Neuroimaging in epilepsy

Current understanding of stroke and stroke mimics in adolescents and young adults: a narrative review

BACKGROUND

Stroke in adolescents and young adults are uncommon, and unlike in older adults, the etiology can be a challenging puzzle to solve. Patients often lack traditional risk factors such as hypertension or may be too young for suspected atherosclerotic disease. Additionally, among this group, various stroke mimics exist that can cloud physician judgment, leading to under- or overtreatment.

AIM

There is a significant gap in the current literature and clinical evidence regarding stroke in this population. This review of the literature aims to extract important information surrounding the etiology, risk factors, diagnosis, management, and complications of stroke in younger people and address stroke mimics and how they can appear similar and different from ischemic or hemorrhagic stroke. Additionally, we discuss the importance of furthering research in this specific population in all areas due to a concerning rise in stroke frequency and unique associated disabilities.

CONCLUSION

The acute treatment of stroke in young patients is similar to older adults. While stroke mimics may complicate suspicion and cause hesitance, delays in stroke care should be avoided. There remains a need for research in the areas of diagnosis, management, and assessment of long-term care and challenges in this population of patients.

A Prospective Cohort Study on the Effect of Antiseizure Medications on Thyroid Function in Children Aged 6 Months to 12 Years with Epilepsy

Objectives

This study aimed to explore the effect of antiseizure medications (ASM) on thyroid function in children with epilepsy.

Methods

A prospective study involving children between 6 months and 12 years of age with new-onset seizures who took ASM within 2 months was conducted in the Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India, between August 2019 to March 2022. Thyroid function tests-free T3, free T4 and thyroid stimulating hormone (TSH)-were done at baseline and after completing 3 months by competitive immunoassay using direct chemiluminescent technology. The primary outcome was the proportion of patients diagnosed with thyroid dysfunction (subclinical or overt hypothyroidism).

Results

In total, 126 patients were enrolled. Median (interquartile range [IQR]) age and follow-up months were 10 years (7-12) and 6 months (4-8), respectively. Most patients (n = 103, 81.7%) had generalised seizures, while the remaining (n = 23, 18.3%) had focal seizures. There was a significant difference noted in median (IQR) TSH (micro-IU/mL) at baseline (2.08 [1.41-3.31]) and follow-up (2.56 [1.65-4.14]; P ≤0.001). Thyroid dysfunction (subclinical hypothyroidism) was noted in 7 patients. Among the 7 children with subclinical hypothyroidism, 6 (4.8%) were on sodium valproate either as monotherapy (n = 3, 2.4%) or polytherapy (n = 3, 2.4%), while the remaining child was on phenytoin. No difference was noted between the monotherapy and polytherapy groups (4% versus 11.5%; P = 0.15).

Conclusion

The incidence of thyroid dysfunction (subclinical hypothyroidism) was 5.6% in children taking ASM with a median follow-up period of 6 months. A longer follow-up period and larger sample size study is warranted in the future.

Differentiation of Epileptic Brain Abnormalities among Neurological Patients at Taif Region Using MRI

This study was conducted to assess the prevalence of epilepsy among different age groups and gender of neurological patients in the Taif region and define the most common brain lesion, affecting epileptic patients living in the Taif city using MRI. Data from 150 patients who were clinically diagnosed with epilepsy and had brain MRIs were analyzed using SPSS. Statistical significance was considered when the p value is 0.05. The percentage of epilepsy was generally higher in males than in females in the Taif city, and seizures were different between the studied age groups. However, epilepsy was more pronounced in females than in males at certain age groups. Moreover, white matter lesions were most commonly found in the studied group (27.7%), followed by focal lesions, edema, and stroke with equal percentages (16.9%) and less commonly with congenital diseases (12%) and atrophic changes (9.6%). Epilepsy was more pronounced in females than in males at certain age groups. White matter lesions were identified as the most common lesion, presenting in epilepsy patients in the Taif city.

