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Alasdair - Neurology > Facial nerve palsy > Flashcards

Facial nerve palsy Flashcards

1
Q

Facial nerve palsy signs on inspection

A 
Unilateral facial droop
Absent nasolabial fold
± absent forehead creases
Parotid scar or mass
Ear rash
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2
Q

Muscles affected in facial nerve palsy

A 
Frontalis (raising eyebrows)
Orbicularis oculi (screwing up eyes)
Orbicularis oris (smiling)
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3
Q

What is Bell’s phenomenon

A

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.

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4
Q

Differentiating whether facial nerve palsy is LMN or UMN

A

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

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5
Q

Features of Millard-Gubler Syndrome

A

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

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6
Q

Cerebellopontine angle lesion features

A

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

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7
Q

Cranial nerves that pass through the auditory canal

A

CN7, CN8

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8
Q

Completion of facial nerve palsy exam

A

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.

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9
Q

Causes of Bell’s palsy

A

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)

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10
Q

Causes of bilateral facial palsy

A 
Bilateral Bell's
Sarcoidosis
Gullan-Barre
Lyme
Pseudopalsy: myasthenia gravis, myotonic dystrophy
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11
Q

Specific history for facial nerve palsy

A

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.

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12
Q

Pathophysiology of ageusia and hyperacusis in Ramsay-Hunt syndrome

A

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.

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13
Q

Investigations for facial nerve palsy

A

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)

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14
Q

Management of Bell’s palsy

A
  1. Protect eye: dark glasses, artificial tears, tape closed at night
  2. Prednisolone within 72 hours
  3. Valganciclovir if VZV suspected
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15
Q

Prognosis in Bell’s palsy

A

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

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16
Q

Aberrant neural connections in Bell’s palsy

A

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

17
Q

Pathophysiology of Bell’s palsy

A

75% of facial palsies

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

18
Q

Features of Bell’s palsy

A 
Sudden onset
Complete LMN facial palsy
Ageusia: corda timpani
Hyperacusis: nerve to stapedius
Associated with other cranial nerve involvement in 8%
19
Q

Cause of Ramsay Hunt symdrome

A

Reactivation of VZV in geniculate ganglion of CN7

20
Q

Features of Ramsay Hunt syndrome

A

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
Q

Treatment of Ramsay Hunt syndrome

A
  1. Protect eye

2. Valganciclovir + prednisolone within 72h

22
Q

Prognosis for Ramsay Hunt syndrome

A

If treated within 72h: 75% full recovery

Otherwise, 1/3 full recovery, 1/3 partial, 1/3 poor.

23
Q

Pathophysiology of cholesteatoma

A

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

24
Q

Presentation of cholesteatoma

A

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

25
Q

Complications of cholesteatoma

A

Deafness due to ossicle destruction

Meningitis, cerebral abscess

26
Q

Management of cholesteatoma

A

Surgery

27
Q

Causative organism in Lyme disease

A

Borellia burgdorferi

28
Q

Features of Lyme disease

A 
Early local phase: erythema migrant + systemic malaise
Late disseminated:
CN palsy, esp. facial palsy
Polyneuropathy
Meningoencephalitis
Arthritis
Myocarditis
Heart block
29
Q

Examination of facial anaesthesia

A

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
Q

Causes of facial anaesthesia

A
  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)

Alasdair - Neurology (16 decks)

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