Neural Tube Defects/Spina Bifida Flashcards
Neural Tube Defects
Grouping of malformations of the…
- Spinal Cord
- Brain
- Vertebrae
3 Major NTDs
- Encephalocele
- Ancephaly
- Spina Bifida
Enecephalocele (3 Major NTDs)
- A malformation of the skull which allows a portion of the brain to protrude in a sac.
- Most encephaloceles occur in the occipital region of the brain; though sometimes in the frontal region.
- Typically results in intellectual disabilities, hydrocephalus, neuromuscular spasticity and seizure disorder.
Anencephaly (3 Major NTDs)
- A most severe congenital malformation of both skull and brain in which there is no neural development above the brain stem.
- Half of fetuses with anencephaly do not survive birth.
- Those who survive rarely survive infancy.
Spina Bifida (3 Major NTDs)
Considered to be the most common neural tube defect
- Identified as a split of the vertebral arches that typically result in a protruding meningeal sac that may contain a portion of the spinal cord.
- Greater than 10% of the general population have a benign separation of the vertebral arches without any visual abnormalities on their back, a sac at birth, or other neurologic symptoms.
- These children are not likely referred to OT services based on this diagnosis alone.
Meningocele (Spina Bifida)
- Refers to an exposed membranous sac covering the spinal cord.
- In this form of spina bifida, the spinal cord is not entrapped; thus, children have no symptoms.
- This is referred to as spinal bifida occulta and is the most common and benign form of NTD.
Meningomyelocele (Spina Bifida)
- Associated with a malformed spinal cord within the sac.
- This disorder is MOST associated with spina bifida and accounts for most likely OT referrals of all NTDs.
- Evidence-based support a strong link between NTDs and maternal folic acid deficiency.
Meningomyelocele Symptoms (Spina Bifida)
- Complete or partial paralysis
- Sensory loss below the lesion of the spinal abnormality
- Chiari type II malformation with hydrocephalus
- Neurogenic (absence of innervation) to bowel and bladder
- Hydrocephalus
Chiari type II
Malformation in which brainstem and part of the cerebellum are displaced downward toward the neck, rather than within the skull
What is the Incidence of Chiari type II among children with Spina Bifida?
Nearly all children with a meningomyelocele above the pelvic, or sacral level will have this abnormality.
What are the Signs and Symptoms of Chiari type II?
The child may have difficulty swallowing, apnea episodes, difficulty breathing during sleep, arching of the head backwards to relieve the pressure resulting from brainstem and spinal cord compression.
What is the Medical Intervention for Chiari type II?
Decompression surgery
Hydrocephalus Incidence and Diagnosis
- Occurs in 75-95% of children with meningomyelocele or spina bifida, especially in lower thoracolumbar spinal lesions.
- Results from an abnormal cerebral spinal fluid flow, resulting in enlargement on the ventricles of the brain.
- Diagnosed by neuroimaging studies: ultrasound, CT, or MRI
What is the Medical Management of Hydrocephalus?
- Surgically implanted shunt that diverts the CSF from ventricles to abdominal cavity where it can be absorbed.
- Ongoing evaluation for shunt blockage or infection
Diagnosis of NTDs
- In utero, or before the child is born: Malformation of NTDs occur during the first stages of CNS formation; usually occurs by 26 days post egg fertilization and before a woman knows she is pregnant.
- NTDs are diagnosed prenatally by measuring levels of alpha-fetoprotein (AFP) via maternal blood test at approx. 17 weeks of pregnancy. AFP is a chemical found in fetal spinal fluid, and in the presence of an NTD, AFP can leak from the open spine into the amniotic fluid, then into the maternal blood stream.
- If suspected, a follow up MRI or 3D ultrasound may be done. Early diagnosis helps parents and delivery team plan for a C-Section delivery in a center with a NICU and a pediatric neurosurgeon.
