Cerebral metabolic alterations in rats with diabetic ketoacidosis: effects of treatment with insulin and intravenous fluids and effects of bumetanide

Diabetic Ketoacidosis in Pediatric Emergency Medicine: Risk Factors, Myths, and Evidence-Based Management of Complications

Purpose

Diabetic ketoacidosis (DKA) is a common condition among type 1 diabetics, commonly affecting those below the age of 20.

Methods

A comprehensive literature search was conducted in databases like PubMed to identify primary studies conducted in children with DKA. Finally, 79 studies were included for qualitative synthesis.

Results

The disease is characterized by acute-onset metabolic and pathological derangements, necessitating immediate intervention. With the rising incidence, concerns have been emerging regarding the disparities in the presentation and treatment of DKA among different countries with inequitable resources. Within its management lies the common misconceptions, both among patients and primary physicians, prohibiting an optimistic approach to the disease. Pediatric children in particular need specialized treatment and care during an episode of DKA due to its long-term cognitive and neurological sequelae. Hence, efforts have been undertaken to ensure minimization of neurological damage when treating DKA. While guidelines are in place for treatment of DKA, there are considerable differences in their protocols across different regions.

Conclusion

It is imperative to analyze recent evidence and continually update treatment guidelines for DKA. Additionally, maximal efforts need to be taken to bridge the gap between different nations, allowing accessibility to equitable resources to all.

Prevalence and clinical features of severe diabetic ketoacidosis treated in pediatric intensive care unit: a 5-year monocentric experience

BACKGROUND

Diabetic ketoacidosis (DKA) is one of the most alarming concerns in the management of type 1 diabetes (T1D) in pediatric age. Prevalence of DKA at the onset of diabetes ranges from 30 to 40%. In selected cases of severe DKA, admission to pediatric intensive care unit (PICU) should be considered.

METHODS

This study aims to assess the prevalence of severe DKA treated in PICU in our 5-year monocentric experience. Secondary outcome of the study was to describe the main demographical and clinical features of individuals who required admission to PICU. All clinical data were collected by retrospectively reviewing the electronic medical records of children and adolescents with diabetes hospitalized in our University Hospital from January 2017 to December 2022.

RESULTS

During the study period, 103 children and adolescents were newly diagnosed with T1D. Among these, 51.5% presented clinical criteria for DKA and almost 10% needed to be treated in PICU. A higher rate of new T1D diagnoses was observed in 2021, as well as episodes of severe DKA being more frequent than in previous years. Due to severe clinical manifestations of DKA, 10 subjects (9.7%) with T1D onset needed to be treated in PICU. Of these, four children were younger than 5. The great majority came from a low household income and some of them had also immigrant background. The most common complication of DKA was acute kidney injury presented by four children. Other complications were cerebral edema, papilledema and acute esophageal necrosis. A 15-year-old girl had deep vein thrombosis (DVT) that evolved into multiple organ failure leading to death.

CONCLUSIONS

Our findings demonstrated that severe DKA is still quite common in children and adolescents at T1D onset, especially in some areas such as Southern Italy. Public awareness campaigns should be increasingly promoted to facilitate the recognition of early symptoms of diabetes and to reduce morbidity and mortality related to DKA.

Current recommendations for management of paediatric diabetic ketoacidosis

Treatment of paediatric diabetic ketoacidosis (DKA) includes careful attention to fluids and electrolytes to minimize the risk of complications such as cerebral injury (CI), which is associated with high morbidity and mortality. The incidence of cerebral edema in paediatric DKA has not decreased despite the use of fluid-limiting protocols based on restricting early fluid resuscitation. New evidence suggests that early isotonic fluid therapy does not confer additional risk and may improve outcomes in some patients. Protocols and clinical practice guidelines are being adjusted, with a particular focus on recommendations for initial and ongoing fluids and electrolyte monitoring and replacement. Initial isotonic fluid resuscitation is now recommended for all patients in the first 20 to 30 minutes after presentation, followed by repletion of volume deficit over 36 hours in association with an insulin infusion, electrolyte supplementation, and careful monitoring for and management of potential CI.

Les recommandations en vigueur pour la prise en charge de l'acidocétose diabétique pédiatrique

Pour traiter l'acidocétose diabétique pédiatrique, il faut porter une attention particulière aux liquides et aux électrolytes pour limiter le risque de complications, telles qu'une lésion cérébrale, associée à une morbidité et une mortalité élevées. L'incidence d'œdème cérébral en cas d'acidocétose diabétique n'a pas diminué malgré les protocoles visant la limitation des liquides qui s'appuient sur la restriction de la réanimation liquidienne initiale. Selon de nouvelles données probantes, l'administration précoce de liquides isotoniques n'entraîne pas de risque supplémentaire et peut améliorer les résultats cliniques chez certains patients. Les protocoles et les directives cliniques sont adaptés et axés particulièrement sur la surveillance et le remplacement initiaux et continus des liquides et des électrolytes. Il est maintenant recommandé de commencer par une réanimation à l'aide de liquides isotoniques chez tous les patients dans les 20 à 30 minutes suivant leur arrivée à l'hôpital, suivie par la réplétion du déficit volumique sur une période de 36 heures, en association avec une perfusion d'insuline et des suppléments d'électrolytes, ainsi qu'avec la surveillance et la prise en charge attentives d'une éventuelle lésion cérébrale.

