Bell’s palsy is an acute affliction of the facial nerve, resulting in sudden weakness or paralysis of the muscles on one side of the face. First described by Sir Charles Bell, a Scottish surgeon and anatomist in the early 1800s, it is an acute finding that often brings affected individuals into the emergency room with a possible diagnosis of stroke. The condition can affect people of any age but is most common between the ages of 40 and 50. Partial paralysis almost always recovers, but in some cases a permanent affliction may occur.
The facial nerve (7th cranial nerve of 12) is in charge of passing electrical impulses through the facial muscles, which controls expression and movement on each side of the face (there are two facial nerves, one on each side). Inflammation of one of those nerves causes it to swell and be compressed in the channel that leads from the brain stem and makes it unable to conduct nerve impulses to the muscles on the affected side. The paralysis that results can be either partial or total. The severity ranges from either slight weakness on close inspection all the way to a complete nonfunctioning of the facial muscles on the affected side.
The paralysis comes on over a time frame of minutes to hours. The corner of the mouth begins to droop, the side of the face affected becomes flattened and unable to show expression, and the lower eyelid starts to fall. Often it is noticed by someone else rather than the individual, but soon there may be difficulty with drinking or eating, headache, or impaired taste, and sometimes hearing sensitivity is likewise affected. Diabetes has been shown to be involved more often in those with Bell’s palsy, and at times facial palsy is also associated with Lyme disease. Other viruses can cause Bell’s palsy, and doctors do careful examination to rule out stroke, with the finding that only the territory involving the facial nerve is affected.
Bell’s palsy generally has a predictable pattern—between 70 and 80 percent will completely recover within weeks or up to three months after the diagnosis. Those who have continued problems may undergo an MRI to see the pattern of swelling and whether surgical management to free the nerve is indicated. Corticosteroids orally are instituted early in the disease process. Antiviral medication has not been shown to be helpful, but is sometimes instituted at the same time when facial palsy is severe. Physical therapy, electro-stimulation, exercise and massage are often employed, but only of mild help until the disease has run its course.
Underwriting Bell’s palsy generally means ruling out more significant neurological disease and being sure the findings are contained to the facial nerve distribution. A definite diagnosis is required and any underlying cause (such as diabetes or Lyme disease) has to be evaluated independently. A waiting period of three to four months is generally observed, after which time best class may be allowed with complete recovery. Permanent paralysis is evaluated on a case-by-case basis.
