– Causes, Diagnosis and treatment – know everything about Bell’s palsy.
Bell’s palsy is the sudden onset ,unilateral idiopathic form of peripheral facial paralysis or paresis having no known cause. One of the most common neurological disorder of cranial nerve is Bell’s palsy and incidence increase especially in winters. In majority of cases unilateral involvement occurs however very rarely bilateral involvement can occur.
Knowledge of Anatomy
Bell’s palsy: This is the lower motor neuron lesion of the facial nerve and resultant paralysis of the muscles that it supplies.
Course of the nerve: It start from seventh cranial nerve nucleus. It is situated in the ventral part of tegmentum of pons, rounds 6th nucleus along its course elaborate to form geniculate ganglion, and it give a branch to stapedius muscle, a branch supplying anterior two-third of tongue. Emerging from stylomastoid foramen it enters the partoid gland and divides into:
- Cervical branches
- Orbicularis Oculi
- Corrugator and procerus
- Zygomaticus major and minor
- Levator angulis oris
- Levator labii superioris
- Orbicularis oris
- Depressor anguli oris
- Depressor labii inferioris
The exact cause of Bell’s palsy is still not known however the following conditions may put the facial nerve to undergo temporary and irreversible inflammation of the Bell’s palsy.
- Rupture of ear drum
- The infection of ear canal
- Otitis media( either it is acute or chronic)
- Parotid tumours
- Herpes zooster
- The surgery in the ear or throat region
- Cardiofacial syndrome ( lower lip palsy)
- Anesthesia during middle ear surgery
- Dislocation of temporomandibular joint
- Dropping of the face
- Dropping of the lower corner of mouth
- Eye closure is not complete and while closing it the eye roll upward
- Weakness of facial muscles
- Speaking and whistling is difficult
- The non verbal gestures like laughing , pleasure, facial expression , surprise , interest , worries are lost.
- Inability in making facial expressions
The exact cause is not known however idiopathic involvement is established and temporary disfunction of the 7th cranial nerve i.e facial nerve has been reported. Doctor may perform physical examination to check the muscle weakness and MRI scan can be done to check the involvement of the nerves in your face.
- Bell’s phenomenon
- Loss of facial expression
Management – Management of Bell’s palsy include medical management as well as physiotherapy management. The management starts immediately after its onset and continues even when the results of the investigative procedures are awaited. Medical management includes
- Corticosteriods drugs , which reduce inflammation
- Antiviral and antibacterial medication
- Acetaminophen for mild pain relief
- Eyes drops
- Muscle stimulator
- Exercises of facial muscles like Look surprise, happy , fill air in balloon, whistle, close eyes tightly , blow off the candle
- Facial massage
- Look surprised and then “Frown”.
- Smile, grin, say “O”.
- Say a, e, i, o, u
- Squeeze eyes closed then make wide open
- Hold straw in mouth, suck and blow
- Avoid excessive dryness of eyes
- During sleep eyes maybe covered with wet cloth to avoid excessive dryness
- Use saline eye drops each half hourly
- Eye lubricants or artificial tears are used to avoid the dryness of eye and prevent corneal ulceration.
- Avoid intake of cold substances
- Cover up the head and face with a scarf
- Avoid taking in hot substances when there is sensory loss in anterior two-third of tongue.