NEUROTUBE DEFECTS

Clinical Features

These are the commonest CNS anomalies. The defect can occur in any part of the CNS starting from the head and down the spine. The abnormalities vary from the extreme anencephaly, through encephalomyelocoele and encephalocoele, to
spina bifida with or without myelocoele or meningomyelocoele.

HEAD DEFECTS

Anencephaly is the complete absence of the brain apart from the brain stem, while encephalocoele and encephalomyelocoele are most commonly occipital but can be frontal.

SPINE DEFECTS

Spina Bifida

This results from failure in the development of vertebral arches and is frequently associated with mal-development of the spinal cord and membranes. There are two main types:

  1. Spina bifida occulta
  2. spina bifida cystica.

Spina Bifida Occulta

  • Many cases are asymptomatic and are undiagnosed.
  • There may be tell-tale signs on the back such as
    • Lipoma
    • Dimple
    • Tuft of hair (hypertrichosis)
    • Naevus
    • Telangiectasia.
  • In other cases, the patient may present with;
    • Nocturnal enuresis
    • Foot-drop
    • Persistent urinary tract infections due to neurogenic bladder,
    • Recurrent meningitis due a communicating dermal sinus.
Investigations
  • X-ray of full spine will show absent lamina on one side or bilaterally.
  • Myelogram may be useful to rule out associated conditions such as diastematomyelia.
  • A CT scan can also show the associated anomalies.
Management

This focuses on any complication noted. Excision of a communicating sinus is important in the prevention of recurrent meningitis.

Spina Bifida Cystica

  • Defect in the spine
  • There is an obvious mass on the back. This may be a meningocoele (a bulge of the meninges usually covered with skin), or
    meningomyelocoele (a bulge of the meninges that contain neural tissue). sequence,
  • There is paralysis below the level of the lesion with or without incontinence of stool and/or urine.

Investigations

  • Cranial ultrasound or CT scan
  • Abdominal ultrasound to exclude intrabdominal anomalies especially the kidney
  • Echocardiogram if indicated

Management

Management requires a multidisciplinary team approach including surgeons, paediatrician, and physical therapists. The patient should therefore be referred to a specialized centre for care.

Appropriate sterile dressing of open lesions is necessary to prevent infection. Counsel the parents carefully so as to accept the child and be aware of what can be done.

Prevention

Pre-pregnancy folate supplementation is known to reduce chance of recurrence.