Spina bifida is a congenital abnormality arising due to defects in the process of neural tube closure. It also occurs due to folic acid deficiency during pregnancy. Here we describe the etiology, epidemiology, clinical manifestations, types, treatments and preventions of spina bifida.
2. INTRODUCTION
Spina Bifida is a congenital anomaly that arises from
incomplete development of the neural tube.
It may also refer to any degree of defect in neural
tube closure.
It can be further subdivided into Spina bifida Occulta
and Spina bifida Aperta.
• Spina bifida Occulta or closed spinal dysraphism
• Spina bifida Aperta or open spinal dysraphism
3. NEURULATION
It is the process of neural tube formation. Normally
occurs between 17 and 30 days of gestation.
The process of neuralization occurs in two phases
• Primary neuralization refers to the closure of
the neural tube forming the brain and spinal
cord.
• Secondary neuralization involves the
formation of the caudal structures of the
neural tube forming the sacral and coccygeal
portion.
A defect in neural tube closure causes spina
bifida.
4.
5. WHAT CAUSES DEFECTS IN
NEURAL TUBE CLOSURE?
Multifactorial factors including environmental and
genetic influences neural tube closure.
Genetic factors
● Polymorphism of the gene encoding the
MTHFR enzyme (1p36. 6) involved in folate
metabolism
● Trisomy 13 and 18
● Family history of neural tube defects
6. Environmental factors
• Folate deficiency or folic acid-sensitivity
• Maternal obesity
• Maternal diabetes
• Exposure to teratogens such as valproic
acid (Valproic acid has the highest
association with development of NTDs)
• Hyperthermia in the early weeks of
pregnancy
7. EPIDEMIOLOGY
• Affects an estimated 1 in 2,500 newborns worldwide.
• Four out of every 1,000 children born in India have spina
bifida.
• Hispanic women seem to have a high rate of pregnancies
affected by NTD.
• There is an increased risk of recurrence of about 3-8%
after one affected pregnancy or maternal history of the
defect.
8. TYPES OF SPINA BIFIDA
There are two major types of spina
bifida:
• Spina bifida Occulta
• Spina bifida Aperta - It could
be further divided into
meningocele and
myelomeningocele
9. SPINA BIFIDA OCCULTA
• Occulta is the mildest and most common
form in which one or more bones of the
vertebral column are malformed.
• They may have a dimple, patch of hair, or
a red mark at the base of the spine.
• Usually doesn't cause symptoms.
• Most people with spina bifida occulta do
not need medical treatment.
10. MENINGOCELE
• Meningocele is a rare type of spina bifida.
• It occurs when the meninges protrude through
the spine and cause a sac of spinal fluid on the
back.
• The malformation contains no nerves and may
or may not be covered by a layer of skin.
• Individuals may have minor symptoms and
problems with bladder and bowel function.
• A baby born with a meningocele require
surgery.
11. MYELOMENINGOCELE
Myelomeningocele is the most severe form of spina
bifida.
A portion of the spinal cord or nerves are exposed in a
sac through an opening in the spine that may or may not
be covered by the meninges.
The symptoms of myelomeningocele are -
• Weakness, loss of feeling, or trouble moving lower
body parts
• Problems with bladder and bowel control
• Hydrocephaly
• Problem with cerebral structure formation
• Learning problems
• Seizures
Ventricular shunts are used to treat these babies.
12. DIAGNOSING SPINA BIFIDA
Diagnosed prenatally or postnatally
• Prenatal diagnosis -
• Maternal serum alpha fetoprotein screen at 16 to
18 weeks of pregnancy
• Ultrasound during the first trimester and the
second trimester
• Amniocentesis
• Postnatal diagnosis -
• Ultrasound
• X-ray imaging of the spine
• MRI and CT Scan for better visualization of spinal
cord and vertebrae.
13. Prenatal Surgery – In utero surgery to close the opening
of spinal cord before the 26th week of pregnancy.
Postnatal Surgery - Surgery within the first few days of
life to close the defect.
TREATMENT
PREVENTION
Diet rich in folic acid before and during early pregnancy.
Daily supplement of 400 micrograms (mcg) of folic acid.
Consumption of foods rich in folic acid - Dark green, leafy vegetables, egg yolks, fruits
(banana, citrus, papaya)
14. REFERENCES
Brea CM, Munakomi S. Spina Bifida. [Updated 2022 Aug 9]. In:
StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022
Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK559265/
Spina Bifida. (2023, January 27). National Institute of Neurological
Disorders and Stroke. https://www.ninds.nih.gov/health-
information/disorders/spina-bifida
Ferri FF. Spina bifida. In: Ferri's Clinical Advisor 2020. Elsevier; 2020.
Dukhovny S, et al. Open neural tube defects: Risk factors, prenatal
screening and diagnosis, and pregnancy management.
