinical response to these interventions modify outcomes in critically ill African children with CM.

Involvement of Inflammatory Cytokines, Renal NaPi-IIa Cotransporter, and TRAIL Induced-Apoptosis in Experimental Malaria-Associated Acute Kidney Injury

The murine model of experimental cerebral malaria (ECM) induced by Plasmodium berghei ANKA was used to investigate the relationship among pro-inflammatory cytokines, alterations in renal function biomarkers, and the induction of the TRAIL apoptosis pathway during malaria-associated acute kidney injury (AKI). Renal function was evaluated through the measurement of plasma creatinine and blood urea nitrogen (BUN). The mRNA expression of several cytokines and NaPi-IIa was quantified. Kidney sections were examined and cytokine levels were assessed using cytometric bead array (CBA) assays. The presence of glomerular IgG deposits and apoptosis-related proteins were investigated using in situ immunofluorescence assays and quantitative real-time PCR, respectively. NaPi-IIa downregulation in the kidneys provided novel insights into the pathogenesis of hypophosphatemia during CM. Histopathological analysis revealed characteristic features of severe malaria-associated nephritis, including glomerular collapse and tubular alterations. Pro-inflammatory cytokines, such as TNF-α, IL-1β, and IL-6, were upregulated. The TRAIL apoptosis pathway was significantly activated, implicating its role in renal apoptosis. The observed alterations in renal biomarkers and the downregulation of NaPi-IIa shed light on potential mechanisms contributing to renal dysfunction in ECM. The intricate balance between pro- and anti-inflammatory cytokines, along with the activation of the TRAIL apoptosis pathway, highlights the complexity of malaria-associated AKI and provides new therapeutic targets.

A systematic review and meta-analysis of the relationship between magnesium levels and malaria severity

Magnesium is associated with Plasmodium infections and malaria severity. This systematic review and meta-analysis was conducted to synthesize the link between Plasmodium infections and magnesium levels for improved clinical guidance and therapeutic interventions in malaria-affected regions. A systematic literature search was conducted across multiple databases, including ProQuest, Scopus, Embase, Ovid, MEDLINE, PubMed, and Google Scholar. The risk of bias in the selected studies was assessed using the Joanna Briggs Institute critical appraisal tools. A thematic synthesis was employed to demonstrate the magnesium levels across selected studies, for analyzing and grouping based on geographic regions, age demographics, and clinical manifestations of malaria. Meta-analyses determined differences in magnesium levels between individuals with malaria, uninfected controls, and patients with different clinical severities of malaria. The effect sizes from individual studies were pooled using the random-effects model. Out of 2533 records identified, 13 studies were included in the review. The thematic synthesis revealed complex and varied results, with studies showing different magnesium levels in malaria patients across different geographies, age groups, and clinical presentations. The meta-analysis indicated elevated magnesium levels in malaria patients compared with uninfected controls (P < 0.01, Hedges' g: 1.94, 95% CI 0.86-3.03, I2: 98.38%, 9 studies). No statistically significant difference was observed in magnesium levels between patients with severe and nonsevere malaria (P: 0.34, Hedges' g: 0.62, 95% CI - 0.64-1.88, I2: 91.46%, 2 studies). A significant increase in magnesium levels was seen in patients with malaria who died compared with those who survived (P < 0.01, Hedges' g: 0.39, 95% CI 0.13-0.64, I2: 3.39%, 3 studies). This systematic review and meta-analysis presented relationship between magnesium levels and malaria. While the meta-analysis indicated a general trend of increased magnesium levels in patients with malaria, the substantial heterogeneity and instability of the results hint toward a rich yet uncharted territory requiring more research depth. The intricate interplay between magnesium levels and malaria beckons a multidimensional approach in future studies.

Regional and Age-Related Variations in Blood Calcium Levels among Patients with Plasmodium falciparum and P. vivax malaria: A Systematic Review and Meta-Analysis

