Facial palsy is condition in which there is lesion of the facial nerve and the resultant paralysis in the muscles that it supplies. So there will be following features on the side of lesion:
Loss of facial expression.
Drooping of the face- Low eyelid, eyebrow and corner of mouth sag.
Closing the eye is difficult.
Eating is difficult because food collects in the side of the cheek and fluid seeps out of the corner of mouth.
Speaking, whistling and drinking are impaired.
Non-verbal communication is lost as the patient cannot register the pleasure, laughter, surprise, interest and worry.
The patient tends to sit with the hand over the side of face.
There is difference between an upper motor neuron lesion and lower motor neuron lesion of the facial palsy.
A unilateral UMN lesion usually spares the forehead as it is also innervated from the other side of the brain; however an LMN lesion affects all of one side of the face.
An upper motor neuron lesion causes weakness of lower part of face on the side opposite the lesion. The frontalis muscle is spared; the normal furrowing of the brow is preserved, and the eye closure and blinking are not affected.
Moreover, in upper motor neuron lesion there relative preservation of spontaneous 'emotional' movement (e.g. smiling) compared with voluntary movement.
Causes of facial weakness:
These are as under:
The common cause of facial weakness is a supranuclear lesion e.g. cerebral infarction leading to upper motor neuron facial weakness and hemiparesis.
Lesions at four other levels may be recognized by the associated signs.
PONS. The sixth nerve nucleus is encircled by the seventh nerve fibers and is therefore involved in the pontine lesions of the nerve, causing lateral rectus palsy.
If there is accompanying damage to the neighboring centre for the lateral gaze and the cortispinal tract, there is the combination of:
LMN facial weakness
Failure of congugate lateral gaze (toward the lesion)
Contra lateral hemiparesis
Causes include pontine tumours (e.g. glioma), demyelination and vascular lesions.
The facial nucleus is affected in poliomyelitis and motor neuron disease; the lateral usually causes the bilateral weakness.
CEREBELLOPONTINE ANGLE. The fifth, sixth and eight nerves are affected with the seventh nerve in lesions in the cerebellopontine angle. Causes are acoustic neuroma and miningoma.
WITHIN THE PETROUS TEMPORAL BONE. The geniculate ganglion (a sensory ganglion for taste) lies at the genu of the facial nerve. Fibers join the facial nerve in the chorda tympani and carry taste from the anterior two third of the tongue. The (motor) nerve to the stapedius muscle leaves the facial nerve distal to the genu.
Lesions within the petrous temporal bone cause:
Loss of taste on the anterior two third of the tongue
Hyperacusis ( an unpleasant loud distortion of noise) due to the paralysis of the stapedius muscle
Causes include:
Bell's palsy
Trauma
Infectin of middle ear
Herpes zoster (Ramsay hunt syndrome)
Tumours (e.g. glomus tumour)
WITHIN THE FACE. Branches of the facial nerve pierce the parotid gland and supply the muscle of the facial expression. The nerve can be damaged here by parotid gland tumours, mumps (epidemic parotitis), sarcoidosis and trauma. The nerve is also affected in the polyneuritis (e.g. G.B. Syndrome) usually bilaterally.
Weakness of face also occurs in primary muscle disease and disease of neuromuscular junction. Weakness is usually bilateral. Causes include:
Dystrophia myotonica
Facio-scapulo humeral dystrophy
Myasthenia gravis
Bell's palsy
this is a common acute, isolated facial nerve palsy believed to be due to viral infection (most probably herpes simplex) that causes swelling of the nerve within the petrous temporal bone.
MANAGEMENT:
Spontaneous recovery occurs toward the end of second week. Thereafter, continuing recovery occur. Fifty percent recover within three months. Continuing recovery may take 12 months to become complete. About 15 percent of patients are left with a severe unsightly residual weakness.
Medical:
Steroids (prednisolone 60mg daily reducing to nil over 10 days.)
