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Flashcards in Facial nerve palsy Deck (30):
1

Facial nerve palsy signs on inspection

Unilateral facial droop
Absent nasolabial fold
± absent forehead creases
Parotid scar or mass
Ear rash

2

Muscles affected in facial nerve palsy

Frontalis (raising eyebrows)
Orbicularis oculi (screwing up eyes)
Orbicularis oris (smiling)

3

What is Bell's phenomenon

AKA palpebral oculogyric reflex.
Normal reflex in most of population when cornea threatened or eyelids forcibly closed. But only becomes apparent if orbicularis oculi is weak.

4

Differentiating whether facial nerve palsy is LMN or UMN

UMN - sparing of frontalis and orbicularis oculi (upper spares the upper part of face)
Due to to bilateral cortical representation

5

Features of Millard-Gubler Syndrome

Lesion at pons: CN6, CN7, and corticospinal tract lesion.
Ipsilateral lateral rectus palsy
Ipsilateral LMN facial palsy
Contralateral hemiparesis

6

Cerebellopontine angle lesion features

Ipsilateral CN5,6,7,8 palsies + cerebellar signs.
Facial anaesthesia + absent corneal reflex
Lateral rectus palsy
LMN facial nerve palsy
Sensorineural hearing loss
Cerebellar: DANISH

7

Cranial nerves that pass through the auditory canal

CN7, CN8

8

Completion of facial nerve palsy exam

If UMN: likely stroke.
Examine limbs for ipsilateral spasticity, visual fields for ipsilateral homonymous hemianopia.
If LMN: likely Bell's palsy.
Examine PNS, CN and cerebellar function, test taste.

9

Causes of Bell's palsy

75% idiopathic
Supranuclear: vascular, MS, SOL
Pontine: vascular, MS, SOL
CPA: vestibular Schwannoma, meningioma, secondary met
Intra-temporal: Ramsay-Hunt, cholesteatoma, trauma
Infra-temporal: parotid tumour, trauma
Systemic: neuropathy (DM, Lyme, sarcoidosis), pseudopalsy (myasthenia gravis)

10

Causes of bilateral facial palsy

Bilateral Bell's
Sarcoidosis
Gullan-Barre
Lyme
Pseudopalsy: myasthenia gravis, myotonic dystrophy

11

Specific history for facial nerve palsy

Symptoms: eye dryness, drooling, decreased taste, hyperacusis
Cause: onset (rapid in Bell's), rash or external ear pain (Ramsay-Hunt), Hx of DM, headache or nausea (SOL), other CN (vertigo, tinnitus, diplopia), limb weakness, rash, fever.

12

Pathophysiology of ageusia and hyperacusis in Ramsay-Hunt syndrome

Chorda tympani and nerve to stapedius arise just distal to geniculate ganglion within the temporal bone. Loss of these functions indicates a proximal lesion: Ramsay Hunt is VZV at geniculate ganglion.

13

Investigations for facial nerve palsy

Urine dip: glucose
Bloods: DM (glucose, HbA1c), serology (VZV and Lyme), antibodies (anti-ACh receptor)
Imaging: MRI posterior cranial fossa
Pure tone audiometry
Lumbar puncture to exclude infection
Nerve conduction studies (myasthenia gravis)

14

Management of Bell's palsy

1. Protect eye: dark glasses, artificial tears, tape closed at night
2. Prednisolone within 72 hours
3. Valganciclovir if VZV suspected

15

Prognosis in Bell's palsy

Incomplete paralysis: recovers completely within weeks.
Complete paralysis: 80% get full recovery. Remainder have delayed recovery or permanent neurological/cosmetic abnormalities.

16

Aberrant neural connections in Bell's palsy

Complication of resolved Bell's palsy.
Synkinesis: blinking causes up-turning of mouth.
Crocodile tears: eating stimulates unilateral lacrimation, not salivation.

17

Pathophysiology of Bell's palsy

75% of facial palsies
Inflammatory oedema leads to compression of CN7 in narrow facial canal. Probably of viral origin (HSV1).

18

Features of Bell's palsy

Sudden onset
Complete LMN facial palsy
Ageusia: corda timpani
Hyperacusis: nerve to stapedius
Associated with other cranial nerve involvement in 8%

19

Cause of Ramsay Hunt symdrome

Reactivation of VZV in geniculate ganglion of CN7

20

Features of Ramsay Hunt syndrome

Preceding ear pain or stiff neck
Vesicular rash in auditory canal ± tympanic membrane, pinna, tongue, hard palate (no rash + 'zoster sine herpete')
Ipsilateral facial weakness, ageusia, hyperacusis
May affect CN8 - vertigo, tinnitus, deafness

21

Treatment of Ramsay Hunt syndrome

1. Protect eye
2. Valganciclovir + prednisolone within 72h

22

Prognosis for Ramsay Hunt syndrome

If treated within 72h: 75% full recovery
Otherwise, 1/3 full recovery, 1/3 partial, 1/3 poor.

23

Pathophysiology of cholesteatoma

Locally destructive expansion of stratified squamous epithelium within the middle ear.
Usually secondary to attic perforation in chronic suppurative otitis media.

24

Presentation of cholesteatoma

Foul smelling white discharge
Vertigo, deafness, headache, pain, facial paralysis
Appears pearly white with surrounding inflammation

25

Complications of cholesteatoma

Deafness due to ossicle destruction
Meningitis, cerebral abscess

26

Management of cholesteatoma

Surgery

27

Causative organism in Lyme disease

Borellia burgdorferi

28

Features of Lyme disease

Early local phase: erythema migrant + systemic malaise
Late disseminated:
CN palsy, esp. facial palsy
Polyneuropathy
Meningoencephalitis
Arthritis
Myocarditis
Heart block

29

Examination of facial anaesthesia

Reduced or absent sensation in trigeminal distribution - note modality, note with branch(es)
Weak masseter and temporalis
Jaw jerk: brisk - UMN, absent - LMN
Loss of corneal reflex

30

Causes of facial anaesthesia

1. Supranuclear (UMN): demyelination, infarct, SOL
2. Nuclear (LMN): CPA lesion if other CN palsies present, lateral medullary syndrome (loss of pain and temperature)
3. Mononeuropathy: DM, sarcoid, vasculitis, cavernous sinus (ophthalmic and maxillary divisions. bilateral)