Adherence to the 2015 and 2020 British Society of Paediatric Endocrinology and Diabetes guidelines and outcomes in critically ill children with diabetic ketoacidosis: a retrospective cohort study

OBJECTIVES

To compare clinical management and key outcomes of critically ill children with diabetic ketoacidosis (DKA) in two cohorts (2015 cohort: managed according to the 2015 British Society of Paediatric Endocrinology and Diabetes (BSPED) guidelines; 2020 cohort: managed according to the 2020 BSPED guidelines).

DESIGN

Retrospective cohort study using prospectively collected data.

SETTING

A critical care advice and transport service based in London, and referring hospitals within the critical care network.

PATIENTS

All children 0-17 years referred for advice and/or critical care transport with a clinical diagnosis of DKA over a 30-month period (from September 2018 to March 2021).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Admission to intensive care unit (ICU), clinically diagnosed cerebral oedema and death.

RESULTS

There were significant differences in fluid and insulin administration practices between the 2015 and 2020 cohorts (fluid bolus >20 mL/kg: 3% vs 30%, p<0.001; median total fluid given in the first 24 hours: 84 mL/kg vs 117 mL/kg, p<0.01; starting insulin infusion rate 0.1 U/kg/hour: 54% vs 31%, p<0.01). However, these differences were consistent with guideline recommendations (initial fluid infusion rate within 5% of guideline-recommended rate: 80% in the 2015 group vs 84% in the 2020 group). There were no significant differences in outcomes (ICU admission: 26% vs 35%, p=0.2; cerebral oedema: 21% vs 23%, p=0.8).

CONCLUSIONS

Our study findings indicate that changes to fluid and insulin administration occurred after the 2020 BSPED guideline publication, with strong adherence to the guideline, but these changes were not associated with changes in key outcomes.

Pharmacological tools to target NKCC1 in brain disorders

The chloride importer NKCC1 and the chloride exporter KCC2 are key regulators of neuronal chloride concentration. A defective NKCC1/KCC2 expression ratio is associated with several brain disorders. Preclinical/clinical studies have shown that NKCC1 inhibition by the United States FDA-approved diuretic bumetanide is a potential therapeutic strategy in preclinical/clinical studies of multiple neurological conditions. However, bumetanide has poor brain penetration and causes unwanted diuresis by inhibiting NKCC2 in the kidney. To overcome these issues, a growing number of studies have reported more brain-penetrating and/or selective bumetanide prodrugs, analogs, and new molecular entities. Here, we review the evidence for NKCC1 pharmacological inhibition as an effective strategy to manage neurological disorders. We also discuss the advantages and limitations of bumetanide repurposing and the benefits and risks of new NKCC1 inhibitors as therapeutic agents for brain disorders.

Brain injury in children with diabetic ketoacidosis: Review of the literature and a proposed pathophysiologic pathway for the development of cerebral edema

Cerebral edema (CE) is a potentially devastating complication of diabetic ketoacidosis (DKA) that almost exclusively occurs in children. Since its first description in 1936, numerous risk factors have been identified; however, there continues to be uncertainty concerning the mechanisms that lead to its development. Currently, the most widely accepted hypothesis posits that CE occurs as a result of ischemia-reperfusion injury, with inflammation and impaired cerebrovascular autoregulation contributing to its pathogenesis. The role of specific aspects of DKA treatment in the development of CE continues to be controversial. This review critically examines the literature on the pathophysiology of CE and attempts to categorize the findings by types of brain injury that contribute to its development: cytotoxic, vasogenic, and osmotic. Utilizing this scheme, we propose a multifactorial pathway for the development of CE in patients with DKA.

Lactate infusion increases brain energy content during euglycemia but not hypoglycemia in healthy men

