Neurology - Cranial Nerves

Question 1

Olfactory nerve palsy Ddx

Answer 1

1. Trauma
2. Frontal lobe tumour
3. Meningitis

Question 2

Optic nerve palsy Ddx

Answer 2

1. Monocular blindness - MS, GCA
2. Bitemporal hemianopia - pituitary adenoma, internal carotid artery aneurysm
3. Homonymous hemianopia - stroke, tumour, abscess

Question 3

Oculomotor nerve palsy Ddx

Answer 3

1. Partial - diabetes

2. Complete - PCA aneurysm, raised ICP with tentorial herniation

Question 4

Trochlear nerve palsy Ddx

Answer 4

Orbit trauma

Question 5

Trigeminal nerve palsy Ddx

Answer 5

1. Idiopathic (trigeminal neuralgia)
2. Acoustic neuroma
3. Herpes zoster

Question 6

Abducens nerve palsy Ddx

Answer 6

1. Petrous temporal bone fracture
2. Nasopharyngeal carcinoma
3. Raised ICP

Question 7

Facial nerve palsy Ddx

Answer 7

LMN (forehead affected)
1. Bell's palsy
2. Malignant parotid tumour
3. Herpes zoster
UMN
4. Stroke
5. Tumour

Question 8

Vestibulocochlear nerve palsy Ddx

Answer 8

1. Excessive noise exposure
2. Ménière’s disease
3. Furosemide
4. Aminoglycoside antibiotics (gentimicin)

Question 9

Glossopharyngeal, vagus, hypoglossal nerve palsy - LMN Ddx (bulbar palsy)

Answer 9

1. MND
2. Diphtheria
3. Polio
4. GB syndrome
5. Syringobulbia

Question 10

Glossopharyngeal, vagus, hypoglossal nerve palsy - UMN Ddx (pseudobulbar palsy)

Answer 10

1. MND
2. Bilateral strokes
3. MS

Question 11

V, VII, VIII, palsy (IX, X sometimes involved)

Answer 11

Cerebellopontine angle tumour (acoustic neuroma or meningioma)

Question 12

V, VII, VIII palsy

Answer 12

Paget’s disease of the bone (impingement of nerve as the pass through bony foramina)

Question 13

V, VI nerve palsy

Answer 13

Gradenigo’s syndrome (complication of otitis media)

Question 14

V, VII, VIII, IX, X, XII nerve palsy

Answer 14

Syringobulbia

Question 15

UMN CN signs

Answer 15

1. Facial nerve palsy with forehead sparing
2. Brisk jaw jerk
3. Pseudobulbar palsy

Question 16

Opthalmoplegia Ddx

Answer 16

1. Myasthenia gravis
2. Cranial nerve palsy
3. Graves’ disease
4. Wernicke’s encephalopathy (can’t look up)
5. Progressive supra nuclear palsy (can’t look down)

Question 17

Internuclear opthalmoplegia (INO) charactistics

Answer 17

Failure to ADduct eye on affected side when looking laterally.
Nystagmus is seen on the unaffected side when this attempted.
Accomodation is normal.

Question 18

Internuclear palsy Ddx (INO)

Answer 18

1. MS
2. Stroke
3. Lyme’s disease, tricyclics (rare)

Question 19

Central weber, air>bone rinne

Answer 19

Normal

Question 20

Left weber, air>bone rinne

Answer 20

Right sensorineural hearing loss

Question 21

Left weber, bone>air rinne

Answer 21

Left conductive hearing loss

Question 22

Right weber, bone>air (left) rinne

Answer 22

Complete sensorineural hearing loss on the left

Question 23

Bulbar palsy - tongue appearance

Answer 23

1. Flaccid
2. Wasted
3. Fasiculating

Question 24

Psuedobulbar palsy - tongue appearance

Answer 24

1. Spastic

2. Contracted

Question 25

Dysphasia - expressive aphasia vs. sensory aphasia

Answer 25

Expressive - can comprehend but cannot express. Patient will speak with broken words
Sensory - cannot comprehend but can express fluently

Question 26

Dysarthria - CN involved

Answer 26

1. Facial nerve - muscles of the face
2. Glossopharyngeal/vagus - muscles of the larynx
3. Hypoglossal - muscles of the tongue

Question 27

Facial nerve palsy - Ddx

Answer 27

1. Bell’s palsy (idiopathic)
2. Lyme disease
3. Autoimmune (Guillain barre, tends to be bilateral)
4. Mass lesion
5. MS
6. Stroke
7. Trauma

Question 28

Causes of any CN palsy

Answer 28

1. Vascular (diabetes, stroke, vasculitis)
2. Inflammation (MS, sarcoid, SLE)
3. Space occupying lesion (tumour)