Despite several studies examining the relationship between calcium levels and malaria, inconsistencies and varied results remain in the literature. This study aimed to synthesize the evidence on the association between blood calcium levels and malaria severity. A systematic literature search was conducted in the Embase, Scopus, PubMed, Ovid, and Google Scholar databases. The studies that investigated calcium levels in participants with malaria were reviewed and included for synthesis. The quality of included studies was assessed based on a standardized checklist by the Joanna Briggs Institute (JBI) critical appraisal checklists. The thematic synthesis had been used for qualitative synthesis. For the quantitative synthesis, the meta-analysis was performed to estimate the pooled effect sizes for differences in calcium levels between groups of participants using a random effect model using Hedge's g as a measure of effect size. Out of the 4574 identified records, 14 studies were reviewed. The thematic synthesis across these studies noted a consistent theme: reduced calcium levels in malaria patients compared to uninfected controls. However, the meta-analysis encompassing three specific analyses-comparing calcium levels between malaria patients and controls, severe and non-severe malaria cases, and fatal cases versus survivors-showed no significant difference in calcium levels. The statistics were as follows: (1) p = 0.15, Hedge's g: -1.00, 95% CI: -2.37-0.38, I2: 98.97, 9 studies; (2) p = 0.35, Hedge's g: -0.33, 95% CI: -1.02-0.36, I2: 81.61, 3 studies; and (3) p = 0.71, Hedge's g: -0.14, 95% CI: -0.91-0.62, I2: 87.05, 3 studies. Subgroup analyses indicated that regional disparities, especially between Africa and Asia, and participant age groups may influence these outcomes. While a trend of decreased calcium levels in malaria patients was observed, the meta-analytical results suggest regional and age-related variations. Further investigations should emphasize these differences to better guide clinical management, prognostic applications, and the crafting of policies concerning malaria's metabolic effects.

Predictors of outcome in childhood Plasmodium falciparum malaria

Plasmodium falciparum malaria is classified as either uncomplicated or severe, determining clinical management and providing a framework for understanding pathogenesis. Severe malaria in children is defined by the presence of one or more features associated with adverse outcome, but there is wide variation in the predictive value of these features. Here we review the evidence for the usefulness of these features, alone and in combination, to predict death and other adverse outcomes, and we consider the role that molecular biomarkers may play in augmenting this prediction. We also examine whether a more personalized approach to predicting outcome for specific presenting syndromes of severe malaria, particularly cerebral malaria, has the potential to be more accurate. We note a general need for better external validation in studies of outcome predictors and for the demonstration that predictors can be used to guide clinical management in a way that improves survival and long-term health.

Hypophosphatemia in critically ill adults and children - A systematic review

BACKGROUND & AIMS

Phosphate is the main intracellular anion essential for numerous biological processes. Symptoms of hypophosphatemia are non-specific, yet potentially life-threatening. This systematic review process was initiated to gain a global insight into hypophosphatemia, associated morbidity and treatments.

METHODS

A systematic review was conducted (PROSPERO CRD42020163191). Nine clinically relevant questions were generated, seven for adult and two for pediatric critically ill patients, and prevalence of hypophosphatemia was assessed in both groups. We identified trials through systematic searches of Medline, EMBASE, Scopus, Cochrane Central Register of Controlled Trials, CINAHL, and Web of Science. Quality assessment was performed using the Cochrane risk of bias tool for randomized controlled trials and the Newcastle-Ottawa Scale for observational studies.

RESULTS

For all research questions, we identified 2727 titles in total, assessed 399 full texts, and retained 82 full texts for evidence synthesis, with 20 of them identified for several research questions. Only 3 randomized controlled trials were identified with two of them published only in abstract form, as well as 28 prospective and 31 retrospective studies, and 20 case reports. Relevant risk of bias regarding selection and comparability was identified for most of the studies. No meta-analysis could be performed. The prevalence of hypophosphatemia varied substantially in critically ill adults and children, but no study assessed consecutive admissions to intensive care. In both critically ill adults and children, several studies report that hypophosphatemia is associated with worse outcome (prolonged length of stay and the need for respiratory support, and higher mortality). However, there was insufficient evidence regarding the optimal threshold upon which hypophosphatemia becomes critical and requires treatment. We found no studies regarding the optimal frequency of phosphate measurements, and regarding the time window to correct hypophosphatemia. In adults, nutrient restriction on top of phosphate repletion in patients with refeeding syndrome may improve survival, although evidence is weak.

CONCLUSIONS

Evidence on the definition, outcome and treatment of clinically relevant hypophosphatemia in critically ill adults and children is scarce and does not allow answering clinically relevant questions. High quality clinical research is crucial for the development of respective guidelines.

HIV infection has a profound effect on hematological factors but not on electrolyte profile of Malawian adults presenting with uncomplicated malaria and severe malaria

Aim

Although malaria and HIV infections independently affect the electrolyte and hematologic profiles, little is known of how these profiles are affected in individuals coinfected with malaria and HIV. We therefore conducted this study to investigate the electrolyte and hematologic profiles of Malawian adults presenting with either uncomplicated malaria (UM), severe malaria (SM), and those presenting with HIV and UM or HIV and SM.

