Let us talk a little about Bells palsy a relatively common neurological condition affecting the function of the seventh cranial nerve (that is the facial nerve). The muscles of the face are suplied by the facial nerve. It is this nerve which helps you to smile, frown, wrinkle up your forehead, purse your lips and all other facial expressions. The facial nerve is also the nerve which supplies taste sensation to the anterior part of the tongue. It suppiles a muscle called stapedius in the middle ear which helps in damping loud sounds and also supplies the lacrimal gland (helps in tear function).
In Bells palsy patients develop weakness of all the muscles of one half of the face (they cannot close their eye on that side, have a crooked smile as the face gets pulled to the normal healthy side when they attempt to smile, cannot puff their cheeks or purse their lips to whistle). Depending upon the site of involvement of facial nerve, they may also be unable to tear (complaint of dry eye), unable to taste food or complain of excessive loud sounds in the ear on the side of the facial nerve palsy.
In Bells palsy there is inflammation of the facial nerve somewhere along its course from the brainstem to the muscles of the face. In Bells palsy, this inflammation is idiopathic (no definite cause for inflammation is found) though inflammation by the herpes group of viruses has been implicated in its etiology. Some patients have developed Bells palsy after been exposed to cold air (this has never been proved though). Bells palsy is not life threatening but can be quite socially disabling especially if severe (you can imagine how socially disruptive it might be to have one half of your face paralysed and be unable to smile or emote with your face).
Diagnosis and management of Bells palsy: the diagnosis of Bells palsy is clinical (can be made by a clinical examination by a neurologist). In the typical case no further investigations are warranted, though in some cases if the history is atypical (slow onset with addition neurological findings) your doctor may order an MRI study of the brain.
Most of the patients recover spontaneously from Bells palsy. All that we advise them is to cover the eye at night with an eye patch and wear sunglasses when they go out during the day (this is to protect the eye from keratitis as the eye does not shut). If you present acutely to your doctor with Bells palsy, he may recommend a course of steroids and acyclovir (antiviral drug with efficacy against herpes virus). It is thought that this hastens recovery though some studies have shown that the recovery is the same whether or not acyclovir is used or not).
Your doctor shall also recommend facial exercises (just as you undergo physical therapy if you have a stroke, in the same way we want to encourage facial exercises to hasten recovery). Facial exercises are easy to do and I usually recommend my patients to stand in front of the mirror and attempt to smile, frown, pout and whistle. I ask them to do this for at least 10 mins two times a day. Massaging the face has not been shown to be beneficial. In case the recovery is slow or incomplete your doctor might order a nerve conduction study of the facial nerve to assess the degree of damage to the nerve.
As I stated earlier most patients have a good recovery. At times when the facial nerve regenerates, it regenerates in an arbitary fashion. Patients develop crocodile tears (they start tearing when attempting to eat) or have synkinesis (all the muscles of the face contract at once when attempting to smile that is the fine control of individual facial muscles is lost). If you have these problems you should contact your doctor and ask for advise.
I hope this short post on Bells palsy shall be helpful to some of you.
Nitin Sethi, MD