Bell's palsy

 

What is Bell's palsy?

Bell's Palsy is the partial or complete paralysis of (usually) one side of the face due to the loss of function of a nerve called the facial nerve. This nerve travels from the brain through a bony canal in the skull just behind the ear, to the muscles of the face. It carries electrical instructions which result in movements of the face such as smiling and raising the eyebrows. It also carries back some signals from the front of the tongue relating to taste. There are two facial nerves, one to each side of the face. Bell's Palsy usually only affects one side of the face but in rare cases it can occur on both sides simultaneously. It may develop at any age but most commonly affects people between the ages of 20-50 and it affects both sexes equally.

Why does it occur?

The cause of Bell's Palsy is unknown but it is thought to be due to infection of the nerve by a virus, possibly the same virus which causes cold sores, resulting in the nerve swelling. Because the nerve travels through a narrow tunnel through the skull just behind the ear it does not have room to swell up. Therefore the nerve fibres become "crushed" and stop working. Although a virus is thought to be the cause of Bell's Palsy, the condition is not contagious.

Bell's Palsy is more common in pregnant women for reasons which are not known. Because it may relate to a viral infection, people with low immunity such as those with HIV or AIDS are more susceptible to it.

 

What are the symptoms?

The effects of Bell's Palsy usually come on fairly rapidly over the course of two days or so and include:

  • Partial or complete paralysis of one side of the face. This is most noticeable when the individual tries to smile or blink, as they will not be able to do this on one side. The side of the face which is affected sags and sometimes the sufferer is not able to close their eye on that side, even when they are asleep.
  • If the paralysis is severe, it may result in difficulty with articulating some words and difficulty in eating because of food collecting between the gums and the cheek. The person may have problems holding water in their mouth without it dribbling out of the sides of the mouth because of the muscle weakness.
  • In the early days of the condition some people experience an aching pain behind the ear.
  • In severe cases there is loss of taste over the front region of the tongue on the affected side.
  • Because the facial nerve also goes to a tiny muscle in the ear which controls the "volume" of sounds heard by the ear, this muscle becomes paralysed too, and the sufferer experiences certain sounds louder than is normal.
 

How is it diagnosed?

Usually the diagnosis is made simply from the symptoms and examination of the patient because there are very few other conditions which give rise to the same group of symptoms and findings. However, in some cases the doctor may wish to confirm the diagnosis by referring the individual to a specialist. A special scan (such as a CT or MRI scan ) may be done to exclude other causes. Occasionally the diagnosis may be confirmed by performing a test called electroneurography on the facial nerve. This involves passing a small electrical current along the affected nerve. Information about the speed and pattern of transmission of the impulse along the nerve tells the specialist if it is Bell's Palsy or another type of nerve problem. 

 

What does treatment involve?

Bell's Palsy is usually temporary and 80-90% of sufferers make a full recovery without any treatment. Occasionally either steroids and/or anti viral treatment (such as Aciclovir or Valaciclovir) is prescribed. The reason for this is that it is thought by some doctors that steroids reduce the swelling of the nerve and anti viral treatment may help to treat the virus thought to cause Bell's Palsy. There is some evidence to show that giving the patient steroids and anti vral treatment within the first few days after the onset of the condition may make a full recovery more likely although this is not yet proven.

In those people who are unable to fully close their eye on the affected side it is important to protect the eye from becoming dry. The doctor may advise lubricating eye drops and taping the eyelid down at night until the condition gets better. Sometimes physiotherapy can aid recovery by exercising the muscles of the face.

In the 10% of cases in which full recovery does not occur, surgery is sometimes performed to help the person close their eye and to correct any resulting facial deformity. Occasionally special surgery can be done to use a different nerve to supply the muscles of the face. However, this is very sophisticated surgery and is not without its disadvantages. Surgery is not usually advised until a reasonable time has elapsed to allow any recovery to take place.

 

Where can I obtain further information?

Apart from contacting your GP, the following organisation may be of further help:

Let's Face It (Support Group For The facially Disfigured) (UK)
Christine Piff
Let''s Face It
72 Victoria Avenue
Westgate on Sea
Kent
CT8 8BH
Telephone: 01843 833724
Website: www.lets-face-it.org.uk

Bells' Palsy Association
Telephone: 0870 4445460
Website: www.bellspalsy.org.uk