A special characteristic of the brain is the usage of lactate as alternative fuel instead of glucose to preserve its energy homeostasis. This physiological function is valid for sufficient cerebral glucose supply, as well as presumably during hypoglycemia, given that exogenous lactate infusion suppresses hormonal counterregulation. However, it is not yet clarified whether this effect is mediated by the use of lactate as an alternative cerebral energy substrate or any other mechanism. We hypothesized that under conditions of limited access to glucose (ie, during experimental hypoglycemia) lactate infusion would prevent hypoglycemia-induced neuroenergetic deficits in a neuroprotective way. In a randomized, double-blind, crossover study, lactate vs placebo infusion was compared during hyperinsulinemic-hypoglycemic clamps in 16 healthy young men. We measured the cerebral high-energy phosphate content - ie, adenosine triphosphate (ATP), phosphocreatine (PCr) and inorganic phosphate (Pi) levels - by ³¹ P-magnetic resonance spectroscopy as well as the neuroendocrine stress response. During euglycemia, lactate infusion increased ATP/Pi as well as PCr/Pi ratios compared with baseline values and placebo infusion. During hypoglycemia, there were no differences between the lactate and the placebo condition in both ratios. Hormonal counterregulation was significantly diminished upon lactate infusion. Our data demonstrate an elevated cerebral high-energy phosphate content upon lactate infusion during euglycemia, whereas there was no such effect during experimental hypoglycemia. Nevertheless, lactate infusion suppressed hypoglycemic hormonal counterregulation. Lactate thus adds to cerebral energy provision during euglycemia and may contribute to an increase in ATP reserves, which in turn protects the brain against neuroglucopenia under recurrent hypopglycemic conditions, eg, in diabetic patients.

Is Age a Risk Factor for Cerebral Edema in Children With Diabetic Ketoacidosis? A Literature Review

Cerebral edema (CE) is a rare but potentially fatal complication of diabetic ketoacidosis (DKA) in children with type 1 diabetes. CE is frequently mentioned as being more common in young children. The primary objective of this study was to review the evidence suggesting that younger age is a risk factor for the development of CE during DKA. The secondary objective was to assess if younger children are at a higher risk of DKA and severe DKA. A literature review was performed, and studies which reported the frequency of CE, DKA and severe DKA in children <3 and 3 to 5 years of age were included. Among the 6 studies reporting the frequency of CE that were identified, 5 good-quality studies found no significant association between younger age and higher risk of CE. Twenty-seven studies (DKA frequency: 11.3% to 54%) reported DKA frequency as a function of age. Most published studies found a higher frequency of DKA in children <5 years of age (20/25 studies), and in particular in those in the first 2 to 3 years of life (8/8 studies). There was inconclusive evidence to determine whether the severity of DKA was influenced by age. In conclusion, the commonly held view that CE is more common in younger children is not supported by the existing literature. Published data suggest that DKA (and possibly severe DKA) is more common in very young children. Regardless of age, all children with DKA should be monitored carefully for the development of CE.

Fluid treatment for children with diabetic ketoacidosis: How do the results of the pediatric emergency care applied research network Fluid Therapies Under Investigation in Diabetic Ketoacidosis (FLUID) Trial change our perspective?

The optimal fluid treatment protocol for children with diabetic ketoacidosis (DKA) has long been a subject of controversy. Until recently, there was no high-quality evidence from randomized clinical trials to support an optimal guideline, and recommendations were mainly based on theoretical considerations. As a consequence, fluid treatment protocols for children with DKA vary between institutions (and countries). In June 2018, the results from the Fluid Therapies Under Investigation in DKA Trial conducted in the Pediatric Emergency Care Applied Research Network were published. This large, factorial-designed randomized controlled trial assessed neurological outcomes of 1387 children with DKA who were treated with one of four fluid protocols that varied in infusion rate and sodium content. In this commentary, we review and discuss the results of this new study and the implications for clinical care of DKA in children.

Intralipid/Heparin Infusion Alters Brain Metabolites Assessed With 1H-MRS Spectroscopy in Young Healthy Men

CONTEXT

We previously demonstrated that insulin infusion altered metabolite concentrations in cerebral tissues assessed with proton magnetic resonance spectroscopy (1H-MRS) in young subjects with high insulin sensitivity, but not in those with low insulin sensitivity. Fat overload is an important factor leading to insulin resistance.

OBJECTIVE

The purpose of the current study was to examine the effect of elevated circulating free fatty acid (FFA) levels on metabolites in cerebral tissues assessed with 1H-MRS.

DESIGN

The study group comprised 10 young, healthy male subjects. 1H-MRS was performed at baseline and after 4-hour Intralipid (Fresenius Kabi)/heparin or saline infusions administered in random order. Voxels were positioned in the left frontal lobe, left temporal lobe, and hippocampus. The ratios of N-acetylaspartate (NAA), choline (Cho)-containing compounds, myo-inositol (mI), and glutamate/glutamine/γ-aminobutyric acid complex (Glx) to creatine (Cr) and nonsuppressed water signal were determined.

RESULTS

Intralipid/heparin infusion resulted in a significant increase in circulating FFAs (P < 0.0001). Significant changes in brain neurometabolite concentrations in response to Intralipid/heparin infusion were increases in frontal mI/Cr (P = 0.041) and mI/H2O (P = 0.037), decreases in frontal and hippocampal Glx/Cr (P = 0.018 and P = 0.015, respectively) and Glx/H2O (P = 0.03 and P = 0.067, respectively), and a decrease in hippocampal NAA/Cr (P = 0.007) and NAA/H2O (P = 0.019). No changes in neurometabolites were observed during the saline infusion.

