Bell's Palsy
Original Editor Wendy Walker
Lead Editors
Introduction
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Bell's Palsy, or Bell Palst, is facial paralysis which is caused by dysfunction of Cranial Nerve VII, the Facial Nerve.
Also known as Idiopathic Facial Palsy. It is named after Sir Charles Bell [1774 to 1842], who was a Scottish surgeon, neurologist and anatomist.
It results in inability or reduced ability, to move the muscles on the affected side of the face ie. Facial Palsy.
Bell's Palsy is an idiopathic condition, ie. no specific cause has been conclusively established. It is a diagnosis of exclusion: once other causes of facial palsy have been eliminated, the patient is said to have Bell's Palsy.
Mechanism of Injury / Pathological Process
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The facial nerve is damaged by inflammation within the nerve causing it to become enlarged; at the point where the nerve exits the skull through the stylomastoid foramen.
Ischemia occurs as the nerve swells in its bony canal, blocking neural blood supply.
Having said that Bell's Palsy is a diagnosis of exclusion, and that we are not certain what causes the nerve inflammation[1], there is some evidence to suggest that in the majority of cases it is likely to be linked to Herpes Simplex infection[2].
Clinical Presentation[edit | edit source]
Loss of control of the muscles on one side of the face is the main physical presentation.
Some patients also report general malaise in the first few days on onset, as well as some pain in the region of the ipsilateral mastoid (known as otalgia), but many of patients have no otalgia or malaise.
At onset the paralysis may be complete, or partial (paresis) and although it frequently affects all branches of the facial nerve on the affected side, resulting in loss of control of that side of the mouth and the ipsilateral eye, in a few cases only one or two branches of the facial nerve are affected.
For a more detailed description of the clinical presentation, please see the Facial Palsy page.
Diagnostic Procedures[edit | edit source]
Bell's Palsy is essentially a diagnosis of exclusion, so once other causes of facial palsy have been eliminated, we call an isolated facial palsy Bell's Palsy, or Idiopathic Facial Palsy[3].
MRI scanning can be used to exclude other causes of facial nerve dysfunction, such as Facial Schwannoma or Acoustic Neuroma.
Medical Management[edit | edit source]
Corticosteroids and antiviral medication are generally considered to be the 1st line treatment for Bell's Palsy, providing the best results when treatment starts within 72 hours of onset of symptoms[4]. There are a number of studies showing benefit for steroids given within this time-frame[5].
However, many studies do not demonstrate any advantage of using antiviral medication combined with corticosteroids over corticosteroids along.
The Cochrane review: "Antiviral treatment for Bell's palsy"[6] (idiopathic facial paralysis concludes:"Moderate-quality evidence from randomised controlled trials showed no additional benefit from the combination of antivirals with corticosteroids compared to corticosteroids alone for the treatment of Bell's palsy of various degrees of severity. Moderate-quality evidence showed a small but just significant benefit of combination therapy compared with corticosteroids alone in severe Bell's palsy."
Physiotherapy Interventions
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Physiotherapy management of the facial paralysis or weakness is as detailed in the section on Facial Palsy.
It is also important to provide information on care of the eye in order to prevent formation of corneal ulcer: see advice page on Dry Eye. Referral to an opthalmologist should be considered.
Bell's Palsy patients with long term facial paralysis may also start to experience dental problems: see advice page on Dental Issues in Facial Palsy.
Differential Diagnosis
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add text here relating to the differential diagnosis of this condition
Key Evidence[edit | edit source]
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Resources
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The charity Facial Palsy UK have a page on RHS
The website RamsayHunt.org offers information and support
Case Studies[edit | edit source]
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Recent Related Research (from Pubmed)[edit | edit source]
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References[edit | edit source]
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- ↑ Peiterson,E. Bell's Palsy; the spontaneous course of 2,500 peripheral facial nerve palsies of different etiologies. Acta Oto-Laryngologica. Supplementum 2002;549:4-30
- ↑ Holland NJ, Weiner GM. Recent developments in Bell's Palsy. BMJ 2004; 329(7465):553-7
- ↑ Ahmed A. When is facial paralysis Bell palsy? Current diagnosis and treatment. Cleve Clin J Med. 2005 May;72(5):398-401, 405
- ↑ Hato N, Murakami S, Gyo K. Steroid and antiviral treatment for Bell's palsy. Lancet 2008; 371: 1818–20
- ↑ Engstrom M, Berg T, Stjernquist-Desatnik A, Axelsson S, Pitkaranta A, Hultcrantz M, et al. Prednisolone and valaciclovir in Bell's palsy: a randomised, double-blind, placebo-controlled, multicentre trial. Lancet Neurol. 2008 Nov. 7(11):993-1000
- ↑ Gagyor I1, Madhok VB, Daly F, Somasundara D, Sullivan M, Gammie F, Sullivan F. Antiviral treatment for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2015 Jul 1;(7):CD001869.
