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Facial paralysis

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Facial paralysis



Introduction 

Bell's palsy is a condition that causes temporary weakness or paralysis of the muscles in one side of the face. It is the most common cause of facial paralysis.

Other causes of facial paralysis include:



congenital facial palsy – children born with facial weakness



injury to the facial nerve in an accident – such as a cut to the cheek or skull base fracture



injury from surgery – which is most common during surgery of the parotid gland and neck



What are the symptoms?

The symptoms of Bell’s palsy vary from person to person. The weakness on one side of the face can be described as either:



partial palsy, which is mild muscle weakness



complete palsy, which is no movement at all (paralysis) – although this is very rare



Bell's palsy can also affect the eyelid and mouth, making it difficult to close and open them. In rare cases, it can affect both sides of a person’s face.

 

When to seek medical advice

As well as being a symptom of Bell's palsy, facial weakness or paralysis can also be a sign of a more serious condition – such as astroke.

Visit your nearest A&E department immediately or call 999 for an ambulance if you or someone you are with develops sudden facial paralysis, so a doctor can determine the cause.

Bell's palsy is only diagnosed if other possible causes of your symptoms are ruled out.

 

Why does it happen?

Bell's palsy is believed to occur when the nerve that controls the muscles in your face becomes compressed.

The exact cause is unknown, although it's thought to be because the facial nerve becomes inflamed, possibly due to a viral infection. 

The herpes virus is thought to be the most common cause but other viruses may also be responsible.

 

Who is affected?

Bell's palsy is a rare condition that affects about one in 5,000 people a year. It's most common in people aged 15-60, but people outside this age group can also suffer from the condition. Both men and women are affected equally.

Bell's palsy is more common in pregnant women and those withdiabetes and HIV, for reasons that are not yet fully understood.

Treating Bell's palsy

Around seven out of 10 people with Bell's palsy make a complete recovery, with or without treatment.

Most people notice an improvement in their symptoms after about two to three weeks but a complete recovery can take up to nine months. The recovery time varies from person to person and will depend on the amount of nerve damage.

Prednisolone, a type of corticosteroid, is used to reduce the swelling of the facial nerve.

Eye drops may be required to prevent problems if you are unable to close your eye. Tape may also be used to close the eye while sleeping.

 

Symptoms of Bell's palsy 

The symptoms of Bell's palsy can vary – from a mild numbness of the face to total paralysis.

The symptoms develop quickly and reach their peak within 48 hours. They include:



weakness or paralysis in one side of the face, which may make it difficult to close the eyelid and cause the side of the mouth to droop



irritation of the affected eye, such as dryness or increased tear production



earache or pain underneath the ear on the affected side of the face



an altered or reduced sense of taste



increased sensitivity to sound in the affected ear



drooling from the mouth on the affected side of the face



dryness of the mouth



pain around the jaw



headache



ringing in one or both ears (tinnitus)



dizziness



difficulty eating or drinking



impaired speech



In most cases of Bell's palsy, the symptoms will begin to improve within two to three weeks. Most people make a full recovery within nine months.

When to seek medical advice

As well as being a symptom of Bell's palsy, facial weakness or paralysis can also be a sign of a more serious condition – such as astroke.

Therefore, you should visit your nearest A&E department immediately or call 999 for an ambulance if you or someone you are with develops sudden facial paralysis so a doctor can determine the cause.

 

Complications

Around three in 10 people with Bell’s palsy will continue to experience weakness in their facial muscles, and two in 10 will be left with a more serious long-term problem.

Complications include:



persistent facial weakness



eye problems



difficulty with speech, eating and drinking



reduced sense of taste



facial muscle twitching



Causes of Bell's palsy 

Bell’s palsy occurs when the nerve that controls the facial muscles (facial nerve) becomes inflamed or compressed.

It's not known what causes the facial nerve to become inflamed, although it's thought that a virus, possibly a herpes virus, may be responsible.

The facial nerve

The facial nerve passes through a narrow gap of bone near the upper jaw on its way from the brain to the face. If the facial nerve is compressed or swollen it can interfere with the signals that your brain sends to the muscles in your face.

This interference can restrict the blood and oxygen supply to your nerve cells and cause the facial weakness or paralysis that is characteristic of Bell's palsy.

