Focal neuronal loss, reversible subcortical focal T2 hypointensity in seizures with a nonketotic hyperglycemic hyperosmolar state

A Case of Hyperglycemia-Induced Epileptic Homonymous Hemianopsia

Hyperglycemia sometimes initially presents with neurological manifestations, including seizures, visual hallucinations, choreoathetosis, hemiballismus, myoclonus, tremor, and consciousness disturbance. Epileptic seizures induced by hyperglycemia are reported to occur predominantly in the occipital lobe, and the epileptic form is mainly epilepsia partialis continua. Of the two patterns of hyperglycemia (ketotic or nonketotic), nonketotic hyperglycemia is more commonly associated with seizures because ketosis has an anticonvulsive effect, so hyperglycemia-induced seizures are generally seen in nonketotic patients. Here, we report a 51-year-old Japanese male with intermittent homonymous hemianopsia who presented high hemoglobin A1c (19.1%). He had been drinking 3 L of the sugared soft beverage every day. After admission, he showed left-sided hemiconvulsion. Anti-seizure medications and insulin treatment were administered, and his seizure was aborted. The magnetic resonance imaging (MRI) showed a high-intensity lesion in the diffusion-weighted image and fluid-attenuated inversion recovery with gadolinium enhancement in the occipital lobe. In hyperglycemic convulsions, MRI sometimes shows leptomeningeal or parenchymal gadolinium enhancement. In addition, most hyperglycemic seizures are associated with nonketotic hyperglycemia and show occipital-dominant imaging abnormalities. We report this case by reviewing the differential diagnosis.

The Dark side of the White Matter. Diffuse subcortical White Matter Hypointensity on T2/FLAIR: A systematic review of a frequently underrecognized sign

BACKGROUND AND OBJECTIVES

Many reversible brain MRI abnormalities have been described, among these the most frequently reported are cortical hyperintensities on FLAIR/T2 occurring during seizures. Much less attention has been given to those situations where White Matter goes Dark: subcortical white matter hypointensity on T2/FLAIR. Our aim is to identify the medical condition "Dark White Matter" (DWM) is more frequently associated with. This is the first systematic review on DWM.

METHODS

PubMed was searched in August 2023. Included studies were those reporting Diffuse Subcortical White Matter Hypointensity on T2/FLAIR. Mainly case reports were included. Individual patient-level data was included whenever available. Frequency measures of the different diseases were calculated.

RESULTS

56 studies were included, 228 patients were eligible for analysis. DWM happened in isolation, with no cortical abnormalities, in 71 cases and was associated with seizures in >61.4% of cases. The most frequently DWM-associated disease was Non-Ketotic Hyperglycaemic hyperosmolar state (NKH), followed by Encephalitis, Moyamoya disease, Genetic Causes, and Subdural Hematoma. Frequency of NKH was 32%. NKH was associated with seizures in 100% of cases and the most frequently involved lobe was the occipital one. When considering only the subgroup of patients with seizures, DWM was indicative of NKH in 51.4% of cases and Encephalitis in 26.4% of cases. Key limitations are heterogeneity and missing data.

DISCUSSION

DWM is frequently underdiagnosed. This sign can exist alone and it is not merely a consequence of cortical involvement. Moreover, it has important implications, both diagnostic and therapeutic, as it is more frequently associated with NKH, especially in the context of seizures, where anti-seizure medication is not the first line of treatment. We also discuss the pathogenesis of DWM by finding a common link between the most frequently associated diseases.

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.

Glycine encephalopathy

Inherited neurotransmitter diseases are a subset of rare neurometabolic disorders characterized by hereditary deficiencies in neurotransmitter metabolism or transport. Non-ketotic hyperglycinaemia (NKH), called glycine encephalopathy, is an autosomal recessive glycine metabolism disorder characterized by an abnormal accumulation of glycine in all bodily tissues, including the CNS. The SLC6A9 gene, which codes for the GLYT1 protein, a biochemical abnormality in the GCS, and dihydrolipoamide dehydrogenase enzymes, which function as a GCS component, are responsible for the neonatal form's symptoms, which include progressive encephalopathy, hypotonia, seizures, and occasionally mortality in the first few days of life. By changing the MAPK signalling pathways, glycine deprivation in the brain damages neurons by increasing NMDA receptor activation, increasing intracellular Ca levels, and leading to DNA breakage and cell death in the neuron region. In addition to the previously mentioned clinical diagnosis, NKH or GE would be determined by MLPA and 13C glycine breath tests. Pediatricians, surgeons, neurologists, and geneticists treat NKH and GE at the newborn period; there is no cure for either condition.

What does epileptic nystagmus show us in cases presenting acute neurological symptoms?

PURPOSE

This study aims to determine the clinical significance of epileptic nystagmus in patients with acute neurological symptoms.

METHOD

The clinical findings of patients with documented epileptic nystagmus, their original video and EEG data, and cranial imaging and laboratory tests were analyzed retrospectively.