Acyclovir for viral infection
Physiotherapy:
During the paralysis:
Ultrasound given over the nerve trunk in front of the tragus of ear and in area between mastoid process and mandible. There is no fear of applying ultrasound while doing the treatment of patient with Bell's palsy. The ultrasound is always applied on the side of lesion in front of the tragus of ear & in area between the mastoid process and mandible where the maximum tenderness of the facial nerve is determined by palpation. It is applied in slow circular motion with a starting dosage of 1 watt per square centimeter. The dosage may be increased on the subsequent sessions if no remarkable improvement is noted. Let me explain that ultrasound waves cannot traverse the bone. That means ultrasound has zero penetration in the bone. Infact, ultrasound waves are reflected away from the bone. So there is no fear in applying the ultrasound on face. (This is only for LMN lesion type)
low level laser therapy (infrared 808 nanometer wavelength 400 mill watt power for 5 minutes continuous)
Infra-red: Infra red may be applied to warm the muscles and improve the function, but you must ensure that eyes are protected with linens when you are applying infra-red to face. Timing should be for 15 to 20 minutes.
Ultraviolet Therapy: Formerly ultraviolet was frequently used to give third degree erythema doses over the facial nerve trunk and in area between mastoid process and mandible to combat the infection and inflammation.
Microwave diathermy: As far as micro wave diathermy application is concerned, there is strict contra indication for the use of micro wave diathermy for the treatment of face as micro waves can spread randomly and can damage the lense of eye causing the opacity of the lense. So there is no room for the application of micro wave to face.
Short Wave Diathermy: SWD can be safely applied for the treatment of facial palsy. The technique used may be monopolar or bi polar. In bipolar technique using the capacitor field method, the one facial mask electrode is used as an active electrode for applying the rays to face while the second or indifferent electrode used on some distant part of the body to complete the circuit. In monopolar electrode method only one electrode is used to direct the rays to the target treatment area site and no second electrode is used at all.
Electrical Stimulation: The only form of electrical current used on face is interrupted direct current (I.D.C.). This is requested only to preserve the bulk of facial muscle and to prevent their atrophy while waiting them to be in faction whenever their re innervations arrives in case of axotomesis or reconditioning after neuropraxia if the nerve is not damaged completely. There is no room for the use of faradic current use on the face as it could lead to cause secondary contractures of the face.
Massage: Massage may be taught to the patient
stroking in the upward, outward direction.
Slow finger kneading applied over the paralyzed muscles maintains skin suppleness and muscle elasticity.
These techniques applied daily for 5 minutes or so help to maintain lymphatic and blood flow and prevent contractures.
During Recovery:
PNF techniques are used for re-education:
Quick stretch can be applied to regain rising of eye brow and the movement of the corner of mouth.
The physiotherapist can produce the movement passively and then ask the patient to hold, and then try to produce the movement.
Icing, brushing, tapping or brisk stroking may be applied along the length of the muscles. e.g. Zygomaticus
Exercises:
Look surprised then frown
Squeeze eyes closed then open wide
Smile, grin, say 'o'.
Say a, e, i, o, u.
Hold straw in mouth-suck and blow
Whistle
Heliotherapy:I have found traditional old lay men to use the convex lense to focus the sun rays to produce the third or four degree erythematic dosage to facial nerve trunk and in area between mandible and mastoid process behind the ear and it frequently gives dramatic result with excellent recovery of facial palsy. The treatment was needed to repeat after one week to repeat the same session of the dosage. Only three or four sessions of this kind were needed to do the excellent management of the patient. Infact, it is one kind of heliotherapy treatment which is available from the natural source of power i.e. the sun. This is most common form of physiotherapy medicine that is used by conventional lay men here in Pakistan with excellent results of the treatment.
FARADIC Vs GALVANIC CURRENT
The faradic current has a frequency of 50 Hz and hence so produces the tetanic muscle contraction. It is ,therefore, surged to produce the alternate contraction and relaxation of the muscles. Moreover, faradic current having short pulse duration can not be used to stimulate dennervated muscles as dennervated muscles requre pulses of longer duration for having its effects. So galvanic current has fair long duration impulses selections that can be used to stimulate dennervated muscles. Although in early days of nerve injury a response of muscle can be obtained witth faradic or faradic type of current depending upon the reaction of degeneration but when walerian degenration takes place, it is not possible to get the response from faradic type of current. Furthermore, facial muscles are very delicate and soft as they can tolerate the tetanic type of contraction produced by faradic current and this could lead to the secondary contractures of the facial muscle. Hence the most suitable current in that case will be interrupted galvanic current, that produces a brisk twitches of the facial muscles. And there will no danger secondary contractures.