Bilateral Reappearance of the N20 Potential in a Normothermic Young Woman Post-Anoxic Brain Injury.

SUMMARY: Hypoxic-ischemic brain injury is a well-known consequence of cardiac arrest and providing an accurate prognostication remains a challenge, especially in decisions related to withdrawal of care. Bilateral absence of the cortical response (N20 potential) on median somatosensory evoked potentials, on days 1 to 3 after the return of spontaneous circulation, is widely considered as the most reliable predictor of poor outcome with a high specificity and a low false-positive rate. The authors describe the case of a young comatose woman after hypoxic injury because of cardiac arrest whose initial median somatosensory evoked potentials revealed bilateral absence of the N20 response associated with evidence of selective injury to both perirolandic cortices and basal ganglia on brain MRI. This patient made a substantial recovery associated with bilateral reappearance of the N20 potential and resolution of the neuroimaging abnormalities.This case revealed that an acute selective and reversible hypoxic injury to both perirolandic cortices may lead to a temporary loss of the N20 responses and an inaccurate prediction of poor outcome after cardiac arrest. It emphasizes on the importance of adopting a multimodal approach in the prognostic assessment of survivors of cardiac arrest.

COVID-19-Associated Acute Asymmetric Hemorrhagic Necrotizing Encephalopathy: A Case Report.

Background: Coronavirus disease 2019 (COVID-19) has been associated with many neurological complications affecting the central nervous system. Purpose: Our aim was to describe a case of COVID-19 associated with a probable variant of acute necrotizing encephalopathy (ANE). Results: A 60-year-old man who presented with a 3-day history of dyspnea, fever, and cough tested positive for severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). Five days following his admission, the patient was intubated secondary to respiratory failure. Following his extubation 16 days later, he was found to have a left-sided weakness. Magnetic resonance imaging (MRI) of the brain showed hemorrhagic rim-enhancing lesions involving the right thalamus, left hippocampus, and left parahippocampal gyrus. These lesions showed decreased relative cerebral blood flow on MR perfusion and restricted on diffusion-weighted imaging. These neuroimaging findings were consistent with ANE. The left-sided weakness gradually improved over the subsequent weeks. Conclusions: We concluded that COVID-19 can be associated with ANE, a condition believed to be the result of an immune-mediated process with activation of the innate immune system. Future studies must address whether biological drugs targeting the pro-inflammatory cytokines could prevent the development of this condition.

A novel possible familial cause of epilepsy of infancy with migrating focal seizures related to SZT2 gene variant.

Seizure threshold-2 (SZT2) gene variants have been associated with a decrease in seizure threshold resulting in variable phenotypic expressions ranging from mild-moderate intellectual disabilities without seizures, to an early-onset epileptic encephalopathy with severe cognitive impairment. In addition, hypotonia and distinctive facial dysmorphism, including a high forehead and to a lesser extent ptosis and down-slanting palpebral fissures, were present in the majority. We herein report a novel SZT2 variant in one of two siblings both diagnosed with epilepsy of infancy with migrating focal seizures (EIMFS). This report is the fourth to document a possible familial case in EIMFS, a condition that was not previously associated with SZT2 variant. This report expands the phenotypic expression of SZT2, corroborates the importance of genetic counseling in some cases of EIMFS, and highlights the efficacy of potassium bromide in controlling the seizures associated with this condition.

The importance of acknowledging diagnostic uncertainty in patients with new-onset paroxysmal spells.