RESULTS

20 patients were included in the study and 21 epileptic nystagmus attacks were determined from patients' clinical and video-EEG recordings. All recorded seizures with epileptic nystagmus were focal onset in nature. The ictal discharge pattern was rhythmic fast activity with a mean frequency of 15 Hz. The ictal discharges originated from the parieto-occipital (n = 8), temporo-occipital (n = 7), parieto-occipito-temporal (n = 3), temporal (n = 2), occipital (n = 1), and centroparietal (n = 1) areas. In the fast phase, the nystagmus was beating away from the side of ictal discharges. The origin of the ictal discharges on EEG images was compatible with the lesion localization at cranial MRI in all patients. Etiologies were epilepsy in seven patients, non-ketotic hyperglycemia in four, ketotic hyperglycemia in one, PRES in three, acute stroke in three, HSV encephalitis in one, and MELAS in one.

CONCLUSIONS

Epileptic nystagmus represents a guide to the lateralization and localization of the lesion in cases presenting with acute neurological symptoms. In these patients, the lesion is frequently in the posterior regions of the hemispheres. Although various diseases affect these regions in terms of etiology, such cases should be evaluated in terms of the presence of hyperglycemia.

Acute stroke-like deficits associated with nonketotic hyperglycemic hyperosmolar state: an illustrative case and systematic review of literature

Introduction

Nonketotic hyperglycemic hyperosmolar state (NKHHS) is associated with a wide spectrum of neurological syndromes including acute stroke-like deficits. Clinical features and etiology have not been established yet.

Methods

Here we provide a case illustration and systematic review on non-epileptic acute neurological deficits in NKHSS. The systematic literature search followed PRISMA guidelines and a predefined protocol, including cases of NKHSS with acute stroke-like presentation.

Results

The database search yielded 18 cases. Hemianopia was the most common clinical presentation (73%), followed by partial or total anterior circulation syndrome (26%). Patients with symptoms of acute anterior circulation infarct were significantly older (69.5 ± 5.1 vs. 52.2 ± 13.9 years; p = 0.03) and showed higher mean glucose levels at the admission vs. those with hemianopia (674.8 ± 197.2 vs. 529.4 ± 190.8 mg/dL; p = 0.16). Brain MRI was performed in 89% of patients, resulting abnormal in 71% of them, especially hemianopic (91%). Subcortical hypointensities in T2-FLAIR MR sequences were present in all the analyzed cases. Cortical DWI hyperintensities were also common (64%). EEG showed diffuse or focal slow wave activity in 68% of patients, especially with visual hallucinations (85%). Neurological symptoms completely resolved in 78% of patients within 6 (IQR 3–10) days, following aggressive treatment and glucose normalization.

Conclusions

Our results suggest neuronal dysfunction on a metabolic basis as the leading cause of acute neurological deficits in NKHHS. Despite the generally favorable prognosis, prompt identification and aggressive treatment are crucial to avoid irreversible damage. Larger cohort studies are needed to confirm our findings.

Fresh Cerebral Infarction-Like MRI Findings Mimicking Hyperosmolar Hyperglycemic Syndrome With Seizures

Hyperosmolar hyperglycemic syndrome (HHS) is a severe diabetes-related condition. Patients with HHS can present with abnormal magnetic resonance imaging (MRI) findings similar to those of fresh cerebral infarction. Here, we present the case of a 95-year-old woman with HHS who was initially misdiagnosed with seizures due to fresh cerebral infarction of the pons. Her MRI revealed small abnormal lesions in bilateral pons which showed hyperintensity on T2-weighted imaging and diffusion-weighted imaging. Thus, the patient was initially diagnosed with seizures associated with fresh cerebral infarction of the pons. However, hyperglycemia and hyperosmolarity were later observed, and the patient was diagnosed with HHS. Intravenous insulin and saline infusions were administered, which led to improvements in laboratory findings and seizures. The MRI findings of the pons disappeared after the treatment of HHS. Cortical restricted diffusion is observed in about 60% of cases with HHS, even if no obstruction of the artery is detected. On the contrary, patients with HHS have an increased risk of stroke during the treatment of HHS. Therefore, it is crucial for clinicians to examine patients with neurological symptoms associated with HHS not only based on MRI findings but also on neurological examination over time. In conclusion, clinicians should be aware of fresh cerebral infarction-like MRI findings in patients with HHS.

Epileptic manifestations, pathophysiology, and imaging characteristics of non-ketotic hyperglycaemia: a review of the literature and a report of two cases with irreversible cortical vision loss

The purpose of this review is to create more awareness regarding the epileptic manifestations of non-ketotic hyperglycaemia, which are not widely recognised, and to assist understanding of the pathophysiology involved. Given that type II diabetes is one of the common causes of morbidity worldwide, it is important to appreciate the various neurological manifestations of non-ketotic hyperglycaemia.Here, I present two cases and review the existing literature. Both patients developed irreversible vision loss, which is a novel finding because only transient visual defects have previously been reported. The review includes a detailed discussion of the pathophysiology and characteristic magnetic resonance imaging (MRI) findings of patients with defects in cerebral lobar regions, which were associated with a variety of clinical manifestations. These manifestations can be ascribed to epileptic phenomena involving various parts of the cerebrum.Hyperglycaemia can lead to the irreversible loss of vision. Early diagnosis and treatment on the basis of the clinical features and characteristic MRI findings are important to avoid an epilepsia partialis continua-like state and irreversible visual impairment.