CONCLUSIONS

Acute circulating FFA elevation influenced cerebral metabolites in healthy humans and lipid-induced insulin resistance could be partly responsible for these effects.

Clinical Trial of Fluid Infusion Rates for Pediatric Diabetic Ketoacidosis

BACKGROUND

Diabetic ketoacidosis in children may cause brain injuries ranging from mild to severe. Whether intravenous fluids contribute to these injuries has been debated for decades.

METHODS

We conducted a 13-center, randomized, controlled trial that examined the effects of the rate of administration and the sodium chloride content of intravenous fluids on neurologic outcomes in children with diabetic ketoacidosis. Children were randomly assigned to one of four treatment groups in a 2-by-2 factorial design (0.9% or 0.45% sodium chloride content and rapid or slow rate of administration). The primary outcome was a decline in mental status (two consecutive Glasgow Coma Scale scores of <14, on a scale ranging from 3 to 15, with lower scores indicating worse mental status) during treatment for diabetic ketoacidosis. Secondary outcomes included clinically apparent brain injury during treatment for diabetic ketoacidosis, short-term memory during treatment for diabetic ketoacidosis, and memory and IQ 2 to 6 months after recovery from diabetic ketoacidosis.

RESULTS

A total of 1389 episodes of diabetic ketoacidosis were reported in 1255 children. The Glasgow Coma Scale score declined to less than 14 in 48 episodes (3.5%), and clinically apparent brain injury occurred in 12 episodes (0.9%). No significant differences among the treatment groups were observed with respect to the percentage of episodes in which the Glasgow Coma Scale score declined to below 14, the magnitude of decline in the Glasgow Coma Scale score, or the duration of time in which the Glasgow Coma Scale score was less than 14; with respect to the results of the tests of short-term memory; or with respect to the incidence of clinically apparent brain injury during treatment for diabetic ketoacidosis. Memory and IQ scores obtained after the children's recovery from diabetic ketoacidosis also did not differ significantly among the groups. Serious adverse events other than altered mental status were rare and occurred with similar frequency in all treatment groups.

CONCLUSIONS

Neither the rate of administration nor the sodium chloride content of intravenous fluids significantly influenced neurologic outcomes in children with diabetic ketoacidosis. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the Health Resources and Services Administration; PECARN DKA FLUID ClinicalTrials.gov number, NCT00629707 .).

Treatment with the KCa3.1 inhibitor TRAM-34 during diabetic ketoacidosis reduces inflammatory changes in the brain

BACKGROUND

Diabetic ketoacidosis (DKA) causes brain injuries in children ranging from subtle to life-threatening. Previous studies suggest that DKA-related brain injury may involve both stimulation of Na-K-Cl cotransport and microglial activation. Other studies implicate the Na-K-Cl cotransporter and the Ca-activated K channel KCa3.1 in activation of microglia and ischemia-induced brain edema. In this study, we determined whether inhibiting cerebral Na-K-Cl cotransport or KCa3.1 could reduce microglial activation and decrease DKA-related inflammatory changes in the brain.

METHODS

Using immunohistochemistry, we investigated cellular alterations in brain specimens from juvenile rats with DKA before, during and after insulin and saline treatment. We compared findings in rats treated with and without bumetanide (an inhibitor of Na-K-Cl cotransport) or the KCa3.1 inhibitor TRAM-34.

RESULTS

Glial fibrillary acidic protein (GFAP) staining intensity was increased in the hippocampus during DKA, suggesting reactive astrogliosis. OX42 staining intensity was increased during DKA in the hippocampus, cortex and striatum, indicating microglial activation. Treatment with TRAM-34 decreased both OX42 and GFAP intensity suggesting a decreased inflammatory response to DKA. Treatment with bumetanide did not significantly alter OX42 or GFAP intensity.

CONCLUSIONS

Inhibiting KCa3.1 activity with TRAM-34 during DKA treatment decreases microglial activation and reduces reactive astrogliosis, suggesting a decreased inflammatory response.

Emergency Medicine Myths: Cerebral Edema in Pediatric Diabetic Ketoacidosis and Intravenous Fluids

BACKGROUND

Pediatric diabetic ketoacidosis (DKA) is a disease associated with several complications that can be severe. One complication includes cerebral edema (CE), and patients may experience significant morbidity with this disease.

OBJECTIVE

This review evaluates the myths concerning CE in pediatric DKA including mechanism, presentation of edema, clinical assessment of dehydration, and association with intravenous (i.v.) fluids.

DISCUSSION

Multiple complications may occur in pediatric DKA. CE occurs in < 1% of pediatric DKA cases, though morbidity and mortality are severe without treatment. Several myths surround this disease. Subclinical CE is likely present in many patients with pediatric DKA, though severe disease is rare. A multitude of mechanisms likely account for development of CE, including vasogenic and cytotoxic causes. Clinical dehydration is difficult to assess. Literature has evaluated the association of fluid infusion with the development of CE, but most studies are retrospective, with no comparator groups. The few studies with comparisons suggest fluid infusion is not associated with DKA. Rather, the severity of DKA with higher blood urea nitrogen and greater acidosis contribute to CE. Multiple strategies for fluid replacement exist. A bolus of 10 mL/kg of i.v. fluid is likely safe, which can be repeated if hemodynamic status does not improve.

