Neuroimaging in patients with abnormal blood glucose levels

Central nervous system microstructural alterations in Type 1 diabetes mellitus: A systematic review of diffusion Tensor imaging studies

AIMS

Type 1 diabetes mellitus (T1DM) is a chronic childhood disease with potentially persistent CNS disruptions. In this study, we aimed to systematically review diffusion tensor imaging studies in patients with T1DM to understand the microstructural effects of this entity on individuals' brains METHODS: We performed a systematic search and reviewed the studies to include the DTI studies in individuals with T1DM. The data for the relevant studies were extracted and a qualitative synthesis was performed.

RESULTS

A total of 19 studies were included, most of which showed reduced FA widespread in optic radiation, corona radiate, and corpus callosum, as well as other frontal, parietal, and temporal regions in the adult population, while most of the studies in the juvenile patients showed non-significant differences or a non-persistent pattern of changes. Also, reduced AD and MD in individuals with T1DM compared to controls and non-significant differences in RD were noted in the majority of studies. Microstructural alterations were associated with clinical profile, including age, hyperglycemia, diabetic ketoacidosis and cognitive performance.

CONCLUSION

T1DM is associated with microstructural brain alterations including reduced FA, MD, and AD in widespread brain regions, especially in association with glycemic fluctuations and in adult age.

Diabetic striatopathy in an adult with ketotic hyperglycaemia

Diabetic striatopathy (DS) is a rare and life-threatening mani- festation of diabetes. The disease commonly affects individuals of Asian descent, women and the elderly. DS is characterized by dyskinesias with basal ganglia hyperintensities on imaging. Despite being rare, prompt recognition of a hyperglycaemia- induced hemichorea-hemiballismus is essential because the symptoms are reversible with correction of hyperglycaemia. Diagnosis is based on blood analysis and neuroimaging findings. Laboratory tests reveal raised glycosylated haemoglobin (HbA1c) levels, which indicate poorly controlled diabetes. Neuroimaging provides suggestive findings of DS. It is usually associated with non-ketotic hyperglycaemia. We report a 50-year-old woman who presented with ketotic hyperglycaemia and left-sided hemichorea and partial seizures with secondary generalization.

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.

Imaging of metabolic and overload disorders in tissues and organs

Metabolic and overload disorders are a heterogeneous group of relatively uncommon but important diseases. While imaging plays a key role in the early detection and accurate diagnosis in specific organs with a pivotal role in several metabolic pathways, most of these diseases affect different tissues as part of a systemic syndromes. Moreover, since the symptoms are often vague and phenotypes similar, imaging alterations can present as incidental findings, which must be recognized and interpreted in the light of further biochemical and histological investigations. Among imaging modalities, MRI allows, thanks to its multiparametric properties, to obtain numerous information on tissue composition, but many metabolic and accumulation alterations require a multimodal evaluation, possibly using advanced imaging techniques and sequences, not only for the detection but also for accurate characterization and quantification. The purpose of this review is to describe the different alterations resulting from metabolic and overload pathologies in organs and tissues throughout the body, with particular reference to imaging findings.

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.

Thalamus L-Sign: A Potential Biomarker of Neonatal Partial, Prolonged Hypoxic-Ischemic Brain Injury or Hypoglycemic Encephalopathy?

BACKGROUND AND PURPOSE

Considerable overlap exists in the MR imaging features of hypoglycemic injury and hypoxic-ischemic brain injury, with similar predilections for the occipital and parietal lobes. In partial, prolonged hypoxia-ischemia, there is cortical destruction at the interarterial watershed zones, and in concomitant hypoglycemia and hypoxia-ischemia, an exaggerated final common pathway injury occurs. We interrogated secondary white matter tract-based thalamic injury as a tool to separate pure injuries in each group.

MATERIALS AND METHODS

A retrospective observational study of the MRIs of 320 children with a history of hypoxia-ischemia and/or hypoglycemia was undertaken with 3 major subgroups: 1) watershed-type hypoxic-ischemic injury, 2) neonatal hypoglycemia, and 3) both perinatal hypoxia-ischemia and proved hypoglycemia. Cerebral and thalamic injuries were assessed, particularly hyperintensity of the posterolateral margin of the thalami. A modified Poisson regression model was used to assess factors associated with such thalamic injury.

