Child Neuro Flashcards
When does primary neurulation occur? What is it?
3-4 wks
formation of the brain and spinal cord exluding formation of the lower spinal cord. secondary neurulation: later events inovled in sacral spinal cord
\What is the most sever neural tube defect? What happens?
craniorachischisis. failure of primary neurulation, absence of overlying skeleton and dermal covering.
leads to spontaneous early abortion
What is anencephaly?
failure of anterior neural tube closure. absent forebrain and upper brainstem; present lower brainstem. Usually stillbirths; if not, death in a first few days of life
What is myelomeningocoele?
spina bifida. limited failure in posterior neural tube closure. see primitive nerual tube-like structure in the lumbosacral region. defects in axial skeleton and dermal covering; protrusion of a sac containing meninges, CSF, and spinal cord elements. varying degress of motor, sensory, and sphincter dysfunction.
What is myeloschisis?
complete failure of posterior nerual tube closure. spinal cord incomplete w/ absent vertebrae and dermal covering. usually stillborns
What is spina bifida occulta?
weakness but no apparent problem
what is an meningocele?
just a protrusion of CSF in lumbosaccral region- no cord material
What is primary prevetion for neural tube defects?
folate supplementation prior to conception
When does prosencephalic development peak?
2-3 mo. gestation
What are key events of prosencephalic development?
formation at rostral end of neural tube after anterior neural tube closure. then,horizonal cleave to form optic veicles, olfactory bults, olfactory tracts; transverse cleavage form telencephalon and diencephalon, saggital cleave to form cerebral hemispheres, basal ganglia, lateral ventricles
then midline devo: corpus callosum septum pellucidu, optic chiasm, hypothalamus
What is one clue about the degree of prosencephalic problems?
degree of facial abnormalities
What is aprosencephaly?
failure of prosencephalic formation. absent telencephalon and diencephalon with a primitive brainstem. they have an overlying skeleton and dermal covering, so NOT anencephaly. infants still born or die in early infancy
What is holoprosencephaly? Spectrum?
failure of prosencephalic cleavage. may be alobar, or lobar
What are some features of holoprosencephaly?
absence of olfactory bulbs and tracts, single optic nerve and single median eye, hypotelorism, rudimentary nasal structure, single central incisor
What happens with agenesis of corpus callosum?
disorder of midline prosencephalic development affecting the commissural plate. red flag for other neuronal migration problems, but usually asymptomatic if occurring in isolation
