Bell's Palsy

Question 1

Define Bell’s Palsy?

Answer 1

Idiopathic lower motor neurone facial nerve palsy

Question 2

What is the aetiology of Bell’s Palsy?

Answer 2

IDIOPATHIC
60% are preceded by an upper respiratory tract infection
This suggests that it has a viral or post-viral aetiology

Question 3

What is the epidemiology of Bell’s Palsy?

Answer 3

Most Cases: 20-50 yrs

Question 4

What are the presenting symptoms of Bell’s Palsy?

Answer 4

Prodrome of pre-auricular pain (in some cases)
This is followed by unilateral facial weakness and droop
Maximum severity: 1-2 days
50% experience facial, neck or ear pain or numbness
Hyperacuisis
Loss of taste (uncommon)
Tearing or drying of exposed eye

Question 5

What is Hyperacuisis due to in Bell’s Palsy?

Answer 5

This is due to stapedius paralysis

Question 6

What is tearing or drying of exposed eye due to?

Answer 6

Because it may be difficult to close the eye fully

Question 7

What are the signs of Bell’s palsy on physical examination?

Answer 7

Lower motor neurone weakness of facial muscles
Bell’s Phenomenon
Despite reporting unilateral facial numbness, clinical testing of sensation is normal
Examine the ears to check for other causes of facial nerve palsy (e.g. otitis media, herpes zoster infection)

Question 8

What happens when Lower Motor Neurone Weakness of Facial Muscles occurs in Bell’s Palsy?

Answer 8

Affects ipsilateral muscles of facial expression

Doesn’t spare the muscles of the upper part of the face (unlike upper motor neurone facial nerve palsy)

Question 9

What is Bell’s Phenomenon?

Answer 9

Eyeball rolls up but the eye remains open when trying to close their eyes

Question 10

What investigations would you do for Bell’s Palsy?

Answer 10

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

Question 11

What is the management plan for Bell’s Palsy?

Answer 11

Protection of cornea with protective glasses/patches or artifical tears
High-Dose corticosteroids is useful within 72 hrs
Surgery - lateral tarsorrhaphy (suturing the lateral parts of the eyelids together)

Question 12

What needs to be excluded for corticosteroids to be given for Bell’s Palsy?

Answer 12

Only given if Ramsey-Hunt Syndrome is excluded

Question 13

When is surgery performed for Bell’s Palsy?

Answer 13

If imminent or estabished corneal damage

Question 14

What are the possible complications for Bell’s Palsy?

Answer 14

Corneal Ulcers
Eye infection
Aberrant Reinnervation

Question 15

What is an example of Aberrant Reinnervation for Bell’s Palsy?

Answer 15

Blinking may cause contraction of the angle of the mouth due to aberrant sympathetic innervation of orbicularis oculi and oris

Question 16

What is Crocodile Tears Syndrome?

Answer 16

Parasympathetic fibres may aberrantly reinnervate the lacrimal glands causing tearing whilst salivating

Question 17

What is the prognosis for patients with Bell’s Palsy?

Answer 17

85-90% recover function within 2-12 weeks with or without treatment