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.

Irreversible Homonymous Hemianopia Associated with Severe Hyperglycemia and Cerebral Hyperperfusion: A Case Report and Literature Review

A 68-year-old man was admitted to our department because of left incomplete homonymous hemianopia accompanied by hyperglycemia. Both T2-weighted and diffusion-weighted imaging revealed a low signal intensity along the subcortex and high signal intensity along the cortex on the right parietal and occipital lobes. Furthermore, arterial spin labeling and single-photon emission computed tomography showed hyperperfusion at the right parieto-occipital lobe. However, the electroencephalography result was normal. Hyperperfusion improved after controlling the blood glucose levels; nevertheless, homonymous hemianopia remained. We suspect that the irreversible brain damage was attributable to hyperperfusion associated with long-term hyperglycemia.

Diagnosis and Management of the Critically Ill Adult Patient with Hyperglycemic Hyperosmolar State

BACKGROUND

Hyperglycemic hyperosmolar state is a life-threatening complication of diabetes mellitus. Therefore, it is important for emergency physicians to be aware of this unique diagnosis and treatment considerations.

OBJECTIVE

This manuscript reviews the emergency department evaluation and management of the adult patient with hyperglycemic hyperosmolar state.

DISCUSSION

Hyperglycemic hyperosmolar state is diagnosed by an elevated glucose, elevated serum osmolality, minimal or absent ketones, and a neurologic abnormality, most commonly altered mental status. Treatment involves fluid resuscitation and correction of electrolyte abnormalities. It is important to monitor these patients closely to avoid overcorrection of osmolality, sodium, and other electrolytes. These patients are critically ill and generally require admission to an intensive care unit.

CONCLUSIONS

Hyperglycemic hyperosmolar state is associated with significant morbidity and mortality. It is important for clinicians to be aware of the current evidence regarding the diagnosis, management, and disposition of these patients.

Hyperglycemic hemianopia: A case report

BACKGROUND

Nonketotic hyperglycemia (NKH) is characterized by hyperglycemia with little or no ketoacidosis. Diverse neurological symptoms have been described in NKH patients, including choreoathetosis, hemiballismus, seizures, and coma in severe cases. Homonymous hemianopia, with or without occipital seizures, caused by hyperglycemia is less readily recognized.

CASE SUMMARY

We describe a 54-year-old man with NKH, who reported seeing round, colored flickering lights with right homonymous hemianopia. Cranial magnetic resonance imaging demonstrated abnormalities in the left occipital lobe, with decreased T2 signal of the white matter, restricted diffusion, and corresponding low signal intensity in the apparent diffusion coefficient map. He responded to rehydration and a low-dose insulin regimen, with improvements of his visual field defect.

CONCLUSION

Patients with NKH may present focal neurologic signs. Hyperglycemia should be taken into consideration when making an etiologic diagnosis of homonymous hemianopia.

Arterial spin labeling hyperperfusion in seizures associated with non-ketotic hyperglycaemia: is it merely a post-ictal phenomenon?

A 53-year-old chronic uncontrolled diabetic patient presented with one episode of generalized seizures followed by drowsiness and post-ictal confusion. MR imaging at admission revealed left temporal subcortical T2/FLAIR hypointensities with overlying cortical T2/FLAIR hyperintensities and increased perfusion on arterial spin labeling (ASL). Follow-up imaging at 4- and 8-week interval revealed persistent ASL hyperperfusion with significant resolution of conventional MR imaging findings. Delayed persistent ASL hyperperfusion suggests that hyperglycemia-induced increased blood-brain barrier permeability rather than a mere post-ictal phenomenon in non-ketotic hyperglycemia (NKH) and may result in long-term cognitive disturbances.

Transient Homonymous Superior Quadrantanopsia in Nonketotic Hyperglycemia: A Case Report and Systematic Review

Background and Purpose

Nonketotic hyperglycemia often causes transient visual field defects, but only scattered anecdotes are available in the literature.

Methods

We report a patient with homonymous superior quadrantanopsia due to nonketotic hyperglycemia and provide a systematic literature review of the clinical features of 40 previously reported patients (41 in total, including our case) with homonymous visual field defects in association with nonketotic hyperglycemia.

Results

The typical visual field defect was congruous (84.6%), homonymous hemianopsia (87.8%) with macular splitting (61.5%) or sparing (38.5%). It was transient and repetitive in 54.5% of the patients, but it developed as a persistent form in the remainder. Positive visual symptoms such as hallucinations and phosphenes developed in 73.2% of patients. Brain MRI revealed corresponding abnormalities in most patients (84.8%), characterized by a low-intensity white-matter signal or a high-intensity gray-matter signal on T2-weighted or fluid-attenuated inversion recovery images with diffusion restriction or gadolinium enhancement. Most (97.0%) patients recovered completely, with 48.5% treated by glycemic control alone and the remainder also receiving antiepileptic agents.

Conclusions

Nonketotic hyperglycemia should be considered a possible cause of transient visual field defects, especially when it is associated with repetitive positive visual symptoms and typical MRI findings in hyperglycemic patients.

