Neuro

Question 1

Hydrocephalus caused by Spina Bifida

Answer 1

Spinal cord becomes adherent to vertebrae (overlying tissues that have failed to develop normally)
Vertebral column growth -> spinal cord pulled down
Foramen magnum pulled down, compression of brain stem structures (such as 4th ventricle)
Impairs drainage of CSF into sub-arachnoid space
Increase ICP -> hydrocephalus

Question 2

How to prevent neural tube defects

Answer 2

Folate supplementation - 400 mg daily
Start 3 months before conception, until week 12 of pregnancy
Mechanism unknown
? Fusion of epithelial cells during development

Question 3

Craniorachischisis

Answer 3

Entire neural tube remains open - severe
Incompatible with life - usually still born
Neural folds have failed to close

Question 4

Anencephaly

Answer 4

Incompatible with life - die soon after birth

Brain fails to develop, failure of closure of cranioneuropore

Question 5

Myelocoele / rachischiasis

Answer 5

Neural tube fails to invaginate
Neural folds fail to fuse together
Open spinal cord - channel open due to incomplete vertebral arch
No spinous process or midline structure so something felt either side of midline (as if spine in 2 x half)
Severe neurological defects, often involving lower limb

Question 6

Meningomyelocoele

Answer 6

Cystic lesion protrudes our through defect - failure of closure of neural arch
Subarachnoid space containing CSF, spinal cord + dura and arachnoid mater
Meningeal cyst - herniate
Normal neural tube development - dorsal aspect of arches not formed (less severe neurological defect)

Question 7

Meningocoele

Answer 7

Spinal cord in normal location
CSF filled area protrudes through defect in neural arch (subarachnoid space containing CSF + dura and arachnoid mater)
Little neurological defects

Question 8

Spina bifida occulta

Answer 8

Tuft of hair at level of lumbar spine
Failure of closure of dorsal arch of vertebrae - dorsal sclerotic problem
Dorsal aspect of some lumbar vertebrae missing
No severe neurological deficit
Occurs in about 10% of the population

Question 9

Spina bifida / neural tube disorders / dysraphism susceptibility

Answer 9

All conditions susceptible to meningitis

As spinal cord + meninges not protected by bone

Question 10

Neural crest disorders

Answer 10

Di George syndrome

Hirschprung’s disease

Question 11

Di George syndrome

Answer 11

Immunodeficiency - thymus involvement
Facial anomalies - contribution of neural crest to facial development
Heart abnormalities
Hypercalcaemia - involvement of parathyroids

Question 12

Hirschprung’s disease

Answer 12

(Neural crest cells migrate to gut wall)
Lack of enteric neurones in sections of the large intestine - no enteric nervous system = constipation
Hypomobility + constipation

Question 13

Neural tube defects / disorders

Most to least severe

Answer 13

Craniorachischisis
Anencephaly
Myelocoele

Question 14

Disorders with normal neural tube but failure of development of posterior vertebral arch

Answer 14

Myelomeningocoele
Meningocoele
Spina bifida occulta

Question 15

Internuclear opthalmoplegia

Answer 15

Paralysis of eyeballs caused by loss of connections between cranial nerve nuclei

Question 16

Huntington’s chorea

Answer 16

Increased movement - hyperkinetic
Autosomal dominant
Choreiform movements, dystonia, in coordination
Psychiatric features

Question 17

Parkinson’s disease

Answer 17

Decreased movement - hypokinetic
Loss of cortical activity
Degeneration of dopaminergic neurons within SN
Tremour, rigidity, bradykinesia, psychiatric features
Degeneration of basal ganglia nuclei

Question 18

Hemiballismus

Answer 18

Increased movement - hyperkinetic
Involuntary, explosive unilateral movements
STN lesions
Increased cortical activity

Question 19

Cerebellar lesions

Answer 19

Vomiting, vertigo, difficulty walking
Ipsilateral if lesion is in hemisphere (upper + lower limb)
Affecting trunk is lesion in vermis
Dysdiadochokinesis, ataxia, nystagmus, intention tremour, slurred speech, hypotonia