What is Bell’s Palsy?
Bell’s palsy is a weakness or paralysis of the facial muscles which is innervated by the seventh cranial nerve. It is usually temporary and unilateral. Between 40 and fifty thousand people in America develop Bell’s palsy. It is much more common in diabetics. It was first described in 1829 by Sir Charles Bell (surgeon in Scotland). It is the most common type of acute facial paralysis.
What Causes Bell’s Palsy?
There are many different causes for Bell’s palsy though none definitive. Viruses are thought to be a major cause of Bell’s palsy. It is thought to be an inflammatory condition causing swelling of the facial or seventh cranial nerve as it exits from the skull. Lyme disease can cause facial paralysis. Tumors and strokes can also cause a facial paralysis. Patients with a known cause for the paralysis are not really considered to have Bell’s palsy.
Signs and Symptoms of Bell’s Palsy
Patients with Bell’s palsy present with facial weakness or drooping of the face. The facial nerve innervates the muscles of the face. It also controls or innervates taste buds anterior 2/3 of the tongue, lacrimation, salivation, and the stapes muscle of the middle ear. Patients will have problems with tasting, tear film production, smiling, blinking, mouth drooping with drooling, and unable to close their eyes.
Other symptoms include headache or pain, tingling, weakness, balance problems, and neck pain. The forehead is spared from the paralysis as there is innervation to the forehead from both sides of the brain.
Ectropion of lower lid (eyelid turns out away from the eye)
Exposure keratitis ( due to the eye not able to close or blink the eye gets very irritated from constant expose to the air or environment)
Tearing (secondary to exposure keratitis, poor or no blinking, and ectropion of lower eyelid)
Blurred vision (due to altered tear film)
Diagnosis of Bell’s Palsy
The diagnosis is made by excluding other possible causes.
Treatment of Bell’s Palsy
The treatment depends on the severity of the paralysis. Mild cases may need no treatment and severe or complete paralysis may need a variety of treatments.
Corticosteroids have been shown to improve the recovery of Bell’s palsy.
Smile or reconstruction surgery may help people who have permanent paralysis.
Patients need to use artificial tears as often as necessary to keep their eyes comfortable. If the ectropion and exposure keratitis is severe enough then a lateral tarsorraphy or ectropion repair may be indicated. The tarsorraphy can be released if the lid function returns.