A birth defect where the neural arch does not properly form - leaving behind various degrees of opening in the back
The most common neural tube defect
Risk factors:
- Multifactoral - genetic, environmental factors
- Pregnancy - folate deficiency, anti-convulsant use
- obesity
- poorly managed diabetes-mellitus
Pathophysiology
- congenital spinal column changes - meninges malformation
- Occurs in the 4th week of pregnancy
- The neural tube fails to close completely, there is a defect or absence of the vertebral arches (failure of mesoderm to organise): Usually in the lumbar spine region allowing the meninges/spinal cord to proturude dorsally out of the spinal canal
Types:
- Myelomeningocele (most severe): spinal cord and surrounding meninges protrude out of an opening in the bony vertebrae held only by a pouch of skin
- in really severe cases there can be no skin at all - Open spina bifida, causing serious damage to exposed nerves and risk of infection
- Typically associated with an arnold chiarry 2 malformation (cerebellar and brainstem tissue herniate into foramen magnum)
- Meningocele (meningeal cyst): only meninges slip into gaps between deformed vertebra
- spinal cord not damaged so usually no severe symptoms
- spina bifida occulta (most common/mild): spinal cord and surrounding tissue dont protrude
- often asymptomatic - people may have hair, dimple or birth mark on thier mark above the lesion
Symptoms/signs