Hypoglycemic encephalopathy mimicking acute ischemic stroke in clinical presentation and magnetic resonance imaging: a case report

Background

The imaging findings of hypoglycemic encephalopathy can be considerably similar to those of ischemic infarction or toxic leukoencephalopathy. We demonstrated unusual magnetic resonance (MR) imaging features of hypoglycemic encephalopathy which can be confused with other pathology both on imaging and acute clinical presentation. The diffusion-weighted imaging (DWI) and apparent diffusion coefficients (ADC) map findings in our case further supports the hypothesis of hypoglycemia-induced “excitotoxic injury” of glial cells and myelin sheath that might protect neuron axons from intracellular edema and irreversible damage.

Case presentation

A 72-year-old woman presented with poor appetite and was initially drowsy at home; the symptoms progressed to loss of consciousness accompanied by mild incontinence. The initial glucose level was 44 mg/dL, but no nausea, vomiting, fever, or cold sweating was reported. Physical examination after intravenous glucose supplementation revealed the absence of focal neurological signs, facial palsy, and tongue or eye deviations. The images obtained 24 h after symptoms onset revealed symmetrical hyperintensities on DWI (b-value: 1000) associated with hypointensities on ADC map along the corticospinal tract, from the levels of the cerebral peduncle and the posterior limbs of the internal capsule to the level of the corona radiata, which may mimic the imaging findings of acute ischemic infarction or amyotrophic lateral sclerosis. The patient received sliding-scale insulin therapy and rehabilitation, and she recovered consciousness without motor function deficits after 1 month. Moreover, repeat DWI and ADC map showed the complete disappearance of the lesions.

Conclusions

In the phenomenon of excitotoxic injury, axons could be protected from intracellular edema and irreversible damage, which may explain the reversible clinical symptoms and imaging abnormality after controlling for blood glucose because of the preserved motor axon. The diagnosis of acute symptomatic hypoglycemic encephalopathy through clinical and imaging features can be challenging. It is crucial to differentiate it from ischemic encephalopathy since the management and clinical outcome are different.

Electronic supplementary material

The online version of this article (10.1186/s12880-019-0310-z) contains supplementary material, which is available to authorized users.

Blood glutamate EAAT2-cell grabbing therapy in cerebral ischemia

Background

Excitatory amino acid transporter 2 (EAAT₂) plays a pivotal role in glutamate clearance in the adult brain, thereby preventing excitotoxic effects. Considering the high efficacy of EAAT₂ for glutamate uptake, we hypothesized that the expression of this transporter in mesenchymal stem cells (MSCs) for systemic administration could yield a cell-based glutamate-grabbing therapy, combining the intrinsic properties of these cells with excitotoxic protection.

Methods

To address this hypothesis, EAAT₂-encoding cDNA was introduced into MSCs and human embryonic kidney 293 cells (HEK cells) as the control cell line. EAAT₂ expression and functionality were evaluated by in vitro assays. Blood glutamate-grabbing activity was tested in healthy and ischemic rat models treated with 3 × 10⁶ and 9 × 10⁶ cells/animal.

Findings

The expression of EAAT₂ in both cell types conferred the expected glutamate-grabbing activity in in vitro and in vivo studies. The functional improvement observed in ischemic rats treated with EAAT₂–HEK at low dose, confirmed that this effect was indeed mediated by the glutamate-grabbing activity associated with EAAT₂ functionality. Unexpectedly, both cell doses of non-transfected MSCs induced higher protection than transfected EAAT₂–MSCs by another mechanism independent of the glutamate-grabbing capacity.

Interpretation

Although the transfection procedure most likely interferes with some of the intrinsic protective mechanisms of mesenchymal cells, the results show that the induced expression of EAAT₂ in cells represents a novel alternative to mitigate the excitotoxic effects of glutamate and paves the way to combine this strategy with current cell therapies for cerebral ischemia.

Prognostic and Mechanistic Factors Characterizing Seizure-Associated Crossed Cerebellar Diaschisis

BACKGROUND

Crossed cerebellar diaschisis is a rare finding of hemispheric cerebellar depression following contralateral cerebral injury, hypothesized to result from excessive neuronal excitatory synaptic activity along cortico-pontine-cerebellar pathways. The phenomenon is typically observed following ischemic stroke, but has also been characterized during seizure activity--in particular, status epilepticus (SE). Neurological outcome has varied widely in published reports, with some patients achieving full neurologic recovery, while others experience persistent disability.

METHODS

Case report and literature review.

RESULTS

We present a 54-year-old man found unresponsive with a right hemispheric syndrome several days after discharge following amygdalohippocampectomy for refractory right temporal lobe epilepsy. Prolonged electroencephalogram demonstrated one subclinical right frontal seizure, along with right frontal periodic lateralized epileptiform discharges, presumed to be associated with SE preceding his admission. Initial MRI demonstrated restricted diffusion on diffusion weighted imaging in the right cerebral hemisphere, ipsilateral thalamus, and contralateral cerebellum. A head CT one week later showed diffuse sulcal effacement with loss of gray-white differentiation in the right frontal and insular regions with low attenuation changes of right thalamus. An MRI showed worsened diffusion restriction, despite a corresponding increase in perfusion. The patient remained paretic at discharge and follow-up. Follow-up MRI at 2 months demonstrated pronounced right cerebral and left cerebellar atrophy, loss of gray matter in much of the right cerebrum, and scattered areas of T2 hyperintensity, consistent with permanent right fronto-temporal neuronal loss.

CONCLUSIONS

Collectively, these observations indicate that imaging findings of persistent cerebral restricted diffusion and cytotoxic edema in the subacute post-ictal period may predict irreversible neuronal injury and poor long-term outcome-even when accompanied by evidence of cortical hyperperfusion and recovery of second- and third-order neurons along the involved circuit.