CONCLUSIONS

Pediatric CE in DKA is rare but severe. Multiple mechanisms result in this disease, and many patients experience subclinical CE. Intravenous fluids are likely not associated with development of CE, and 10-mL/kg or 20-mL/kg i.v. bolus is safe.

Diabetic ketoacidosis in juvenile rats is associated with reactive gliosis and activation of microglia in the hippocampus

BACKGROUND

Type 1 diabetes may be associated with structural and functional alterations in the brain. The role of diabetic ketoacidosis (DKA) in causing these alterations has not been well explored.

METHODS

We used immunohistochemical staining to investigate cellular alterations in brain specimens from juvenile rats with DKA before, during, and after treatment with insulin and saline, and compared these to samples from diabetic rats and normal controls.

RESULTS

Glial fibrillary acidic protein (GFAP) staining intensity was increased in the hippocampus during DKA and increased further during insulin/saline treatment. Twenty-four and 72 h after treatment, hippocampal GFAP intensity declined but remained above control levels. There were no significant changes in GFAP intensity in the cortex or striatum. OX42 staining intensity was increased during untreated DKA and increased further during insulin/saline treatment in the hippocampus and cortex. NeuN staining intensity was decreased after DKA treatment in the striatum but not in other regions.

CONCLUSIONS

DKA causes inflammatory changes in the brain including reactive gliosis and activation of microglia. These findings are present during untreated DKA, but intensify during insulin/saline treatment. The hippocampus was disproportionately affected, consistent with previous studies showing deficits in hippocampal functions in rats after DKA recovery and decreased memory capacity in children with a history of DKA.

Effect of Volume of Fluid Resuscitation on Metabolic Normalization in Children Presenting in Diabetic Ketoacidosis: A Randomized Controlled Trial

BACKGROUND

The optimal rate of fluid administration in pediatric diabetic ketoacidosis (DKA) is unknown.

OBJECTIVE

Our aim was to determine whether the volume of fluid administration in children with DKA influences the rate of metabolic normalization.

METHODS

We performed a randomized controlled trial conducted in a tertiary pediatric emergency department from December 2007 until June 2010. The primary outcome was time to metabolic normalization; secondary outcomes were time to bicarbonate normalization, pH normalization, overall length of hospital treatment, and adverse outcomes. Children between 0 and 18 years of age were eligible if they had type 1 diabetes mellitus and DKA. Patients were randomized to receive intravenous (IV) fluid at low volume (10 mL/kg bolus + 1.25 × maintenance rate) or high volume (20 mL/kg bolus + 1.5 × maintenance rate) (n = 25 in each).

RESULTS

After adjusting for initial differences in bicarbonate levels, time to metabolic normalization was significantly faster in the higher-volume infusion group compared to the low-volume infusion group (hazard ratio [HR] = 2.0; 95% confidence interval [CI] 1.0-3.9; p = 0.04). Higher-volume IV fluid infusion appeared to hasten, to a greater extent, normalization of pH (HR = 2.5; 95% CI 1.2-5.0; p = 0.01) than normalization of serum bicarbonate (HR = 1.2; 95% CI 0.6-2.3; p = 0.6). The length of hospital treatment HR (0.8; 95% CI 0.4-1.5; p = 0.5) and time to discharge HR (0.8; 95% CI 0.4-1.5; p = 0.5) did not differ between treatment groups.

CONCLUSIONS

Higher-volume fluid infusion in the treatment of pediatric DKA patients significantly shortened metabolic normalization time, but did not change overall length of hospital treatment. ClinicalTrials.gov ID NCT01701557.

Simulated diabetic ketoacidosis therapy in vitro elicits brain cell swelling via sodium-hydrogen exchange and anion transport

A common complication of type 1 diabetes mellitus is diabetic ketoacidosis (DKA), a state of severe insulin deficiency. A potentially harmful consequence of DKA therapy in children is cerebral edema (DKA-CE); however, the mechanisms of therapy-induced DKA-CE are unknown. Our aims were to identify the DKA treatment factors and membrane mechanisms that might contribute specifically to brain cell swelling. To this end, DKA was induced in juvenile mice with the administration of the pancreatic toxins streptozocin and alloxan. Brain slices were prepared and exposed to DKA-like conditions in vitro. Cell volume changes were imaged in response to simulated DKA therapy. Our experiments showed that cell swelling was elicited with isolated DKA treatment components, including alkalinization, insulin/alkalinization, and rapid reductions in osmolality. Methyl-isobutyl-amiloride, a nonselective inhibitor of sodium-hydrogen exchangers (NHEs), reduced cell swelling in brain slices elicited with simulated DKA therapy (in vitro) and decreased brain water content in juvenile DKA mice administered insulin and rehydration therapy (in vivo). Specific pharmacological inhibition of the NHE1 isoform with cariporide also inhibited cell swelling, but only in the presence of the anion transport (AT) inhibitor 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid. DKA did not alter brain NHE1 isoform expression, suggesting that the cell swelling attributed to the NHE1 was activity dependent. In conclusion, our data raise the possibility that brain cell swelling can be elicited by DKA treatment factors and that it is mediated by NHEs and/or coactivation of NHE1 and AT.

