Download - Congenital Anomalies of Nervous System

Congenital Malformations of the Central Nervous System

Neural Tube DefectsDr. Dhaval ShuklaAssociate Professor

Department of NeurosurgeryNIMHANS, Bangalore.

Epidemiology

• 1/3rd of all congenital malformations

• 75% of fetal deaths

• 40% of deaths during the first year of life

• Cause not known in 75%

Epidemiology

• Most fetuses with major malformations are stillborn or die

during the neonatal period

• Survivors are seriously incapacitated, ranging from

unresponsiveness throughout their entire life to profound

mental retardation, muteness, severe motor deficits, and

seizures

• Minor anomalies manifest with mental retardation,

behavioral changes, motor disorders, and seizures.

Etiology

Development

Major Developmental Events

Normal and abnormal spinal cord

Neural Tube Defects

• 0.5 to 2 per 1,000 births

• Genetic risk factors, maternal diabetes mellitus,

and the use of the anticonvulsants valproic acid

and carbamazepine

• Brain or the spinal cord, or both, with their

coverings

Classification

Cutaneous manifestations

Spina bifida occulta

• Sacral or lumbosacral is commonest

• Requires no treatment at birth

• Potential for the spinal cord to become fixed

(tethered) at the site of the lesion during

growth of child

Meningocele

• Neurological function outcome is usually more

favorable

• Surgery to close the lesion

• Long-term needs will depend on the extent of

neurological deficits and level of involvement

Myelomeningocele

• Apparent at birth

• Legs, bladder and bowel are usually affected

• Hydrocephalus is usually present

Preoperative care

• Prevent infection– At the site of the lesion– Meningitis– Ventriculitis– Urinary infections

• Avoid drying and injury• Dressing– Clear Film– Non-abrasive– Non-adherent

Nurse proneMeticulous nappy care

Surgery for open defects

• Within 24 hours of birth if no other life

threatening malformations

• Dissecting the neural tissue

• Covering the tissue with fibrous dura

• Skin graft may be necessary

• Shunt may be inserted

Postoperative care

• Maintaining the airway and providing adequate

oxygenation

• Maintaining adequate circulatory fluid volumes and

replacing blood loss

• Ensuring hypoprothrombinaemia is minimized by

giving vitamin K preoperatively

Postoperative care

• Ensuring the environment minimizes heat loss

• Monitoring and preventing metabolic

abnormalities such as hypoglycaemia,

hypocalcaemia or acidosis

• Maintaining strict precautions to minimize the

risk of infections

Postoperative care

• Nurse the infant prone

• The wound must be observed for CSF leak and

signs of infection

• Nylon sutures are removed after 10–14 days

• Hydrocephalus is likely to develop within 10

days

Neurological care

• Correct positioning of the limbs

• Observation of the skin for any signs of pressure

damage

• Regular position changes

• Regular passive exercisesPerform above with other routines such as

feeding and nappy care

Bladder care

• Continuous urine leakage or full bladder after voiding

• Regular renal ultrasound scans

• Intermittent catheterization

• Prophylactic antibioticsExpressing the bladder by applying pressure over the lower abdomen during nappy changes may increase the risk of

urinary reflux into the ureters

Care of parents

• Future predictions relating to the potential physical and cognitive outcomes

Antenatal Detection

• Maternal ultrasound examination

• High α – fetoproteins in amniotic fluid– Maternal serum - 12 weeks

– 30 per cent chance of a false-positive

• Amniocentesis is offered at 16–18 weeks for chromosomal

aberrations by karyotyping

• DNA studies on chorionic villi - 8 weeks

• Magnetic resonance imaging (MRI)

Prevention

Before and during pregnancy

• Folic acid (0.4mg daily)

• Increase to 5mg daily for high risk women

• Avoid smoking and alcohol intake

• Avoid aminopterin, methotrexate, trimethoprim,

valproic acid, carbamazepine, and phenobarbitone

If you are not taking contraceptives take FOLIC ACID