Herpes virus

The types of herpes virus thought to cause inflammation of the facial nerve are:



the herpes simplex virus (HSV), including either herpes type 1 (HSV-1), which causes cold sores, or herpes type 2 (HSV-2), which causes genital herpes



the varicella-zoster virus, which causes chickenpox and shingles



The varicella-zoster virus is a less common cause of Bell’s palsy than the herpes simplex virus, but can lead to the more serious condition called Ramsay Hunt Syndrome.

Other viruses

In addition to herpes, Bell's palsy has been linked with many other viral infections, such as:



Lyme disease



syphilis



the Epstein-Barr virus – which causes glandular fever



cytomegalovirus



Other risk factors

People with diabetes and HIV are thought to be at a higher risk of developing Bell's palsy, although the reason for this is not fully understood.

Diagnosing Bell's palsy 

There is no specific test to diagnose Bell’s palsy. But tests can be used to rule out other conditions that cause facial paralysis.

If someone experiences sudden facial paralysis, visit your nearest A&E department immediately or call 999 for an ambulance. It's important to see a doctor to determine the cause.

Studies have also shown that treatment for Bell's palsy is most effective if it's started quickly, within 72 hours of symptoms developing.

Ruling out other conditions

Bell's palsy is diagnosed using a process known as diagnosis by exclusion. Your doctor will look for any evidence that might suggest your symptoms are caused by a different health condition, such as:



stroke



Lyme disease – a bacterial infection caused by ticks



a tumour – an abnormal tissue growth



Moebius syndrome – a rare condition that is present from birth (congenital)



middle ear infection



cholesteatoma (an abnormal collection of skin cells in the middle ear)



head injury



Your doctor will examine your head, ears and neck. They will also check the muscles in your face to determine whether it's only the facial nerve that has been affected.

If your doctor is unable to find evidence of symptoms associated with other conditions, Bell's palsy may be diagnosed.

Further testing

If your doctor is still uncertain, or there are no signs of symptoms improving after a month, you may be referred to an ear, nose and throat (ENT) specialist for further testing. You may have electromyography or an imaging scan. These are explained below.

Electromyography

During electromyography (EMG), a thin needle electrode is inserted through the skin and into your muscle. A machine called an oscilloscope is then used to measure the electrical activity in your muscles and nerves. The information provided by an EMG can be used to assess the extent of any nerve damage.

Imaging scans

Imaging scans such as magnetic resonance imaging (MRI) may be used to determine the cause of the pressure on your facial nerve. MRI scans use radio waves and a strong magnetic field to produce a detailed image of the inside of your body.

A computerised tomography (CT) scan may also be used to detect other causes of your symptoms, such as an infection or tumour. A facial CT scan may also be carried out to rule out facial fractures.

Treating Bell's palsy 

Prednisolone is recommended as the most effective treatment for Bell’s palsy, and it should be started within 72 hours of the symptoms appearing.

Most people recover fully from Bell's palsy within nine months, but it's important to maintain good eye care during this time.

Antiviral medications are not recommended as a treatment for Bell's palsy.

Prednisolone

Prednisolone is a corticosteroid which works by helping to reduce inflammation (swelling), helping to speed up your recovery.

People with Bell's palsy are usually advised to take prednisolone tablets twice a day for 10 days.

Possible side effects of prednisolone include:



nausea (feeling sick)



headache



increased sweating



indigestion



increased appetite



difficulty sleeping



oral thrush



dizziness



These side effects should improve within a few days as your body begins to get used to the medication.

Some people also experience mood changes, such as anxiety or depression, after taking steroids for a short period of time. You should visit your GP immediately if you experience mood changes, or if you have other side effects that are particularly troublesome.

 

Speak to your GP before taking prednisolone if you are pregnant or breastfeeding.

Eye care

Tears play an important role in protecting your eyes and keeping them free of the dirt and bacteria that can cause eye infections.

If you have Bell’s palsy, you might find it difficult to close your eye, which can cause your tears to evaporate and leave your eye vulnerable to infection. So it's very important to keep your eye lubricated.

Your GP may prescribe eye drops that contain 'artificial tears' for daytime use, plus an ointment that you should use at night. If you're unable to shut your eye at night time, your GP will give you some surgical tape to close your eye.

