1.2.2 Neural Tube Defects Flashcards
What are neural tube defects called?
Spina bifida/ spinal dysraphism/ neural tube defects or disorders
What are neural tube defects caused by?
Failure of the neural tube to zip up (neural folds don’t fuse) in the cranial or caudal directions
All disorders result in failure of development of the posterior vertebral arches at one or more levels
Neural tube must therefore be responsible for inducing migration of the sclerotome from somites to form the posterior arch
What happens when the neural tube fails to close in the cranial direction?
Brain involvement, e.g. anencephaly, baby has no brain
What happens when the neural tube fails to close caudally?
Spine/spinal cord involvement (classic spina bifida)
What is craniorachischisis?
Most severe neural tube disorder
Entire neural tube remains open, both brain and spinal cord fail to form
Incompatible with life
What is anencephaly?
Cranial neural tube fails to close
Failure of brain to form, children may be born alive but do not live for long
What disorders appear to have a normal neural tube for development of the posterior vertebral arch fails?
Meningomyelocoele
Meningocoele
Spina bifida occulta
What is a meningomyelocoele?
CSF- filled cyst containing the spinal cord
Transilluminates poorly (due to solid tissue in cyst)
Children may have neurological deficits
Repair is necessary
What is a meningocoele?
Presence of a CSF filled cyst
Cord is sited in the vertebral canal
Transilluminates very well
Children tend to have good neurological prognosis
Cyst needs repair as predisposes to infection
What is spina bifida occulta?
Lack of posterior vertebral arch
May have a tuft of hair or large naevus (birthmark) pver defect
No association with neurological problems
10% of the population
How can neural tube defects be prevented?
Folic acid (B9)
400 micrograms daily from 3 months before conception until 12 weeks of pregnancy
Mechanism unknown
