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Bell’s Palsy

Bells palsy-A rapid onset , isolated , unilateral , lower motor neurone facial weakness 
of unknown cause ( idiopathic )

Named after Scottish anatomist Sir Charles Bell – described 1st in 1829 Most common acute mononeuropathy ( accounts for 60 % of all cases of sudden onset facial paralysis ) Relatively uncommon- affects 20-40 per 100,000 people per year 
( ie in UK about 12,400- 24,800 people / year ) Equal sex distribution No side preference ( ie can happen equally either side ) Treatment is controversial ( about 70 % recover spontaneously untreated ) No seasonal or geographical predisposition Affects more -
○ peak incidence 2nd and 4th decade of life
○ diabetics
○ immunocompromised
○ obese
○ hypertensives
○ pregnant (↑ ed risk 3rd trimester )

cause –Cause is unknown Pathophysiology – vascular distension , inflammation and oedema with ischaemia of the facial nerve Viral aetiology is widely suspected
○ reactivation of herpes simplex virus or herpes zoster virus
○ destruction of ganglion cells and infection of Schwann cells → demyelination and neuronal inflammation Suspected theories
○ infective
○ inflammatory
○ autoimmune
○ ischaemia. Exact pathogenesis is controversial and significance of these factors remains unclear.

Grading scales can be used to judge severity and ascertain prognostic information e.g (House-Brackmann and Sunnybrook scales , eFACE )

Diagnosis of exclusion Rapid in onset ( over 24-72 hrs ) B/L BPa is rare Patient may report ear pain or a period of flu like illness prior to onset

Facial N supplies impulse to muscles of face , lacrimal glands , salivary glands , stapedius muscle , taste fibers from anterior tongue and general sensory fibers from the typmpanic membrane- hence
 weakness or paralysis of the upper and lower facial muscles drooping of the ispilateral eyelids inability to close the eye completely excessive tearing ( epiphora ) drooping of the corner of mouth ispilateral impaired / loss of taste sensation difficulty with eating dribbling of saliva , problems with speech articulation altered sensation – on the affected side ↑ ed sensitivity to sound ( hyperacusis )

Try and determine if the facial weakness is central or peripheral
○ In central lesion- the patient can lift forehead symmetrically 
( due to b/l cortical innervation of the frontalis muscle )
○ peripheral facial palsy ( LMN )- weakness of all muscles of facial expression occurs ( including the frontalis and orbicularis oculi )
Asymmetry in forehead wrinkles is a sign of peripheral N palsy
 Also-Notice ( see image )
○ furrow lost from brow e.g- ask
 ” raise you forehead like you’re surprised “
 patient cannot elevate the brow
○ ask to close eyes tightly -eyelids will not close and lower lid sags
 eye rolls upward on attempted closure -> Bell’s phenomenon
○ palpabral fissure is wider
○ nasolabial fold is flattened
○ cheek cannot be puffed out
○ nares do not flare with a hard inspiration
○ patient cannot whistle
○ mouth drawn to intact side- when smiling or showing teeth
○ sensory testing will usually be normal
 Look /ask for recent rashes , arthralgias , fevers , h/o peripheral N palsy , exposure to influenza vaccine or new medication , ticks ( areas where Lyme disease epidemic ) Ask about – family history ( +ve in 4-17 % )

History- ask the patient
Ischaemic stroke will be acute in onset reaching maximum severity within seconds to minutes

Brain strokes – cause central facial weakness involving the mouth and sparing the eye and forehead

Brainstem stroke – can mimic a peripheral lesion causing weakness of mouth , eye and forehead but this will be accompanied by other focal neurological deficits ( see below )

BPa would happen over hours to few days – often noticed by others and patient may not be able to tell the exact time
 Neurological exam
as on left will help identify the if the lesion is central or peripheral. A central lesion cannot be BPa and is likely to be a stroke.

A brainstem stroke – can present with similar features but it would be associated with other deficits so check for

○ weakness or numbness in the arm or leg ( can be on same side or on 
opposite side )
○ slurred speech
○ double vision – check eye movements
○ swallowing problem
○ incoordination ( ataxia )
○ vertigo ( can happen with brainstem or cerebellar strokes )

peripheral causes-Lyme disease Otitis media Ramsay Hunt syndrome Sarcoidosis Guillain-Barre syndrome HIV Tumours central causes- Facioscapulohumeral Dystrophy Multiple sclerosis Stroke Tumours

red flags- No improvement within 3 months B/L facial palsy Other cranial N involvement Limb or bulbar weakness parotid gland enlargement vesicles in external auditory canal , tympanic membrane or oropharynx.frontal headache , fever , gen malaise previous episode of Bell’s palsy cervical adenopathy signs of Lyme dis e.g skin rash HIV- if any risk factors present Other ear symptoms other than mild otalgia , hyperacusis or post-auricular pain