Methods

Study participants were recruited at Queen Elizabeth Central Hospital, and malaria infection was confirmed by rapid diagnostic test and malaria slides, and full blood count, HIV, and wet chemistries were analyzed.

Results

Sodium, potassium, calcium, and chloride levels of all 4 study groups were similar to those of healthy controls. Both HIV-infected groups (UM and SM) had lower red blood cell counts and lower hemoglobin concentration than the reference range. Platelet counts were lower in both HIV-uninfected SM cases (64×10⁹/L) and in the HIV-infected SM cases (66×10⁹/L) compared to the reference range (115–290×10⁹/L). HIV− UM cases had higher proportion and absolute counts of neutrophils and white blood cell counts compared to the HIV+ UM cases.

Conclusion

HIV infection did not affect the electrolyte profile of Malawian adults presenting with UM or SM but had an effect on red blood cells, Hb concentration, neutrophils, and platelet counts.

Young Sprague Dawley rats infected by Plasmodium berghei: A relevant experimental model to study cerebral malaria

Cerebral malaria (CM) is the most severe manifestation of human malaria yet is still poorly understood. Mouse models have been developed to address the subject. However, their relevance to mimic human pathogenesis is largely debated. Here we study an alternative cerebral malaria model with an experimental Plasmodium berghei Keyberg 173 (K173) infection in Sprague Dawley rats. As in Human, not all infected subjects showed cerebral malaria, with 45% of the rats exhibiting Experimental Cerebral Malaria (ECM) symptoms while the majority (55%) of the remaining rats developed severe anemia and hyperparasitemia (NoECM). These results allow, within the same population, a comparison of the noxious effects of the infection between ECM and severe malaria without ECM. Among the ECM rats, 77.8% died between day 5 and day 12 post-infection, while the remaining rats were spontaneously cured of neurological signs within 24-48 hours. The clinical ECM signs observed were paresis quickly evolving to limb paralysis, global paralysis associated with respiratory distress, and coma. The red blood cell (RBC) count remained normal but a drastic decrease of platelet count and an increase of white blood cell numbers were noted. ECM rats also showed a decrease of glucose and total CO2 levels and an increase of creatinine levels compared to control rats or rats with no ECM. Assessment of the blood-brain barrier revealed loss of integrity, and interestingly histopathological analysis highlighted cyto-adherence and sequestration of infected RBCs in brain vessels from ECM rats only. Overall, this ECM rat model showed numerous clinical and histopathological features similar to Human CM and appears to be a promising model to achieve further understanding the CM pathophysiology in Humans and to evaluate the activity of specific antimalarial drugs in avoiding/limiting cerebral damages from malaria.

Calcium and phosphate levels in Nigerian children with malaria

Calcium and phosphate levels were investigated in 39 children with malaria (six severe and 33 uncomplicated) and in 39 healthy children. Hypocalcaemia (calcium <2.13 mmol/L, adjusted for albumin level) was detected in 23.1% of malaria cases and in 5.1% of controls, and hypophosphataemia (<1 mmol/L) in 38.5% of cases and in 15.4% of controls. Mean (SD) calcium levels in cases [2.26 (0/15)] were similar to those in controls [2.24 (0.12)]. In Nigerian children, hypocalcaemia and hypophosphataemia are associated with malaria.

Adjunctive management of malaria

PURPOSE OF REVIEW

Artesunate treatment reduces mortality in severe malaria when compared with quinine. Nevertheless, severe malaria is associated with mortality rates between 1.4 and 9.5% after hospitalization. This review puts into context the recent developments in understanding the pathophysiology of malaria and how these may be reflected in renewed attempts at improving adjunct therapies. Identifying new adjunct approaches has been particularly difficult for severe malaria because most interventions have either caused harm or failed to confer benefit.

RECENT FINDINGS

Imaging and postmortem findings in children with severe and cerebral malaria have given impetus to study new interventions that could be added to antimalarial treatment. Some pilot studies have (re)tested different approaches to improve complications of cerebral malaria such as the use of N-acetyl cysteine or mannitol. Fluids administration, blood transfusions and red cell exchanges in severe malaria are controversial and important areas that are also reviewed with new evidence. Other interventions such as measures to increase nitric oxide, manage acute renal failure or optimize artesunate dosing are discussed.