RESULTS

Parieto-occipital injuries occurred commonly in patients with hypoglycemia and/or hypoxia-ischemia. Eighty-five of 99 (86%) patients with partial, prolonged hypoxia-ischemia exhibited the thalamus L-sign. This sign was also observed in patients who had both hypoglycemia and hypoxia-ischemia, predominantly attributable to the latter. Notably, the risk of a thalamus L-sign injury was 2.79 times higher when both the parietal and occipital lobes were injured compared with when they were not involved (95% CI, 1.25-6.23; P = .012). The thalamus L-sign was not depicted in patients with pure hypoglycemia.

CONCLUSIONS

We propose the thalamus L-sign as a biomarker of partial, prolonged hypoxia-ischemia, which is exaggerated in combined hypoglycemic/hypoxic-ischemic injury.

Case Report: MRI, Clinical, and Pathological Correlates of Bromethalin Toxicosis in Three Dogs

Bromethalin toxicosis is an increasingly common clinical presentation in dogs that may be fatal depending on the extent of intoxication. Antemortem diagnosis of bromethalin toxicosis was achieved in three dogs by demonstration of the active metabolite desmethylbromethalin in fat or serum. Magnetic resonance imaging (MRI) findings were consistent with a diffuse leukoencephalopathy with restricted diffusion and prominent involvement of the corticospinal motor tracts on T2-weighted and diffusion-weighted sequences. Imaging findings were confirmed in one non-surviving dog at necropsy. Resolution of MRI abnormalities was demonstrated in one surviving dog that was consistent with the associated resolution of clinical signs. Initial findings in these dogs support further investigation of specific MRI patterns in cases of leukoencephalopathy to aid differential diagnosis. While antemortem detection of bromethalin and its metabolites confirms exposure, quantitation may be informative as a prognostic biomarker.

An Updated Overview of the Magnetic Resonance Imaging of Brain Iron in Movement Disorders

Brain iron load is one of the most important neuropathological hallmarks in movement disorders. Specifically, the iron provides most of the paramagnetic metal signals in the brain and its accumulation seems to play a key role, although not completely explained, in the degeneration of the basal ganglia, as well as other brain structures. Moreover, iron distribution patterns have been implicated in depicting different movement disorders. This work reviewed current literature on Magnetic Resonance Imaging for Brain Iron Detection and Quantification (MRI-BIDQ) in neurodegenerative processes underlying movement disorders.

Left Hemiplegia Possibly Due to Glucose Reperfusion Injury after Recovery of Severe Hypoglycemia in a Woman with Type 2 Diabetes Mellitus

A 79-year-old woman with type 2 diabetes receiving insulin was rushed to our hospital due to severe hypoglycemia. Glucose was administered, and the consciousness disturbance was promptly improved. A few hours later, conjugate deviation of the eyes to the right and left hemiplegia occurred at a normal glucose level. Cerebral magnetic resonance imaging (MRI) showed hyperintensities of the right posterior limb of the internal capsule and the medial thalamus on diffusion-weighted imaging sequences. However, the changes observed using MRI disappeared completely on the third day, and her symptoms subsequently improved. This may have been a case of glucose reperfusion injury.

Hypoglycemic hemiparesis as stroke mimic with transient splenial lesion and internal capsule involvement: A reversible clinico-radiological concurrence

Hypoglycemia presents with a spectrum of neurological manifestations ranging from lightheadedness to confusion and coma. We report here the case of a 61-year-old woman with right hemiparesis presenting within the window period for stroke thrombolysis. MRI brain showed diffusion restriction in posterior limb of left internal capsule and splenium. Patient had documented hypoglycemia of 38 mg/dL. Patient's hemiparesis resolved after glucose correction, and radiological findings completely resolved after 10 days. We present this case to highlight the rare radiological finding of simultaneous internal capsule and splenium involvement in hypoglycemic hemiparesis and the importance to rule out stroke mimics to avoid unwanted thrombolysis.

Uremic encephalopathy

Uremic encephalopathy encompasses a wide range of central nervous system abnormalities associated with poor kidney function occurring with either progressive chronic kidney disease or acute kidney injury. The syndrome is likely caused by retention of uremic solutes, alterations in hormonal metabolism, changes in electrolyte and acid-base homeostasis, as well as changes in vascular reactivity, blood-brain barrier transport, and inflammation. There are no defining clinical, laboratory, or imaging findings, and the diagnosis is often made retrospectively when symptoms improve after dialysis or transplantation. The diagnosis is also made difficult because of the many confounding and overlapping conditions seen in patients with chronic kidney disease and acute kidney injury. Thus, institution of kidney replacement therapy should be considered as a trial to improve symptoms in the right clinical context. Neurological symptoms that do not improve after improvement in clearance should prompt a search for other explanations. Further knowledge linking possible uremic retention solutes with neurological symptoms is needed to better understand this syndrome as well as to develop more tailored treatments that aim to improve cognitive function.

