Facial palsy, also called Bell’s palsy, is an acute disorder of the facial nerve; it is caused by brief paralysis of the muscles on one side of the face, thus, the grooves surrounding the lips, nose and forehead are flattened in the person, and when trying to smile, the mouth deviates to the opposite side of the affected area.
Bell’s palsy is the most common form of cranial nerve palsy; it represents an annual prevalence of 20 to 30 cases per 100,000 inhabitants; it affects men and women equally, being more frequent between 20 and 30 years of age and between 50 and 60 years of age. It is recurrent in 8 to 10% of patients.
Bell’s palsy means lesion of the VII cranial nerve (facial nerve). The cause is unknown, but it has been suggested that there is a compression and ischemia (stopping or slowing of blood circulation) of the nerve, inside the facial canal. Genetic factors, vascular disorders, immune disorders and some type of viral infection (herpes simplex virus type I) have been proposed.
Functions of the Facial Nerve
There are two facial nerves, one on the right side and one on the left side, each one performs its functions on one side of the face and these are: control the muscles (eyelids and facial expression), carry the nerve impulse to the lacrimal glands, salivary glands and specialized muscles of the stapes (middle ear bone), also transmits taste sensations, which come from the tongue.
When the paralysis occurs, which is usually of sudden onset (24-48 hours), the information that the brain sends through the facial nerve is interrupted, which triggers on the affected side:
1. Disappearance of forehead wrinkles.
2. Inability to raise the eyebrow.
3. Difficulty in closing the eye. When trying to close it, the eye remains open and the eyeball goes upwards, leaving in sight only the white part of the sclera (Bell’s sign).
4. The nasolabial fold disappears.
5. The mouth deviates towards the healthy side.
6. The patient has difficulty blowing, whistling, or inflating the cheek.
7. Tearing due to overflow.
8. Saliva may run out of the corner of the mouth and the cheek may swell.
9. Predisposition to infection or ulceration of the cornea, due to irritation, because of the difficulty to close the affected eye.
10. Partial loss of taste.
The diagnosis is made by clinical examination and questioning by the physician. There is no special test to confirm the presence of this disorder.
This disease must be differentiated from other disorders such as:
Facial paralysis of central origin (region where the facial nerve originates) usually caused by stroke, ischemic or hemorrhagic, or brain tumors. In paralysis of central origin there is usually hemiplegia (paralysis of the same side), alterations in the level of consciousness; in addition, the patient can raise his eyebrows and close his eyes, and there are no disorders of the sense of taste.
Some of the general measures that can be implemented include:
-Protection from the sun’s rays with glasses.
-Nocturnal occlusion of the affected eye by means of a patch, which allows keeping the upper eyelid lowered, to protect the cornea.
-Massage of the face three times a day for 10 minutes, to avoid the appearance of muscular atrophy.
Analgesics (paracetamol, ibuprofen) are used for pain and inflammation, artificial tears to maintain adequate lubrication of the affected eye. B complex vitamins to help regenerate the nerve. In some cases, the specialist doctor (neurologist) may use corticosteroids to reduce inflammation and relieve pain.
In general, the prognosis of this disease is good, since more than 75% of patients recover spontaneously, and without medical treatment, with no sequelae within 4-6 months, however, some patients may take more than six months to fully recover. In patients > 60 years of age with chronic diseases such as diabetes or hypertension, permanent sequelae may remain, such as difficulty in eating, drinking liquids, speaking or whistling.