SUMMARY

Outcomes with adjunct therapies for severe malaria have been poor, but as insights into pathophysiological processes are deepened it may be possible eventually to reduce mortality further.

Atypical manifestations of malaria

Malaria remains a major cause of morbidity and mortality worldwide. The classic presentation of malaria with paroxysms of fever is seen only in 50%-70% of patients. Development of immunity, increasing resistance to antimalarial drugs, and indiscriminate use of antimalarial drugs have led to malaria presenting with unusual features. This review compiles a description of the various atypical manifestations of malaria.

Biochemical markers of nutritional status and childhood malaria severity in Cameroon

To investigate the part played by undernutrition in malaria severity, some biomarkers of nutritional status were assessed in children with severe malarial anaemia (MA) and cerebral malaria (CM) in comparison with healthy children or those with uncomplicated malaria. Undernutrition was assessed using the weight-for-age Z score (WAZ). Retinol was determined by HPLC; lipid profile, Ca, Mg and albumin were determined by spectrophotometry. Severe and moderate undernutritions were more prevalent in children with MA and those with the combined symptoms of CM and MA, but not in those with CM alone. Some perturbations were noticed in the lipid profile, but most of the values remained within the normal ranges. The risk of vitamin A deficiency, as assessed by plasma retinol concentration, was noteworthy in children with severe malaria: 0.48 × 10(-6) and 0.50 × 10(-6) mol/l, respectively, in children with MA and CM (reference value: >0.7 × 10(-6) mol/l). A significant difference was obtained for retinol values after an ANOVA of all the groups (P = 0.0029), with the value in the MA group being significantly low than that in the control group (P < 0.05); likewise, a significant difference was obtained after comparison of all the groups for Mg and albumin (P = 0.0064 and 0.0082, respectively). Despite their low number (n 6), fatal cases of CM had a normal mean WAZ on admission, but low values of retinol, albumin and HDL:LDL ratio. Despite these associations, undernutrition itself did not appear to be a primary factor associated with fatal outcome.

Hyponatraemia and hypokalaemia in adults with uncomplicated malaria in Thailand

In a retrospective study of 1415 patients aged 15 and over, we determined the incidence of clinically important hyponatraemia and hypokalaemia in adults with uncomplicated malaria. On admission, serum concentrations of sodium (135-145 mmol/L) and potassium (3.5-5.0 mmol/L) were found outside these reference ranges in 81% of patients. Severe hypokalaemia (K+ <3.0 mmol/L) and severe hyponatraemia (Na+ <125 mmol/L occurred in 4.4% and 0.6% of the patients, respectively. For hypokalaemia (43%) and hyponatraemia (37%), hypovolaemia, blood urea to creatinine ratio and high serum glucose (>100 mg/dL) were all independent factors (P < 0.001). Other independent predictors for hypokalaemia were Plasmodium vivax infection, female gender; and for hyponatraemia, P. falciparum infection, male gender, concentrations of G-6-PD and serum bicarbonate.

Safety profile of L-arginine infusion in moderately severe falciparum malaria

BACKGROUND

L-arginine infusion improves endothelial function in malaria but its safety profile has not been described in detail. We assessed clinical symptoms, hemodynamic status and biochemical parameters before and after a single L-arginine infusion in adults with moderately severe malaria.

METHODOLOGY AND FINDINGS

In an ascending dose study, adjunctive intravenous L-arginine hydrochloride was infused over 30 minutes in doses of 3 g, 6 g and 12 g to three separate groups of 10 adults hospitalized with moderately severe Plasmodium falciparum malaria in addition to standard quinine therapy. Symptoms, vital signs and selected biochemical measurements were assessed before, during, and for 24 hours after infusion. No new or worsening symptoms developed apart from mild discomfort at the intravenous cannula site in two patients. There was a dose-response relationship between increasing mg/kg dose and the maximum decrease in systolic (rho = 0.463; Spearman's, p = 0.02) and diastolic blood pressure (r = 0.42; Pearson's, p = 0.02), and with the maximum increment in blood potassium (r = 0.70, p<0.001) and maximum decrement in bicarbonate concentrations (r = 0.53, p = 0.003) and pH (r = 0.48, p = 0.007). At the highest dose (12 g), changes in blood pressure and electrolytes were not clinically significant, with a mean maximum decrease in mean arterial blood pressure of 6 mmHg (range: 0-11; p<0.001), mean maximal increase in potassium of 0.5 mmol/L (range 0.2-0.7 mmol/L; p<0.001), and mean maximal decrease in bicarbonate of 3 mEq/L (range 1-7; p<0.01) without a significant change in pH. There was no significant dose-response relationship with blood phosphate, lactate, anion gap and glucose concentrations. All patients had an uncomplicated clinical recovery.