Acute Acquired Metabolic Encephalopathy Based on Diffusion MRI

Metabolic encephalopathy is a critical condition that can be challenging to diagnose. Imaging provides early clues to confirm clinical suspicions and plays an important role in the diagnosis, assessment of the response to therapy, and prognosis prediction. Diffusion-weighted imaging is a sensitive technique used to evaluate metabolic encephalopathy at an early stage. Metabolic encephalopathies often involve the deep regions of the gray matter because they have high energy requirements and are susceptible to metabolic disturbances. Understanding the imaging patterns of various metabolic encephalopathies can help narrow the differential diagnosis and improve the prognosis of patients by initiating proper treatment regimen early.

Intracranial Abnormalities with Diffusion Restriction

Multiple pathologic conditions can cause changes in the random movement of water, which can be detected with diffusion-weighted imaging (DWI). DWI plays a powerful clinical role in detecting restricted diffusion associated with acute brain infarction. Other disorders can also result in restricted diffusion. This article focuses on showing examples of common and uncommon disorders that have restricted diffusion secondary to cytotoxic and/or intramyelinic edema. These disorders include ischemia, infection, noninfectious demyelinating diseases, genetic mutations affecting metabolism, acquired metabolic disorders, toxic or drug exposures, neoplasms and tumorlike lesions, radiation treatment, trauma, and denervation.

3 Tesla serial magnetic resonance imaging of human African trypanosomiasis (Trypanosoma brucei gambiense) and review of the literature

We report serial magnetic resonance imaging (MRI) findings and follow-up in a case of human African trypanosomiasis (HAT) presenting with limited lesions followed by early and complete resolution. We searched the literature for documented cases and reviewed MRI findings before treatment. A 30-year-old Lebanese man, who had lived in Gabon for six years, presented with a two-year history of rash, anorexia, weight loss, arthralgia, paresthesia, and hypersomnia. Previously, the patient had received corticosteroid therapy for unconfirmed ANCA-associated vasculitis. Physical examination revealed a painless chancre on the left arm located at the site of an old insect bite, enlarged cervical, axillar and inguinal lymph nodes, hepatosplenomegaly and impaired concentration. Blood analysis showed an elevated protein level (90g/L) with hypoalbuminemia (24.2g/L) and elevated IgM (26.4g/L). Bone marrow aspirate and biopsy failed to detect any parasite. Polymerase chain reaction tests on blood and cerebrospinal fluid were positive for Trypanosoma. Serology tests confirmed the diagnosis of HAT due to Trypanosoma brucei gambiense infection. 3T MRI showed lesions in the hypothalamus and basal ganglia, the internal capsule, and the mesencephalon bilaterally. Follow-up MRI showed interval progression of the abnormalities. Treatment with melarsoprol was followed by clinical improvement with regression of the lesions on the three-month MRI, then total resolution at the 10-month follow-up. This case highlights a pattern of mild MRI lesions in T. brucei gambiense HAT with a total and rapid resolution under treatment. The literature review (16 HAT cases with sufficient radiological data, included ours) revealed an MRI pattern of brain lesion distribution that could be helpful for diagnosis and orienting biological tests.

Structural Gray and White Matter Differences in Patients With Type 1 Diabetes and Impaired Awareness of Hypoglycemia

CONTEXT

Type 1 diabetes (T1D) is associated with an increased risk of cognitive decline, where severe hypoglycemia (SH) and impaired awareness of hypoglycemia (IAH) may play a role. While there is evidence of a possible association between IAH and brain damage, the potential brain changes remain poorly characterized by magnetic resonance imaging (MRI).

OBJECTIVE

To investigate whether there are structural brain differences in a group of T1D patients with IAH compared with normal awareness of hypoglycemia (NAH).

DESIGN

General practice, population-based, cross-sectional study (July 2018 to July 2019).

SETTING

Endocrinology Department, Hospital Santa Creu i Sant Pau.