If your eye symptoms get worse, you should ask your GP to refer you to the facial palsy clinic or ophthalmology department of your local hospital for assessment. If ointments and taping are not effective you may benefit from surgery to help protect your eye.

Further treatment

Most people with Bell's palsy will make a full recovery within nine months. However, if you have not recovered by this time, there is a risk of more extensive nerve damage and further treatment may be needed.

Physiotherapy

Physiotherapy may be recommended. Your physiotherapist will teach you a series of facial exercises that will strengthen the muscles in your face to improve their co-ordination and range of movement.

Physiotherapy has been successful in a number of Bell's palsy cases, although it may not be suitable or effective for everyone.

Plastic surgery

Plastic surgery is another possible option. Plastic surgeons work as part of a team of facial palsy specialists to help manage your facial weakness. Surgery may not be able to restore nerve function, but may be able to protect your eye, improve your function and improve the appearance of your face.

Eye procedures include surgery to help you close your upper eyelid or improve the position of your lower eyelid. A brow lift can improve your vision and facial appearance.

A number of procedures can improve the position of your mouth and help with speech, eating and drinking and facial symmetry. Some can restore a smile, including cross-facial nerve grafts, nerve transfers and muscle and tendon transfers.

Botulinum toxin injections

Botulinum toxin (Botox) injections can be used to treat either the affected or the unaffected side of the face in some people with long-term Bell's palsy.

Botox may be injected into the affected side of the face to relax any facial muscles that have become tight, or to reduce any unwanted muscle movements.

If the muscles in the unaffected side have become overactive or dominant, Botox may be injected into this side of the face to reduce muscle activity and balance the movement of the face.

Some of the long-term complications of Bell’s palsy can also be treated using Botox injections. These include:



tears when eating



eye-mouth synkinesias – where the facial nerve grows back in a different way, which can lead to a winking eye when eating, smiling or laughing



 

The Botox injections can help ease any discomfort experienced while eating and can also help to improve the overall appearance of the face. The injections need to be repeated every four months.

Other treatments

Research has suggested that facial exercises, relaxation techniques and acupuncture may help speed up the recovery of Bell’s palsy and restore facial nerve function.

Complications of Bell's palsy  

A number of complications can occur as a result of Bell's palsy, depending on the extent of nerve damage.

Most people fully recover from Bell's palsy within nine months. However, long-term complications of Bell’s palsy are more likely to occur if:



you have been affected by a complete palsy, resulting in no movement at all (paralysis) on one side of your face



you are over 60 years of age



you had severe pain when you first experienced symptoms



you have high blood pressure



you have diabetes



you are pregnant



your facial nerve is badly damaged



recovery doesn't begin until two months have passed



there are no signs of recovery after four months



Up to 14% of people may find that Bell's palsy returns at a later date, on either side of the face. This is thought to be more likely if you have a family history of Bell's palsy.

Long-term complications

About two in 10 people experience long-term problems resulting from Bell’s palsy, which may include any of the following:



Eye drying and corneal ulceration – Corneal ulceration can occur when the eyelid is too weak to close completely and the protective tear film becomes less effective. This can lead to infection and cause blindness.



Facial weakness – permanent facial weakness is seen in 20-30% of people after Bell's palsy. Some children are born with facial palsy and others develop weakness after operations or injury to the facial nerve. Specialists in a facial palsy clinic can help treat facial weakness.



Speech problems – This can occur as a result of damage to the facial muscles.



Eye-mouth synkinesias – This happens as a result of the nerve in your face growing back in a different way. It can cause your eye to wink when eating, laughing or smiling. Sometimes it can become so severe that the eye can close completely during meals.



Facial tightness (contracture) – This is where your facial muscles are permanently tense. It can lead to facial disfigurement such as the eye becoming smaller, the cheek becoming more bulky, or the line between the nose and the mouth becoming deeper.



Loss or reduced sense of taste – This can happen if any damaged nerves do not repair properly.



Tears when eating, known as 'crocodile tears'.



Ramsay Hunt syndrome

If you have Bell’s palsy caused by the varicella-zoster virus, there is a possibility you could develop a rare, but serious, condition called Ramsay Hunt syndrome.

Ramsay Hunt syndrome can cause blisters to appear on your tongue and the inside of your ears. It can usually be treated with steroids and antiviral medication.


Facial paralysis