Bell's Palsy

Question 1

What is Bell’s palsy

Answer 1

Acute, unilateral, idiopathic, facial nerve paralysis

Question 2

What are the features of Bell’s palsy?

Answer 2

Abrupt onset
Complete unilateral facial weakness at 24-72h
Ipsilateral numbness or pain around the ear
Reduced/altered taste
Hyperacusis from stapedius palsy
Dry eye

Question 3

What is seen on examination?

Answer 3

Patient unable to wrinkle forehead - LMN pathology
Unable to whistle (tests buccinator)
Unilateral sagging of mouth
Drooling of salive
Food trapped between gum and cheek
Speech difficulty
Failure of eye closure may cause watery or dry eye
Ectropion
Injury from foreign bodies
Conjunctivits

Question 4

What are other causes of CN7 palsy?

Answer 4

If rashes, bilateral, UMN signs (forehead sparing), other CN involved, limb weakness

Infective: RamsayHunt syndrome, Lyme disease, meningitis, TB

Brainstem lesions: stroke, tumour, MS

Cerebellopontine angle tumours: acoustic neuroma, meningioma

Systemic disease: DM, sarcoidosis, Guillain-Barre

Local disease: parotid tumour, otitis media, cholesteatoma,

UMN: stroke or MS

LMN: Bell’s, Ramsay Hunt, acoustic neurone, parotid tumour, HIV, MS, DM

Question 5

What investigation in Bell’s palsy?

Answer 5

Rule out other causes:

Blood: ESR, gloucose, VZV antibodies in Ramsay Hunt

CT/MRI for SOL, stroke, MS

Question 6

What is management of Bell’s palsy

Answer 6

Prednisolone within 72h of onset speeds recovery
Protect the eye:
Dark glasses and artificial tears (hypromellose)
Encourage regular eyelid closure by pulling down lid manulally
Tape eyes close at night
Consider surgery if eye closure remains long term problem

Question 7

What are aberrant reconnections?

Answer 7

Synkinesis - eye blinking causes synchrony upturning of the mouth
Crocodile tears - gusto-lacrimal reflex - eaton stimulates unilateral lacrimation not salivation - misconnection of parasympathetic firbes

Question 8

What is Ramsay Hunt syndrome?

Answer 8

Latent VZV reactivates in the geniculate ganglion on the VIIth nerve

Painful veisucalr rash on the auditory canal and on drum, pinna, tongue palate, or iris
Ipsilateral facial palsy
Loss of taste
Vertigo
Tinnitus
Deafness
Dry mouth and eyes

Mx:
Antivirals (aciclovir) + prednisolone

1/3 good recovery, 1/3 reasonable, 1/3 poor

Question 9

What does CN7 supply?

Answer 9

Face, ear, taste, tear
Muscles of facial expression
Nerve to stapedius
Anterior 2/3 tongue
Parasympathetic fibres to lacrimal and salivary glands

Question 10

What is the difference between LMN and UMN CN7 lesion?

Answer 10

UMN spares forehead

LMN affects all msucles