A 32 year old man presents to you with sudden onset of weakness on the left side of his face. He also says that he is unable to close his left eye. He is otherwise well and last saw a doctor five years ago. He is anxious and thinks he has had a stroke.
Associated symptoms—Patients with Bell's palsy commonly feel pain in or behind the ear. Numbness can occur on the affected side of the face. Loss of taste on the ipsilateral anterior two thirds of the tongue is common. Ask about associated hyperacusis and any presence of rash that may indicate herpes zoster.
Aetiology—Ask about recent viral infection and recent immunisation. The causes of Bell's palsy are unknown, but the possibilities include viral infection, heredity, autoimmune or vascular ischaemia, of which the most likely cause is viral.
Incidence—Bell's palsy is commonest in the age group 10 to 40 years. Each year about 20 cases per 100 000 people occur.
You will need to differentiate between an upper and lower motor neurone lesion of the facial nerve. A lower motor neurone lesion occurs with Bell's palsy, whereas an upper motor neurone lesion is associated with a cerebrovascular accident. A lower motor neurone lesion causes weakness of all the muscles of facial expression. The angle of the mouth falls. Weakness of frontalis occurs, and eye closure is weak. With an upper motor neurone lesion frontalis is spared, normal furrowing of the brow is preserved, and eye closure and blinking are not affected.
Check that no other cranial nerves are involved. Bell's palsy is seventh nerve palsy in isolation. Look also for a painful rash over the ear, which indicates Ramsay Hunt syndrome caused by herpes zoster virus.
Look for pointers to a more serious underlying cause that might require urgent referral of the patient: bilateral Bell's palsy; recurrent Bell's palsy; association with a rash elsewhere or with feeling generally unwell (which may indicate sarcoid or Lyme disease); or a previous episode that could have been the effect of demyelination. Although it is rare, always bear in mind the possibility of a seventh nerve palsy caused by a space occupying lesion.
Information websites for patients
Bell's Palsy Information Site (www.bellspalsy.ws). This site has information on causes, symptoms, treatment, and rehabilitation. It also has a good “frequently asked questions” page.
Bell's Palsy Association (www.bellspalsy.org.uk). This is a UK based information site for patients.
Useful reading
Bandolier. Bell's palsy systematic reviews. www.jr2.ox.ac.uk/bandolier/booth/neurol/Bellsyre.html
Holland NJ, Weiner GM. Recent developments in Bell's palsy. BMJ 2004;329: 553-7
Salinas R. Bell's palsy. In: Clinical evidence concise. Issue 11. London: BMJ Publishing, 2004: 311
Two recent systematic reviews concluded that Bell's palsy can be effectively treated with corticosteroids in the first seven days after onset, with a further 17% of patients having a good outcome in addition to the 80% that spontaneously improve. Recovery rates in patients treated within 72 hours were enhanced with the addition of aciclovir. It is thought that prednisolone acts by reducing oedema of the facial nerve. Antivirals inhibit viral replication. So, recent evidence supports the use of oral prednisolone and aciclovir in patients with moderate to severe palsy, ideally within 72 hours but up to seven days from onset of symptoms. Prednisolone should be prescribed at a dosage of 1 mg/kg/day (maximum 80 mg daily) for the first week, with the dosage tapering off over the second week. Aciclovir is given at a dosage of 800 mg five times a day for five days.
As blinking is affected, and his eye may not close, consider an eye pad or taping of the lid so that he can sleep. His cornea will be dry, so prescribe artificial tears.
Reassure him. Patients are often highly anxious and will need to be firmly reassured that this is not a cerebrovascular accident. Tell him that most patients get better but that a minority won't.
Two thirds of patients recover spontaneously, and 85% report some improvement in the first three weeks. In the other 15% of patients some improvement occurs by 3-6 months. Patients need follow up for assessment of recovery and support.
Referral to an ear, nose, and throat specialist is advisable for all cases after treatment is begun. Patients with incomplete recovery of facial nerve function may ultimately need to be referred to an ophthalmologist for tarsorrhaphy.
This is part of a series of occasional articles on common problems in primary care
The series is edited by general practitioners Ann McPherson and Deborah Waller (ann.mcpherson{at}dphpc.ox.ac.uk)