Magnetic resonance imaging findings in patients with non-ketotic hyperglycaemia and focal seizures

We present the neuroimaging findings of three cases of non-ketotic hyperglycaemia (NKH) associated with focal seizures and a review of the previous cases and series reported in literature. NKH is a cause of seizures in both long-standing and newly diagnosed diabetic patients. They are usually focal motor seizures, rarely with a secondary generalisation. This condition does not fully respond to anticonvulsant therapy if glycaemic levels are not normalised. Of interest, magnetic resonance imaging (MRI) of NKH could be different from those observed during other kinds of seizures. Indeed, seizure-related MRI abnormalities mainly involve the cortical grey matter, while NKH-related seizures usually appear as reversible subcortical T2/fluid attenuation inversion recovery (FLAIR) hypointensity. This latter abnormality shows a good spatial correlation with the area of the ictal focus on electroencephalogram and could be associated with other more common post-ictal MRI changes (cortical grey matter T2/FLAIR hyperintensity, cortical or leptomeningeal enhancement). Although these abnormalities tend to be transient, a focal volume loss or gliosis can result on follow-up imaging. Our cases confirm T2/FLAIR subcortical hypointensity as a main neuroradiological hallmark of NKH-induced seizures.

"Negative T2 shine through" in patients with hyperglycemia and seizures: a frequently overlooked MRI pattern

Epileptic seizures associated with hyperglycemia have a rare but characteristic MR imaging pattern which however is frequently missed. It consists of a T2 hypointensity and an apparent diffusion coefficient (ADC) decrease of the white matter underlying the epileptic cortex; the cortex itself may be DWI hyperintense and show a blood-brain barrier disruption. Prompt diagnosis is relevant since treatment of the hyperglycemic state rather than treatment with anti-epileptic drugs frequently interrupts the seizures. Subcortical T2 hypointensity and ADC decrease may be completely reversible.

Brain MRI findings in non-ketotic hyperglycemic crisis: Case report

Introduction: Seizures related to metabolic disorders are common phenomena in many clinical contexts. However, clinical manifestations and neuroimaging findings in the context of a hyperglycemic crisis are less frequent phenomena with unclear pathophysiology.Case report: A 68-year-old man presented focal seizures and right homonymous hemianopsia after a non-ketotic hyperglycemic crisis. Brain MRI showed cortical diffusion restriction and subcortical T2 / FLAIR hypointensity in left occipital, temporal (mesial) and parietal lobes. Spectroscopy was performed showing a nonspecific pattern, cerebrospinal fluid was normal and there was improvement with glycemic control. MRI findings were considered secondary to the hyperglycemic crisis.Conclusion: Non-ketotic hyperglycemic states can manifest with several rare neurological alterations and recognizing them early is of vital importance given their potential reversibility. As in other metabolic disorders, epileptic seizures in this context can have focal-type characteristics. Although pathophysiological mechanisms are not clearly elucidated yet, multiple neuroimaging techniques promise to establish patterns that allow accurate and timely diagnosis.

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.

Hyperglycemia-induced seizures - Understanding the clinico- radiological association

Objectives:

To highlight the typical magnetic resonance imaging (MRI) findings in hyperglycemia-induced seizures and compare the results with similar previous studies with a brief mention of pathophysiological mechanisms.

Materials and Methods:

This retrospective study included medical and imaging records of six consecutive patients with hyperglycemia-induced seizures. The data analysis included a clinical presentation and biochemical parameters at admission. The MRI sequences were evaluated for region involved, presence of subcortical T2 hypo-intensity, cortical hyper-intensity, and restricted diffusion. Similar previous studies from the National Library of Medicine (NLM) were analyzed and compared with our study.

Results:

Twenty-four patients were included from four studies in previous literature for comparison. In our study, on imaging, posterior cerebral region was predominantly involved, with parietal involvement in 83.3%, followed by occipital, frontal, and temporal involvement in 33.3% patients compared with occipital in 58.3%, parietal in 45.8%, and frontal and temporal in 16.6% of patients in previous literature. The subcortical T2 hypo-intensity was present in 83.3% of the patients, cortical hyper-intensity in all patients, and restricted diffusion in 66.6% of the patients in our study compared with subcortical T2 hypo-intensity in 95.8% of the patients, cortical hyper-intensity in 62.5%, and restricted diffusion in 58.3% of the patients in previous literature.

Conclusion:

Although many etiologies present with subcortical T2 hypointensity, cortical hyperintensity, restricted diffusion, and postcontrast enhancement on MRI, the clinical setting of seizures in a patient with uncontrolled hyperglycemia, hyperosmolar state, and absence of ketones should suggest hyperglycemia-induced seizures to avoid misdiagnosis, unnecessary invasive investigations, and initiate timely management.

Advances in Knowledge:

Our study highlights the presence of posterior predominant subcortical T2, fluid-attenuated inversion recovery (FLAIR), and susceptibility-weighted angiography (SWAN) hypointensity; cortical hyperintensity; and restricted diffusion in hyperglycemia-induced seizures. The presence of T2 and SWAN hypointensity could support the hypothesis of possible deposition of free radicals and iron in the subcortical white matter.

