Neural Tube defects ( NTD )
- Anterior - normally closes at 25 days
- Posterior - normally closes at 27 days
NTD due to failure of closure.
- Anterior nonclosure - Ancephalocele , Encephalocele
- Posterior nonclosure - Spina Bifida , Meningocele , Meningomyelocele
Risk factor :
- Maternal folic acid deficiency (Most important)
- Maternal Zn deficiency
- Materanl Malnutrition
- Maternal Alcohol , Diabetes , Radiation
- Maternal Anticonvulsan (Valproate , phenytoin)
To prevent recurrence : give 4mg Folic acid (i.e 10 times)
Meningocele : Herniation of meninges
Meningomyelocele : Herniation of meninges + nerve roots
if Lumbosacral Meningomyelocele - Complications
- Paraplegia /parasis
- Posterior dislocation of hip
- Bowel and bladder incontinence Do MRI head - because 80% will have obstructive hydrocephalus , because of Arnold Chiari type 2 malformation.
Encephalocele : Herniation of brain tissue.
Occipital is more common than frontal.
Earliest Congenital anomaly that can be diagnosed by USG : Anencephaly (at 10-11 wks)
Tests for NTD
- Amniocentesis : Acetyl cholinesterase and Alpha feto protein
- Maternal Serum : AFP (MSAFP)