PARTICIPANTS

A total of 40 T1D patients (20 each with IAH and NAH) matched for age, sex, T1D duration, and education level.

MAIN OUTCOME MEASURES

Using different neuroimaging techniques, we compared whole-brain gray matter (GM) and white matter (WM) differences. We used voxel-based morphometry and cortical surface area analysis methods to assess GM differences, and fractional anisotropy (FA) to assess WM differences.

RESULTS

Compared with patients with T1D-NAH, patients with T1D-IAH had reduced GM volumes and cortical surface areas, especially in frontal and parietal regions (P < 0.05 corrected), and also showed reduced FA values in major WM tracts. The observed MRI differences correlated with both SH frequency and IAH severity.

CONCLUSIONS

MRI for patients with T1D show that IAH is associated with brain changes involving both GM and WM. Further research is needed to elucidate whether the observed differences are a consequence of increased SH episode frequency and increased IAH severity.

Clinical and Neuroimaging Features in a Patient with Non-Ketotic Hyperglycemia

Hemichorea–hemiballism (HC–HB) is a spectrum of involuntary flinging and flailing, non-patterned, irregular movements involving one side of the body. A rare dysfunction of glucose metabolism leading to a state of non-ketotic hyperglycemia (NKH) is thought to be a cause of these symptoms. In previous case studies, imaging findings have been in the basal ganglia as hyperintense lesions on magnetic resonance imaging (MRI) or hyperdensities on computerized tomography (CT). This case is unique due to abnormal findings in the MRI T2/fluid-attenuated inversion recovery (FLAIR) sequence in areas not previously reported—the thalamus and midbrain/pons. As in other NKH cases, the patient improved both clinically and radiologically. In patients with uncontrolled diabetes and abnormal movements, monitoring of blood glucose is imperative as it can lead to recognition of HC–HB. Other etiologies, including stroke, neoplasm, demyelination, and inflammatory processes, have uncertain prognoses with unfavorable outcomes. The prognosis for NKH is usually favorable, and thus important to identify.

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.

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.

Brain MRI Findings in Patients in the Intensive Care Unit with COVID-19 Infection

Online supplemental material is available for this article.

Bilateral lesions of the basal ganglia and thalami (central grey matter)-pictorial review

The basal ganglia and thalami are paired deep grey matter structures with extensive metabolic activity that renders them susceptible to injury by various diseases. Most pathological processes lead to bilateral lesions, which may be symmetric or asymmetric, frequently showing characteristic patterns on imaging studies. In this comprehensive pictorial review, the most common and/or typical genetic, acquired metabolic/toxic, infectious, inflammatory, vascular and neoplastic pathologies affecting the central grey matter are subdivided according to the preferential location of the lesions: in the basal ganglia, in the thalami or both. The characteristic imaging findings are described with emphasis on the differential diagnosis and clinical context.

Gyriform restricted diffusion in adults: looking beyond thrombo-occlusions

Gyriform restricted diffusion (GRD) refers to hyperintense signal involving the cerebral cortex on diffusion-weighted images (DWI) with corresponding hypointensity on apparent diffusion coefficient (ADC) images. These changes are commonly seen following a vascular occlusion, reflecting the limitation of water molecule movement across cell membranes (restricted diffusion) due to the failure of Na⁺/K⁺-ATPase pumps (cytotoxic oedema). However, GRD can occur in several other neurological conditions as well. A thorough understanding of these conditions and their anatomic predilection plays a critical role in identifying and differentiating them from vascular thrombo-occlusion, with impact towards appropriate clinical management. This review highlights the less commonly encountered, non-stroke causes of GRD in adults with case-based examples. A tabulated chart of the patterns of cortical and subcortical involvement associated with these aetiologies is provided for a quick, pattern-based reference for daily radiological reporting.

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.

New-Onset Diabetes Presenting as Monoballism Secondary to a Mixed Hyperglycemic Crisis

Monoballism secondary to a mixed hyperglycemic crisis is a rare initial symptom of new-onset diabetes, which commonly affects the elderly and Asian women having inadequate glycemic control. In hyperglycemic states, the elevated serum glucose levels raise the viscosity of the blood reducing cerebral perfusion, decreasing gamma-aminobutyric acid levels, the latter being an inhibitory neurotransmitter of thalamocortical stimuli. In this case, we report a previously healthy 41-year-old male who attended the emergency department because of an abrupt onset movement disorder of the left arm, this being compatible with monoballism. He was diagnosed with a mixed hyperglycemic crisis.

