Spina Bifida P1 Flashcards
general definition of spina bifida
aka spinal dyspharism and neural tube defect
congenital malformation and VC and SC
failure of neural tube to close in 3rd-4th wk
epidemiology of spina bifida
whites
females
hispanic ethniity
etiology of spina bifida
inc risk:
low folic acid intake
if may anak na may spina bifida = higher chance
pregestational diabetes and obesity
teratogenic drugs - valproate and carbamazepine
drugs used to induce ovulation
inc age
midspring conception
recommended doses for folic acid
normal: 400 ug or 0.4 mg daily
previous NDT mother or high risk: 4000 ug or 4 mg daily (1-3 mo. prior to conception)
week 2 of development
gastrulation = 3 germ layers
primitive streak in epiblast
significance of ectoderm
outer most layer where nervous system is derived
week 3 of development
neurulation = forming of neural tube
- primary and secondary phse
notochord secretes growth factor = ectoderm –> neuroectoderm –> neural endplate
primary phase
week 3-4
neural plate thickens and bends –> folds to form hollow tube
cranial = brain
caudal = SC
secondary phase
week 4-7
caudal part of neural tube becomes lumbar, sacral and coccyx segment
upper part does not close: anencephaly
lower part does not close: spino bifida
discuss neural plate
forms by day 18 and becomes tube and crest
tube - CNS
crest - PNS
closure of cranial end
24th day
closure of caudal end
26th day
discuss anencephaly
most severe NTD - dead na
neural tube does not close at base of skull
discuss encephalocele
rare NDT - can be repaired surgically but c deficits
part of brain herniates through skull defect
day 53 of development
caudal regression c rostral ext = SC
kaya lesions are before day 53 and usually sa lumbar and sacral
2 major types of spina bifida
oculta
cystica:
- menigocele
- myelomenigocele
- myelocele
discuss spina bifida oculta
mildest form - no herniation
lumbosacral segments
failure of one or more vertebral arches to fuse
(+) pigmented nevus, cafe au lait, hair on back, balat
(-) neuro and MSK deficits; arnold chiari and hydrocephalus
possible complication of spina bifida oculta
bowel and bladder sx d/t tethered cored
type of spina bifida that has neuro deficits
mga cystica
discuss meningocele
herniation of meninges only - uncommon
lumbosacral
normal neuro exam and no chiari/hydrocephalus
at risk of tethered cord
discuss myelomeningocele
herniation of meninges and neural tissue - most common and severe
lumboscaral
c chiari and hydrocephalus
abnormal motor and sensory below lesion
nuerogenic bowel and bladder
discuss myelocele
cavity is ant to wall of SC - rare
lumbosacral
discuss lipomeningocele
excess fat in VC and attached to SC
cyst has meninges and fat
discuss rachischisis
most severe form - open sone
whole thoracic or cervical
assoc c anencephaly
deads
discuss arnold chiari type 2
caudal herniation of medulla, lower pons, 4th ventricle, cerebellar vermis
c hydrocephalus and common in myelomeningocele
stridor
apnea
paralysis of vocal cords
discuss tethered cord syndrome
causes arnold chiari
2nd most common cause of neuro decline
hila pababa SX
sudden spasticity/flaccid, weakness or worsening of LE and scolio
common forebrain malformations
polymicrogyria
heterotopia
hyploplasia of thalamus
agenesis of olfactory bulb and tracts
agenesis of corpus callosum
