What is Bell’s palsy?
Paralysis of one side of the facial muscles caused by trauma to the facial nerve is known as Bell’s palsy. The condition is characterized by its sudden onset and loss of control over activity of facial muscles on the affected side. The condition often leads to weakness or complete paralysis of the facial muscles, which causes difficulty in activities such as blinking and lip movements. It is also known as unilateral lower motor neuron paralysis.
What are the symptoms of Bell’s palsy?
Bell’s palsy is often noted for the first time after waking up in the morning. The patient experiences a sudden loss of control over the entire side of the face. The patient experiences on one side difficulty with or the inability to :
- close the eye
- wrinkle the forehead
In an attempt to close the eyelid, the eyeball rolls upwards so that the pupil is covered and only the sclera is visible. The inability to close the eye causes excessive tears or dry eye, making the eye susceptible to infections. The corner of the mouth droops due to loss control over lip muscles, this leads to drooling of saliva. The patient cannot whistle or raise the affected side eyebrow.
Bell’s palsy also affects the tongue and the speech. The speech becomes slurred and there is loss of taste sensation. As the facial nerve has branches supplying the muscles inside the ear, ear pain or increased sensitivity to sounds may be experienced in Bell’s palsy. The other symptoms may include numbness or tingling sensations over the affected side of the face.
What causes Bell’s palsy?
Bell’s palsy is the type of facial nerve paralysis caused by or associated with several conditions. Reactivation of herpes simplex virus infection is believed to be one of the causes. Certain viruses such as varicella zoster (chickenpox), influenza and Epstein-Barr viruses are also linked with development of the condition.
Bell’s palsy is often caused by an abnormal immune response to these viruses thereby leading to inflammation the facial nerve and facial paralysis. Exposure to extreme environment, trauma and psychological stress are often involved in reactivation of the disease. Excess carbon dioxide, vasospasm and ischemia due to extreme cold is also associated with the development of Bell’s palsy.
How is Bell’s palsy treated?
The treatment of Bell’s palsy is aimed at achieving functional stability, restoring facial symmetry and aesthetics. Audiogram, CT and MRI are the diagnostic tests to be performed.
The early phase of treatment includes physical therapy to maintain the muscle tone. Physical therapy consists of electrical stimuli by galvanism, gentle massage and facial exercises. Early medication (within first 2 weeks of treatment) includes steroids such as prednisolone. Anti-viral medication such as acyclovir is prescribed in cases associated with viral infections.
As Bell’s palsy can cause significant damage to the eye on affected side, artificial lubrication, tear replacement or tarsorrhaphy are considered as treatment options. Botox can be used to improve facial muscle tone. Surgical options such as nerve decompression and nerve grafting surgeries are considered in severe and long standing cases.