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Developmental Diseases of the Nervous System
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
James H. Tonsgard, Nikolas Mata-Machado
Nervous system in 90%: Brain malformations including hemimegalencephaly.Mental retardation in 60%.Borderline IQ in 15%.Seizures in 50%.Hyperactivity.Hypotonia, motor delay.Moyamoya vascular disease.Autism in 10%.
Paediatric Neurology
Published in John W. Scadding, Nicholas A. Losseff, Clinical Neurology, 2011
Focal malformations thought to result from interference with neuronal and glial proliferation are now commonly encountered in children with drug-resistant epilepsy being assessed for possible surgical treatment of their epilepsy. Pathologically, balloon cells are a marker for non-neoplastic malformations due to abnormal proliferation. Hemimegalencephaly is an MRI and pathological diagnosis, although classified as a disorder of proliferation, abnormalities of migration and organization coexist. It may be an isolated condition or be associated with neurocutaneous disorders including neurofibromatosis and tuberous sclerosis. The ‘tumour’ group consists of gangliogliomas, gangliocytomas and dysembryoplastic neuroepithelial tumours (DNETs). These benign lesions are characterized by the presence of mature neuronal and glial cells. Many will be missed or misinterpreted on computed tomography (CT) scan and will only be fully elucidated on MRI.
Causes of epilepsy
Published in Timothy Betts, Lyn Greenhill, Managing Epilepsy with Women in Mind, 2005
� Hemimegalencephaly: is characterized by learning difficulty, hemiplegia, severe epilepsy starting in infancy and abnormal enlargement of one cerebral hemisphere, often containing polymicrogyria (see below). It is believed to be due to failure
Treatment of infantile spasms: why do we know so little?
Published in Expert Review of Neurotherapeutics, 2020
Nicola Specchio, Nicola Pietrafusa, Alessandro Ferretti, Luca De Palma, Marta Elena Santarone, Chiara Pepi, Marina Trivisano, Federico Vigevano, Paolo Curatolo
Children refractory to drug therapy should be evaluated for epilepsy surgery, especially if focal brain lesions are present [126]. Up to now, the efficacy of epilepsy surgery in patients with IS is highly related to etiology and in particular to the presence of a lesion on brain MR [129]. From reports from a few cohorts of patients, overall seizure freedom rate has been between 60 and 83% [129–135]. The earlier surgery is performed seems to be an important predictor of seizure freedom80% seizure freedom could be achieved in children under 3 years of age [132]. The most frequent surgical approaches are multilobar resection/disconnection or hemispherotomy as very frequently the lesions are quite diffuse or hemispheric [134]. Invasive recordings, and in particular stereo-electroencephalography (SEEG), could be very useful in patients with discordant neuroimaging results (Figure 5A) or in patients with TSC, in which the epileptogenic tubers display a focal organization of the epileptogenic zone (Figure 5B). Early surgical intervention has been hypothesized to protect children with intractable IS from developmental regression and could result in better developmental outcome and quality of life [136]. In wide malformations of cortical development, such as hemimegalencephaly (HME), the sooner the surgery is performed, the better the cognitive outcome is expected, even if a normal intellectual development is difficult to achieve [137].
Avoiding complacency when treating uncontrolled seizures: why and how?
Published in Expert Review of Neurotherapeutics, 2020
Ushtar Amin, Selim R. Benbadis
Hemispherectomy, the complete removal of a cerebral hemisphere, or hemispherotomy, the functional disconnection of a cerebral hemisphere, are other palliative surgeries that are used in patients with refractory epilepsy due to unilateral diffuse hemispheric pathology [49]. This surgery is typically used in children and has, less so, been performed in adults, with favorable results reported [50]. Complications may include moderate deficits in motor function, language, and cognition [50]. Rassmusen’s encephalitis is an example of a hemispheric syndrome where there is unilateral inflammation of the cerebral cortex, refractory epilepsy, and progressive neurological and cognitive decline [51]. Hemimegalencephaly is another example of a hemispheric syndrome due to a congenital malformation of cortical development resulting in enlargement of all or parts of one cerebral hemisphere. Patients present with intractable seizures, contralateral weakness, hemianopia, and cognitive delay [49]. Unfortunately, ASMs are of limited benefit in these syndromes and functional hemispherectomy is the only solution for seizure control and possibly even seizure freedom. Although hemispherectomy surgery is very successful in achieving seizure freedom (54%-90% of patients), there is very little literature in regards to overall post-surgical outcomes as the procedure is rarely performed [49]. Patients with bitemporal epilepsy with a side predominance can also benefit from palliative resective surgery.
Neuropsychological and Social Characteristics of a 7 Year Old Child with Hypomelanosis of Ito Followed for 11 Years
Published in Developmental Neuropsychology, 2022
George P. Prigatano, Alexandra Novak, Vinodh Narayanan
In some cases, cerebral malformations, including hemimegalencephaly or cortical dysplasia, have been described in children with HI (Ono, Harada, Kodaka, Ishida, & Okada, 1997). Mosaic mammalian target of rapamycin (MTOR) pathogenic variants have been reported in patients with HI and localized brain overgrowth (Carmignac et al., 2021).