Decreased Subcortical T2 FLAIR Signal Associated with Seizures

Abnormally decreased T2/T2 FLAIR signal can be seen on brain imaging of patients who are experiencing clinical or subclinical seizures and can be associated with various intracranial pathologies. We identified 29 such patients. The abnormal signal was unilateral in 75.9% of patients. It affected various lobes of the brain, but only in the anterior circulation. In 28 patients (96.6%), there was corresponding decreased signal on DWI. The ADC was normal in all cases. In 26 patients (89.7%), there was corresponding low signal on SWI/gradient recalled-echo; 44.8% of patients underwent contrast-enhanced scans, and there was no abnormal enhancement. Twenty-two (75.9%) patients had documented clinical seizures on the day of imaging. The most frequent concomitant pathology was a subdural hematoma. Electroencephalograms obtained within 24 hours of imaging were available in 65.5%. Findings of all of these electroencephalograms were abnormal, and these electroencephalogram changes were either localized to the area of the abnormal MR imaging signal (where the signal was unilateral) or were bilateral (where the MR imaging changes were bilateral). In summary, decreased white matter T2/T2 FLAIR signal changes can be seen in patients with remarkably similar clinical findings (particularly seizures). These changes are often correlated with abnormal electroencephalogram activity localized to the involved lobes.

Mimickers of neuropsychiatric manifestations in systemic lupus erythematosus

Systemic lupus erythematosus (SLE), presenting with new onset or worsening neuropsychiatric (NP) symptoms, is a challenge in clinical practice. Mimickers such as infections, drug-induced side effects, metabolic abnormalities, malignancies, and alcohol-related disorders have to be excluded, before attributing the manifestations to disease activity. Proper diagnosis is essential to guide adequate management and reduce morbidity and mortality. In this review article, we will highlight clinical, laboratorial, and neuroradiological features that are helpful to assist in the differential diagnosis.

Unusual Magnetic Resonance Imaging Abnormality in Nonketotic Hyperglycemia - related Epilepsia Partialis Continua

Epilepsia partialis continua (EPC) is a rare epileptic syndrome, presenting as continuous focal motor seizures for a period of minutes, hours, or days. EPC may develop in patients with cerebral cortical lesions and occasionally may develop in patients with metabolic disorders, such as nonketotic hyperglycemia (NKH). Here, we report a case of EPC following NKH, showing an unusual magnetic resonance imaging (MRI) finding of concurrent hypointensity on susceptibility-weighted image (SWI) and T2-weighted image (T2WI) with leptomeningeal and cortical enhancement, which have never been reported. A 68-year-old woman presented to our emergency department with a 3-day history of involuntary repeated contraction of the right side of the face and upper limb. Laboratory data revealed NKH of diabetes mellitus. Electroencephalography (EEG) was unremarkable. Brain MRI revealed focal cortical and leptomeningeal enhancement together with subcortical T2 shortening and SWI hypointensity of the left frontal operculum. She responded well for hyperglycemia and antiepileptic drug therapy. Follow-up brain MRI performed 1 week later showed complete resolution of the abnormal signal and enhancement in the same region. Although EPC caused by NKH occurs rarely, it may result in an MRI abnormality of subcortical hypointensity on SWI and T2WI with leptomeningeal and cortical enhancement, which may be misinterpreted as other brain pathologies. Rapidly recognition is important because timely treatment with hydration and correction of hyperglycemia can lead to better outcome. We recommend such cases of metabolic disorder (such as hyperglycemia) for early consideration, particularly in the elderly.

An exploration of the spectrum of peri-ictal MRI change; a comprehensive literature review

PURPOSE

The aim of this review was to identify published studies in the literature relating to ictal induced MRI change and to identify certain common themes, practical points for clinicians and areas for future research.

METHODS

We identified 96 articles that satisfied our inclusion criteria yielding 575 cases. All articles were analysed; number of subjects, spectrum of MRI and EEG change, aetiology, and follow-up (both clinical and imaging) were noted.

RESULTS

The most frequent imaging changes were restricted diffusion, T2-hyperintensity and reduced ADC values. The mesial temporal structures and neocortex were most commonly affected locations though subcortical structures like the thalamus and pulvinar were also described. Practical clinical points included; the development of PLEDS concordant with ictal imaging change was associated with worse clinical prognosis, patients with seizures due to symptomatic aetiology may be more likely to develop ictal related imaging change and follow up is vitally important to ensure that ictal related oedema is not misidentified as a mass lesion or conversely that a mass lesion is not misidentified as ictal related change.

CONCLUSION

Qualitative MRI studies have provided clinicians with useful in-vivo insights into the dynamic ictal neuronal environment. Changes are not only localised to the ictal focus but can be remote and irreversible. Small patient numbers varying study design and high numbers of symptomatic seizures makes comparison between studies problematic. Also there is possible microstructural quantitative MRI changes that are missed on qualitative MRI. There is a need for prospective quantitative MRI studies in patients with epilepsy peri-icatlly with a uniform period of follow up and comparison to control data.

