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| {{Infobox_Disease | | {{Infobox_Disease |
| | Name = Bell's palsy | | | Name = Bell's palsy |
| | Image = Gray781.png | | | Image = Gray781.png |
| | Caption = | | | Caption = |
| | DiseasesDB = 1303
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| | ICD10 = {{ICD10|G|51|0|g|50}}
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| | ICD9 = {{ICD9|351.0}}
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| | ICDO =
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| | OMIM =
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| | MedlinePlus = 000773
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| | eMedicineSubj = emerg
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| | eMedicineTopic = 56
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| | eMedicine_plus = {{eMedicine2|neuro|413}} {{eMedicine2|ent|719}} {{eMedicine2|oph|508}}
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| | MeshID = D020330
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| }} | | }} |
| {{SI}} | | {{Bell's palsy}} |
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| '''For patient information click [[{{PAGENAME}} (patient information)|here]]''' | | '''For patient information click [[{{PAGENAME}} (patient information)|here]]''' |
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| '''Editor-in-Chief:''' Gilbert Dagher, M.D.
| | {{CMG}}; {{AE}}{{M.B}} ,{{MMJ}} {{NE}} |
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| {{Editor Join}} | |
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| ==Overview==
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| '''Bell's palsy''' (or '''facial [[palsy]]''') is characterised by facial drooping on the affected half, due to malfunction of the [[facial nerve]] (VII [[cranial nerve]]), which controls the [[muscle]]s of the face. Named after Scottish anatomist Charles Bell, who first described it, Bell's palsy is the most common acute [[mononeuropathy]] (disease involving only one [[nerve]]), and is the most common cause of [[acute facial nerve paralysis]]. The paralysis is of the infranuclear/lower motor neuron type. Bell’s palsy affects about 40,000 people in the United States every year. It affects approximately 1 person in 65 during a lifetime. Until recently, its cause was unknown in most cases, but it has now been related to both [[Lyme disease]] and [[Herpes Zoster]].
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| ==Epidemiology==
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| The annual incidence rate is between 13 and 34 cases per 100,000 population.
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| There is no race, geographic, or gender predilection.
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| The risk is three times greater during pregnancy, especially in the third trimester or in the first postpartum week.
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| Diabetes is present in about 5 to 10 percent of patients.
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| ==Etiology== | | {{SK}} Idiopathic facial paralysis,Idiopathic facial nerve paresis,Facial nerve disorder |
| | ==[[Bell's palsy overview|Overview]]== |
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| Many cases likely due to [[Herpes Simplex Virus]] (HSV) reactivation
| | ==[[Bell's palsy historical perspective|Historical Perspective]]== |
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| '''Infectious causes ''' | | ==[[Bell's palsy classification|Classification]]== |
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| :Herpes simplex virus activation is the likely cause of Bell's Palsy in most cases.
| | ==[[Bell's palsy pathophysiology|Pathophysiology]]== |
| :Herpes Zoster may be the second most common associated viral infection.
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| :Cytomegalovirus
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| :Epstein Barr virus
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| :Adenovirus
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| :Rubella virus
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| :Mumps
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| :Influenza B
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| :Coxsackievirus
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| :Rickettsial infection
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| :Ehrlichiosis
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| | ==[[Bell's palsy causes|Causes]]== |
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| '''Non-infectious causes''' | | ==[[Bell's palsy differential diagnosis|Differentiating Bell's Palsy from other Diseases]]== |
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| :Inactivated intranasal influenza vaccine that was introduced and since withdrawn from the market in Switzerland
| | ==[[Bell's palsy epidemiology and demographics|Epidemiology and Demographics]]== |
| :Genetic predisposition in some cases
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| :Ischemia of the facial nerve
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| :Tumors and compression of the facial nerve
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| :Temporal bone fracture
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| :Systemic Lupus Erythematosus (SLE)
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| :Sarcoidosis
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| == Histopathology == | | ==[[Bell's palsy natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
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| :The facial nerve has a thickened, edematous perineurium with a diffuse infiltrate of inflammatory cells between nerve bundles and around intraneural blood vessels.
