Neural Tube Defects

Question 1

What is gastrulation?

Answer 1

The process of the single layered blastula turning into the 3 (ecto/endo/mesoderm) layers

Question 2

What is the difference between open and closed NTD’s?

Answer 2

Open: Brain or spinal cord exposed at birth
Closed: Covered by skin

Question 3

What is anencephaly?

Answer 3

An open NTD where the head of the NT fails to close, P born with no forebrain- no survival

Question 4

What is an encephalocele?

Answer 4

Protrusion of the brain through the skull at birth

Question 5

What is hydraencephaly?

Answer 5

Part of cerebrum is just CSF fluid (agenesis)

Question 6

What is spina bifida occulta?

Answer 6

Affects 10% population. Outer part of vertebrae not completely closed, however gap is very small so no spinal cord protrusion

Question 7

What is the cause of NTD’s?

Answer 7

Low folate (vit B9) or vitamin B12, needed for nucleic acid/ DNA synthesis

Question 8

Name 5 risk factors for NTD’s?

Answer 8

Low folate (vit B9) or vit B12
Obesity
Uncontrolled diabetes
Antiseizure medication (valproate/ carbamazepine)

Question 9

What is the female to male ratio in NTD’s?

Answer 9

F 4:1 M

Question 10

In spina bifida cystica, what is the difference between a meningocele and a myelomeningocele?

Answer 10

Meningocele: Just meninges pushed out through opening in vertebrae (often no SC damage)
Myelomeningocele: SC also pushed out between vertebrae, leading to damage (most severe form)

Question 11

Name 4 common symptoms seen in a patient born with a myelomeningocele?

Answer 11

Partial/ total lower limb paralysis
Bowel/ urinary incontinence
Loss of skin sensation
Cognitive sympt (caused by arnold chiari malformation)

Question 12

What is a chiari malformation?

Answer 12

Where all or part of the cerebellum and brain stem has descended below the level of the foreamen magnum

Question 13

What are the two main types of chiari malformation?

Answer 13

1- Only cerebellar tonsils below brainstem
2- (ka arnold-chiari malformation)- Part of cerebellum and medulla oblongata pushed down, often results in hydrocephalus (seen in 95% myelomeningocele)

Question 14

What is the lemon sign?

Answer 14

Seen on ultrasound before 24wks, it is a bilateral concavity in the anterior skull (making it look like a lemon)- Highly indicative of spina bifida

Question 15

In patients with spina bifida why is hydrocephalus also seen?

Answer 15

Due to a malformation (arnold-chiari) causing it to be misshapen and narrow area’s of the ventricular system to become blocked

Question 16

What is checked on in a quadruple blood test and what would be seen in a baby with spina bifida?

Answer 16

AFP, hCG, uE3, inhibin A
High AFP could indicate spina bifida
(Low AFP plus high hCG could indicate downs)

Question 17

What is the most common immediate treatment for spina bifida?

Answer 17

Surgery within 48hrs of birth to place cord and tissue back in and seal gap in vertebrae
Shunt for hydrocephalus

Question 18

What long term treatment is given to patients with spina bifida?

Answer 18

Physio- prevent muscle waiting
OT- Boost self esteem and independence
Incontinence treatments

Question 19

Spontaneous leg movements in the womb are often associated with what?

Answer 19

Damaged spinal cord (i.e. spina bifida)

Baby can’t kick itself round so many SB babies are born breech