CONCLUSIONS/SIGNIFICANCE

Infusion of up to 12 g of intravenous L-arginine hydrochloride over 30 minutes is well tolerated in adults with moderately severe malaria, with no clinically important changes in hemodynamic or biochemical status. Trials of adjunctive L-arginine can be extended to phase 2 studies in severe malaria.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00147368.

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.

Research priorities in the management of severe Plasmodium falciparum malaria in children

Severe malaria is a common reason for admission to paediatric wards in hospitals across sub-Saharan Africa. Despite over 100 years of research, mortality remains high. Deaths are associated with severe metabolic acidosis, shock, severe anaemia, hypoglycaemia, impaired consciousness, raised intracranial pressure, and status epilepticus. Most inpatient deaths occur within 24 h of admission to hospital, before the beneficial effects of treatment with antimalarial drugs are achieved. This review covers the priority areas for research in the care of children with severe malaria, addressing each of the main risk factors associated with death, in a bid to reduce the inpatient mortality.

Characterisation of metabolic acidosis in Kenyan children admitted to hospital for acute non-surgical conditions

Metabolic acidosis is associated with most severe malaria deaths in African children, and most deaths occur before maximum antimalarial action is achieved. Thus, specific acidosis treatment may reduce mortality. However, the underlying mechanisms remain poorly understood and no specific interventions have been developed. A detailed characterisation of this acidosis is critical in treatment development. We used the traditional and Stewart's approach to characterise acidosis in consecutive paediatric admissions for malaria and other acute non-surgical conditions to Kilifi District Hospital in Kenya. The overall acidosis prevalence was 21%. Gastroenteritis had the highest prevalence (61%). Both the mean albumin-corrected anion gap and the strong ion gap were high (>13 mmol/l and >0 mmol/l, respectively) in malaria, gastroenteritis, lower respiratory tract infection and malnutrition. Presence of salicylate in plasma was not associated with acidosis but was associated with signs of severe illness (odds ratio 2.11, 95% CI 1.1-4.2). In malaria, mean (95% CI) strong ion gap was 15 (14-7) mmol/l, and lactate, creatinine and inorganic phosphorous explained only approximately 40% of the variability in base excess (adjusted R2 = 0.397). Acidosis may be more common than previously recognised amongst paediatric admissions in Africa and is characterised by the presence of currently unidentified strong anions. In malaria, lactate and ketones, but not salicylate, are associated with acidosis. However, unidentified anions may be more important.

The prognostic value of measures of acid/base balance in pediatric falciparum malaria, compared with other clinical and laboratory parameters

BACKGROUND

Identifying severe, life-threatening falciparum malaria in African children allows for the prompt institution of appropriate management. In the past 2 decades, hyperlactatemia and acidosis have been identified as being associated with mortality in patients with severe malaria, but measurement of blood lactate concentration and base excess is expensive and technically demanding. In this large, prospective study, we examined the prognostic value of acidosis and hyperlactatemia and compared these markers to clinically assessed variables.

METHODS

We examined several clinical and laboratory measurements as prognostic markers of mortality in 14,605 parasitemic children admitted to 3 hospitals in Africa. Whole-blood lactate concentration and acid/base status were used to identify subjects who had hyperlactatemia and acidosis.

RESULTS

Using cut-points established by sensitivity and specificity curves, the sensitivities and positive predictive values for both lactate concentration and base excess were low, the specificities were moderate, and the negative predictive values were high (>97%). No reliable clinical surrogates for hyperlactatemia or acidosis were identified. Addition of lactate concentration and base excess to predictive models with previously identified clinical features (Blantyre Coma Score, deep breathing, prostration, and weight-for-age Z score) and 1 laboratory measure (blood glucose level) did not appreciably improve models to predict mortality.

CONCLUSIONS

Measurements of lactate concentration and acid/base balance are expensive to perform, and performance of the latter can be problematic. Severe falciparum malaria may be readily recognized in children at admission to hospitals in sub-Saharan Africa with use of simple, inexpensive means and does not require knowledge of lactate concentration and base excess.