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Nerve Hypoplasia (nerve + hypoplasia)

Distribution by Scientific Domains
Medical Sciences85%

Kinds of Nerve Hypoplasia

  • optic nerve hypoplasia
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    Selected Abstracts

    Pulfrich's phenonenon in a case of optic nerve hypoplasia

    OPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2008
    Gordon Heron
    Introduction:, Optic nerve hypoplasia (ONH) is a congenital deficiency of retinal ganglion cells and their axons that form the optic nerve. This condition is associated with visual deficits ranging from no light perception in severe cases to vision within normal ranges in mild cases of ONH. In mild cases, deficits can be limited to sectoral anomalies in the visual field and normal vision with colour vision anomalies have been reported. We report here a case of mild ONH with visual symptoms relating to Pulfrich phenomenon (PP) occurring spontaneously. Methods:, A 12 year girl presented with typical visual symptoms (bumping into objects when walking, poor object location at tennis) associated with the spontaneous PP. A simple pendulum revealed a perceived anticlockwise ellipse indicative of a left eye defect. This was neutralised by an 85% transmission filter placed before the right eye. The inter-ocular latency difference was calculated to be 0.88 (S.D., 0.55) ms. Results:, Fundus biometry showed an asymmetry in optic nerve size, the left being smaller than the right. Visual fields, anomaloscope and other colour vision tests, and both flash and pattern-reversal stimuli Visually Evoked Potentials showed no difference in visual function between the right and left eyes. Conclusions:, A case of very mild ONH gives inter-ocular normal vision and visual function and yet a subtle inter-ocular delay occurs resulting in visual symptoms associated with PP. These were completely removed with tinted spectacles. [source]

    Septo-optic dysplasia as a manifestation of valproic acid embryopathy

    BIRTH DEFECTS RESEARCH, Issue 2 2001
    Carrie L. McMahon
    Background The use of valproic acid during pregnancy has been associated with adverse fetal outcomes, including major and minor congenital malformations, intrauterine growth retardation (IUGR), hyperbilirubinemia, hepatotoxicity, transient hyperglycemia, and fetal and neonatal distress. In addition, intrauterine exposure to valproic acid has been associated with an increased risk of central nervous system abnormalities, primarily neural tube defects. Optic nerve hypoplasia has been reported in association with other prenatal anticonvulsant exposures, but the occurrence of septo-optic dysplasia as a manifestation of valproic acid embryopathy has not been reported previously. Results We report on a woman who received Depakote (valproic acid) throughout her pregnancy for the treatment of a seizure disorder. The patient presented with features typical of valproic acid embryopathy, including bitemporal narrowing, hypertelorism, short palpebral fissures, epicanthal folds, microphthalmia, a flat broad nasal bridge, small mouth, hypoplastic nails, mild clinodactyly, and camptodactyly. MRI showed hypoplasia of the optic chiasm and absence of the septum pellucidum. Conclusions We report the first case of septo-optic dysplasia associated with maternal exposure to valproic acid throughout pregnancy. This case expands the clinical phenotype of valproate embryopathy. Teratology 64:83,86, 2001. © 2001 Wiley-Liss, Inc. [source]

    Optic nerve hypoplasia in North America: a re-appraisal of perinatal risk factors

    ACTA OPHTHALMOLOGICA, Issue 5 2010
    Pamela Garcia-Filion
    Abstract. Purpose:, The purpose of this study is to describe and clarify the birth and prenatal characteristics of a large cohort of children with optic nerve hypoplasia. Methods:, This is a descriptive report of 204 patients aged , 36 months and enrolled in a prospective study at the Children's Hospital Los Angeles. Birth characteristics, including complications, were abstracted from study files and medical records. Systematic maternal interviews were conducted to obtain detailed prenatal histories. National birth data were used for comparison with birth findings. Results:, Birth characteristics were unremarkable for birthweight and gestation, but significant for increased frequency of caesarean delivery and fetal and neonatal complications. Young maternal age and primaparity were dominating maternal features. Preterm labour, gestational vaginal bleeding, low maternal weight gain and weight loss during pregnancy were prevalent. Conclusions:, These findings confirm young maternal age and primaparity as associated risk factors, challenge many other suggested factors such as alcohol and drug abuse, and introduce potentially significant prenatal characteristics such as maternal weight loss and early gestational vaginal bleeding as aetiological correlates. [source]

