neural tube defects

Question 1

recurrence risk of NTD with families:
1 previous affected
2 previous affected
3 affected

Answer 1

1 previous affected = 1/20
2 previous affected = 1/10
3 affected = 1/4

Question 2

risk factors for NTD

Answer 2

1. folate def
2. inherited risk
3. genetic syndrome
4. mat fever 1st trim
5. diabetes
6. obesity
7. amniotic bands

Question 3

classification/types of spinal dysraphism

Answer 3

closed = no defect in overlying skin, vertebral backs just didn’t fuse = spina bifida occulta inc. lipomeningocoele and lipomyelomeningoceoele

open = overlying skin defect -> meningocele (less bad) or myelomeningocele (very bad)

Question 4

most common type of spina bifida, and which spinal level most commonly involved

Answer 4

90% myelomeningocele
90% L3 or below

Question 5

what Ix prenatally suggests NTD?

Answer 5

AFP - leaks from the spine > amniotic fluid, bc no vertebral spines

Question 6

differentiate between the following brain NTD:
anencephaly
encephalocele

Answer 6

anencephaly = open brain i.e. lethal
encephalocele = herniation of meninges and brain

Question 7

what is tethered cord syndrome

Answer 7

spinal cord fixation to spinal canal wall causing damage&raquo_space; bladder/bowel dysfunction, foot position or weakness, back/lower limb pain

Question 8

what level of NTD is a/w worse outcomes, and why?

Answer 8

> T11 worse outcome - renal failure (almost no perineal sensation)

Question 9

Mx areas for NTD

Answer 9

1. neurological - hydrocephalus, tethered cord
2. cognition / ID / psych
3. neuropathic bladder
4. neuropathic bowel
5. musculoskeletal
6. sensation - pressure areas, home mods
7. social stuffs

Question 10

what are some bx options for neuropathic bladder

Answer 10

Rx anti-cholinergics, botox
CICs
surgery - bladder aug, mitrofanoff, sphincterotomy

Question 11

lissencephaly vs schizencephaly vs poroncephaly

Answer 11

lissencephaly = absence of cerebral convolutions
schizencephaly = uni/bilat clefts within the cerebral hemispheres, surrounded by microgyria
poroncephaly = cysts in brain, true ones will communicate

Question 12

key features of aicardi syndrome

Answer 12

1. Agenesis of corpus callosum
2. Distinctive Chorioretinal lacunae
3. Infantile spasms
4. Severe ID
5. almost all female

Question 13

triad of a dandy-walker malformation

Answer 13

-cystic dilatation of fourth ventricle
-hydrocephalus
-enlarged posterior fossa

Question 14

most common posterior fossa/hindbrain malformation

Answer 14

chiari malformation = herniation of the cerebellar tonsils through the foramen magnum +/- abnormality of bones with small posterior fossa

Question 15

type I vs II chiari malformation

Answer 15

type I = cerebellar tonsils below foramen magnum
- present in adolescence, can be asymptomatic
- hydrocephalus + syrinx, cerebellar dysfunction

type II = cerebellar tonsils + vermis below foramen magnum
- present in childhood
- a/w myelomeningocoele
- above + occipital headaches worse with valsalva, cerebellar dysfunction, impaired cough/gag with medulla oblongata problems

Question 16

syringomyelia - key features

Answer 16

= cystic enlargement of spinal cord
damage to spinothalamic tract
main cause is chiari II malformation