Bilateral Anterior Shoulder Dislocations Following a Clozapine-Induced Seizure

Posterior shoulder dislocations are a recognised complication of generalised seizure episodes. Although less frequent, anterior shoulder dislocations are now being acknowledged as an emerging consequence. Particularly when they occur bilaterally, they can contribute to diagnosing a seizure disorder in a patient who shows no other signs during the post-ictal period. This article presents a case of bilateral anterior shoulder dislocations in an otherwise physically healthy young Sudanese gentleman following a generalised seizure episode on clozapine for a schizoaffective disorder. The case aims to raise awareness of the occurrence of this phenomenon and emphasises the importance of timely diagnostic testing, seizure prophylaxis, and follow-up to minimise the risk of further seizure episodes and potential consequences. Additionally, there is a discussion regarding the utility of monitoring clozapine concentrations.

Neuroimaging in Pediatric Epilepsy

Pediatric epilepsy presents with various diagnostic challenges. Recent advances in neuroimaging play an important role in the diagnosis, management and in guiding the treatment of pediatric epilepsy. Structural neuroimaging techniques such as CT and MRI can identify underlying structural abnormalities associated with epileptic focus. Functional neuroimaging provides further information and may show abnormalities even in cases where MRI was normal, thus further helping in the localization of the epileptogenic foci and guiding the possible surgical management of intractable/refractory epilepsy when indicated. A multi-modal imaging approach helps in the diagnosis of refractory epilepsy. In this review, we will discuss various imaging techniques, as well as aspects of structural and functional neuroimaging and their application in the management of pediatric epilepsy.

Association of Child Neurology-Indian Epilepsy Society Consensus Document on Parental Counseling of Children with Epilepsy

When a child is diagnosed with epilepsy, counseling regarding the same is done by the treating doctor. Most parents are frightened and have poor knowledge about epilepsy. Therapeutic advice including drug dosage, administration and side effects takes up the major part of physician's time, thereby neglecting important issues like home seizure management, follow up and others. These lacunae in knowledge require systematic patient and family education. To address these issues, an expert group meeting of pediatric neurologists and epileptologists in India along with social workers/epilepsy educators, legal experts, parents, and teachers was held. The various aspects regarding parental counseling in children with epilepsy were discussed and a consensus document was formulated. Here authors present the group consensus statement on counseling parents and caregivers of children with epilepsy. This document is intended to help physicians and pediatricians counsel the families when a child is diagnosed with epilepsy.

The neurology-psychiatry interface in epilepsy

Epilepsy and mental illness have a bidirectional association. Psychiatrists are likely to encounter epilepsy as comorbidity. Seizures may present as mental illness. Equally, the management of psychiatric conditions has the potential to destabilise epilepsy. There is a need for structured epilepsy awareness and training amongst psychiatrists. This paper outlines key considerations around diagnosis, treatment and risk while suggesting practical recommendations.

Identification of variants in the mitochondrial lysine-tRNA (MT-TK) gene in myoclonic epilepsy-pathogenicity evaluation and structural characterization by in silico approach

Variations in mitochondrial genes have an established link with myoclonic epilepsy. In the present study we evaluated the nucleotide sequence of MT-TK gene of 52 individuals from 12 unrelated families and reported three variations in 2 of the 13 epileptic patients. The DNA sequences coding for MT-TK gene were sequenced and mutations were detected in all participants. The mutations were further analyzed by the in silico analysis and their structural and pathogenic effects were determined. All the investigated patients had symptoms of myoclonus, 61.5% were positive for ataxia, 23.07% were suffering from hearing loss, 15.38% were having mild to severe dementia, 69.23% were males, and 61.53% had cousin marriage in their family history. DNA extracted from saliva was used for the PCR amplification of a 440 bp DNA fragment encompassing complete MT-TK gene. The nucleotide sequence analysis revealed three mutations, m.8306T>C, m.8313G>C, and m.8362T>G that are divergent from available reports. The identified mutations designate the heteroplasmic condition. Furthermore, pathogenicity of the identified variants was predicted by in silico tools viz., PON-mt-tRNA and MitoTIP. Secondary structure of altered MT-TK was predicted by RNAStructure web server. Studies by MitoTIP and PON-mt-tRNA tools have provided strong evidences of pathogenic effects of these mutations. Single nucleotide variations resulted in disruptive secondary structure of mutant MT-TK models, as predicted by RNAStructure. In vivo confirmation of structural and pathogenic effects of identified mutations in the animal models can be prolonged on the basis of these findings.

