Neural Tube Defects

Question 1

Classify the neural tube defects

Answer 1

Open Spinal Dysraphism
–> Cleft in vertebral column and skin defect
- Myelomeninocele (meninges + Neural tissue)
- Meningocele (Meninges only)

Closed Spinal Dysraphism
–> Cleft in Vertebral column only
- Spina Bifida Occulta

Question 2

What is the most common form of neural tube defect

Answer 2

Myelomeningocele
- Cleft in vertebral column and cleft in skin

Question 3

Where are myleomeningocele’s most commonly located

Answer 3

Lower lumbar region (90%)

Question 4

What is the increzsed risk of myelomeningcele in subsequent pregnancies?

Answer 4

The risk triples after each affected pregnancy

Question 5

What are the environmental factors that are associated with increased risk of myelmeningocele

Answer 5

1. Folate deficiency (supplement 400ug daily)
2. Antiepileptics (Valproate and Carbamazepine)
3. Maternal fever in 1st trimester
4. Poorly controlled pregestational diabetes and prepregnancy obesity
5. Low socioeconomic status
6. Environmental pollutants and pesticides

Question 6

How are mothers screened for NTDs

Answer 6

18 - 22 week ultrasound and AFP levels

high resolution US in 2nd trimester allows for accurate diagnosis

Question 7

What proportion of patients with myelomenigocele develop Chiari II malformation

Answer 7

Almost all of them

Question 8

What are the clinical effects of Chiari II malformation

Answer 8

brainstem and cognitive dysfunction, swallowing difficulties, vocal cord paralysis, stridor, and apnea in these patients.

Question 9

What percentage of patients with meningomyelocele with Chiari II malformation develop obstructive hydrocephalus

Answer 9

70 - 90 %

Requires ventriculoperitoneal shunting and multiple revisions

Question 10

List the clinical problems associated with myelomeningocele

Answer 10

1. Chiari II
   –> Cognitive (learning, attention, social) and brainstem dysfunction:
   —–> Vocal cord palsy
   —–> Swallowing abnormality
   —–> Stridor
   —–> Apnoea
2. Obstructive hydrocephalus (Multiple revision VP shunt)
3. Motor and sensory dysfunction (lower limbs, pressure sores)
4. Bowel and Bladder
   —–> Catheterization / UTI
   —–> Fecal incontinence and constipation
5. Orthopedic
   —–> CLub foot. hip subluxation, Joint contracture, scoliosis
   6.