Hypometabolism and Dipole Localization in Hemimegalencephaly: A Case Report

Ohta, Yukiko; Hiraiwa, Mikio; Murayama, Kei; Nonaka-Mishima, M; Kaneko, Yuu; Yumoto, Masato; Yotsumoto, Hideki; Iio, M

doi:10.1055/s-2008-1073031

Cited by 7 publications

(5 citation statements)

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“…The distribution of dipole sources in the periphery of the dysplastic lesion in patient 3 was similar to that seen in HME [17]. Innervation with glutamatergic afferents at the periphery of lesions has been observed in cases with polymicrogyria [18], which may explain the similar findings in HME.…”

Section: Discussionsupporting

confidence: 61%

“…However, surgical intervention was not applicable for the present patients since their epilepsy was well controlled by medication. In this point, it is interesting that steroid therapy [13] and intravenous gammaglobulin [17] showed excellent effects on the infantile spasms in some patients with HME. The EEG findings in patients 2 and 3 could be regarded as continuous spike-wave during slow sleep (CSWS), for which these immunotherapies have been claimed as efficacious.…”

Section: Discussionmentioning

confidence: 96%

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Three cases of right frontal megalencephaly: Clinical characteristics and long-term outcome

Ono

Saito

Maegaki

et al. 2016

Brain and Development

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Section: Discussionsupporting

confidence: 61%

Section: Discussionmentioning

confidence: 96%

Three cases of right frontal megalencephaly: Clinical characteristics and long-term outcome

Ono

Saito

Maegaki

et al. 2016

Brain and Development

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“…[Ohta et al, 1994; Calzolari et al, 1996; Brodtkorb et al, 1998; Battaglia et al, 1999; Di Rocco and Iannelli, 2000; Wieselthaler et al, 2002]…”

Section: Discussionunclassified

Epidemiology of hemimegalencephaly: A case series and review

Tinkle

Schorry

Franz

et al. 2005

American J of Med Genetics Pt A

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Hemimegalencephaly (HME) is a congenital brain malformation characterized by unilateral enlargement of the cerebral hemisphere. Clinically, HME is typically associated with hemiparesis, psychomotor retardation, and intractable seizures usually apparent soon after birth. HME is often an isolated finding, but it has been described as an occasional feature of a large number of syndromes, many of which may not be readily identified at birth. There are a multitude of case series and reports of HME in the English literature; however, there is no comprehensive, unbiased, detailed survey characterizing the proportion of cases of HME that are associated with a syndrome. We performed a retrospective study of all cases of HME seen at our institution from 1990 to 2003. Of the 15 cases of HME identified, 53% (8/15) were non-syndromic and 47% (7/15) of the cases were associated with a known or suspected genetic syndrome. In patients with syndromic HME, many of the syndromic features were not readily discernible at birth or in early infancy. It is, therefore, imperative to continually evaluate any infant with HME for signs and symptoms of these and other syndromes. Knowing the relative differential diagnosis will lead to a more comprehensive evaluation, improvement in expectant management, and appropriate counseling of families before considering radical surgical options such as hemispherectomy.

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“…44,45,50,70,95 A few reports mention specific patterns of other defined epilepsy syndromes like Lennox-Gastaut. 16,71 Paladin et al53 described three types of EEG abnormalities in hemimegalencephaly: 1. Triphasic complexes of very large amplitude, predominating on the affected side. This pattern was observed in patients with partial seizures.…”

Section: Electroencephalographymentioning

confidence: 99%

“…14,23,25,26 Our histopathologic studies, however, suggest that hemimegalencephaly is more likely to be an earlier (ie, the 3rd week of gestation), genetically programmed developmental disorder related to cellular lineage and establishment of synunetry.27,28 This concept has led us to reclassify this malfon-nation. 11 Hemimegalencephaly has also been considered a primary disorder of proliferation 13,17,[11][12][13][14][15][16][17][18][19][20][21][22][23]30,31 ; if this is the case, it occurs early and possibly continues beyond the normal proliferative period. 32…”

mentioning

confidence: 99%

Hemimegalencephaly: Part 1. Genetic, Clinical, and Imaging Aspects

2002

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Hemimegalencephaly is a rare hamartomatous malformation of the brain, remarkable for its extreme asymmetry. It can be isolated or associated with several neurocutaneous syndromes; less frequently, it also involves the brain stem and cerebellum. Traditionally, hemimegalencephaly has been considered a primary neuroblast migratory disturbance. At present, genetic theories of pathogenesis and modern histopathology provide a basis for this complex malformation as a primary disturbance in cellular lineage, differentiation, and proliferation, interacting with a disturbance in gene expression of body symmetry, with earlier onset than radial neuroblast migration. From my personal experience with 10 patients with hemimegalencephaly and review of the literature, I have found the same clinical neurologic, neuroimaging, and neuropathologic features in isolated and syndromic hemimegalencephaly. Magnetic resonance imaging (MRI) reveals abnormal gyration, ventriculomegaly, colpocephaly, an "occipital sign" (displacement of the occipital lobe across the midline), and increased volume and T2 signal of white matter, in addition to the overall increased size of the involved hemisphere. Mild, moderate, and severe grades of severity can be recognized, providing a functional neurologic prognosis and therapeutic plan. Early diagnosis is crucial because despite neuroimaging and pathologic evidence, hemimegalencephaly sometimes still is unrecognized. Also, misdiagnosis of obstructive hydrocephalus or cerebral neoplasm can lead to unnecessary surgical procedures. Although hemispherectomy has a high morbidity, it is recommended early for patients with severe, intractable epilepsy. The mildest forms of hemimegalencephaly are infrequent and the least recognized.

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Hypometabolism and Dipole Localization in Hemimegalencephaly: A Case Report

Cited by 7 publications

References 1 publication

Three cases of right frontal megalencephaly: Clinical characteristics and long-term outcome

Three cases of right frontal megalencephaly: Clinical characteristics and long-term outcome

Epidemiology of hemimegalencephaly: A case series and review

Hemimegalencephaly: Part 1. Genetic, Clinical, and Imaging Aspects

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