Complications –Motor synkinesis -involuntary movement of muscles occurring at the same time as deliberate movement e.g involuntary mouth movement during voluntary eye closure ( in up to 16 % ) Crocodile tears – abnormal lacrimation when eating 
( Bogard syndrome ) Incomplete recovery -30 % will have some sequeale and 4 % have severe residual paresis Eye injury Facial muscle contracture Dry mouth/ reduced taste Speech problems Psychological impact ( if recovery incomplete e.g
 facial disfigurement )

Treatment –Corticosteroids Antivirals Facial exercise Electrostimulation Physiotherapy Acupuncture Decompression surgery. Aged 16 and older within 72 hrs ( improved prognosis if within 72 hrs )
 Consider oral prednisolone
CKS mentions that there is no consensus on optimum dosing 
regimen but to consider

 50 mg / Day x 10 days or

 60 mg / Day x 5 days followed by a daily reduction in dose 
 of 10 mg ( total for 10 days ) if a reducing dose is preferred
 Antiviral treatment alone is not recommended
Combination treatment can be considered in severe cases and CKS recommends specialist advice first

Tests-Diagnosis of exclusion- no routine testing is needed if hx and symptoms consistent with BPa
 Testing is indicated if an alternative diagnosis if being considered and can involve for e.g
○ lyme serology
○ diagnostic audiogram
○ HResolution MRI or CT 
( with or without contrast )

eye care-Untreated this can lead to corneal ulceration and loss of vision Lubrication ( drops or ointment ) Tape ( e.g micropore if unable to close the eye at bedtime ) Outdoor protection e.g sunglasses Refer to Facial Palsy UK website for more info To seek immediate medical help if any irritation , pain or change in acuity

referral-Diagnosis is in doubt or no improvement after 3 weeks of treatment New neurological symptoms develop or the existing symptoms worsen Upper motor neurone cause is suspected for e.g
limb paralysis
facial paraesthesia
suspicion of other cranial N involvement
postural imbalance Cancer Trauma Systemic symptoms or severe local infection Refer for support if any complications develop

Prognosis-Prognosis is usually good recovery starts within 2-3 weeks even if no treatment used complete recovery can be expected by 3-4 months


Facial Palsy UK is an invaluable resource for patient information and you should consider referring all patients to there website

Bells Palsy Association is another large charity supporting people with Bells Palsy

American Academy of Otolaryngology- Head and Neck Surgery has a huge section both for patients and doctors. Link for clinical practice guideline

A comprehensive section on Bells palsy by NIH rare disease info website

RACGP article- A general practice approach to Bells Palsy

Eye care in Bells Palsy- printable document

For patients exploring surgical option for complications consider this link from British Association of Plastic Reconstructive and Aesthetic Surgeons

For evidence of treatment modalities refer to Cochrane review



  1. Baugh, R. F., Basura, G. J., Ishii, L. E., Schwartz, S. R., Drumheller, C. M., Burkholder, R., … Vaughan, W. (2013). Clinical Practice Guideline: Bell’s Palsy. Otolaryngology–Head and Neck Surgery149(3_suppl), S1–S27.
  2. Somasundara, Dhruvashree, and Frank Sullivan. “Management of Bell’s palsy.” Australian prescriber vol. 40,3 (2017): 94-97. doi:10.18773/austprescr.2017.030
  3. CKS NHS Bell’s Palsy
  4. Review on Management of Bell’s Palsy – Satinder Pal Singh Tulsi1
    , Vijayendra Pandey , Jyoti Tripathi,Department of Oral and Maxillafacial Surgery, Carrier Dental College and Hospital Lucknow, 2Periodontics, 3BDS Student, Vananchal Dental College And Hospital, Garh, Jharkhand An Update Journal of Advanced Medical and Dental Sciences Research
( Vol 2 ) Issue 3 July- September 2014
  5. Clinical Practice Guideline Summary : Bell’s Palsy AAO-HNS Bulletin November 2013
  6. Management of Bell’s palsy : clinical practice guideline  2014 Sep 2;186(12):917-22. doi: 10.1503/cmaj.131801. Epub 2014 Jun 16
  7. Bell’s Palsy Review Article American Academy of Neurology Continuum ( Mineapp Minn )  2017 Apr;23(2, Selected Topics in Outpatient Neurology):447-466. doi: 10.1212/CON.0000000000000447.
  8. Differentiating Facial Weakness Caused by Bell’s Palsy vs . Acute Stroke Can you tell the difference? Caitlin Loomis MD et al Journal of Emergency Medical Services 2014
  9. Bell’s Palsy : Diagnosis and Management . 2007 Oct 1;76(7):997-1002
  10. BMJ Best Practice Bell’s palsy


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