Imaging of the brain in children with type I diabetes mellitus

Glycaemic Imbalances in Seizures and Epilepsy of Paediatric Age: A Literature Review

Cerebral excitability and systemic metabolic balance are closely interconnected. Energy supply to neurons depends critically on glucose, whose fluctuations can promote immediate hyperexcitability resulting in acute symptomatic seizures. On the other hand, chronic disorders of sugar metabolism (e.g., diabetes mellitus) are often associated with long-term epilepsy. In this paper, we aim to review the existing knowledge on the association between acute and chronic glycaemic imbalances (hyper- and hypoglycaemia) with seizures and epilepsy, especially in the developing brain, focusing on clinical and instrumental features in order to optimize the care of children and adolescents and prevent the development of chronic neurological conditions in young patients.

Bedside sonographic measurements of optic nerve sheath diameter in children with diabetic ketoacidosis

BACKGROUND

Bedside sonographic assessment of the optic nerve sheath has gained popularity for evaluating intracranial pressure in recent years.

OBJECTIVE

To investigate the bedside sonographic measurements of optic nerve sheath diameter (ONSD) and ONSD/eyeball diameter ratios, which are related with cerebral edema (CE), in children with diabetic ketoacidosis (DKA) before and after treatment.

METHODS

Children aged 12 months to 18 years, who were diagnosed with DKA were included. The ONSD was measured at 3 mm posterior to the globe in the anterior axial transbulbar view. The eyeball transverse diameter (ETD) and eyeball vertical diameter (EVD) were measured and ratios of ONSD/ETD and ONSD/EVD were calculated. Bedside ultrasound (US) examinations were performed at the beginning and at the end of fluid therapy.

RESULTS

About 43 patients were enrolled. About 12 (27.9%) patients had mild, 14 (32.6%) moderate, and 17 (39.5%) severe DKA. At baseline, the ONSD measurements and ratios were significantly higher in severe DKA group than in those with mild or moderate DKA group. All ONSD measurements, ONSD/ETD, and ONSD/EVD ratios at the end of therapy were significantly lower compared with baseline measurements. At the end of therapy, ONSD measurements and ratios were similar among DKA severity groups.

CONCLUSION

The ONSD measurements and ratios decreased from the beginning of DKA treatment, which could be considered as an indicator of an increase in intracranial pressure at the time of admission. Ocular US may serve as a promising tool to perform further risk stratification of children with DKA and to identify DKA-related CE.

Measurement of corneal thickness, optic nerve sheath diameter and retinal nerve fiber layer as potential new non-invasive methods in assessing a risk of cerebral edema in type 1 diabetes in children

AIMS

Some patients with diabetic ketoacidosis develop cerebral edema (CE) in the course of type 1 diabetes mellitus (T1D), which may result in central nervous system disorders and high mortality. The imperfection of existing neuroimaging techniques for early recognition of CE forces us to search for the new and non-invasive methods. The aim of the study was to assess the usefulness of new methods (pachymetry, transorbital ultrasonography-USG, optical coherence tomography-OCT study) in the assessment of the risk of CE occurrence in children with newly diagnosed T1D.

METHODS

The study group included 50 children with newly diagnosed T1D, 54 patients with long-term T1D as a reference group and 40 children without glucose tolerance disorders as controls. In all subjects, a corneal thickness (CCT) index with pachymeter, optic nerve sheath diameter (ONSD) using transorbital USG and retinal nerve fiber layer (RNFL) during OCT study were measured and compared with selected clinical parameters of T1D.

RESULTS

In patients from a study group at onset of T1D, the higher CCT (p < 0.001) and ONSD (p < 0.001) values were observed as compared to the results obtained after 48 h of metabolic compensation. The ONSD correlated negatively with pH value (r = - 0.64; p < 0.001), BE (r = - 0.54, p < 0.001) and HCO^3- (r = - 0.50; p < 0.001). A positive correlation between RNFL and Na⁺ levels (r = 0.47; p < 0.005) was also observed.

CONCLUSIONS

Transorbital USG and pachymetry may serve as the potential promising methods for the non-invasive assessment of the increased risk of development of CE in patients with T1D.