Stroke Mimics: The Quest for Leptomeningeal Anastomoses and Isolated Diffusion-Weigthed MR Signal

Stroke is caused by occlusion of a medium- or large-sized vessel in the brain. The treatment with either intravenous or intra-arterial thrombolysis is based on an accurate and time-sensitive diagnosis. On clinical and imaging grounds a number of entities-seizures, toxic-metabolic, infectious, or demyelinating diseases-can mimic stroke. Identifying them is paramount as the treatment differs significantly. Prior imaging reviews have focused on the nonterritorial distribution of these mimics. However, some important questions arise here. Are the vascular territories and their boundaries invariable in the human brain? Where should we draw the lines separating arterial territories? van der Zwan and colleagues addressed these questions decades ago. For him and others, the leptomeningeal anastomoses-a contentious concept for some but increasingly linked to collateral flow in stroke-is an important anatomic structure with significant variations in their distribution and pathophysiology. Variations in blood supply appear larger that traditionally taught. We revisit this concept and entertained their implications in cases of stroke mimics. For instance, the distribution of abnormalities in some toxic-metabolic processes appear to correlate with areas where rich leptomeningeal anastomoses are expected. We will also explore the concept of hyperintense signal on diffusion weighted-imaging with no correlated changes on apparent diffusion coefficient maps. We name this finding as "isolated DWI signal" and lay-out its importance in the recognition of many entities mimicking stroke. Taking together, the discussed anatomic and imaging concepts will help radiologists and clinicians to recognize not only the common but the unusual entities imitating stroke in the emergency room.

Case 252: Acute Hyperammonemic Encephalopathy Resulting from Late-Onset Ornithine Transcarbamylase Deficiency

History A 19-year-old woman with no pertinent medical history was brought to the emergency department after being found unconscious on her bathroom floor by her roommate. In the preceding weeks, she had reported intractable nausea and vomiting, for which she had been taking ondansetron. No other medications had been prescribed. The day prior to presentation, she had contacted her mother and described increasing confusion. Glasgow coma scale score on arrival in the emergency department was 4. Intravenous naloxone was administered, without immediate response. Initial blood glucose level was 232 mg/dL (12.8 mmol/L) (normal range, 79-140 mg/dL [4.4- 7.7 mmol/L]), and other routine laboratory test results were normal. Urine toxicology results were negative. Cerebrospinal fluid evaluation revealed levels were within normal limits. Neurologic examination revealed dilated pupils, which showed a sluggish response to light, and left lower extremity rigidity with intermittent tremors. Initial unenhanced cranial computed tomographic (CT) findings were negative. Magnetic resonance (MR) imaging of the brain was performed. The patient's condition deteriorated, with increasing cerebral edema over the next week, and she was declared brain dead. Her liver was transplanted into an adult recipient, who subsequently developed cerebral edema and elevated plasma ammonia levels, resulting in death in the immediate postoperative period.

Paediatric non-ketotic hyperglycaemic hemichorea-hemiballismus

Non-ketotic hyperglycaemic hemichorea-hemiballismus (NHHH) is commonly seen among elderly Asian women with type 2 diabetes mellitus. Here, we present a case of a 16-year-old Filipina with type 1 diabetes mellitus who is poorly compliant to her medications and subsequently developed right hemichorea-hemiballismus (HH). She was initially admitted with hyperglycaemia but was negative for ketonuria or metabolic acidosis. Neuroimaging showed bilateral lentiform nuclei and left caudate hyperdensities on CT and T1-weighted hyperintensity on MRI. Blood glucose was controlled with insulin. Haloperidol and clonazepam were started for the HH with gradual resolution of symptoms in 6 weeks. This is the fifth reported case of NHHH seen among the paediatric age group. NHHH in the paediatric population is clinically and radiographically similar to NHHH seen among adults. Correction of hyperglycaemia results in clinical improvement and radiographic resolution of lesions but persistent cases may necessitate specific treatment targeted towards the abnormal movements.

