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  • Writer's pictureNalaka de Silva

Bells Palsy

Updated: Mar 31

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.

Transitent Facial Nerve weakness


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


The commonest cause of VII palsy

incidence: 30/100,000

> 65 years double, and in children half



30% incomplete, and 70% have a complete paralysis


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


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


Hx on Comment 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 forehead is spared this could be due to a central neurological disease

Neuropathy ie Gullian Bare

Slow onset- Tumour unless proven otherwise


VII examination

need to note if complete or not. Complete loss carries 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/ ophthalmology 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, postauricular, palate

Middle ear pathology

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



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


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


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 decompression 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.


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


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


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.

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