NEURAL TUBE DEFECTS
- They account for must congenital anomalies of CNS & results
from failure of the neural tube to close spontaneously between
3rd & 4th week of gestation.
- Though exact reason is not known but following factors may
contribute.
Radiation
Drugs
Malnutrition
Chemicals
Mutation involving folate dependent pathways.
- Folic acid supplementation antenataly reduces incident of
NTDS.
- Major neural tube defects are:-
Spina bifida oculta
Meningocele
Myelomenilgocele
Encephalocele
Anencephaly
Dermal sinus
Tethered cord
Syringomyelia
Diastometomyelia
Lipoma in conus medullaris
- Failure of closure of neural tube allows excretion of fetal
substances (e.g. alpha-fetoprotein acetylcholine
stares) into the amniotic fluids which are biochemical marker
for NTDS.
1. SPINAL DYSRAPHISM (SPINA BIFIDA)
- There is only bony abnormality usually spina bifida-it is of no
clinical significance. In some cases patches of hair, a lipoma,
discoloration of skin or dermal sinus in midline of the low back
signifies an underlying malformation of spinal cord.
- A spine roentgenogram shows defect in closure of posterior
vertebral arches & laminae involving L 5 & S1.
- Occasionally it may be associated with,
Syringomyelia
Diastometomyelia
Tethered cord
- Syringomyelia is cystic cavity within spinal cord that may or
may not communicate with CSF pathways.
- Diastometomyelia is division of spinal cord into two halves by
projection of a fibro cartilaginous or bony spur originating
from posterior vertebral body & extending posteriorly.
- Tethered cord results when a thickened ropelike filum
terminale persists & anchors the conus at or below the L2 level.
- Above 3 conditions present with-
Delayed bladder control
Gait abnormality sometimes with asymmetric
weakness
Foot deformity
Scoliosis or back pain
Recurrent meningitis
2. MENINGOMYELOCELE (MYELOMENINGOCELE)
- Most severe from of dysraphism involving. Vertebral column with
incidence 1/4000 live births.
* CLINICAL FEATURES:-
- It may located anywhere along the neurons but lumbosacral region
accounts for 75% case.
- Lesion in low sacral region causes bowel & bladder incontinence
associated with anesthesia in perineal area (saddle anesthesia) with no
motor impairment.
- Newborns with defect in midlumbar region typically have a sac like
cystic structure covered by a thin layer of partially epithelized tissue.
Remnauts of neural tissue are visible within sac which may rupture
leading to leakage of C.S.F.
- Examination of infants show flaccid paralysis of lower limbs, absent
deep tendon reflexes, absent pain & touch sensation & abnormalities
like clubfoot & subluxation of hip. Constant urinary dribbling &
relaxed anal sphincter may be evident.
- So lesion in midlumbar region produces lower motor neuron signs.
- Due to neurogenic bladder they tend to have vesico-ureteric-reflux
(UVR) recurrent urinary tract infections. If it persists for prolonged
period it may lead to pyelonepharitis, hydronephrosis & renal failure.
- Hydrocephalus in association with type 2 chiari defect develops in
80% cases of myelomeningocele. In general lower the lesion in
neuraxis (e.g. sacrum) lowers the chance of hydrocephalus.
- Ventricular enlargement may be slow or rapid causing bulging
anterior fontanel, dilated scalp veins, sunset eye sign, irritability,
vomiting & macrocephaly.
- Many patients with chiari 2 malformation develop symptoms of
brainstem dysfunction like dysphasia, choking, strider, apnea,
vocalcord paralysis & may lead to death.
MANAGEMENT
1. Councelling of parents:-
- Give them time to adjust
- explain prognosis & complications
2. Antibodies covering coagulase negative
- Staphylococcus (CONS) at birth if sac is rupture & early surgical
Intervention.
3. Surgery
- If sac is unruptured one can wait for few weeks. Evaluation of
Other congenital anomalies & renal function should be done
Preoperatively.
- After repair of myelomeningocele, most infants require shunting
Procedure for hydrocephalus. Ventriculo-peritonial shunt.
- If symptoms or signs of hindbrain dysfunction appear, early
Surgical decompression of medulla & cervical cord is indicated.
- Clubfoot may require casting & dislocated hip may require
Operative intervention.
4. Urological management:
- teaching parent & ultimately patients to regularly catheterize
Neurological bladder to reduce residual urine. This will reduce
Reflux & its complication like UTI & hydronephrosis.
- Regular physical analysis & renal function tests like- urine
Culture, s.creatinine, serum electrolyte, renal scans & USG.
- In complicated cases- surgical derivation are only options.
5. Bowel management:-
- In continence of bowel is common & socially not acceptable but
Not very harm full.
- Many children can be bowel trained with regime of
Timed enemas or suppositories.
- Appendicostomy for ante grade enemas may be helpful.
6. Physiotherapy:-
- To help to achieve functional ambulance of child & to reduce &
Treat foot deformities.
