Bell’s palsy is an acute paralysis or weakness of the muscles of one side of the face. It is a relatively common peripheral nerve disorder and can affect people of all ages, but is most common between 15-45 years.
Many celebrities like Angelina Jolie, Anupam Kher, George Clooney, Pierce Brosnan suffered from Bell’s Palsy.
Under the right treatment most patients have good recovery, although some are left with residual weakness
Bell’s Palsy causes an acute paralysis of all facial muscles supplied by the seventh cranial nerve (facial nerve). It is always unilateral (one side) and involves upper and lower muscles of the face. At onset people may experiencing mild facial numbness as well. Other symptoms may include:
1) Keratitis (infection of the eye) caused by the failure to close the eye
2) Loss of taste: The tip of the tongue is also innervated by the facial nerve.
3) Sensitivity to loud noises (hyperacusis): The facial nerve innervates the stapedius muscle as well.
Bell’s palsy is, by definition, idiopathic, meaning without a specific cause. However, it seems to be associated with certain viral infections. Herpes virus (HSV-1) could be found in 80% of patients. Other viral infections include herpes zoster virus, mumps virus, rubella virus and HIV. Lyme disease has to be taken in consideration as well.
1) Family history (10%)
2) Previous episode (8%)
3) Pregnancy (three-fold risk increase)
4) Diabetes (four-fold risk increase)
For an experienced neurologist, Bell’s Palsy is mainly a clinical diagnosis. If a virus infection is suspected, blood tests may be considered. If a central paralysis cannot be excluded, a MRI might be considered. To verify the diagnosis and to predict the outcome usually a NCV (nerve conducting velocity) is performed.
Important part of the diagnostic process is to exclude other serious underlying conditions leading to similar symptoms. Differentiating between central and peripheral paralysis is the first step. Stroke and multiple sclerosis as causes for central paralysis have to be exclude.
1) Injections or oral medications are improving the outcome and prognosis
2) Eye protection (a patch and eye drops preventing the eye from getting dry and developing keratitis)
3) Exercises of the affected muscles may improve the progress
4) Surgical decompression is generally not recommended
Usually the outcome of Bell’s Palsy is good and most people recover within a few weeks. However, in 8% of the cases the paralysis is recurring.
• Good prognosis: partial paralysis
• Poor prognosis: Complete paralysis, loss of sense of taste after, pathology in the NCV test (nerve conducting velocity)
Most common complication of Bells Palsy are reinnervation problems. If the nerve is recovering and growing, it may by accident connect to other nerves resulting in malfunctions. This may include:
• Crocodile tears (crying while eating)
• Gustatory sweating (sweating while eating)
• Connection to chewing muscles (face twitching while eating)