Glycine Administration Alters MAPK Signaling Pathways and Causes Neuronal Damage in Rat Brain: Putative Mechanisms Involved in the Neurological Dysfunction in Nonketotic Hyperglycinemia

High glycine (GLY) levels have been suggested to induce neurotoxic effects in the central nervous system of patients with nonketotic hyperglycinemia (NKH). Since the mechanisms involved in the neuropathophysiology of NKH are not totally established, we evaluated the effect of a single intracerebroventricular administration of GLY on the content of proteins involved in neuronal damage and inflammatory response, as well as on the phosphorylation of the MAPK p38, ERK1/2, and JNK in rat striatum and cerebral cortex. We also examined glial fibrillary acidic protein (GFAP) staining, a marker of glial reactivity. The parameters were analyzed 30 min or 24 h after GLY administration. GLY decreased Tau phosphorylation in striatum and cerebral cortex 30 min and 24 h after its administration. On the other hand, synaptophysin levels were decreased in striatum at 30 min and in cerebral cortex at 24 h after GLY injection. GLY also decreased the phosphorylation of p38, ERK1/2, and JNK 30 min after its administration in both brain structures. Moreover, GLY-induced decrease of p38 phosphorylation in striatum was attenuated by N-methyl-D-aspartate receptor antagonist MK-801. In contrast, synuclein, NF-κB, iκB, inducible nitric oxide synthase and nitrotyrosine content, and GFAP immunostaining were not altered by GLY infusion. It may be presumed that the decreased phosphorylation of MAPK associated with alterations of markers of neuronal injury induced by GLY may contribute to the neurological dysfunction observed in NKH.

Occipital lobe seizures and subcortical T2 and T2* hypointensity associated with nonketotic hyperglycemia: a case report

Background

Nonketotic hyperglycemia often causes seizures. Recently, seizures associated with nonketotic hyperglycemia have been found to be associated with subcortical T2 hypointensity on magnetic resonance imaging, especially in the occipital lobes. However, the mechanism remains unclear, although iron accumulation is suggested. We present a case of occipital lobe seizures associated with nonketotic hyperglycemia supporting the hypothesis that the mechanism of subcortical T2 hypointensity is iron accumulation using gradient-echo T2*-weighted magnetic resonance imaging.

Case presentation

A 65-year-old Japanese man complained of intermittent pastel-colored flashing lights. On neurological examination, he also had lower right-side quadrant hemianopia. No other abnormal neurological findings were found. On laboratory analysis, his blood glucose level was 370 mg/dL, HbA1c was 11.4 %, and serum osmolarity was 326 mOsm/L. No ketones were detected in urine. A magnetic resonance imaging scan of his head showed subcortical T2 and T2* hypointensity in his left occipital lobe. Single-photon emission computed tomography with I123-N-isopropyl-iodoamphetamine revealed hyperperfusion in the left dominant occipital lobe. These magnetic resonance imaging abnormalities resolved during clinical recovery and treatment to control his blood sugar level. Therefore, a diagnosis of occipital lobe seizures associated with nonketotic hyperglycemia was made.

Conclusions

To the best of our knowledge, this is the first case of occipital lobe seizures associated with nonketotic hyperglycemia supporting the role of iron accumulation as a mechanism for subcortical T2 hypointensity using T2*-magnetic resonance imaging.

Occipital lobe seizures: Rare hyperglycemic sequelae of type 1 diabetes mellitus

A 15-year-old boy presented with osmotic symptoms and photopsia. He had short-term memory impairment, visual hallucinations, and headache. His random blood sugar was 474 mg/dl, HbA1c -9.4%, and glutamic acid decarboxylase -65 >2000 IU/ml. Magnetic resonance imaging brain and cerebrospinal fluid study were normal. Digital electroencephalography was suggestive of bilateral hemispheric occipital lobe seizures. He responded well to insulin and antiepileptic medications.

Intracerebral Glycine Administration Impairs Energy and Redox Homeostasis and Induces Glial Reactivity in Cerebral Cortex of Newborn Rats

Accumulation of glycine (GLY) is the biochemical hallmark of glycine encephalopathy (GE), an aminoacidopathy characterized by severe neurological dysfunction that may lead to early death. In the present study, we evaluated the effect of a single intracerebroventricular administration of GLY on bioenergetics, redox homeostasis, and histopathology in brain of neonatal rats. Our results demonstrated that GLY decreased the activities of the respiratory chain complex IV and creatine kinase, induced reactive species generation, and diminished glutathione (GSH) levels 1, 5, and 10 days after GLY injection in cerebral cortex of 1-day-old rats. GLY also increased malondialdehyde (MDA) levels 5 days after GLY infusion in this brain region. Furthermore, GLY differentially modulated the activities of superoxide dismutase, catalase, and glutathione peroxidase depending on the period tested after GLY administration. In contrast, bioenergetics and redox parameters were not altered in brain of 5-day-old rats. Regarding the histopathological analysis, GLY increased S100β staining in cerebral cortex and striatum, and GFAP in corpus callosum of 1-day-old rats 5 days after injection. Finally, we verified that melatonin prevented the decrease of complex IV and CK activities and GSH concentrations, and the increase of MDA levels and S100β staining caused by GLY. Based on our findings, it may be presumed that impairment of redox and energy homeostasis and glial reactivity induced by GLY may contribute to the neurological dysfunction observed in GE.

