Cranial Nerve Lesions

Question 1

Pathology of CN XII

Answer 1

Deviation of tongue to damaged side on protrusion, possible muscle wasting and fasciculations

Question 2

Cause of CNXII palsy

Answer 2

Possibly from head and neck malignancy and penetrating trauma

Question 3

Recurrent layngeal nerve pathology

Answer 3

Dysphonia, aphonia, stridor

Question 4

Causes of recurrent layngeal nerve pathology

Answer 4

Heart defects can irritate nerve, cancer of larnyx, thyroid gland, surgical complications

Question 5

Pharyngeal and other vagus nerve pathology

Answer 5

Dysphagia, uvula deviation, loss of gag reflex, vasovagal syncope

Question 6

Pathology of CNXI symptoms

Answer 6

Ipsilateral muscle wasting and paralysis of SCM and trapezius. Unable to move neck, shrug shoulders or rotate head

Question 7

Causes of CNXI pathology

Answer 7

Mostly iatrogenic from procedures to cervical lymph nodes (biopsy/excision) and central line insertion

Question 8

Symptoms of vestibular nerve damage

Answer 8

Vertigo, nystagmus, loss of equilibrium, nausea, vomiting

Question 9

Causes of vestibular nerve damage

Answer 9

Vestibular neuritis, labyrinthitis, basillar skull fracture can damage nerve within acoustic meatus

Question 10

Symptoms of cochlear nerve damage

Answer 10

Sensorineural hearing loss, tinnitus

Question 11

Causes of cochlear nerve damage

Answer 11

Labyrinthitis, basillar skull fracture

Question 12

Symptoms of glossopharyngeal neuralgia

Answer 12

Paroxysmal attacks of unilateral brief brain

Question 13

Causes of glossopharyngeal neuralgia

Answer 13

Compression, less commonly from tumour, aneurysm or demyelination

Question 14

Causes of abducent nerve pathology

Answer 14

SOL, diabetic neuropathy, thromboplebitis of cavernous sinus, small vessel disease, any pressure on brainstem

Question 15

Intracranial features of CN VII palsy

Answer 15

Muscles of facial expression paralysed or weakened, reduced salivation, loss of taste on ipsilateral 2/3 tongue, ipsilateral hyperacusis (stapedus nerve), ipsilateral reduced lacrimal fluid (greater petrous nerve)

Question 16

Causes of intracranial CN VII palsy

Answer 16

Infection related to external or middle ear

Question 17

Extracranial features of CN VII palsy

Answer 17

Only muscle function is affected

Question 18

Extracranial causes of CN VII palsy

Answer 18

NErve infection or parotid gland pathology

Question 19

Causes of trochlear nerve palsy

Answer 19

Microvascular damage from diabetes or hypertension, congenital malformation, raised ICP, thrombophlebitis of cavernous sinus

Question 20

Causes of trigeminal nerve palsy

Answer 20

Compression at root of nerve by intracranial artery, compression of venous loop as it enters brainstem, tumour, aneurysm or plaque

Question 21

Features of CNV palsy

Answer 21

Severe paroxysmal facial pain

Question 22

Features of CN VI palsy

Answer 22

Horizontal diplopia, resting adduction, inability to adduct eye

Question 23

Features if Meyer’s loop is affected

Answer 23

Left superior quadrantanopsia

Question 24

Causes of meyers loop pathology

Answer 24

Temporal lobe tumour

Question 25

If there was a thrombosis of PCA what effects would if have on the optic nerve

Answer 25

Left homonymous hemianopsia with macular sparing

Question 26

Features of Oculomotor palsy

Answer 26

Ptosis, down and out position, dilated pupil

Question 27

Causes of oculomotor palsy

Answer 27

Raised ICP, PCA aneurysm, cavernous sinus infection, trauma, diabetes, MS, myasthenia gravis, giant cell arteritis

Question 28

Olfactory nerve pathology symptoms

Answer 28

Anosmia

Question 29

Causes of olfactory pathology

Answer 29

Infection, head injury, trauma, tumour in olfactory groove, parkinsons, AD, Kallman syndrome

Question 30

Pathology of direct CN II lesion

Answer 30

Complete loss of vision in nerve supplying eye

Question 31

Causes of CN II lesion

Answer 31

MS, trauma, glaucoma

Question 32

Features of optic chaism pathology

Answer 32

Bitemporal hemianopsia

Question 33

Features of right optic tract pathology

Answer 33

Left homonymous hemianopsia

Question 34

Causes of bitemporal hemianopsia

Answer 34

Pituitary tumour