Lecture Notes: Spina Bifida

Overview

• Definition: Spina bifida means "split spine" in Latin.
• Description: A birth defect where the spinal tissue fails to close completely, leaving an opening in the lower back.

Embryonic Development

• Ectoderm Development: Early fetal development creates a neural tube from the ectoderm.
• Neural Tube Function: Becomes the spinal cord, brain, and meninges.
• Defect Formation: Failure of the neural tube to close properly results in spina bifida.

Types of Spina Bifida

1. Myelomeningocele

• Severity: Most severe type.
• Characteristics: Spinal cord and meninges protrude through an opening in the vertebrae.
• Symptoms: Exposure can lead to infections, paralysis, loss of sensation, and deformities.
• Associated Condition: Often linked to Arnold Chiari II malformation and hydrocephalus.

2. Meningocele

• Characteristics: Only meninges slip through vertebrae gaps.
• Symptoms: Less severe, spinal cord not damaged.
• Prevalence: Least common form.

3. Spina Bifida Occulta

• Severity: Most common and mildest form.
• Characteristics: No protrusion of spinal tissue.
• Detection: Often asymptomatic and discovered later in life.
• Symptoms: Possible hair, dimple, or birthmark over lesion site.

Causes and Risk Factors

• Unknown Causes: Exact causes are unknown.
• Folate Deficiency: Lack of folate (Vitamin B9) increases risk.
• Preventive Measures: Folic acid in prenatal vitamins and enriched grains.
• Other Risk Factors: Obesity, poorly controlled diabetes, certain medications.

Diagnosis

• Myelomeningocele Detection: Elevated alpha fetoprotein (AFP) levels in maternal serum.
• Additional Tests: Blood tests for HCG, inhibin A, estriol, and ultrasound.
• Amniocentesis: Direct sampling from amniotic sac for serious cases.

Treatment

• Prenatal Surgery: Dangerous but possible to close myelomeningocele.
• Postnatal Surgery: Done soon after birth to reduce infection risks.
• Additional Interventions: Urinary catheterization, crutches, or wheelchairs due to nerve damage.

Recap

• Spina Bifida Types:
  • Occulta: Most common, least severe.
  • Meningocele: Least common, mild.
  • Myelomeningocele: Most severe.

Conclusion

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