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| :The ppearance similar to that found with Herpes Zoster infection, consistent with an inflammatory and possibly an infectious cause
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| ==Peripheral versus central lesions ==
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| :Sparing of the forehead muscles is suggestive of a central (upper motor neuron) lesion because of bilateral innervation to this area.
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| :However, it does not exclude a peripheral site of pathology in all cases.
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| == History and Symptoms ==
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| Onset over hours (maximal symptoms by 48 hours)
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| :*Eyebrow sag with inability to close eye
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| :*Nasolabial fold flattening with mouth drawn to affected side
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| :*Inability to wrinkle forehead (peripheral lesion)
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| :*May be associated with or preceded by ear pain (~20%)
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| :*May be associated with:
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| :#Impaired taste 23%
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| :#Increased lacrimation 24%
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| :#Hyperacusis 7%
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| ==Diagnosis== | | ==Diagnosis== |
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| Bell's palsy is a [[diagnosis of exclusion]]; in many cases, no specific cause can be ascertained. | | [[Bell's palsy history and symptoms|History and Symptoms]] | [[Bell's palsy physical examination|Physical Examination]] | [[Bell's palsy laboratory findings|Laboratory Findings]] | [[Bell's palsy CT|CT]] | [[Bell's palsy MRI|MRI]] | [[Bell's palsy other diagnostic studies|Other Diagnostic Studies]] |
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| Testing for Lyme ''not'' indicated unless other suggestive symptoms or risk factors.
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| === Other Imaging Findings ===
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| Imaging only if atypical symptoms or slow progression (risk of tumor). Electromyography (EMG) may help with prognosis in patients with complete cranial nerve (CN) VII paralysis
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| ===Investigation===
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| Clinicians should determine whether all branches of the facial nerve are involved, or whether the forehead muscles are spared. Since these receive innervation from both sides of the brain, the forehead can still be wrinkled by a patient whose facial palsy is caused by a problem in the brain rather than in the facial nerve itself.
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| Facial palsy results from inability to control movement in the facial muscles. The facial muscles become weak or paralyzed. There is no specific treatment for Bell's palsy, and it typically subsides on its own within 2-3 weeks.
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| == Risk Stratification and Prognosis==
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| Excellent or complete recovery in 80% within weeks-months. Recovery depends on initial severity
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| :* '''''Incomplete lesions:''''' 94% recover to normal function
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| :* '''''Complete lesions:''''' 60% recover to normal function
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| ==Treatment== | | ==Treatment== |
| | [[Bell's palsy medical therapy|Medical Therapy]] | [[Bell's palsy surgery|Surgery]] | [[Bell's palsy primary prevention|Primary Prevention]] | [[Bell's palsy secondary prevention|Secondary Prevention]] | [[Bell's palsy cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Bell's palsy future or investigational therapies|Future or Investigational Therapies]] |
| | == Case Studies == |
| | [[Bell's palsy case study one|Case #1]] |
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| '''Eye care:''' nocturnal patch, lacrilube, artificial tears if poor lid closure
| | ==Related Chapters== |
| | | *[[Central facial palsy]] |
| === Pharmacotherapy ===
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| '''Glucocorticoids:''' +/- higher rate of recovery if reaction at onset <br>
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| '''Antivirals:''' ACV 400 mg 5xd + prednisone better than prednisone alone <br>
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| '''Valacyclovir:''' 1 g tid x 7d = easier alternative to ACV <br>
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| Treatment is a matter of controversy. In patients presenting with incomplete facial palsy, treatment may be unnecessary. However, patients presenting with complete [[paralysis]], marked by an inability to close the eyes and mouth on the involved side, are usually treated with anti-inflammatory [[corticosteroids]]. [[Prednisolone]], a corticosteroid, if used early in treatment of Bell's palsy, significantly improves the chances of complete recovery at 3 and 9 months when compared to treatment with [[acyclovir]], an anti-viral drug, or no treatment at all. The likely association of Bell's palsy with the herpes virus has led most American neurologists to prescribe a course of anti-viral medication (such as [[acyclovir]]) to all patients with unexplained facial palsy.<ref> Sullivan FM, Swan IRC, Donnan PT, et al. Early treatment with prednisolone or acyclovir in Bell's palsy. N Engl J Med 2007;357:1598-1607. [[Surgical]] procedures to decompress the facial nerve have been attempted, but have not been proven beneficial. [[Acupuncture]] has also been studied, with inconclusive results.<ref>He, L., D. Zhou, B. Wu, N. Li, and M.K. Zhou. (2004). [http://www.cochrane.org/reviews/en/ab002914.html "Acupuncture for Bell's palsy."] ''Cochrane Database of Systematic Reviews'' 2004, Issue 1. Art. No.: CD002914. DOI: 10.1002/14651858.CD002914.pub2. Retrieved on 2007-09-06.</ref>
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| People who think they may have Bell's Palsy should consult their doctor as soon as possible. Many times, the medications will not be effective if administered too late after the onset.
