Random Extra Neuro

Question 1

How is neurofibromatosis inherited?

Answer 1

Autosomal dominant inheritance
Expression variable in NF1
50% of NF2 are de novo

Question 2

Prevalence of neurofibromatosis type 1 and 2

Answer 2

NF1 = 1 in 2500 
NF2 = 1 in 35,000

Question 3

Signs of NF1 x7

Answer 3

1) Cafe au lait spots - seen in 1st year of life and increase in number with age
2) Freckling - especially in skin folds - axillae, groin, neck base - usually present age 10
3) Dermal neurofibromas - small, violet, gelatinous nodules - appear at puberty and no increase with age. Not painful but may itch.
4) Nodular neurofibromas - arise from nerve trunks - firm and clearly demarcated- paraesthesia if pressed
5) Lisch nodules - brown/translucent mounds on iris - develop by age 6 in 90%
6) Short stature
7) Macrocephaly

Question 4

Complications of NF1 x5

Answer 4

Arise in 30%
1) Mild learning difficulty

2) Local effects of fibromas
- Neuro = weakness, pain and paraesthesia
- GI - bleeds, obstruction
- Bone - cystic lesions, scoliosis, pseudarthrosis, high BP

3) Plexiform neurofibromas (huge subcutaneous swellings)
4) Malignancy - 5% - Optic glioma, sarcomatous change of neurofibroma
5) Slight increase risk of epilepsy

Question 5

Management of NF1

Answer 5

Yearly measurement of BP

Cutaneous survey yearly

Excision of dermal neurofibromas if troublesome

Question 6

Features of NF2

Answer 6

Fewer cafe au lait spots than NF1

Bilateral vestibular schwannoma (acoustic neuroma)

• Present in 20s
• Sensorineural hearing loss is first sign
• Tinnitus, vertigo
• Benign but press on local structures and raise ICP

Juvenile Posterior subcapsular lenticular opacity - opacity in the eyes - occurs before other changes

Question 7

Complications of NF2

Answer 7

Schwannomas of cranial and peripheral nerves and spinal nerve roots

Meningiomas (45% - often multiple)

Glial tumours

Question 8

Management of NF2

Answer 8

Yearly hearing tests
MRI if abnormality
Clear scan at age 30 indicates gene has not been inherited (unless family Hx of late onset)

Surgery to remove vestibular schwannoma but risk of deafness and facial palsy

Question 9

Mean survival from Dx of NF2

Answer 9

15 years - best practise can be better

Question 10

What is Schwannomatosis?

Answer 10

Tender cutaneous schwannomas without vestibular schwannoma

DDX - Mosaic NF2 - vestibular schwannomas also absent - analysis of tumour biopsy for DX

Typically large tumour load - seen on MRI

Life expectancy is normal

Question 11

Route of spinothalamic tracts

Answer 11

Pain and temp
Immediately decussate on entering spinal cord
Therefore lesion will cause contralateral pain and temperature loss

Question 12

Route of dorsal columns

Answer 12

Fine touch, proprioception and vibration
Fibres decussate in the medulla (medical leminiscus)
Therefore lesion will cause ipsilateral loss

Question 13

Motor pathways

Answer 13

Decussate in medulla in pyramidal decussation

Therefore ipsilateral UMN defect if spinal cord lesion

Question 14

UMN damage signs

Answer 14

Spastic paraparesis
Babinski’s positive
Hyperreflexia
Increased tone

Question 15

Damage to sphincters in spinal cord lesions

Answer 15

Early in intrinsic lesions

Late in extrinsic lesions

Question 16

What is Brown-Sequard Syndrome

Answer 16

Rare unilateral cord lesion
Ipsilateral UMN signs, fine touch, vibration and proprioception
Contralateral pain and temp loss
Sensory occurs a few levels below motor

Question 17

What happens in complete transection of spinal cord

Answer 17

1) Initial phase has spinal shock - loss of all reflexes, flaccid limbs, atonic bladder (overflow incontinence), atonic bowel, loss of vasomotor control
2) 1-2 weeks later, spasticity develops including spastic bladder (small capacity, urgency and frequency increased), hyperactive autonomic function

Question 18

What occurs in partial transection of spinal cord?

