China
Africa
Explore chapters and articles related to this topic
Neurology and neurosurgery
Published in Jagdish M. Gupta, John Beveridge, MCQs in Paediatrics, 2020
Jagdish M. Gupta, John Beveridge
12.23. A distended fontanelle is a characteristic feature in infants suffering fromcommunicating hydrocephalus.meningitis.non-communicating hydrocephalus.vitamin A intoxication.megalencephaly.
Glutaric aciduria (type I)
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
Progressive megalencephaly may be present at birth [3] and may necessitate cesarean section, or it may develop in the first weeks or months of life [2, 3]. Initially, affected babies show relatively mild physical signs such as muscular hypotonia with prominent head lag, high palate, feeding difficulties and irritability [15–17]. All these symptoms are reversible and of little prognostic significance. By six months, head circumference may be well above the 98th percentile [2] or 2–5 SD above the mean [3]. At this time, magnetic resonance imaging (MRI) or computed tomography (CT) may reveal the characteristic findings of temporal hypoplasia (95 percent of all patients; [Figure 9.2]), wide anterior temporal and sylvian CSF spaces, subependymal pseudocysts, an immature gyration pattern, delayed myelination, and isolated T2 hyperintensity in the globus pallidus. Temporal hypoplasia may develop in utero in the third trimester. The neuroradiologic studies are usually ordered to rule out hydrocephalus, and they do. Macrocephaly is not found in every patient, but in a series of 11 infants [3] it was present in all but two, and these two never had an acute encephalopathic crisis. A real clue to early diagnosis is the crossing of percentiles for head growth; this acceleration is maximal at three to nine months.
ENTRIES A–Z
Published in Philip Winn, Dictionary of Biological Psychology, 2003
(from Greek, mega: big, kephale: head) Megalencephaly is an abnormally large head size (defined as being above the 98th percentile). It is a condition associated with BRAIN enlargement, not simple enlargement of the head (for example, because of thickening of the SKULL). It is more extreme than MACROCEPHALY and is associated with MENTAL RETARDATION, but not primary sensory impairment. There has been a suspicion that it is associated with AUTISM, but this is not the case: incidence of megalencephaly in autism appears to be no greater than in the non-autistic population. There is an animal model of megalencephaly: expression of a recessive (see RECESSIVE ALLELE) GENE in the HOMOZYGOUS condition (mcephlmceph) in a mouse is
Seizure and cognitive outcomes of posterior quadrantic disconnection: a series of 12 pediatric patients
Published in British Journal of Neurosurgery, 2020
Yao Wang, Chao Zhang, Xiu Wang, Lin Sang, Feng Zhou, Jian-Guo Zhang, Wen-Han Hu, Kai Zhang
According to the underlying pathology, patients were divided into developmental (5 MCD patients) and acquired groups (7 malacic patients). The age at onset and operation in the developmental group was earlier than that of the acquired group. Guerrini and Dobyns19 reported that seizures in most MCD patients occur in an early stage. In detail, microcephaly and megalencephaly are the most severe types of MCD, with mostly bilaterally symmetrical or asymmetrical diffuse distributions. Relatively speaking, unilateral focal MCD is the least severe type, and the onset age is later. The median age at onset in the MCD patients in our study was 2.40 years, compared to the report of Devlin et al., in which the patients who underwent hemispherectomy had neonatal onset. The onset age in our study was later because the MCD was focal and possibly less severe.
Chylous Ascites in an Infant with Thanatophoric Dysplasia Type I with FGFR3 Mutation Surviving Five Months
Published in Fetal and Pediatric Pathology, 2018
Jeon Soo-kyeong, Narae Lee, Mi Hye Bae, Young Mi Han, Kyung Hee Park, Shin Yun Byun
TD has severe central nervous system abnormalities, the most characteristic of which are megalencephaly and cerebral cortical disorganization (18). Moreover, since the initial report of temporal lobe abnormalities in 1971 (19), there have been many reports on temporal lobe dysplasia. Other defects including hydrocephalus, temporal lobe hyperplasia, brainstem hypoplasia, and hippocampal dysplasia result from the activation of FGFR3 tyrosine kinase (2). The patient in the present case showed gradual progression of ventriculomegaly that was initially identified in the brain ultrasonography performed on day of life 3. The cause of death of this patient was most likely respiratory failure. However, considering the findings of exacerbated ventriculomegaly, brainstem compression may have contributed to the death. For a more accurate assessment of the brain, a brain MRI was necessary, but it was not performed because of the refusal of the parents.
Neuroimaging and genetic characteristics of malformation of cortical development due to mTOR pathway dysregulation: clues for the epileptogenic lesions and indications for epilepsy surgery
Published in Expert Review of Neurotherapeutics, 2021
Nicola Specchio, Chiara Pepi, Luca De Palma, Marina Trivisano, Federico Vigevano, Paolo Curatolo
PI3K/AKT signaling is associated with development of the brain, limbs and vascular system. Of related interest is that megalencephaly capillary malformation and megalencephaly-polymicrogyria-polydactyly-hydrocephalus, two syndromes associated with sporadic overgrowth with markedly enlarged brain size and other features in common with HME, have also been associated with de novo germline or postzygotic mutations of AKT3, PIK3R2 and PIK3CA [105,106].