The Impact of Diabetes on Brain Function in Childhood and Adolescence

A constant supply of glucose to the brain is critical for normal cerebral metabolism. The dysglycemia of type 1 diabetes (T1D) can affect activity, survival, and function of neural cells. Clinical studies in T1D have shown impairments in brain morphology and function. The most neurotoxic milieu seems to be young age and/or diabetic ketoacidosis at onset, severe hypoglycemia under the age of 6 years followed by chronic hyperglycemia. Adverse cognitive outcomes seem to be associated with poorer mental health outcomes. It is imperative to improve outcomes by investigating the mechanisms of injury so that neuroprotective strategies independent of glycemia can be identified.

Brain cell swelling during hypocapnia increases with hyperglycemia or ketosis

BACKGROUND

Severe hypocapnia reduces cerebral blood flow (CBF) and is known to be a risk factor for diabetic ketoacidosis (DKA)-related cerebral edema and cerebral injury in children. Reductions in CBF resulting from hypocapnia alone, however, would not be expected to cause substantial cerebral injury. We hypothesized that either hyperglycemia or ketosis might alter the effects of hypocapnia on CBF and/or cerebral edema associated with CBF reduction.

METHODS

We induced hypocapnia (pCO₂ 20 ± 3 mmHg) via mechanical ventilation in three groups of juvenile rats: 25 controls, 22 hyperglycemic rats (serum glucose 451 ± 78 mg/dL), and 15 ketotic rats (β-hydroxy butyrate 3.0 ± 1.0 mmol/L). We used magnetic resonance imaging to measure CBF and apparent diffusion coefficient (ADC) values in these groups and in 17 ventilated rats with normal pCO₂ (40 ± 3 mmHg). In a subset (n = 35), after 2 h of hypocapnia, pCO₂ levels were normalized (40 ± 3 mmHg) and ADC and CBF measurements were repeated.

RESULTS

Declines in CBF with hypocapnia occurred in all groups. Normalization of pCO₂ after hypocapnia resulted in hyperemia in the striatum. These effects were not substantially altered by hyperglycemia or ketosis. Declines in ADC (suggesting brain cell swelling) during hypocapnia, however, were greater during both hyperglycemia and ketosis.

CONCLUSIONS

We conclude that brain cell swelling associated with hypocapnia is increased by both hyperglycemia and ketosis, suggesting that these metabolic conditions may make the brain more vulnerable to injury during hypocapnia.

Blood-brain barrier Na transporters in ischemic stroke

Blood-brain barrier (BBB) endothelial cells form a barrier that is highly restrictive to passage of solutes between blood and brain. Many BBB transport mechanisms have been described that mediate transcellular movement of solutes across the barrier either into or out of the brain. One class of BBB transporters that is all too often overlooked is that of the ion transporters. The BBB has a rich array of ion transporters and channels that carry Na, K, Cl, HCO3, Ca, and other ions. Many of these are asymmetrically distributed between the luminal and abluminal membranes, giving BBB endothelial cells the ability to perform vectorial transport of ions across the barrier between blood and brain. In this manner, the BBB performs the important function of regulating the volume and composition of brain interstitial fluid. Through functional coupling of luminal and abluminal transporters and channels, the BBB carries Na, Cl, and other ions from blood into brain, producing up to 30% of brain interstitial fluid in healthy brain. During ischemic stroke cerebral edema forms by processes involving increased activity of BBB luminal Na transporters, resulting in "hypersecretion" of Na, Cl, and water into the brain interstitium. This review discusses the roles of luminal BBB Na transporters in edema formation in stroke, with an emphasis on Na-K-Cl cotransport and Na/H exchange. Evidence that these transporters provide effective therapeutic targets for reduction of edema in stroke is also discussed, as are recent findings regarding signaling pathways responsible for ischemia stimulation of the BBB Na transporters.

Neurological consequences of diabetic ketoacidosis at initial presentation of type 1 diabetes in a prospective cohort study of children

OBJECTIVE

To investigate the impact of new-onset diabetic ketoacidosis (DKA) during childhood on brain morphology and function.

RESEARCH DESIGN AND METHODS

Patients aged 6-18 years with and without DKA at diagnosis were studied at four time points: <48 h, 5 days, 28 days, and 6 months postdiagnosis. Patients underwent magnetic resonance imaging (MRI) and spectroscopy with cognitive assessment at each time point. Relationships between clinical characteristics at presentation and MRI and neurologic outcomes were examined using multiple linear regression, repeated-measures, and ANCOVA analyses.

