Bell’s palsy is a facial paralysis of acute onset presumed to be due to non-supppurative inflammation of unknown etiology of the facial nerve within its canal above the stylomastoid foramen.
CAUSES:-
- History of exposure of the ear to extreme cold
- Water retention in pregnancy
- Infection of the ear
- Herpes Zoster infection.
- Upper respiratory tract infection
- Diabetes
- Trauma
- Tumors
- Lyme disease
INCIDENCE:-
- It occurs any time from infancy to old age.
- More seen among younger population and males are more are affected than females.
SIGNS AND SYMPTOMS:-
SENSORY:-
- No sensory loss
(sensory branches arise from proximal part of the fascial nerve, wheras bell’s palsy involves the distal area of the nerves)
MOTORS:-
1)The muscles that are paralyses are
- Frontails (wrinkling)
- Corrugator supercili (frowning,vertical wrinkles of forehead)
- Orbicularis oculi (closure of eyes)
- Nasalis
- Levator labi superioris and inferioris
- Risorius
- Buccinators (puffing the mouth)
- Depressor labi orbicularis oris ( whistling) and mentalis
2) Lesion is usually unilateral and rarely bilateral.
3) Frequently pain is at onset in the
- Ear
- Mastoid region
- Angle of the jaw
4) Patient may have temporal headache which can be considered as a warning signal.
5) The following features may be seen in bell’s palsy-
- Drooping of the corner of the mouth
- Creases and skin fold of the face becomes smoothened.
- There will be drooping of the eyebrows and wrinkles of the brow are smoothened out.
- Forehead is without furrowing
- Owing of the paralysis of the orbicularis oculi, the palpebral fissures is wider in the affected side and closure of the eye is impossible.
6) When the patient attempts to close his eyes his eye ball will move upword and slightly inward this called as “bell’s phenomenon”.
7) Eversion of the lower eyelid called as Ectoprism impairs Absorption of tears which tend to overflow the lower eyelid.
8) Retraction of mouth and pursing of the lips not possible.
9) Paralysis of buccinators leads to accumulation of food between the teeth and the cheek, their will also be dribbling of saliva from the corner of the mouth.
10) Patient complains of heaviness or numbness of the face.
11) Taste is intact ( loss of taste sensation anterior 2/3 of the tongue)
12) Distortion of the mouth causes the tongue to deviated to the sound side when protruded thus giving false impression of the hypoglossal lesion.
INVESTIGATIONS:-
- Strength duration curve
- Electromyography (EMG). This test can confirm the presence of nerve damage and determine its severity. An EMG measures the electrical activity of a muscle in response to stimulation and the nature and speed of the conduction of electrical impulses along a nerve.
- Imaging scans. Magnetic resonance imaging (MRI) or computerized tomography (CT) may be needed on occasion to rule out other possible sources of pressure on the facial nerve, such as a tumor or skull fracture.
- Nerve conduction studies(NCV)– it is a test to see how fast electrical signals move through a nerve.
PROGNOSIS:-
More than 70% of the patient may recover.
MANAGEMENT FOR BELL’S PALSY:-
1) Resolving the inflammation:- if the patient comes immediately following the onset of paralysis.
- Then may be treated with eighter SWD or IR to increase circulation in the stylomastoid foramen.. So the inflammation can be resolved.
- Corticosteroids may reduce swelling around the facial nerve.
2) Maintenance of muscle properties:-
This can be achieved with interrupted galvanic stimulation to the paralyzed muscles.
3) Facial massage :-
Massage is essential to maintain the circulation to the face as well as to keep the face supple.
The direction of the manipulation used should be in upward direction ( downward manipulation have deleterious effect).
4) Taping or splinting:-
These method are used to decrease that facial asymmetry noticed in bell’s palsy.
5) Eye care:-
- Patient may be instructed to wear protective goggles to prevent entry of foreign bodies into his eyes.
- Lubricating eye drops or eye ointments to keep the surface of eye moist.
- Advice to wear an eye patch while you sleep.
6) Continuous monitoring:-
- SDC (strength duration curve) is helpful in knowing the prognosis of the patient.
7) Faradic redducation:-
only if patient can tolerate sensory stimulus of faradic current to the face, faradic reeducation is given.
- Other mean of re-educating the movement is by using PNF techniques, visual feedback exercises etc.
8) Visual feedback exercise:-
- patient may be asked to do facial exercise in front of the mirror-
- So that he gets a visual feedback and perform exercise more efficiently.
9) Strengthening exercise:-
Once the facial muscles reach grade 3 or fair then resistance can be given to muscle action to further strengthen them.
Exercises
The Bell’s Palsy Association in the United Kingdom recommends the following exercises:
Facial workout
- Sit relaxed in front of a mirror
- Gently raise the eyebrows, using the fingers to help, if needed
- Pull the eyebrows together and frown
- Wrinkle the nose
- Breathe in deeply and flare the nostrils
- Try to move the corners of the mouth outward
- Pull one side of the mouth up, then the other, to form a smile
- If you used your fingers, see if you can keep the smile after removing them
To close the eye
- Keeping the head still, look down with your eyes only
- Place one index finger gently over one eyelid to hold it closed
- With the other hand, pull the eyebrow up slightly, massaging along the browline to prevent stiffness
- Without using the hands, gently try pressing the eyelids together
- Hold the eyes half open