中文翻译：

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贝尔的麻痹

一名32岁的男子突然出现左侧脸部虚弱的症状。他还说自己无法闭上左眼。否则，他状况良好，最后一次去看医生是在五年前。他很着急，认为自己得了中风。
相关症状-患有贝尔麻痹的患者通常会感到耳内或耳后疼痛。麻木可能发生在面部的患侧。同侧前三分之二的舌头上的味觉丧失是常见的。询问相关的听觉过敏和任何可能指示带状疱疹的皮疹的存在。
病因学—询问最近的病毒感染和最近的免疫接种。贝尔麻痹的原因尚不清楚，但可能性包括病毒感染，遗传，自身免疫或血管缺血，其中最可能的原因是病毒。
发生率—贝尔氏麻痹在10至40岁年龄段最常见。每年每十万人中约有20例发生。
您将需要区分面神经的上运动神经元病变和下运动神经元病变。下运动神经元病变伴有贝尔氏麻痹，而上运动神经元病变伴有脑血管意外。较低的运动神经元病变会导致面部表情所有肌肉无力。嘴角下降。额肌无力，闭眼无力。使用上运动神经元病变时，额肌得以保留，保留了眉头的正常犁沟，并且不影响闭眼和眨眼。
检查是否没有其他颅神经受累。贝尔麻痹孤立地是第七神经麻痹。还要在耳朵上寻找皮疹，这表明带状疱疹病毒引起的拉姆齐·亨特综合征。
寻找指示可能需要紧急转诊的更严重潜在病因的指针：双侧贝尔麻痹；双侧贝尔麻痹；双侧贝尔麻痹 反复发作的贝尔麻痹；与其他地方的皮疹或一般感觉不适有关（可能表明结节病或莱姆病）；或以前可能是脱髓鞘作用的发作。尽管很少见，但要始终记住由占位性病变引起的第七神经麻痹的可能性。
病人
的信息网站贝尔氏麻痹信息网站（www.bellspalsy.ws）。该站点提供有关原因，症状，治疗和康复的信息。它也有一个很好的“常见问题”页面。
贝尔麻痹协会（www.bellspalsy.org.uk）。这是英国的患者信息网站。
有用的阅读
Bandolier。贝尔的麻痹性系统评价。www.jr2.ox.ac.uk/bandolier/booth/neurol/Bellsyre.html
Holland NJ，Weiner GM。贝尔麻痹的最新发展。BMJ 2004; 329：553-7
Salinas R.Bell的麻痹。见：临床证据简明。第11期，伦敦：BMJ出版社，2004年：311
最近的两项系统评价得出的结论是，在发病后的前7天，可以使用皮质类固醇有效地治疗贝尔麻痹，除80％的患者自发改善外，还有17％的患者预后良好。添加阿昔洛韦可提高72小时内接受治疗的患者的恢复率。认为泼尼松龙通过减轻面神经水肿起作用。抗病毒药抑制病毒复制。因此，最近的证据支持在中度至重度麻痹患者中使用口服泼尼松龙和阿昔洛韦，理想情况是在症状发作后的72小时内，最长达7天使用口服泼尼松龙和阿昔洛韦。首周的泼尼松龙的处方剂量为1 mg / kg /天（每天最多80 mg），第二周的剂量逐渐减少。
由于眨眼受到影响，并且他的眼睛可能无法合上，因此请考虑使用眼垫或轻拍眼睑以使他可以入睡。他的角膜会干燥，所以要开人工眼泪。
让他放心。患者通常会非常焦虑，需要放心，这不是脑血管意外。告诉他，大多数患者会好转，但少数患者不会好转。
三分之二的患者自发康复，其中85％的患者在前三周内有所改善。在其他15％的患者中，3到6个月会有所改善。患者需要跟进以评估康复和支持。
在开始治疗后的所有情况下，建议转诊至耳鼻喉专科医生。面神经功能恢复不完全的患者可能最终需要转诊给眼科医生进行镜检。
这是有关初级保健中常见问题的系列偶然文章的一部分。该系列文章
由全科医生Ann McPherson和Deborah Waller编辑（ann.mcpherson {at} dphpc.ox.ac.uk）