Facial Palsy

Question 1

Where does the facial nerve leave the skull

Answer 1

Via the stylomastoid foramen in close proximity to the parotid gland

Question 2

Where does the CN VII travel with CN VIII

Answer 2

Through the internal auditory meatus

Question 3

What is innervated by CN VII

Answer 3

Muscles of facial expression Taste fibres from the anterior two thirds of the tongue Parasympathetic fibres to the salivary glands and stapedius

Question 4

What kind of lesion causes forehead sparing facial weakness

Answer 4

UMN lesion

Question 5

Why is their forehead sparing in a UMN lesion causing facial weakness

Answer 5

The muscles of the forehead have dual innervation, from the contralateral and ipsilateral sides

Question 6

What side of the face is affected in a facial nerve palsy

Answer 6

The contralateral side

Question 7

What are some causes of bilateral facial nerve weakness

Answer 7

Guillain-Barre Lyme Disease Sarcoidosis Bilateral Bell’s palsy Myasthenia gravis - with ptosis so no Bell’s sign

Question 8

What is Bell’s Sign

Answer 8

When a patient attempts to close their eyes but are unable to fully and you can see the whites of their eyes as they roll up and out

Question 9

What muscle closes the eye

Answer 9

Orbicularis oculi

Question 10

Which nerve innervates the orbicularis oculi muscle

Answer 10

CN VII - facial nerve

Question 11

What muscle raises the upper eyelid

Answer 11

Levator palpebrae superioris

Question 12

Which nerve innervates the levator palpebrae superioris

Answer 12

CN III - occulomotor nerve

Question 13

What are some UMN causes of facial weakness

Answer 13

Stroke Tumour

Question 14

What are some LMN causes of facial weakness

Answer 14

Lesion at the pons - infarction, demyelination (MS) Cerebellopontine angle tumour Lesions in the facial canal - middle ear infection, Bell’s palsy, fracture of the base of skull Lesions in the geniculate ganglion - Herpes zoster infection Lesion of the peripheral branches of CN VII - mumps, sarcoidosis, trauma

Question 15

What other signs would you expect to find in a lesion of the pons

Answer 15

Ipsilateral 6th nerve lesion Contralateral pyramidal weakness

Question 16

What other signs would you to expect to find in a cerebellopontine angle tumour

Answer 16

Facial sensory loss Loss of corneal reflex Hearing loss

Question 17

What is the definition of Bell’s palsy

Answer 17

Paralysis of the facial nerve where no specific cause can be found (LMN)

75% of all facial palsies are a Bell’s palsy

Question 18

What medication do you give for Bell’s palsy

Answer 18

• Prednisolone - high dose, provided started in first week
• Aciclovir - 800mg 5x daily for 1 week
  
  • IV in Ramsay Hunt syndrome
• Corneal protection: Eye lubricant and tape if eye can’t be voluntarily closed

Question 19

What are some causes of Bell’s palsy?

Answer 19

• Idiopathic (>90% cases)
• Structural lesion:
  
  • Brainstem: tumour, stroke, demyelination
  • Cerebellopontine angle: Acoustic neuroma
  • Middle ear: Infection
  • Parotid gland: INfection, tumour, surgery
• Mononeuritis multiplex

Question 20

How would you investigate a patient with a Bell’s palsy?

Answer 20

• Typical acute Bell’s palsy (develops over 1-2 days): only random glucose required
• Slow progreesive history/other CNs involved/prominent pain:
  
  • Bloods:
    
    • CRP and ESR
    • Serum ACE
    • Infectious serology: HIV, Lyme
    • Auto-antibodies
  • Imaging: MRI brain (T2 for idiopathic Bell’s palsy)
  • Further:
    
    • LP: mononueritis multiplex or meningeal inflammation
    • Nerve conduction studies (GBS)
    • Pure tone audiometry

Question 21

What are the complications of a Bell’s palsy?

Answer 21

• Persistent facial weakness
• Corneal abrasions
• Pain and/or sensory disturbance in the distribution of the facial nerve
• Aberrant reinnervation: “Crocodile tears” when talking or eating, or jaw-eyelid synkinesia
• Hemifacial spasm

Question 22

What is the prognosis of a facial nerve palsy?

Answer 22

• Complete palsy: 80% get full recovery
  
  • 20%- delayed recovery or remaining deficit or cosmetic appearance

Question 23

What is Ramsay-Hunt syndrome?

Answer 23

An acute perifacial neuropathy due to reactivation of VZV in the geniculate ganglion of CNVII

Question 24

What are the signs and symptoms of Ramsay Hunt syndrome?

Answer 24

• Preceding pain in ear or stiff neck
• Vesicular rash in auditory canal +/- TM, pinna, tongue and hard palate
  
  • No rash = zoster sine herpete
• Ipsilateral facial weakness, ageusia and hyperacusis
• CNVIII affected –> vertigo, tinnitus, deafness

Question 25

How would you manage Ramsay-Hunt syndrome?

Answer 25

First 72 hours- IV valaciclovir

Prednisolone

Question 26

What is the prognosis for Ramsay-Hunt syndrome?

Answer 26

• Treated within 72 hours:
  
  • 75% full recovery
• Otherwise rule of 3rds: 1/3rd full recovery, 1/3rd partial, 1/3rd poor