Bell's Palsy (BP) is the most common cause of facial paralysis worldwide. Its incidence is about 20 cases per 100,000 persons. Although not age-specific, it affects young and middle-aged adults most often. There is no bias towards either sex.
Right- and left-side facial palsy occurs equally.
Climate is not a contributing factor. BP does, however, have a higher prevalence among lower socioeconomic groups. 70% of patients with BP relate a previous upper respiratory infection, and 10% have a family incidence of the disorder. During pregnancy or pregnancy-induced hypertension, the significant increase in vascular volume, particularly in the last trimester, triples the risk of facial neuropathy due to edema of the facial nerve and the resulting compression.
Its cause remains unknown but reactivated herpes simplex virus (HSV) heads the list as the most probable cause. An acute inflammatory response results in swelling of the facial nerve within the myelin sheath, causes reduced circulation in the nerve.
The disorder usually progresses for 7 to 10 days, with sudden onset of facial weakness. Symptoms of Bell's palsy include:
BP is a diagnosis of exclusion. Nerve conduction does not become altered until about 3 days after degeneration has occurred. These changes are then detected by observing a widened palpebral fissure (the space between the margins of the eyelids), reduced nasolabial fold (smile line), and drooping corner of the mouth. A dry eye may result from reduced blinking. Pain behind the ear is a common symptom, along with fever, tinnitus, and a mild hearing deficit. A tumor should be suspected when there is (1) associated tics or spasms, (2) slow onset of paralysis, and (3) paralysis of isolated branches of the facial nerve.
The first priority in treating Bell's palsy or any type of facial paralysis is to eliminate the source of damage to the nerve as quickly as possible. Minor compression for a short time period can result in mild and temporary damage. As time goes on with constant or increasing compression, damage to the nerve can also increase.
Recovery from BP begins at 3 weeks for most (85%) patients, with a full recovery by 6 months. Between 4 and 6% experience severe deformity with very little return to normal facial movement, and 10 to 15% will be bothered by asymmetrical movement of the facial muscles. Recurrence may be on the same or opposite side.
The facial nerve also innervates some of the taste buds of the tongue, sometimes causing a reduction in the sense of taste.
If you do decide to use conventional medications that may help relieve the compression, such as prednisone and antivirals, they should be started as quickly as possible. The "window of opportunity" for starting these medications is thought to be 7 days from the onset of Bell's palsy.
MSM, an organic form of sulfur, is reported to be of benefit in reducing pain associated with Bell's Palsy.
The use of eye drops can be important in treating BP. The 'dry eye' and associated problems are caused by a combination of things. For some people the tear gland may not be producing moisture. Blinking is the mechanism that protects the eye from external debris and spreads tears over the cornea. Under normal circumstances we blink every 5-7 seconds and with every blink the eyelid spreads moisture over the cornea. With facial paralysis the ability to blink may be disrupted; eyelid closure can be weak or the eye can be stuck wide open. Take action if the eye feels uncomfortable. Manually blink your eye using the back of your finger at regular intervals, especially when it feels dry. A stinging or burning sensation can mean the eye is too dry, even if tears are apparent. The 7th nerve does not control focus, so if you are experiencing blurred vision, don't ignore it. It may be a warning of a dry cornea that needs to be protected.
Methylcobalamin, a form of vitamin B12, was compared with steroids in a trial involving 60 patients with Bell's palsy. The shortest time required for complete recovery of facial nerve function occurred in the group receiving Methylcobalamin alone. A therapeutic dose would be a minimum of 1500mcg and a maximum of 6000mcg per day, by injection. It was administered by intramuscular injection 3 times weekly for 8 weeks (or until recovery). The results of this study have not been validated, and administration of methylcobalamin has not become a common treatment.
Cyanocobalamin is reported to have worked in a couple chronic cases at high doses also. [J Indian Med Assoc 33: pp.129- 31, 1959]
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