The relationship between structural MRI, FDG-PET, and memory in temporal lobe epilepsy: Preliminary results

Structural and metabolic abnormalities of the temporal lobe are frequently found in temporal lobe epilepsy (TLE). In the present retrospective study, we investigated whether structural abnormalities evident in magnetic resonance imaging (MRI) and hypometabolism evident in [¹⁸F]fluorodeoxyglucose positron emission tomography (FDG-PET) independently influence verbal and nonverbal learning and delayed memory in patients with TLE. Sixty-eight patients with refractory unilateral TLE (35 left TLE, 33 right TLE) were divided into three groups: (1) no evidence of pathology in either MRI or FDG-PET studies (MRI-/PET-, n=15), (2) temporal FDG-PET determined hypometabolism with normal MRI findings (MRI-/PET+, n=21), and (3) evidence of temporal abnormalities in both MRI and FDG-PET studies (MRI+/PET+, n=32). A fourth group (MRI+/PET-, n=4) was too small for further statistical analysis and could not be included. Patients with MRI+/PET+ showed worse verbal memory than patients with MRI-/PET- (p<0.01), regardless of side of seizure focus. Verbal memory performance of patients with MRI-/PET+ was located between patients with MRI+/PET+ and MRI-/PET-, although group differences did not achieve statistical significance (ps>0.1). No group differences were found for nonverbal memory (p=0.27). Our results may suggest an interactive negative effect of metabolic and structural temporal lobe abnormalities on verbal memory. Still, our results are preliminary and need further validation by studies involving larger patient groups and up-to date quantitative imaging analysis methods.

Refractory Epilepsy-MRI, EEG and CT scan, a Correlative Clinical Study

OBJECTIVES:

Refractory epilepsies (RE), as well as, the surgically correctable syndromes, are of great interest, since they affect the very young population of children and adolescents. The early diagnosis and treatment are very important in preventing the psychosocial disability. Therefore MRI and EEG are highly sensitive methods in the diagnosis and localization of epileptogenic focus, but also in pre-surgical evaluation of these patients. The aim of our study is to correlate the imaging findings of EEG, MRI and CT scan in refractory symptomatic epilepsies, and to determine their specificity in detecting the epileptogenic focus.

METHODS:

The study was prospective with duration of over two years, open-labelled, and involved a group of 37 patients that had been evaluated and diagnosed as refractory epilepsy patients. In the evaluation the type and frequency of seizures were considered, together with the etiologic factors and their association, and finally the risk for developing refractory epilepsy was weighted. EEG and MRI findings and CT scan results were evaluated for their specificity and sensitivity in detecting the epileptogenic focus, and the correlation between them was analyzed.

RESULTS:

Regarding the type of seizures considered in our study, the patients with PCS (partial complex seizures) dominated, as opposed to those with generalized seizures (GS) (D=1.178, p < 0.05). Positive MRI findings were registered in 28 patients (75.7%). Most of them were patients with hippocampal sclerosis, 12 (42.8%), and also they were found to have the highest risk of developing refractory epilepsy (RE) (Odds ratio = 5.7), and the highest association between the etiologic factor and refractory epilepsy (p < 0.01). In detecting the epileptogenic focus, a significant difference was found (p < 0.01) between MRI and CT scan findings, especially in patients with hippocampal sclerosis and cerebral malformations. There was a strong correlation between the MRI findings and the etiologic factor (R = 1), and for CT scan and etiologic factor an R=0.75 correlation. There was a significant difference between imaging methods MRI/CT (p < 0.1), and CT/EEG (p < 0.05) in detecting the etiologic factor, and little difference was noticed between findings of EEG/MRI.

CONCLUSION:

Our study confirms that for an accurate diagnosis of refractory epilepsy in patients, a combination of neuroimaging and neurophysiologic methods is required. MRI showed to be highly sensitive in detecting the etiologic factor in RE patients, whereas EEG was sensitive in localization of the epileptogenic focus, with high correlation between these two methods. An early diagnosis of these patients is very important in having a better therapeutic response and prognosis for them.