03/25/2026
Neural tube defect
Neural Tube Defects (NTDs) are congenital malformations that occur when the neural tube fails to close properly during early embryonic life (around 3rd–4th week of gestation).
🔹 Types of Neural Tube Defects
Spina bifida
Occulta – mild, skin intact
Meningocele – meninges protrude (usually no neural deficit)
Myelomeningocele – spinal cord + meninges protrude (severe deficits)
Anencephaly
Absence of major parts of brain and skull (incompatible with life)
Encephalocele
Herniation of brain tissue through skull defect
🔹 Causes / Risk Factors
Folic acid deficiency (most important)
Genetic predisposition
Maternal diabetes
Drugs (e.g., antiepileptics like valproate)
Maternal obesity
Hyperthermia (fever, hot baths early pregnancy)
🔹 Pathophysiology
Failure of closure of the neural tube leads to:
Defective formation of brain and spinal cord
Exposure or malformation of neural tissue
🔹 Clinical Features
Visible sac/swelling over spine (in spina bifida)
Neurological deficits:
Limb weakness/paralysis
Sensory loss
Bladder & bowel dysfunction
Associated anomalies (e.g., hydrocephalus, Chiari II malformation)
🔹 Diagnosis
Antenatal
↑ Maternal serum AFP
Ultrasound (18–20 weeks)
Postnatal
Clinical exam
MRI/CT
🔹 Complications
Hydrocephalus
Paralysis / motor deficits
Neurogenic bladder → recurrent UTI
Orthopedic deformities (clubfoot, scoliosis)
Infection (especially meningitis)
🔹 Prevention (Very Important)
Folic acid supplementation
400 mcg/day (all women of reproductive age)
5 mg/day (high-risk cases)
Good glycemic control in diabetics
Avoid teratogenic drugs
🔹 Management
At birth
Cover defect with sterile saline dressing
Prevent infection
Surgery
Early closure (within 24–48 hrs for myelomeningocele)
Long-term care
Physiotherapy
Bladder/bowel management
VP shunt if hydrocephalus
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