A Systematic Review and Meta-analysis of Executive Function Performance in Type 1 Diabetes Mellitus

OBJECTIVE

The aims of the study were to examine the current evidence for executive function (EF) performance differences between groups with type 1 diabetes mellitus (T1DM) and nondiabetic control groups during adolescence and early adulthood and to explore the relationships between EF and diabetes-related risk factors.

METHODS

A systematic review of the literature examining EF performance in groups with T1DM was conducted according to the PRISMA guidelines. Electronic database searches for published and unpublished literature yielded a final set of 26 articles after application of inclusion and exclusion criteria. A meta-analysis was conducted on a subset of these articles (n = 17) comparing EF performance in T1DM and control groups, across a total sample size of 1619.

RESULTS

Sixteen of 26 studies found significantly lower EF on at least one task in groups with T1DM. Meta-analyses of the performance difference between T1DM groups and control groups without diabetes showed that inhibition (g = -0.28, p < .001), working memory (g = -0.34, p < .001), set-shifting (g = -0.31, p = .012), and overall EF performance across these domains (g = -0.42, p < .001) were all significantly lower in groups with T1DM. Performance on specific EF domains also seemed to be differentially associated with early age of diabetes onset, chronic hyperglycemia and its complications, and severe hypoglycemia.

CONCLUSIONS

T1DM and its associated risk factors are related to subtle impairments across the inhibition, working memory, and set-shifting domains of EF. Lower EF may be a key factor contributing to behavioral and clinical problems experienced by individuals with T1DM.

Can Neuroimaging Markers of Vascular Pathology Explain Cognitive Performance in Adults With Sickle Cell Anemia? A review of the Literature

Adults with homozygous sickle cell anemia have, on average, lower cognitive function than unaffected controls. The mechanisms underlying cognitive deterioration in this population are poorly understood, but cerebral small vessel disease (CSVD) is likely to be implicated. We conducted a systematic review using the Prisma Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines of articles that included both measures of cognitive function and magnetic resonance imaging (MRI) neuroimaging markers of small vessel disease. While all five studies we identified reported small vessel disease by MRI, only two of them found a significant relationship between structural changes and cognitive performance. Differences in methodologies and small sample sizes likely accounted for the discrepancies between the studies. We conclude that while MRI is a valuable tool to identify markers of CSVD in this population, larger studies are needed to definitely establish a link between MRI-detectable abnormalities and cognitive function in sickle cell anemia.

Optic Nerve and Cerebral Edema in the Course of Diabetic Ketoacidosis

In the recent years we have been observing an increased incidence of type 1 diabetes in children and adolescents. This leads to a more frequent acute complication of type 1 diabetes among children with hyperglycemia. The most common of these is diabetic ketoacidosis (DKA), while cerebral edema is the most dangerous. In children with DKA, cerebral edema most often presents with clinical symptoms but may also appear in the so-called "subclinical" form. That is why the search continues for new methods of assessing and monitoring cerebral edema in the course of DKA treatment. Ultrasonographic optic nerve sheath diameter (US ONSD) assessment is performed in various clinical scenarios when cerebral edema is suspected. It is most often performed in adult patients but increasingly often in children. US ONSD assessment is useful in the treatment of DKA in children with type 1 diabetes. This manuscript provides an overview of research results available in PubMed and other available databases on the course of treatment of DKA in children with type 1 diabetes.

Neuroimaging findings in acute pediatric diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is a state of severe insulin deficiency and a serious complication in children with diabetes mellitus type 1. In a small number of children, DKA is complicated by injury of the central nervous system. These children have a significant mortality and high long-term neurological morbidity. Cerebral edema is the most common neuroimaging finding in children with DKA and may cause brain herniation. Ischemic or hemorrhagic stroke during the acute DKA episode is less common and accounts for approximately 10% of intracerebral complications of DKA. Here we present the neuroimaging findings of two children with DKA and brain injury. Familiarity with the spectrum of neuroimaging findings seen in pediatric DKA is important to allow early detection as well as initiation of therapy and, hence, prevent complications of the central nervous system.