RESULTS

Thirty-six DKA and 59 non-DKA patients were recruited between 2004 and 2009. With DKA, cerebral white matter showed the greatest alterations with increased total white matter volume and higher mean diffusivity in the frontal, temporal, and parietal white matter. Total white matter volume decreased over the first 6 months. For gray matter in DKA patients, total volume was lower at baseline and increased over 6 months. Lower levels of N-acetylaspartate were noted at baseline in the frontal gray matter and basal ganglia. Mental state scores were lower at baseline and at 5 days. Of note, although changes in total and regional brain volumes over the first 5 days resolved, they were associated with poorer delayed memory recall and poorer sustained and divided attention at 6 months. Age at time of presentation and pH level were predictors of neuroimaging and functional outcomes.

CONCLUSIONS

DKA at type 1 diabetes diagnosis results in morphologic and functional brain changes. These changes are associated with adverse neurocognitive outcomes in the medium term.

The International Society of Pediatric and Adolescent Diabetes guidelines for management of diabetic ketoacidosis: Do the guidelines need to be modified?

The current version of the International Society of Pediatric and Adolescent Diabetes (ISPAD) guidelines for management of diabetic ketoacidosis (DKA) is largely based on the Lawson Wilkins Pediatric Endocrine Society/European Society of Pediatric Endocrinology (LWPES/ESPE) consensus statement on DKA in children and adolescents published in 2004. This article critically reviews and presents the most pertinent new data published in the past decade, which have implications for diagnosis and management. Four elements of the guidelines warrant modification: (i) The definition of DKA; (ii) insulin therapy; (iii) water and salt replacement; and (iv) blood ß-hydroxybutyrate measurements for the management of DKA.

Cerebral hyperemia measured with near infrared spectroscopy during treatment of diabetic ketoacidosis in children

OBJECTIVE

To use near infrared spectroscopy (NIRS) to evaluate the timing of onset and duration of cerebral hyperemia during diabetic ketoacidosis (DKA) treatment in children, and to investigate the relationship of cerebral hyperemia to intravenous fluid treatment.

STUDY DESIGN

We randomized children aged 8-18 years with DKA to either more rapid or slower intravenous fluid treatment (19 total DKA episodes). NIRS was used to measure rSo2 during DKA treatment. NIRS monitoring began as soon as informed consent was obtained and continued until the patient was transferred out of the critical care unit.

RESULTS

rSo2 values above the normal range (>80%) were detected in 17 of 19 DKA episodes (mean rSo2 during initial 8 hours of DKA treatment: 86% ± 7%, range 65%-95%). Elevated rSo2 values were detected as early as the second hour of DKA treatment and persisted for as long as 27 hours. Hourly mean rSo2 levels during treatment did not differ significantly by fluid treatment group.

CONCLUSIONS

During DKA treatment, children have elevated rSo2 values consistent with cerebral hyperemia. Hyperemia occurs as early as the second hour of DKA treatment and may persist for ≥ 27 hours. Cerebral rSo2 levels during treatment did not differ significantly in patients treated with slower versus more rapid intravenous rehydration.

Pediatric diabetic ketoacidosis, fluid therapy, and cerebral injury: the design of a factorial randomized controlled trial

Treatment protocols for pediatric diabetic ketoacidosis (DKA) vary considerably among centers in the USA and worldwide. The optimal protocol for intravenous (IV) fluid administration is an area of particular controversy, mainly in regard to possible associations between rates of IV fluid infusion and the development of cerebral edema (CE), the most common and the most feared complication of DKA in children. Theoretical concerns about associations between osmotic fluid shifts and CE have prompted recommendations for conservative fluid infusion during DKA. However, recent data suggest that cerebral hypoperfusion may play a role in cerebral injury associated with DKA. Currently, there are no existing data from prospective clinical trials to determine the optimal fluid treatment protocol for pediatric DKA. The Pediatric Emergency Care Applied Research Network FLUID (FLuid therapies Under Investigation in DKA) study is the first prospective randomized trial to evaluate fluid regimens for pediatric DKA. This 13-center nationwide factorial design study will evaluate the effects of rehydration rate and fluid sodium content on neurological status during DKA treatment, the frequency of clinically overt CE and long-term neurocognitive outcomes following DKA.

Subclinical cerebral edema in children with diabetic ketoacidosis randomized to 2 different rehydration protocols

OBJECTIVE

Previous studies show that vasogenic cerebral edema (CE) occurs during diabetic ketoacidosis (DKA) treatment in children, but the role of intravenous fluids in contributing to CE is unclear. We used magnetic resonance diffusion weighted imaging to quantify subclinical CE in children with DKA randomized to 2 intravenous fluid regimens.