Cerebral glucose deficiency versus oxygen deficiency in neonatal encephalopathy

Hypoxic-ischemic encephalopathy (HIE) in newborn infants is generally considered to result from decreased arterial oxygen content or cerebral blood flow. Cerebral injury similar to that of HIE has been noted with hypoglycemia. Studies in fetal lambs have shown that ventilation with 3% oxygen did not change cerebral blood flow, but ventilation with 100% oxygen resulted in marked reduction in cerebral blood flow, glucose delivery and glucose consumption. Blood glucose concentration falls markedly after birth; this, associated with the fall in cerebral blood flow, greatly reduces glucose supply to the brain. In preterm infants, blood glucose levels tend to be very low. Also persistent patency of the ductus arteriosus may reduce cerebral flow in diastole, thus exaggerating the decrease in glucose supply. I propose that glycopenic-ischemic encephalopathy is a more appropriate term for the cerebral insult. We should consider more aggressive management of the low blood glucose concentrations in the neonate, and particularly in preterm infants. Administration of high levels of oxygen in inspired air should be avoided to reduce the enhancement of cerebral vasoconstriction and decreased flow that normally occurs after birth.

Imaging of Creutzfeldt-Jakob Disease: Imaging Patterns and Their Differential Diagnosis

Diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) remains a challenge because of the large variability of the clinical scenario, especially in its early stages, which may mimic several reversible or treatable disorders. The molecular basis of prion disease, as well as its brain propagation and the pathogenesis of the illness, have become better understood in recent decades. Several reports have listed recognizable clinical features and paraclinical tests to supplement the replicable diagnostic criteria in vivo. Nevertheless, we lack specific data about the differential diagnosis of CJD at imaging, mainly regarding those disorders evolving with similar clinical features (mimicking disorders). This review provides an update on the neuroimaging patterns of sCJD, emphasizing the relevance of magnetic resonance (MR) imaging, summarizing the clinical scenario and molecular basis of the disease, and highlighting clinical, genetic, and imaging correlations in different subtypes of prion diseases. A long list of differential diagnoses produces a comprehensive pictorial review, with the aim of enabling radiologists to identify typical and atypical patterns of sCJD. This review reinforces distinguishable imaging findings and confirms diffusion-weighted imaging (DWI) features as pivotal in the diagnostic workup of sCJD, as these findings enable radiologists to reliably recognize this rare but invariably lethal disease. A probable diagnosis is justified when expected MR imaging patterns are demonstrated and CJD-mimicking disorders are confidently ruled out. ^©RSNA, 2017.

Understanding the Epilepsy in POLG Related Disease

Epilepsy is common in polymerase gamma (POLG) related disease and is associated with high morbidity and mortality. Epileptiform discharges typically affect the occipital regions initially and focal seizures, commonly evolving to bilateral convulsive seizures which are the most common seizure types in both adults and children. Our work has shown that mtDNA depletion—i.e., the quantitative loss of mtDNA—in neurones is the earliest and most important factor of the subsequent development of cellular dysfunction. Loss of mtDNA leads to loss of mitochondrial respiratory chain (MRC) components that, in turn, progressively disables energy metabolism. This critically balanced neuronal energy metabolism leads to both a chronic and continuous attrition (i.e., neurodegeneration) and it leaves the neurone unable to cope with increased demand that can trigger a potentially catastrophic cycle that results in acute focal necrosis. We believe that it is the onset of epilepsy that triggers the cascade of damage. These events can be identified in the stepwise evolution that characterizes the clinical, Electroencephalography (EEG), neuro-imaging, and neuropathology findings. Early recognition with prompt and aggressive seizure management is vital and may play a role in modifying the epileptogenic process and improving survival.

Metabolic pathways in the periphery and brain: Contribution to mental disorders?

The association between mental disorders and diabetes has a long history. Recent large-scale, well-controlled epidemiological studies confirmed a link between diabetes and psychiatric illnesses. The scope of this review is to summarize our current understanding of this relationship from a molecular perspective. We first discuss the potential contribution of diabetes-associated metabolic impairments to the etiology of mental conditions. Then, we focus on possible shared molecular risk factors and mechanisms. Simple comorbidity, shared susceptibility loci, and common pathophysiological processes in diabetes and mental illnesses have changed our traditional way of thinking about mental illness. We conclude that schizophrenia and affective disorders are not limited to an imbalance in dopaminergic and serotoninergic neurotransmission in the brain. They are also systemic disorders that can be considered, to some extent, as metabolic disorders.