Cerebral Accidents in Pediatric Diabetic Ketoacidosis: Different Complications and Different Evolutions

Diabetic ketoacidosis (DKA) may be associated with neurologic complications: the most common is cerebral edema while the risk of venous and arterial stroke is rare. There is a pathogenetic link between DKA, hypercoagulability and stroke, whose risk is underestimated by clinicians. Our cases present a wide spectrum of cerebral accidents during DKA, the first one being diffuse cerebral edema, the second one venous stroke after 5 days of DKA resolution, while the third one multifocal edema suspected to be extrapontine myelinolysis although without electrolyte imbalance. Our cases suggest that DKA requires very accurate treatment, particularly at an early age, and it can be complicated by cerebral accidents even with appropriate medical care.

Hyperglycaemia is associated with changes in the regional concentrations of glucose and myo-inositol within the brain

AIMS/HYPOTHESIS

The aim of the study was to assess the effect of hyperglycaemia on regional concentrations of glucose and other substrates within the brain in non-diabetic individuals and in patients with type 1 diabetes.

METHODS

The brain metabolites of 17 men with type 1 diabetes and 12 age-matched non-diabetic men (22-43 years old) were studied after an overnight fast (plasma glucose 9.2 +/- 3.0 vs 4.8 +/- 0.5 mmol/l, respectively). N-Acetylaspartate (NAA), creatine, choline, myo-inositol (mI) and glucose in the frontal cortex, frontal white matter and thalamus were quantified with proton magnetic resonance spectroscopy.

RESULTS

In the non-diabetic participants, the glucose level was 47% higher (p < 0.01) in the frontal cortex than in the frontal white matter. In contrast, this regional variation was not observed in the diabetic participants, in whom the glucose level in the frontal white matter was 64% higher (p < 0.001) and in the frontal cortex 25% higher (p = 0.033) than that of the non-diabetic participants. In the diabetic participants, the glucose level in each of the three regions studied correlated with fasting plasma glucose (r = 0.88-0.67, p < 0.01). In addition, in the diabetic participants, mI was 20% higher (p < 0.001) and NAA 6% lower (p = 0.037) in the frontal white matter, and mI was 8% higher (p = 0.042) in the frontal cortex, than in the non-diabetic participants.

CONCLUSIONS/INTERPRETATION

In type 1 diabetes, hyperglycaemia is associated with accumulation of glucose and mI in the cortex and in the white matter.

Plasticity of central autonomic neural circuits in diabetes

Regulation of energy metabolism is controlled by the brain, in which key central neuronal circuits process a variety of information reflecting nutritional state. Special sensory and gastrointestinal afferent neural signals, along with blood-borne metabolic signals, impinge on parallel central autonomic circuits located in the brainstem and hypothalamus to signal changes in metabolic balance. Specifically, neural and humoral signals converge on the brainstem vagal system and similar signals concentrate in the hypothalamus, with significant overlap between both sensory and motor components of each system and extensive cross-talk between the systems. This ultimately results in production of coordinated regulatory autonomic and neuroendocrine cues to maintain energy homeostasis. Therapeutic metabolic adjustments can be accomplished by modulating viscerosensory input or autonomic motor output, including altering parasympathetic circuitry related to GI, pancreas, and liver regulation. These alterations can include pharmacological manipulation, but surgical modification of neural signaling should also be considered. In addition, central control of visceral function is often compromised by diabetes mellitus, indicating that circuit modification should be studied in the context of its effect on neurons in the diabetic state. Diabetes has traditionally been handled as a peripheral metabolic disease, but the central nervous system plays a crucial role in regulating glucose homeostasis. This review focuses on key autonomic brain areas associated with management of energy homeostasis and functional changes in these areas associated with the development of diabetes.

Cognition and brain imaging in type 1 diabetes

Type 1 diabetes has mild effects on cognition that are influenced by age of onset, hyperglycemia, and hypoglycemic episodes. Some of these changes occur quite early in the disease course. Studies using relatively new brain imaging techniques have also shown brain changes in adults and children that appear to be influenced by metabolic abnormalities present in diabetes. Early detections of brain changes may be early indicators of subsequent cognitive abnormalities.