OBJECTIVE: The aims of this study were to evaluate the frequency of paroxysmal spells of indeterminate nature (PSIN) in a large cohort of children and adults with suspected new-onset seizures, to evaluate the reasons for including patients in this category, and to calculate the rate of erroneous diagnoses if the epileptologists were compelled to label those events as epileptic seizures or nonepileptic paroxysmal spells. METHODS: Patients identified for this study participated in a prospective study evaluating patients with suspected new-onset unprovoked seizures. The workup included a detailed history and a thorough description of the spells, a 3-hour video EEG recording, and an epilepsy protocol brain MRI. Based exclusively on a detailed description of the ictal events, two epileptologists were asked to independently classify each patient into those with a definite diagnosis of unprovoked seizures or a definite diagnosis of a nonepileptic paroxysmal spells (group 1) and those with PSIN (group 2). RESULTS: A total of 1880 consecutive patients were enrolled with 255 (13.6%) included in the PSIN group. Patients with PSIN were significantly younger than those with a definite diagnosis, and PSIN were significantly more frequent in children with developmental delay. The most common reason for including patients in the PSIN group was the inability to categorically discriminate between a seizure and a nonepileptic mimicker. When the raters were compelled to classify the spells in the PSIN group, the frequencies of erroneous diagnoses ranged between 32% and 38%. The final diagnoses on those patients were made based on the results of the EEG, MRI, and follow-up visits. SIGNIFICANCE: Our data indicate that a diagnostic category of PSIN should be recognized and ought to be used in clinical practice. Acknowledging this uncertainty will result in lower frequencies of erroneous diagnoses, possible stigma, and potential exposure to unnecessary antiseizure medications.

A Patient with Combined CADASIL and MTHFR Homozygosity.

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is an inherited disorder caused by a mutation in the NOTCH 3 gene, characterized by early onset of subcortical lacunar infarcts in the absence of vascular risk factors and cerebral microbleeds. Homozygosity for the factor Methylenetetrahydrofolate Reductase (MTHFR) is also associated with lacunar stroke risk and cerebral small-vessel disease regardless of the homocysteine level. The coexistence of MTHFR C677T homozygosity and NOTCH 3 mutation has never been reported in the literature previously, and that brings up the challenge of antithrombotic treatment in the presence of cerebral microbleeds.

Case Report: Distinctive EEG Patterns in SCARB-2 Related Progressive Myoclonus Epilepsy.

Action myoclonus-renal failure syndrome (AMRF) is a rare, recessively inherited form of progressive myoclonus epilepsy (PME) caused by mutations in the SCARB2 gene and associated with end-stage renal failure. In addition to severe progressive myoclonus, the neurological manifestations of this syndrome are characterized by progressive ataxia and dysarthria with preserved intellectual capacity. Since its original description, an increasing number of "AMRF-like" cases without renal failure have been reported. We describe the case of a 29-year-old woman with progressive disabling myoclonus associated with dysarthria and ataxia who was found to have a novel homozygous frameshift mutation in the SCARB2 gene. In addition, this report emphasizes the presence of two EEG patterns, fixation-off phenomenon, and bursts of parasagittal spikes exclusively seen during REM sleep that appear to be characteristic of this condition.

Coma With Absent Brainstem Reflexes and a Burst Suppression on EEG Secondary to Baclofen Toxicity.

Baclofen, a muscle relaxant prescribed for the alleviation of symptoms of spasticity acts primarily at the spinal level but with high doses, it penetrates the blood-brain barrier and can result in prominent central nervous depression. Baclofen toxicity has been associated with a variety of symptoms ranging from dizziness to deep coma. We report the clinical course, management, and outcome of a case of baclofen overdose who presented in deep coma with loss of brainstem reflexes and a burst suppression (BS) pattern on his electroencephalogram (EEG). In addition, we reviewed the presentation and outcomes of all reported cases of baclofen toxicity with a BS pattern on EEG to evaluate if those cases share a common clinical presentation and for the presence of signs and symptoms that would help the clinician to consider this diagnosis. There appears to be a common clinical picture associated with severe baclofen toxicity consisting of deep coma associated with loss of all brainstem reflexes including pupillary reactivity, frequent association with seizures/myoclonic jerks, and a BS pattern on EEG. The outcome is generally good, and serial EEGs are recommended to document a reversal of the abnormal electrographic features.