Answer 18

Loss of function occurs within hours due to secondary oedema

Therefore give high-dose corticosteroids (dexamethasone) to reduce spinal cord oedema

Also stabilise spine and treat any fracture

Question 19

What will compression of spinal cord cause

Answer 19

If below T1 - arms not affected
C5-T1 -LMN and sometimes UMN in arms and UMN in legs
Above c5 - UMN in legs and arms

Sphincter function usually preserved until late severe disease

Question 20

Causes of compression of spinal cord

Answer 20

1) Trauma
2) Disc protrusion (spondylosis)
3) Spinal cord tumours (meningioma, neurofibroma, extradural)

4) Inflammatory lesions (epidural abscess - + fever, back pain - antibiotics and surgical drainage)
(tuberculoma - tb meningitis might be present)

Question 21

What are syringomyelia and syringobulbia?

Answer 21

Fluid filled cavity in spinal cord and brainstem

Can be related to Arnold-Chiari malformation - cerebellar tonsils in FM - non-communicating hydrocephalus

Question 22

Presentation age of syringomyelia

Answer 22

Usually 30s

Question 23

Presentation of syringomyelia?

Answer 23

Pain in upper limb

Cape-like, dissociated sensory loss (dermatomes above and below are preserved)

Wasting or weakness of small muscles of hand - T1 common site for syrinx

Uni or bilateral horner syndrome - damage of sympathetic fibres within spinal cord down to T1

Spastic paraparesis if expands enough

Question 24

Symptoms of vasovagal syncope

Answer 24

Reflex bradycardia + peripheral vasodilation provoked by emotion, fear, standing too long, pain

Onset over seconds, nausea, pallor, sweating and closing in of visual fields

Cannot occur if lying down

Fall to ground - may be jerking, unconscious for about 2mins

Urinary incontinence uncommon but can occur, No tongue-biting, recovery is rapid

Question 25

EGs of situational syncope

Answer 25

Cough, effort (exercise, cardiac origin), micturition (men at night)

Question 26

What are Stokes-Adams attacks?

Answer 26

Transient arrhythmias causing drop in CO and LOC
No warning except palpitations
Slow or absent pulse
Recovery in seconds

Question 27

What are drop attacks?

Answer 27

Typically elderly woman - weakness of legs causes patient to drop to the ground
No warning or LOC, no confusion afterwards
Condition is benign and resolves after a few attacks

Question 28

Symptoms of vertigo

Answer 28

Spinning is rare
Floor may tilt, sink or rise
Illusion of movement - usually rotatory
Always worsened by movement

Question 29

Relieving factors in vertigo

Answer 29

Lying still or sitting down

Question 30

Associated symptoms with vertigo

Answer 30

Nausea, vomiting, pallor, sweating

Question 31

What is not vertigo?

Answer 31

Faintness (palpitations, tremor)
Lost awareness
Light-headeness

Question 32

Causes of vertigo

Answer 32

If tinnitus and deafness - labyrinth or CN VIII involvement
Trauma
VZV
Menieres disease
Benign positional vertigo 
Acute labyrinthitis 
Acoustic neuroma - vestibular schwannoma  
Ototoxic drugs

Question 33

What is benign positional vertigo?

Answer 33

Due to canalolithiasis
Head movement causes momentary vertigo
Nystagmus when perform Hallpikes manoeuvre
Treated with Epley manoevures

Question 34

Signs of acute labyrinthitis?

Answer 34

Abrupt onset
Severe vertigo, nausea, vomiting and prostration
No deafness or tinnitus
Complete recovery takes 3-4 weeks but vertigo subsides in days

Question 35

What is Menieres disease?

Answer 35

Vertigo lasting >20mins with fluctuating sensorineural hearing loss and tinnitus
Bed rest and reassurance with acute attack
Anithistamine - cinnarizine - useful if prolonged
Can do surgery if very severe

Question 36

Ototoxic drugs?

Answer 36

Aminoglycosides, loop diuretics, cisplatin

Question 37

Investigations in SAH

Answer 37

CT initially

Followed by 12h lumbar puncture to look for xanthochromia (yellowing of CSF with bleed from SAH)