Diabetic Striatopathy in Childhood: A Case Report

Diabetic striatopathy is a well-known complication of diabetes in adults. To our knowledge, only 2 cases have been reported in children. We here report the case of a teenager in whom diabetic striatopathy was revealed by the subacute appearance of hemichorea-hemiballism in the context of weight loss, polyuria, and polydipsia. Glycemia control allowed rapid clinical recovery despite established striatal lesions documented on MRI. We also discuss current hypotheses about pathophysiological processes underlying this entity.

Importance of Contrast-Enhanced Fluid-Attenuated Inversion Recovery Magnetic Resonance Imaging in Various Intracranial Pathologic Conditions

Intracranial lesions may show contrast enhancement through various mechanisms that are closely associated with the disease process. The preferred magnetic resonance sequence in contrast imaging is T1-weighted imaging (T1WI) at most institutions. However, lesion enhancement is occasionally inconspicuous on T1WI. Although fluid-attenuated inversion recovery (FLAIR) sequences are commonly considered as T2-weighted imaging with dark cerebrospinal fluid, they also show mild T1-weighted contrast, which is responsible for the contrast enhancement. For several years, FLAIR imaging has been successfully incorporated as a routine sequence at our institution for contrast-enhanced (CE) brain imaging in detecting various intracranial diseases. In this pictorial essay, we describe and illustrate the diagnostic importance of CE-FLAIR imaging in various intracranial pathologic conditions.

Diabetic striatopathy in a patient with hemiballism

Diabetic striatopathy is a rare and life-threatening manifestation of diabetes mellitus. The disease commonly affects individuals of Asian descent, females, and the elderly. Patients usually present with hemiballism-hemichorea caused by nonketotic hyperglycemia. Hemiballism-hemichorea is defined as involuntary continuous random appearing movement involving one side of the body. This movement disorder may develop secondary to stroke, diabetic striatopathy, neoplasm, infection, Wilson's disease, and thyrotoxicosis. Despite being rare, prompt recognition of a hyperglycemia-induced hemiballism-hemichorea is essential because the symptoms are reversible with correction of hyperglycemia. Diagnosis is possible based on blood analysis and neuroimaging findings. Laboratory tests reveal raised blood glucose and hemoglobin A1C levels which indicate poorly controlled diabetes. Neuroimaging provides suggestive findings of diabetic striatopathy which are hyperattenuation on computed tomography and hyperintensity on T1-weighted magnetic resonance imaging in the basal ganglia. In this case report, our aim is to present neuroimaging findings in an adult man with sudden onset of hemiballism associated with nonketotic hyperglycemia.

MR screening of candidates for thrombolysis: How to identify stroke mimics?

Stroke mimics account for up to a third of suspected strokes. The main causes are epileptic deficit, migraine aura, hypoglycemia, and functional disorders. Accurate recognition of stroke mimics is important for adequate identification of candidates for thrombolysis. This decreases the number of unnecessary treatments and invasive vascular investigations. Correctly identifying the cause of symptoms also avoids delaying proper care. Therefore, this pictorial review focuses on what the radiologist should know about the most common MRI patterns of stroke mimics in the first hours after onset of symptoms. The issues linked to the accurate diagnosis of stroke mimics in the management of candidates for thrombolysis will be discussed.

Seizures and movement disorders induced by hyperglycemia without ketosis in elderly

BACKGROUND

Non-ketotic hyperglycemia (NKHG) may increase the probability of seizures and movement disorders.

METHODS

We describe a series of 14 elders admitted for seizures and movement disorders linked to NKHG.

RESULTS

Twelve patients developed motor seizures and two others movement disorders. Glucose levels varied 9.28 to 32 mmol/l, while osmolarity values varied from 302.28 to 328 mosmol/l. All patients responded well to insulin therapy and four of them needed anti-epileptic drugs.

CONCLUSION

Seizures or movement disorders in elderly with NKHG could be misdiagnosed as neurological diseases. Blood glucose must be audited whenever patients with seizures or movement disorders are encountered, as the condition may quickly resolve when NKHG is controlled.

Unilateral striatal CT and MRI changes secondary to non-ketotic hyperglycaemia

A 62-year-old man presented with a right-sided hemichorea-hemiballismus secondary to underlying non-ketotic hyperglycaemia. This condition is recognised to have a unique finding of unilateral basal ganglia lesion, which is hyperdense on CT and hyperintense on T1-weighted MRI. The clinical course of this condition is benign and has a good prognosis with early correction of the hyperglycaemia.