Spina Bifida


Spina bifida is a type of Neural Tube Defect (NTD), where there is incomplete closure of the embryonic neural tube.

Prevention


The importance of folic acid supplementation, in prevention of NTD


Screening


Offer screening: amniocentesis
Fetoprotein monitoring discovers exposure of neural elements to the amniotic fluid

Epidemiology


1-2 persons per 1000 population
Associated factors include anticonvulsants (esp. valproate and carbamazepine), diabetes, obesity and fever during pregnancy.
Genetic component. Increased risk if previous children were found to have spina bifida.

Aetiology


Neuroectoderm thickens into the neural plate, which then folds into a neural grove by teh time somites appear. The groove deepens to become the neural tube, adn dorsal fusion begins centrally.


Multifactorial genetic inheritance e.g. cytoplasmic factors, polygenic inheritance, chromosomal aberrations, environmental influences such as teratogens.
Environmental factors e.g. nutrition, namely FOLIC ACID intake.

Occur between 17th and 30th day of gestation (mother may not be aware of pregnancy at this time).


Classification



Failure of the neural tube to close during first month of embryonic development.

A. Normally, the closure of the neural tube occurs around the 23rd (rostral closure) and 27th (caudal closure) day after fertilization.

B. Spina bifida occulta
Limited defect of the vertebral arch that does not involve protrusion of the cord or membrane.
Most often occuring at the lumbosacral junction.
Appears as an incidental radiographic finding in up to 10% of the healthy population.

C. Meningocele
Pouching with no protrusion of the spinal cord itself.

D. Spina bifica cystica (Myelomeningocele)
Myelo- meaning spinal cord
The most common type of spina bifida, accounting for 94% of cases
Can be found anywhere along the spinal axis but most commonly is found in the lumbar region.
Arnold-Chiari malformation (failure to close cranially) is associated with myelomeningocele (failure to close caudally). It is where there is malfortion of the cerebellum with elongation of the cerebellar tonsils. The cerebellum is drawn into the fourth ventricle.



spina-bifida_now.JPG



E: Myeloschisis is the worst type of Spina Bifida. The myelocele or myeloschisis, variety, is where the open neural plate is covered secondarily by epithelium and the neural plate has spread out onto the surface.


Signs and Symptoms


Neurological bowel and bladder ie incontinence
contracted bladder (cause hydronephrosis along with infections and renal failure)
Renal failure
Motor- muscular imbalance, joint contractures and developmental problems e.g. hip dislocation adn spinal deformities
Intelligence (aggressive shunting for hydrocephalus)
Subtle defect in Coordination (cerebellar defiency from the arnold-chiari malformation)
Seizure
Infections (due to exposed central nervous system)


Presentations range from still birth to radiographic findings

Associated with:
Hydrocephalus (due to excessive accmuluation of cerebrospinal fluid in the ventricles of the brain)
Cephalocele
Arnold-Chiari malformations
(Latex allergy)



Treatment


Intrauterine/Prenatal surgery
Shunting

Myelomeningocele
Neonatal surgery and closure
Surgery which frees lateral muscle and skin for coverage


Genetic Counselling

Thalassaemia Major


Down Syndrome



extra/partial/whole Cr 21
flat facial profil
hypotonia
loose skin on back of neck
severe mental retardation.

General Counselling

Violence against women

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  • being empathetic
  • specific details of violence
  • time of violence
  • nature of violence
  • details of alleged perpetrator
  • involvement of children/others
  • patient's information needs and/or support