    Visually impaired children with posterior ocular malformations: pre- and neonatal data and visual functions

    ACTA OPHTHALMOLOGICA, Issue 4 2003
    Kristina Teär Fahnehjelm
    Abstract. Aim:, To analyse pre- and neonatal data and ocular findings in children with visual impairment caused by posterior ocular malformations. Methods:, Medical records were scrutinized, dried blood spot cards were analysed for virus DNA and ophthalmological assessments were performed in 28 children with optic nerve hypoplasia (ONH) and 10 with optic/chorio-retinal coloboma. Results:, Prenatal exposure to possible teratogens was documented in 5/28, herpes simplex virus type 1 DNA was identified in the dried blood spot cards of 1/26 children and neonatal hypoglycaemia in 12/28 children with ONH. The time delay from ocular to endocrinological diagnosis and treatment was 3 years. Children with ONH and severe visual impairment had endocrinopathy more often (11/13) than ONH children with better visual functions (5/15). Prenatal exposure to teratogens or neonatal hypoglycaemia was not identified in any of the children with coloboma. Conclusion:, Neonatal hypoglycaemia was common in children with ONH. Severe visual impairment predicted endocrinopathy. Analysis of dried blood spot cards could serve as an additional diagnostic tool in children with ocular malformations. [source]

    Congenital hypopituitarism: clinical, molecular and neuroradiological correlates

    CLINICAL ENDOCRINOLOGY, Issue 3 2009
    Ameeta Mehta
    Summary Objective, Recent studies have suggested that mutations in genes encoding several hypothalamo,pituitary (H,P) transcription factors result in hypopituitarism [isolated GH deficiency (IGHD) and combined pituitary hormone deficiency (CPHD)], which may in turn be related to the neuroanatomy revealed by magnetic resonance (MR) imaging. Although studies have focused on patients with either optic nerve hypoplasia (ONH) or isolated hypopituitarism with normal optic nerves, few studies have compared the two groups. We aimed to relate the clinical phenotype of a large cohort (n = 170) of children with congenital hypopituitarism including septo-optic dysplasia (SOD) attending a single centre to the neuroradiological and genetic findings. Design, Clinical, biochemical, MR imaging and molecular data were analysed retrospectively in 170 patients with or ,at-risk' (with ONH) of hypopituitarism to determine predictors of hypopituitarism. Results, The presence of ONH was significantly associated with an absent septum pellucidum [odds ratio (OR) 31·5, 95% confidence intervals (CI) 7·3,136·6, P < 0·001], an abnormal corpus callosum (OR 10·5, 95% CI 3·8,28·6, P < 0·001) and stalk abnormalities (OR 2·3, 95% CI 1·2,4·2, P = 0·009). The risk of hypopituitarism was 27·2 times greater in patients with an undescended posterior pituitary (95% CI 3·6,205·1, P < 0·001). Anterior pituitary hypoplasia (OR 3·1, 95% CI 1·3,7·0, P = 0·006) and an absent pituitary stalk (P < 0·001) were also significantly associated with hypopituitarism. With respect to the type or severity of hypopituitarism, CPHD was more often associated with an abnormal corpus callosum (OR 6·1, 95% CI 1·4,27·4, P = 0·008) and stalk abnormalities (OR 2·8, 95% CI 1·3,6·1, P = 0·006). Male to female ratio was significantly greater in patients with normal optic nerves (3·3:1) as compared with those with ONH (1·2:1). The prevalence of diabetes insipidus, thyrotrophin and ACTH deficiencies was significantly greater in patients with ONH as compared with ,idiopathic' hypopituitarism. Mutations in pituitary transcription factors and genes regulating GH secretion were rare (5/170) in this cohort of patients with sporadic hypopituitarism. Conclusion, Our data suggest that individuals presenting with ONH are at high risk for neuroradiologic and endocrine abnormalities. The neuroradiologic features are predictive not only of the presence, but also of the type, of hypopituitarism. The association of midline abnormalities with hypopituitarism in this cohort suggests a common developmental origin for these features, the aetiology of which remains unidentified in the majority of cases. [source]