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| Although most patients (60–80%) recover completely from Bell's palsy within several weeks, some require several months, and others may be left with deficits of varying degrees.
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| ==Complications==
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| Major complications of the condition are chronic loss of taste ([[ageusia]]), chronic facial [[spasm]] and corneal infections. To prevent the latter, the eyes may be protected by covers, or taped shut during sleep and for rest periods, and tear-like eye drops or eye ointments may be recommended, especially for cases with complete [[paralysis]]. Where the eye does not close completely, the reflex is also affected; great care should be taken to protect the eye from injury.
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| Another complication can occur in case of incomplete or erroneous regeneration of the damaged facial nerve. The nerve can be thought of as a bundle of smaller individual nerve connections which branch out to their proper destinations. During regrowth, nerves are generally able to track the original path to the right destination - but some nerves may sidetrack leading to a condition known as synkinesis. For instance, regrowth of nerves controlling muscles attached to the eye may sidetrack and also regrow connections reaching the muscles of the mouth. In this way, movement of one also affects the other. For example, when the person closes the eye, the corner of the mouth will lift, or when smiling, the eye will close (synkinesis).
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| In addition, around 6% of patients exhibit [[Tears#Diseases and disorders|crocodile tear syndrome]] on recovery, where they will shed tears while eating. This is thought to be due to faulty regeneration of the facial nerve, a branch of which controls the lacrimal and salivary glands.
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| ==References==
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| {{reflist|2}}
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| ==Additional Resources==
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| * Sullivan FM, Swan IRC, Donnan PT, et al. Early treatment with prednisolone or acyclovir in Bell's palsy. N Engl J Med 2007;357:1598-1607.
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| * "The Merck Manual"
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| * ''New England Journal of Medicine'', Sept. 2004
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| * Lambert, Michael. (2007-03-05) [http://www.emedicine.com/emerg/topic56.htm "Bell's Palsy."] (Website.) ''Emedicine''. Retrieved on 2007-09-27.
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| ==External links==
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| *[http://www.facialparalysisinstitute.com managment and treatment of facial paralysis]
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| *[http://www.bellspalsy.ws/ Bell's Palsy Information Site], has a FAQ
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| *[http://pregnancyandbaby.com/read/articles/5398.htm Bell's Palsy and Pregnancy]
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| *[http://www.neurologychannel.com/bellspalsy/ Bell's Palsy Patient Info - Neurology Channel]
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| *[http://www.facial-palsy.com/ Living with Facial Palsy], a site for parents of children with Facial Palsy
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| *[http://www.lib.uiowa.edu/hardin/md/bellspalsy.html Links to pictures of Bells palsy (Hardin MD/Univ of Iowa)]
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| *[http://www.bellspalsy.org.uk/ Bell's Palsy Association]
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| {{SIB}}
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| {{PNS diseases of the nervous system}} | | {{PNS diseases of the nervous system}} |
| [[Category:Neurological disorders]]
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| [[Category:Otolaryngology]]
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| [[ar:شلل العصب الوجهي]]
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| [[ca:Paràlisi de Bell]] | | [[ca:Paràlisi de Bell]] |
| [[de:Fazialislähmung]] | | [[de:Fazialislähmung]] |
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| {{WH}} | | {{WH}} |
| {{WikiDoc Sources}} | | {{WikiDoc Sources}} |
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| | [[Category:Neurological disorders]] |
| | [[Category:Otolaryngology]] |
| | [[Category:Neurology]] |
| | [[Category:Disease]] |
