Cranial Nerve Lesions

Question 1

Presentation of Oculomotor nerve palsy

Answer 1

-Ptosis, down and out eye (paralysis of adduction, elevation, and depression= intorsion)
-Dilated and fixed pupil
-Diplopia (worsens when head is turned away from side of lesion).

OCULOMOTOR PALSY LEAVES YOU DOWN AND OUT

Question 2

Diagnosis of oculomotor nerve palsy

Answer 2

-MRI brain/ angiography (compressive lesion: posterior communicating artery aneurysm)
-Blood pressure
-Blood glucose (poorly controlled DM)
-Risk factors for atherosclerosis or arteritis

Question 3

Presentation of Trochlear nerve palsy

Answer 3

-Vertical diplopia, exacerbated on downgaze away from side of affected muscle- worsens when patient turns head towards paralysed muscle (compensatory head tilt to opposite side of lesion).
-Extorsion of the eye, inability to depress and abduct the eyeball simultaneously (defective downward gaze), tilt head to opposite side.

WITH DAMAGE TO THE CN 4, YOU CANNOT LOOK AT THE FLOOR

Question 4

Diagnosis of trochlear nerve palsy

Answer 4

MRI brain (trauma, cancer, persistent after 3 months, progression of symptoms)

Question 5

Presentation of abducens nerve palsy

Answer 5

-Defective abduction (inability to look laterally in affected eye)
-Horizontal diplopia (worsens when looking at distant objects/ towards affected side)
-Medial deviation of affected eye at primary gaze/ convergent squint.

MOST COMMON- ABDUCENS CANNOT ABDUCT

Question 6

Diagnosis of abducens nerve palsy

Answer 6

MRI head, ischaemic risk factors, autoimmune, thyroid and myasthenia gravis

Question 7

Presentation of optic nerve lesions

Answer 7

-Impaired vision, blindness, Uhthoff phenomenon (MS), jaw claudication and headache (GCA)

-Complete transection: ipsilateral blindness + loss of pupillary reflex
-Pituitary adenoma: bitemporal hemianopia
-Unilateral optic nerve dysfunction: relative afferent pupillary defect

Question 8

Diagnosis of optic nerve lesion

Answer 8

-Fundoscopy
-MRI (optic neuritis, tumour, degenerative diseases)
-CT head (trauma)
-ESR and CRP (GCA).
-Retinal disease (age-related macular degeneration), refractive errors, cataract, corneal scarring

Question 9

Presentation and investigation of Bell’s palsy

Answer 9

-Weakness of all ipsilateral muscles of facial expression (forehead affected)
-Post-auricular pain (may precede paralysis)
-Altered taste, dry eyes, hyperacusis

-Clinical diagnosis and serology for Lyme disease

Question 10

Management of Bell’s palsy

Answer 10

-Oral prednisolone within 72 hours onset
-Antivirals?
-Eye lubricants, tape eye closed using microporous tape at night

Question 11

Presentation of acoustic neuroma

Answer 11

Vestibular schwannomas- 5% intracranial tumours, 90% cerebellopontine angle tumours

-Vertigo
-Hearing loss (unilateral sensorineural)
-Unilateral tinnitus = vestibulocochlear
-Absent corneal reflex (trigeminal)
-Facial palsy/ numbness

Question 12

Diagnosis of acoustic neuroma

Answer 12

-Urgent referral to ENT
-MRI (gadolinium-enhanced) cerebellopontine angle
-Audiometry

Question 13

Management of acoustic neuroma

Answer 13

-Often observed initially (slow-goring, benign)
-Surgery
-Radiotherapy

Question 14

Presentation of vestibular neuronitis

Answer 14

-Recurrent vertigo attacks (rotational) lasting hours or days
-Nausea and vomiting
-Horizontal nystagmus
-No hearing loss, or tinnitus
-Preceding viral infection

Question 15

Diagnosis of vestibular neuronitis

Answer 15

-Clinical
-Head impulse test positive

Question 16

Management of vestibular neuronitis

Answer 16

-Prochlorperazine
-Antihistamine
-Vestibular rehabilitation exercises

Question 17

Presentation of Meniere disease

Answer 17

-Recurrent episodes of spontaneous vertigo
-Roaring tinnitus
-Fluctuating sensorineural hearing loss
-Sensation of aural fullness or pressure
-Nystagmus
-Positive Romberg test (swaying or falling when feet together and eyes closed)
-Episodes last minutes to hours, typically unilateral then bilateral after number of years

Question 18

Diagnosis of Meniere disease

Answer 18

-ENT assessment
-Clinical diagnosis- at least 2 spontaneous episodes of vertigo last 20 mins to 12 hours, fluctuating hearing, tinnitus, and/or perception of aural fullness, hearing loss confirmed by audiometry (low-to-mid frequency)

Question 19

Management of Meniere disease

Answer 19

-Inform DVLA- cease driving until satisfactory control of symptoms achieved
-Acute attacks= buccal or intramuscular prochlorperazine, betahistine and vestibular rehabilitation exercises for prevention, IV labyrinthine sedatives

Question 20

Presentation of Glossopharyngeal nerve lesions

Answer 20

-Cough/ change to quality of voice after ineffective swallow (afferent nerve)
-Absence of gag reflex
-Loss of taste posterior third of tongue
-Sensory loss over soft palate
-Mild dysphagia

Question 21

Presentation of vagus nerve lesions

Answer 21

-Deviation of uvula towards unaffected side
-Asymmetrical elevation of palate away from lesion
-Weak, non-explosive sounding bovine cough (inability to close glottis)
-Cough/ change to quality of voice after ineffective swallow (efferent nerve)
-Nasal speech, dysphagia
-Absence of gag reflex
-Nasal speech, hoarseness (unilateral) vs aphonia/ inspiratory stridor (bilateral recurrent laryngeal nerve palsy)

Question 22

Presentation of accessory nerve lesions

Answer 22

-Shoulder pain and heaviness
-Difficulty or inability to raise hand overhead
-Neckline asymmetry- ipsilateral shoulder drooping, lateral winging of scapula, paresis/ atrophy of sternocleidomastoid and trapezius muscles
-Weakness during elevation of ipsilateral shoulder when shrugging
-Weakness in turning head towards contralateral side

Question 23

Presentation of hypoglossal nerve lesions

Answer 23

-Wasting and fasciculations of tongue/ atrophy of ipsilateral tongue
-Deviation of tongue towards hypoglossal lesion
-Weakness of tongue pressing side of lesion