Management of hyperosmolar hyperglycaemic state in adults with diabetes

Hyperglycaemic hyperosmolar state (HHS) is a medical emergency, which differs from diabetic ketoacidosis (DKA) and requires a different approach. The present article summarizes the recent guidance on HHS that has been produced by the Joint British Diabetes Societies for Inpatient Care, available in full at http://www.diabetologists-abcd.org.uk/JBDS/JBDS_IP_HHS_Adults.pdf. HHS has a higher mortality rate than DKA and may be complicated by myocardial infarction, stroke, seizures, cerebral oedema and central pontine myelinolysis and there is some evidence that rapid changes in osmolality during treatment may be the precipitant of central pontine myelinolysis. Whilst DKA presents within hours of onset, HHS comes on over many days, and the dehydration and metabolic disturbances are more extreme. The key points in these HHS guidelines include: (1) monitoring of the response to treatment: (i) measure or calculate the serum osmolality regularly to monitor the response to treatment and (ii) aim to reduce osmolality by 3-8 mOsm/kg/h; (2) fluid and insulin administration: (i) use i.v. 0.9% sodium chloride solution as the principal fluid to restore circulating volume and reverse dehydration, (ii) fluid replacement alone will cause a fall in blood glucose (BG) level, (iii) withhold insulin until the BG level is no longer falling with i.v. fluids alone (unless ketonaemic), (iv) an initial rise in sodium level is expected and is not itself an indication for hypotonic fluids and (v) early use of insulin (before fluids) may be detrimental; and (3) delivery of care: (i) The diabetes specialist team should be involved as soon as possible and (ii) patients should be nursed in areas where staff are experienced in the management of HHS.

Ornithine transcarbamylase deficiency presenting with acute reversible cortical blindness

Acute focal neurologic deficits are a rare but known presentation of ornithine transcarbamylase deficiency, particularly in females. We describe here a 6-year-old girl with newly diagnosed ornithine transcarbamylase deficiency who presents with an episode of acute cortical blindness lasting for 72 hours in the absence of hyperammonemia. Her symptoms were associated with a subcortical low-intensity lesion with overlying cortical hyperintensity on fluid-attenuated inversion recovery magnetic resonance imaging (MRI) of the occipital lobes. Acute reversible vision loss with these MRI findings is an unusual finding in patients with ornithine transcarbamylase deficiency. Our findings suggest a role for oxidative stress and aberrant glutamine metabolism in the acute clinical features of ornithine transcarbamylase deficiency even in the absence of hyperammonemia.

Postictal subcortical restricted diffusion in a child with focal symptomatic epilepsy

BACKGROUND

Diffusion abnormalities on MRI are well described after prolonged seizures. However, isolated, focal, subcortical restricted diffusion is uncommon.

PATIENT

A girl of Kurdish descent experienced focal-onset epilepsy secondary to a left thalamic infarction at age 3 years. At age 6 years, she developed status epilepticus in the context of a febrile illness.

RESULTS

Four days after the seizure, she had neurological deterioration including involuntary posturing movements and irritability. A brain MRI revealed left hemisphere subcortical restricted diffusion, predominantly in the frontal and occipital regions. She experienced persistent right hemiparesis for 2 months after the initial seizure.

CONCLUSIONS

This presentation is reminiscent of acute encephalopathy with biphasic seizures and late reduced diffusion, a syndrome thus far reported almost exclusively in Japan. This represents one of the few documented examples of acute encephalopathy with biphasic seizures and late reduced diffusion in an individual not of east Asian descent.

Occipital seizures and subcortical T2 hypointensity in the setting of hyperglycemia

INTRODUCTION

Occipital lobe seizures are a recognized manifestation of diabetic nonketotic hyperglycemia, though not as common as focal motor seizures. Occipital lobe white matter T2 hypointensity may suggest this diagnosis.

METHODS

We present a case of a 66-year-old man with hyperglycemia-related occipital lobe seizures who presented with confusion, intermittent visual hallucinations, and homonymous hemianopia.

RESULTS

Magnetic resonance imaging showed subcortical T2 hypointensity within the left occipital lobe with adjacent leptomeningeal enhancement. These findings were transient with disappearance in a follow-up MRI. The EEG captured frequent seizures originating in the left occipital region. HbA1c level was 13.4% on presentation, and finger stick blood glucose level was 400 mg/dl.

CONCLUSION

Hyperglycemia should be considered in the etiology of differential diagnosis of patients with visual abnormalities suspicious for seizures, especially when the MRI shows focal subcortical T2 hypointensity with or without leptomeningeal enhancement.

Neuroimaging in patients with abnormal blood glucose levels

SUMMARY

Smooth neuronal functioning requires an uninterrupted supply of energy that is provided by glucose under normal physiologic conditions. Significant variations in plasma glucose levels, be it hypoglycemia or hyperglycemia, can present with myriad clinical manifestations and may mimic stroke. At times, the diagnosis is either not apparent or not clinically suspected. Imaging can suggest the diagnosis in unsuspected cases and can help in the assessment of the extent of neuronal damage in known cases, making it vital for the neuroradiologist to be aware of both common and atypical neuroimaging findings in hypoglycemia and hyperglycemia.

