Bell's Palsy

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Please note that the following is a general guideline/ discussion only. For a full assessment, exclusion of any other underlying cause for your symptoms and an individualised treatment approach, you will need to be seen by a qualified specialist.

DEFINITION

Idiopathic ACUTE onset lower motor nerve facial paralysis 
if a facial weakness is of slow onset (over 3 weeks) it is due to a malignancy unless proven otherwise

EPIDEMIOLOGY

Commonest cause of VII palsy 
incidence: 30/100,000
 > 65 years double, and in children half
M=F
L=R
30% incomplete, and 70% have a complete paralysis

AETIOLOGY

Now thought to be due to  viral infection-HSV type 1

NATURAL COURSE

1/3 of patients get partial weakness-95% gain full recovery
2/3 of patients get complete weakness- 70% full recovery and 30% incomplete recovery

TAKING A HISTORY

Hx on Commenest Presentation
Most commonly Bells palsy only affects the facial nerve alone
It usually occurs over 2-3 days not over weeks
70% may go on to develop complete paralysis
Viral prodrome may have been noted


Other cranial neuropathies?
Some believe that other cranial neuropathies may also be present in Bell palsy; however, this is not uniformly accepted. The symptoms in question include the following:


Hyperesthesia or dysesthesia of the glossopharyngeal or trigeminal nerves
Dysfunction of the vestibular nerve
Hyperesthesia of the cervical sensory nerves
Vagal or trigeminal motor weakness


Excluding differentials
Further history should be directed towards excluding known causes
Herpes Zoster: has painful vesicles
Middle ear disease: look for middle ear infections/ cholesteotoma- hx of ear discharge, hearing loss
Central: if fore head is spared this could be due to a central neurological disease

Neuropathy ie Gullian Bare
Slow onset- Tumour unless proven otherwise

EXAMINATION

VII examination
need to note if complete or not. Complete loss caries a worse prognosis and need urgent treatment
Lower motor or upper motor?

Eye occlusion
If eyes are not protected/ absent bells phenomenon -need eye care/ opthalmology follow up

Full cranial nerve exam: 
If multiple nerves affected consider an MRI early to exclude other central cause

Look For possible Ramsay Hunt
Vesicles -pinna, EAC, post auricular, palate 

Middle ear pathology
exclude AOM, OME, need to do a hearing test/ clinical free field test

INVESTIGATIONS

Bloods:
No routine blood work up needed-unless another cause is suspected

Imaging
MRI if high chance of another cause-as above
MRI- if no response/ no improvement after 2 months
CT Temp Bones in middle ear disease noted

Audiogram
If middle ear pathology is noted


Electrical testing of the facial nerve: 
Some centres may do these in patients with complete paralysis. The reasoning is that these tests (ENOG, EMG) help identify those who are likely to have poor response to medical treatment. Some may argue de compression of the facial nerve within 2 weeks improves prognosis. However the counter argument is that the risk of this operation may outweigh the benefit achieved. Hence most do not do routine electrical testing of the nerve.

TREATMENT

combinations of steroids and anti viral agents have shown to improve the overall outcome if given within 7 days of onset.

Steroids
Usually prednisone 1 mg per Kg for 7 days then taper over 4 days

Anti-viral 
Should be added if within 7 days of onset
Acyclovir (400mg 5 times a day for 10 days or Valacyclovir 500 mg BD for 5 days
If Herpes Zoster is suspected need higher doses. 


Eye care
Taping, Lacry lube, Opthalmology follow up

Surgical Decompression
Only for those with complete paralysis, with poor prognosis noted by electrical studies. Not done routinely in most centres.