Bell's Palsy

Question 1

What is Bell’s palsy?

Answer 1

idiopathic lower motor neurone facial nerve palsy

Question 2

Describe the aetiology of Bell’s palsy

Answer 2

IDIOPATHIC
60% are preceded by an URTI: suggestive of a viral or post-viral aetiology

Question 3

What age group is most commonly affected by Bell’s palsy?

Answer 3

20-50y

Question 4

List 6 symptoms of Bell’s palsy

Answer 4

Prodrome of pre-auricular pain (in some)
Acute onset unilateral facial weakness + droop. Max. severity: 1-2 days
50% experience facial, neck or ear pain or numbness
Hyperacuisis (stapedius paralysis)
Loss of taste (uncommon)
Tearing or drying of exposed eye

Question 5

Describe the weakness seen in Bell’s palsy

Answer 5

LMN weakness of facial muscles
Affects ipsilateral muscles of facial expression
Does NOT spare the muscles of the upper part of the face (unlike UMN facial nerve palsy)

Question 6

What investigations are required in Bell’s palsy?

Answer 6

Usually unnecessary (except for excluding other causes)  
EMG: may show local axonal conduction block

Question 7

What is involved in the management plan for Bell’s palsy?

Answer 7

Protection of cornea with protective glasses/ patches or artificial tears
High-dose corticosteroids if within 72h
(+ if Ramsey-Hunt Syndrome is excluded)

Question 8

List 4 complications of Bells palsy

Answer 8

Corneal ulcers
Eye infection
Aberrant reinnervation
Crocodile Tears Syndrome

Question 9

Give 2 examples of aberrant reinnervation

Answer 9

Blinking may cause contraction of the angle of the mouth due to aberrant sympathetic innervation of orbicularis oculi + oris
Crocodile Tears Syndrome: Parasympathetic fibres may aberrantly reinnervate the lacrimal glands causing tearing whilst salivating

Question 10

What is the prognosis in Bells palsy?

Answer 10

85-90% recover function within 2-12w with or without tx

Question 11

What is Bell’s Phenomenon?

Answer 11

Eyeball rolls up but eye remains open when trying to close their eyes
Despite reporting unilateral facial numbness, clinical testing of sensation is normal

Question 12

What other area should be checked to identify alternative causes of facial nerve palsy?

Answer 12

Ears e.g. otitis media, herpes zoster infection

Question 13

What surgical procedure may be performed in Bell’s palsy? When?

Answer 13

Lateral tarsorrhaphy (suturing lateral parts of the eyelids together) 
Performed if imminent or established corneal damage

Question 14

Which 2 conditions have higher risk of Bells Palsy?

Answer 14

Diabetes
Pregnancy