Facial Paralysis (Facial Palsy)

Facial paralysis is weakness on one side of the face, caused by damage to the nerve that controls the muscles of expression there. The nerve swells and becomes inflamed. The weakness usually comes on suddenly, and sometimes over a few days.

In most cases the weakness is temporary and improves greatly within weeks.

The weakness makes the affected half of the face droop. When the patient smiles, the mouth pulls towards the healthy side, and the eye on the affected side is hard to close.

What it feels like

• Loss of power in the muscles of expression on one side: the patient cannot close the eye, raise or frown the eyebrow, wrinkle the nose, and the mouth pulls to one side. This brings difficulty eating and drinking, dribbling that cannot be controlled, and difficulty speaking.
• Twitching of the facial muscles on the affected side
• Less tears and less saliva, so the eye and the mouth become dry
• A change in the sense of taste
• Pain inside or behind the ear
• Pain around the jaw joint
• Being over-sensitive to sound in the ear on the affected side
• Headache

What causes it

The exact cause is not clear. A viral infection is generally thought to be involved. The viruses linked to facial paralysis are herpes simplex, herpes zoster, Epstein-Barr virus, cytomegalovirus, adenovirus, measles, mumps, influenza B and coxsackievirus.

In Bell’s palsy the nerve that drives the muscles of expression is compressed in the bony canal it passes through near the ear, before it reaches those muscles.

Treatment

Most people recover completely, with or without treatment. The medicines used are

1. Corticosteroids, such as methylprednisolone. These are powerful anti-inflammatory agents. They reduce the swelling in the bony canal where the facial nerve is compressed, and so relieve it. Corticosteroids work best when they are started within a few days of the symptoms beginning.
2. Antiviral medicines. Their role is not proven. Antiviral agents alone are no better than placebo. Added to corticosteroids they are probably useful, though that is still not proven. Even so, patients with severe facial paralysis are sometimes given valaciclovir or aciclovir together with prednisolone.
3. Physiotherapy. Paralysed muscles can shorten and cause permanent contractures, in which the muscle shortens so much that the joint takes an abnormal shape. Physiotherapy helps the nerve recover in these cases.
4. Surgery. Rarely needed, to repair permanent nerve damage.
5. Alternative methods such as acupuncture and biofeedback are also used.
6. Facial paralysis from other causes is treated by treating the cause. Blood thinners for a blocked vessel, surgery for injury to the nerve, and an operation to remove a brain tumour if one is present.

Diagnosis

The examination by the doctor is the most important part of making the diagnosis. Imaging such as MRI and CT helps, and so does an EMG test, which assesses the extent of the nerve damage in a patient whose recovery is taking a long time.

Exercises

The first physiotherapy method, which can start early, is massage. With your fingers, stretch the skin in circles from the corner of the mouth upwards towards the ear, and then downwards along the jawbone. Do the same circular stretch for the chin and the forehead. A soft toothbrush can be used for the massage.

Exercises for the muscles of expression can start in the second week of the paralysis. In front of a mirror, up to 10 times a day and for a short time, raise the eyebrow, frown, wrinkle the nose, widen the nostrils, purse the lips and pull one corner of the mouth up.

If the nerve is slow to recover, physiotherapy can be given on the advice of a physical medicine doctor.

The outlook

For most people facial paralysis is temporary. The symptoms usually start to improve within a few weeks and recovery is complete in about 6 months. In a small number of people it stays for life, and it rarely comes back.

Facial paralysis happens at any age. It is commoner in pregnant women, especially in the last three months of pregnancy and just after birth, in people with an upper airway infection such as flu or a cold, and in people with diabetes.