Nonketotic hyperglycemia-related epileptic seizures

Interplay between biochemical processes and network properties generates neuronal up and down states at the tripartite synapse

Neuronal up and down states have long been known to exist both in vitro and in vivo. A variety of functions and mechanisms have been proposed for their generation, but there has not been a clear connection between the functions and mechanisms. We explore the potential contribution of cellular-level biochemistry to the network-level mechanisms thought to underlie the generation of up and down states. We develop a neurochemical model of a single tripartite synapse, assumed to be within a network of similar tripartite synapses, to investigate possible function-mechanism links for the appearance of up and down states. We characterize the behavior of our model in different regions of parameter space and show that resource limitation at the tripartite synapse affects its ability to faithfully transmit input signals, leading to extinction-down states. Recovery of resources allows for "reignition" into up states. The tripartite synapse exhibits distinctive "regimes" of operation depending on whether ATP, neurotransmitter (glutamate), both, or neither, is limiting. Our model qualitatively matches the behavior of six disparate experimental systems, including both in vitro and in vivo models, without changing any model parameters except those related to the experimental conditions. We also explore the effects of varying different critical parameters within the model. Here we show that availability of energy, represented by ATP, and glutamate for neurotransmission at the cellular level are intimately related, and are capable of promoting state transitions at the network level as ignition and extinction phenomena. Our model is complementary to existing models of neuronal up and down states in that it focuses on cellular-level dynamics while still retaining essential network-level processes. Our model predicts the existence of a "final common pathway" of behavior at the tripartite synapse arising from scarcity of resources and may explain use dependence in the phenomenon of "local sleep." Ultimately, sleeplike behavior may be a fundamental property of networks of tripartite synapses.

Consideration for Hemiballismus in the Differential Diagnosis: A Rare Case of Hyperosmolar Hyperglycemic State

We present a case of a 58-year-old male with a past medical history of hypertension and diabetes mellitus presenting to the emergency department with a complaint of abnormal and uncontrollable right arm jerking motions occurring since the afternoon on the day prior to presentation. Arm movements such as these may be consistent with either focal seizures or hemiballismus, a movement disorder classified as a choreiform subtype consisting of involuntary violent movements of an extremity with wide amplitudes. Although oftentimes focal seizures and hemiballismus are associated with neurologic etiologies such as strokes, the second most common cause of hemiballismus appears to be non-ketotic hyperosmolar hyperglycemia. While symptomatic treatment in managing focal seizures and hemiballismus may consist of benzodiazepines and dopamine receptor antagonists, respectively, it is important to treat the underlying cause, which in this case was the non-ketotic hyperosmolar hyperglycemic state associated with this patient’s long-standing history of poorly controlled diabetes mellitus.

Epileptic seizures during Non-Ketotic Hyperglycemia (NKH) in French Guiana: A retrospective study

INTRODUCTION

Epileptic seizures during non-ketotic hyperglycemia (NKH) represent a rare complication of uncontrolled diabetes mellitus. The definition associates a blood sugar level > 200mg/dL (11mmol/L), hyperosmolality, absence of ketosis, dehydration and seizure control after normalization of blood sugar levels.

MATERIAL AND METHODS

This retrospective observational study included patients hospitalized for epileptic seizures and NKH in the Cayenne Hospital Center between January 2010 and June 2020. The clinical, biological, and radiological results were collected.

RESULTS

18 out of 228 (7.9%) patients with both diabetes and epileptic seizures had NKH. The mean age of the 12 women and 6 men was 64.8 years. In 8 patients, brain imaging did not show acute lesions and the seizures disappeared with control of hyperglycemia by hydration and insulin. In 6 patients, the seizures revealed a stroke, hemorrhagic in 4 cases, ischemic in 2 cases. 4 patients had a seizure in a context of known vascular epilepsy. The epileptic seizures were mainly focal seizures with motor symptoms that could be repeated, focal to bilateral tonic-clonic or focal status.

CONCLUSION

Seizures in NKH are symptomatic of an acute brain lesion or vascular epilepsy more than 1 in 2 times. However, isolated NKH can cause seizures with a suggestive brain MRI.

Focal Neurological Seizure due to Hyperglycemic Hyperosmolar Non-Ketotic Syndrome in Undiagnosed Diabetes Mellitus

Hyperglycemic hyperosmolar non-ketotic syndrome (HHNS) is a life-threatening complication of type 2 diabetes mellitus with a wide range of presenting symptoms. Neurological symptoms, such as coma, can also be part of the manifestation of HHNS; however, focal seizures remain a rare but notable association. 

A 85-year-old male patient with no history of diabetes presented to our emergency department complaining of a two-day history of twitching movements of his left wrist. Laboratory findings suggested HHNS and his hemoglobin A1c were found to be 10.2%. He was aggressively treated in the intensive care unit with fluids and insulin which also resolved his seizure episodes. He was ultimately discharged in stable condition without any seizure-like activity while having good glycemic control. 

According to the American Diabetes Association, about 25% of all individuals 65 years and older have diabetes mellitus. With an increasing prevalence, the complications of uncontrolled diabetes are also becoming more notable. While the neurological deficits associated with HHNS are focal, the mechanism by which this occurs is still poorly understood and underreported warranting further studies. 

Hyperglycaemia-related occipital lobe seizures

Recognition of the role of hyperglycaemia in seizures is vital, because they tend to refractory to antiepileptic drugs and respond to insulin therapy and hydration.