Seizures and type 1 diabetes mellitus: current state of knowledge

In this review, we will try to analyze the possible coexistence between epilepsy or seizures and type 1 diabetes mellitus (T1DM), in order to establish if there is more than a casual association, and to investigate possible mechanisms underlying this link. Anti-glutamic acid decarboxylase antibodies (GAD-Abs) have been associated with T1DM and a great number of neurological diseases such as epilepsy. Epilepsy can be a feature of a large variety of autoimmune or inflammatory disorders. GAD-Abs can have a role at the basis of the possible link between epilepsy and T1DM, although their real pathogenetic mechanism in neurological diseases is still unknown. Metabolic conditions such as hypoglycemia and hyperglycemia, common problems in diabetic patients, may be also implicated, even if their underlying mechanism is minimally understood.

[Partial visual seizures induced by non-ketosic hyperglycemia: magnetic resonance imaging and visual evoked potential descriptions. A study of two cases reports with radiologic and electrophysiologic abnormalities]

INTRODUCTION

Non-ketosic hyperglycemia (NKH) may increase the likelihood of focal epileptic seizures, including commonly motor expression; rarely, they can have a visual expression.

METHODS

The authors describe the observation of two men, who were hospitalized for visual manifestations; with episodes of homonymous hemianopia and hallucinations, revealing occipital seizure, secondary to NKH. Clinical data and characteristics of the investigations, including radiological imaging (MRI) and electrophysiological results of visual evoked potentials (VEP) are specified.

RESULTS

MRI showed transitory low signal on T2 and FLAIR in occipital areas. Spectro-MR identified a moderate diminution of the NAA and lipids spikes, compatible with laminar necrosis. VEP revealed a transient decrease of the P100 amplitude.

DISCUSSION

These two observations underline the existence of acute symptomatic seizures with a visual starting point which is often indicative of diabetes. Through these observations with a review of 28 patients from the literature, MR imaging characteristics and possible anomalies collected on VEP are discussed. Such seizures are resistant to anticonvulsant treatment and respond best to insulin and rehydration.

CONCLUSION

The visual manifestations indicative of seizures with an occipital starting point in the context of NKH are possible enabling rapid initiation of effective symptomatic treatment with insulin.

Sub-chronic treatment with pioglitazone exerts anti-convulsant effects in pentylenetetrazole-induced seizures of mice: The role of nitric oxide

OBJECTIVES

Pioglitazone delayed the development of seizure responses and shortened the duration of convulsion of genetically epileptic EL mice. The anti-epileptic effect of pioglitazone was attributed partly through the reduction of inflammatory responses and preventing apoptosis. There are also some reports showing that some pioglitazone effects mediate through nitric oxide. In this study we evaluated sub-chronic pioglitazone effects in two models of intravenous and intraperitoneal pentylenetetrazole-induced clonic seizures in mice.

MATERIALS AND METHODS

Different doses of pioglitazone were administered orally for 10 days in different groups of male mice. L-NAME, a non selective inhibitor of nitric oxide synthase, aminoguanidine, a selective inhibitor of inducible nitric oxide synthase, or L-arginine, a nitric oxide donor, was administered acutely or sub-chronically to evaluate the role of nitric oxide in pioglitazone anti-seizure effects.

RESULTS

We demonstrated that sub-chronic administration of pioglitazone exerted anti-convulsant effects in both models of intravenous and intraperitoneal pentylenetetrazole. Acute and sub-chronic pre-administration of L-NAME prevented the anti-convulsant effect of pioglitazone in both models of intravenous and intraperitoneal pentylenetetrazole. Aminoguanidine did not alter the anti-convulsant effect of pioglitazone in two models of intravenous and intraperitoneal pentylenetetrazole. Both acute and sub-chronic pre-treatment of mice with L-arginine exerted anti-convulsant effect when administered with a non effective dose of pioglitazone in intraperitoneal method. In intravenous method, acute administration of L-arginine with a non-effective dose of pioglitazone enhanced the seizure clonic latency.

CONCLUSION

Taken together, sub-chronic pioglitazone treatment exerts anti-convulsant effects in intravenous and intraperitoneal pentylenetetrazole-induced seizures of mice probably through induction of constitutive nitric oxide synthase.

Rare presentation of unilateral weakness, involuntary movements and ataxia with subcortical t2 hypointensity in a diabetic patient: a case report

Subcortical T2 hypointensity on MRI is not a common finding. We present a case of subcortical T2 hypointensity in a diabetic patient, who was referred with weakness of left lower limb and involuntary movements and ataxia of the left upper limb. Lab reports confirmed the diagnosis of nonketotic hyperglycemia. It is rather important to identify subcortical T2 hypointensity which has only been recently found to be associated with nonketotic hyperglycemia. Early identification and prompt correction of blood sugar would help in alleviating the neurological symptoms.

Neuroimaging in seizure patients associated with nonketotic hyperglycemia

Nonketotic hyperglycemia (NKH) is a clinical syndrome consisting of hyperglycemia, hyperosmolality and intracellular dehydration but not ketoacidosis. This prospective study evaluated the clinical and magnetic resonance imaging abnormalities in six patients with NKH complicated with simple or complex partial seizures. Subcortical T2 hypointensity rather than hyperintensity together with contrast enhancement was a characteristic feature of seizures associated with NKH. Restricted diffusion on DWI and decreased NAA and/or Choline on MRS studies were also noted.