What's on the web for family physicians - Bell's palsy

Alfred KY Tang 鄧權恩，Kin-lun Tsang 曾建倫

The name ‘Bell’s palsy’ comes from Scottish anatomist and surgeon Sir Charles Bell, who in 1821 discovered that severing the seventh cranial (or facial) nerve causes facial paralysis. Facial palsy is the most common acute condition involving only one nerve. Another proper name for Bell’s palsy is idiopathic facial paralysis. It is common and lifetime risk is around 1 in 60. Spontaneous full recovery rate is high at around 70-80%. Women in the third trimester of pregnancy are at increased risk. There appears to be a higher incidence of Bell’s palsy in winter but anecdotal observation reveals its incidence parallels viral infections.

Cause of Bell’s palsy is unknown; links have been made with viruses (including herpes, influenza and respiratory tract infections), as well as a depleted immune system and stress. Its onset is acute and peaks within 48- 72 hours. Patients often initially fear that they are having a stroke. Forehead involvement and sparing of limbs can differentiate the two but sometimes is challenging when the deficits are subtle. Half of the patients have posterior auricular pain and the pain can precede facial paresis by 2-4 days. Hyperacuisis and/or taste disturbance happen in one third. Half would complain excessive tearing due to incomplete closure of eyelids.

Management
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4150706/pdf/1860917.pdf

Workup depends on presentations. Straightforward cases do not require imaging study. Magnetic resonance imaging (MRI) or computed tomography (CT) can rule out structural lesions like tumors. Blood tests are done for suspected Lyme disease and Ramsay Hunt Syndrome.

Initial treatment for Bell’s palsy
http://journals.sagepub.com/doi/pdf/10.1177/0194599813505967

The best recovery occurs where the duration and severity of nerve compression (inflammation) is minimised. Oral steroid treatment is most established. It is preferably to be given within 72 hours of symptoms onset but studies showed efficacy still remains if given within one week. Dose is 1mg/kg/day for one week to 10 days. Subgroup analysis showed better outcome with total dose of 450mg. Upper limit of daily dose might be capped at 60-80mg.

Antiviral treatment
http://www.cochrane.org/CD001869/NEUROMUSC_antiviral-treatment-bells-palsy

Anti-viral (acyclovir) alone is not recommended, because many cases are believed not to be due to herpes infection. Oral steroid plus anti-viral are indicated for Ramsay Hunt Syndrome and might be considered for severe cases.

In general, over 70% of people with Bell’s palsy make a full recovery. Improvement can occur as early as two to three weeks from onset; however, a full recovery can take anywhere from three to six months and beyond. Do not expect improvement in the first week as the nerve is still in hyperacute inflammatory stage. In the remaining 20-30% of cases, the nerve damage is more severe and these individuals are left with a degree of permanent facial paralysis. Severe nerve damage is more likely to occur if the patient:

• is over 60;
• had severe pain at onset or reduced lacrimation;
• had complete rather than partial paralysis at onset;
• had a preexisting health condition such as diabetes or high blood pressure;
• was pregnant at the time of onset;
• if recovery had not begun after six weeks.

Electrophysiological study (nerve conduction test and electromyography) can be done 3-14 days after onset of paralysis. It is an objective measure to assess prognosis. If there is more than 90% of axonal loss, prognosis is poor.

Seven per cent of patients have recurrent Bell’s palsy, with the average interval between attacks being ten years. It does not imply worse prognosis on recovery.

• Contracture: Shortening of the facial muscles over time may make the affected side of the face appear to be slightly ‘lifted’ in comparison to the unaffected side, and the affected eye may appear smaller than the unaffected eye. The fold between the outer edge of the nostril and the corner of the mouth may seem deeper due to the increased contraction of cheek muscles on that side.
• Crocodile tears (or Bogorad’s Syndrome): This means that the affected eye waters involuntarily, particularly whilst eating. This is due to faulty ‘re-wiring’ of the nerves during the recovery phase.
• Lagophthalmos: This is an inability to close the affected eye, which if prolonged may result in eye dryness and/or corneal ulceration. This complication can be prevented by the use of artificial tears and taping the eye down at night. In rare cases, the vision may be permanently damaged if care is not taken.
• Synkinesia: This means that when intentionally trying to move one part of the face, another part automatically moves. For example, on smiling the eye on the affected side automatically closes. Similarly, on raising the eyebrows or closing the eyes , involuntary contraction of the cheek or neck muscles occurs. Some neural fibers during recovery take an unusual course and connect to neighboring muscle or nerve fibers.
• Psychological problems including stress, anxiety, depression and low self-esteem.
• Incomplete recovery increases the risk of hemifacial spasm in later years.

Facial rehabilitation
http://www.facialpalsy.org.uk/support/treatmentstherapies/facial-rehabilitation/

Physiotherapy and acupuncture (especially in this locality) are often prescribed, but surprisingly there was no high quality randomised trials supporting their roles. A study showed that early physical therapy appears to be effective only in the more severe Bell’s palsy, whereas for less severe cases, complete spontaneous recovery occurs regardless of physical therapy. http://journals.sagepub. com/doi/abs/10.1177/1545968313481280

Physiotherapy for facial palsy
http://www.physiotherapy-treatment.com/7th-cranialnerve.html

Each patient may present with different functional disability, so there are no general list of exercises. When each muscle group is being assessed, the patient can observe the action of these muscles in the mirror and instructed to perform small symmetrical specific movements on the sound side to identify the right response. As the patient identifies the specific area of dysfunction, patient can begin to perform exercise to improve facial movements' guided by the affected side so isolated muscle response is preserved and coordination improved. Repetitions and frequency of exercises can be modified according to status of recovery.

Some self help videos are available online on exercise which would help facial nerve recovery.

Management of Flaccid Paralysis and Management of Synkinesis
http://www.facialpalsy.org.uk/support/self-help-videos/

Videos with tips on how to manage facial palsy while face is floppy, or when unwanted facial movements occurs as in prolonged facial palsy.

Exercise videos for facial weakness, either as a result of Bell’s palsy or after a stroke
https://www.youtube.com/watch?v=og33hoO-8AQ&t=268s

Developed by the University Hospital Southampton, the videos on facial exercises are intended for people who have a facial weakness, either as a result of a condition such as Bell's palsy or after a stroke.

Exercises for Facial Muscles
https://www.youtube.com/watch?v=0fsGtVqXkUI

Video on facial exercises developed by the Rotherham Stroke Rehabilitation team.