What is the facial nerve?
The muscles that move the face are controlled by the right and left facial nerves. Each nerve supplies half of the face. The facial nerve travels from the brain, through a bony canal in the skull just behind the ear, to the the face. Facial nerve palsy occurs when one of these nerves is damaged and so the facial muscles on that side are partially or completely paralysed.
What are the causes of facial palsy?
- Bell’s palsy – see below
- Ramsay Hunt Syndrome due to shingles caused by the Herpes Zoster/Chickenpox virus. There may be blisters in the ear.
- Lyme Disease due to an infection, usually following a tick bite. There may have been a skin rash before the palsy.
- Tumour of the hearing nerve (acoustic neuroma) or surgery to remove it
- Tumour of the parotid gland or surgery to remove it
- Stroke
What is Bell’s palsy?
The exact cause is not known (‘idiopathic’). It is thought that inflammation develops around the facial nerve as it passes through the bony canal in the skull. This may be due to the Herpes Simplex virus, which also causes cold sores. Since the canal is narrow the inflammation may squash the nerve.
Bell’s palsy usually starts quickly over a day or two. Sometimes there is a little earache or a viral infection a week or so before it starts. The facial weakness may get worse for up to a week. Four out of five sufferers start to recover within 3 weeks and will recover fully and the rest usually make at least partial recovery within six months. Occasionally, if a person does not make a full recovery, we will carry out further investigations to exclude other causes.
What are the symptoms of facial palsy?
- a weakness or total paralysis on one side of your face (may look expressionless and droopy)
- difficulty smiling, talking and eating
- a drooping eyebrow (brow ptosis) which may reduce your side vision
- a weak upper eyelid that may not close fully and therefore not protect the eye
- a drooping lower eyelid (ectropion)
- eye exposure from a poor blink, causing dry, red and sore eyes (this is the most serious problem in facial palsy, as it can lead to a loss of vision if not treated)
How is facial palsy managed?
Mr Lin may arrange blood tests or scans.
Bell’s palsy is treated with steroid tablets for 10 days. Ramsay Hunt Syndrome is treated with antiviral (Aciclovir) tablets for ten days. Lyme disease is treated with antibiotics.
The most important treatment is to protect your eye.
- Lubricating eye drops and ointment will keep the eye moist and comfortable. You should use drops regularly during the day – do not wait until the eye is uncomfortable. Ointment should be used at night to protect the eye. It may make the vision blurred in the morning. If the blink is very poor bad you may be asked to use ointment during the day as well, even though this may blur the vision. The thicker the drop/ointment the longer it will last in the eye and the better it will protect the eye, however the more blurred your vision will be.
- Sticky tape can be used horizontally across the eyelids to keep the eye closed at night or to pull up a droopy lower eyelid. Tape must be applied carefully so that it does not scratch the eye. It helps to dry the skin so the tape can stick properly. Commercial ‘moisture chambers’ are also available.
- Wrap-around sunglasses will help to protect the eye from wind, sunlight and dust when you are outdoors or your optician can fix a side-shield to your regular glasses.
- Physiotherapy exercises and massage can also help.
- Punctal plugs can be inserted into the tear ducts to stop tears draining away and keep the eye lubricated. The eyes may water as a result, but you should not be able to feel the plugs and they can easily be removed at a later date.
- Botox injections can be made into the upper eyelid, which weakens the muscle that opens the eye. It does not work immediately, but after about 2 days the upper lid will start to droop and this will protect the eye. It will still be possible to open the eye with your finger in order to put drops in. The injection wears off after several months by which time the palsy may also have recovered. A possible side effect is double vision, but it should wear off.
- Crocodile tears are a rare result of facial palsy, when the facial nerve tries to grow back but loses its way and grows along the wrong channels. In so doing the nerve fibres that are destined for the salivary glands grow into the tear gland instead. As a result patients may have watering of the eye when they eat or even think of food. The treatment is Botox injections into the tear gland.
- In a similar fashion, regeneration of the nerve along the wrong pathways can also cause involuntary closure of the eyelids with movement of the lower and mid face e.g. when chewing. These patients may also require Botox injections to weaken the eyelid closing muscles.
When is surgery required?
Surgery may be required for facial palsy if it is difficult to protect the eye from drying because the eyelids do not close fully. Surgery can also reduce watering of the eye or improve the symmetry and function of the eyelids and face.
- Some of the upper and lower eyelids can be stitched together to protect the eye. This can be done on a temporary or permanent basis and is quick to perform however the cosmetic outcome is often not as good as the other options.
- A small weight (gold or platinum) can be stitched deep into the upper eyelid to help it close. The size of the weight is measured at a clinic visit using stick-on test weights. Sometimes stick-on weights can be used for a few months to help lid closure.
- The lower lid can be tightened and lifted to help cover the bottom of the eye (ectropion repair)
- A drooping eyebrow can be lifted. The most effective method involves an incision just over the brow hairs.
- A drooping cheek can be lifted to help support the lower eyelid.
- More extensive face surgery may be done by general plastic surgeons to improve the symmetry between the two sides of the face.