Bell’s Palsy as it is commonly known, is a facial nerve disorder or facial paralysis that is fairly prevalent and occurs in1 of 5000 people. It involves a loss of voluntary muscle movement within the face.
FACIAL NERVE & FACIAL NERVE DISORDER
The facial nerve is the nerve fibre that manages muscles on both sides of the face. It is the seventh of the twelve cranial nerves which originate in the brain. Every person has two facial nerves, one on either side of the face. Each nerve fibre transmits electric impulses to a specific facial muscle. These fibres enable us to laugh, cry, wink, blush, and smile. Each of the two facial nerves also controls the muscles of ear, eyes, neck, tongue, and forehead. It carries electric impulses and stimulates secretions of tear glands, salivary glands, and the lower jaw.
Facial nerve disorder will lead to twitching or weakness on one or both sides of the face or complete facial muscle paralysis. This can result in frequent tearing or salivation, dryness in mouth or eye, difficulty in eating, drinking and speaking. Some people with facial nerve disorder find it difficult to even blink or close eye which can result in drying and damage to the cornea.
Causes of facial nerve disorder can vary from person to person. In some people, it could be because of virus or bacteria. In others, it could be because of a life-threatening accident or trauma. Few of the causes are listed below:
Bell’s Palsy, also called as Idiopathic Unilateral Facial Paralysis happens to be the primary cause of facial nerve disorder in 80 percent of the cases. Though the actual mechanism of Bell’s Palsy is not clear, it is speculated that it could be the result of a virus that inflames the nerve, usually the herpes virus which causes cold sores and genital herpes.
Lyme is a bacterial infection acquired when bitten by an infected tick. The infected area will have a target-shaped skin rash, following a headache, fever and weakness. The infected person can also develop neurological symptoms like facial paralysis.
A life-threatening or a severe injury with an impact on the head or face is the predominant cause for permanent facial paralysis. Especially, fractures through the temporal bone in the skull can mostly result in injury to the facial nerve. Further, it can also affect the hearing capacity of the patient.
Skull Base Tumour:
Benign tumours, tumours close to the facial nerve or compressing the facial nerve, or malignant tumours targeting the facial nerve may lead to the weakening of facial nerve. Acoustic Neuroma, Facial Neuroma, and tumours in the region of the Parotid gland are the common tumours associated with the facial paralysis. Further, these tumours can be accompanied by symptoms like hearing loss or mass in the neck.