METHODS

Children with DKA were randomized to receive fluids at a more rapid rate (n = 8) or a slower rate (n = 10), with all other aspects of DKA treatment kept identical. Children underwent diffusion weighted imaging 3 to 6 hours and 9 to 12 hours after beginning DKA treatment and after recovery from DKA (≥ 72 hours after beginning treatment). We calculated brain apparent diffusion coefficient (ADC) values as the average of measurements in the basal ganglia, thalamus, frontal white matter, and hippocampus and determined the mean brain ADC value during DKA treatment by averaging data from the 3- to 6-hour and 9- to 12-hour measurements. The difference in mean brain ADC between DKA treatment and postrecovery was used as an index of the severity of CE during DKA treatment.

RESULTS

Mean brain ADC values during DKA treatment were significantly higher than postrecovery values, consistent with vasogenic CE (842 ± 38 vs 800 ± 41 × 10(-6) mm(2)/second, P = .002). We did not detect significant differences in ADC elevation in children treated with more rapid versus slower rehydration (β coefficient 0.11 for 1 SD change in ADC, 95% confidence interval: -0.91 to 1.13).

CONCLUSIONS

ADC changes during DKA treatment (reflective of vasogenic CE) do not appear to be substantially affected by the rate of intravenous fluid administration.

Effects of hyperglycemia and effects of ketosis on cerebral perfusion, cerebral water distribution, and cerebral metabolism

Diabetic ketoacidosis (DKA) may cause brain injuries in children. The mechanisms responsible are difficult to elucidate because DKA involves multiple metabolic derangements. We aimed to determine the independent effects of hyperglycemia and ketosis on cerebral metabolism, blood flow, and water distribution. We used magnetic resonance spectroscopy to measure ratios of cerebral metabolites (ATP to inorganic phosphate [Pi], phosphocreatine [PCr] to Pi, N-acetyl aspartate [NAA] to creatine [Cr], and lactate to Cr) and diffusion-weighted imaging and perfusion-weighted imaging to assess cerebral water distribution (apparent diffusion coefficient [ADC] values) and cerebral blood flow (CBF) in three groups of juvenile rats (hyperglycemic, ketotic, and normal control). ATP-to-Pi ratio was reduced in both hyperglycemic and ketotic rats in comparison with controls. PCr-to-Pi ratio was reduced in the ketotic group, and there was a trend toward reduction in the hyperglycemic group. No significant differences were observed in NAA-to-Cr or lactate-to-Cr ratio. Cortical ADC was reduced in both groups (indicating brain cell swelling). Cortical CBF was also reduced in both groups. We conclude that both hyperglycemia and ketosis independently cause reductions in cerebral high-energy phosphates, CBF, and cortical ADC values. These effects may play a role in the pathophysiology of DKA-related brain injury.

Cognitive dysfunction associated with diabetic ketoacidosis in rats

BACKGROUND

Type 1 diabetes mellitus in children may be associated with neurocognitive deficits of unclear cause. A recent retrospective study in children suggested possible associations between diabetic ketoacidosis (DKA) and decreased memory. The current investigation was undertaken to determine whether cognitive deficits could be detected after a single episode of DKA in an animal model.

METHODS

Streptozotocin was used to induce diabetes in juvenile rats, and rats were then treated with subcutaneous insulin injections. In one group, insulin was subsequently withdrawn to allow development of DKA, which was then treated with insulin and saline. After recovery from DKA, subcutaneous insulin injections were re-started. In the diabetes control group, rats continued to receive subcutaneous insulin and underwent sham procedures identical to the DKA group. One week after recovery, cognitive function was tested using the Morris Water Maze, a procedure that requires rats to locate a hidden platform in a water pool using visual cues. During a 10 day period, mean time to locate the platform (latency) during 4 trials per day was recorded.

RESULTS

Comparison of latency curves demonstrated longer mean latency times on days 7 and 8 in the DKA group indicating delayed learning compared to diabetic controls.

CONCLUSIONS

These data demonstrate that a single DKA episode results in measurable deficits in learning in rats, consistent with findings that DKA may contribute to neurocognitive deficits in children with type 1 diabetes.

Acute cerebral infarction and extra pontine myelinolysis in children with new onset type 1 diabetes mellitus

Neurological complications of diabetic ketoacidosis (DKA) are still associated with significant mortality and morbidity. We report on two children who suffered from acute cerebral infarction (CI) and extra pontine myelinolysis (EPM) at onset of type 1 diabetes. Initially, clinical management had not been performed according to generally accepted guidelines. Putative risk factors that may have predisposed for the development of acute cerebrovascular complications are discussed. Not only cerebral edema (CE) but also other severe neurological complications such as CI should be suspected when neurological deterioration occurs during DKA. We conclude that not only an exceeded rehydration therapy but also a rapidly reduced serum osmolality due to an unbalanced rapid blood sugar decrease and serum sodium increase may have lead to the neurological disease. We propose that a reserved and well-defined rehydration strategy in the first 6 (-12) h of therapy is crucial for recovery and can reduce neurological complications of patients with DKA.