Bell's Palsy Flashcards
What is Bell’s Palsy?
- A unilateral facial nerve palsy of unknown cause
- Typically an idiopathic facial nerve palsy
- Inflammation and Oedema of the facial nerve secondary to a viral infection or autoimmunity
How many branches does the facial nerve have?
- 5 branches
What is the route of the facial nerve?
- Nucleus is located in the pons which is part of the brainstem
- The nerve root passes through the internal acoustic canal within the temporal bone
- It then enters the facial canal
- It then exits the skull via the stylomastoid foramen
- It splits into 5 terminal motor branches within the parotid gland
What extracranial branches are given off by the facial nerve?
- nerve to the stapedius
- Posterior auricular nerve
- Nerve to the posterior belly of the digastric muscle
- Nerve to the Stylohyoid muscle
- Chorda Tympani ( taste to the anterior 2/3 of the tongue)
What are the 5 branches of the facial nerve?
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
What are the parasympathetic branches of the Facial Nerve?
- Greater Petrosal Nerve: Facial canal - Pterygopalatine ganglion - parasympathetic supply to the lacrimal gland
- Chorda Tympani: Facial canal - Submandibular ganglion - parasympathetic supply to the submandibular and sublingual glands
What are the differential diagnosis for Bell’s Palsy?
- Otitis Media (inner ear disease)
- Parotid Disease (tumour)
- Sarcoidosis
- Guillain- Barre Syndrome
- Lyme disease
- Trauma
- Stroke
- Tumours
- Encephalitis
- Meningitis
- Multiple Sclerosis
- DM related neuropathy
What is the typical onset of Bell’s Palsy?
- Rapid Onset <72 hours - unilateral facial weakness
What are the symptoms of Bell’s Palsy?
- Unilateral facial weakness
- Post- Auricular/ Ear Pain
- Difficulty chewing
- Incomplete Eye Closure
- Drooling
- Tingling
- Hyperacusis ( heightened sensitivity to sound - Chorda tympani)
What are the signs of Bell’s Palsy?
- Loss of nasolabial fold
- Drooping of the eyebrow
- Drooping of the corner of the mouth
- Asymmetrical smile
- Bell’s Sign (upward movement of the eye maintained on attempt to close the eye)
Does Bell’s Palsy affect LMN or UMN?
- LMN
How do you differentiate between LMN and UMN?
- UMN include a Stroke or Cerebral tumour
- UMN lesions there is forehead sparing due to the bilateral supply of the frontalis muscle
- LMN the frontalis is completely unilateral paralysis
What disease would you suspect if there is Bilateral involvement?
- Lyme Disease
- Sarcoidosis
- Guillain- Barre Sundrome
- HIV
What grading system is used for Facial Paralysis?
- House- Brackmann System
What are the grades for House-Brackmann System?
- Grade 1: normal
- Grade 2 : mild
- Grade 3 : moderate
- Grade 4 : moderate- to - severe
- Grade 5 : severe
- Grade 6 : complete paralysis
What Investigations are done for Bell’s Palsy?
- Blood tests
- Neuroimaging
- Specialist tests ( lumbar puncture, lyme serology)
- HIV screening
What are features that may point to a differential diagnosis?
- Insidious onset
- Overt Pain
- Systemic illness
- Vestibular abnormalities
- Hearing abnormalities
- Forehead sparing
- Mass
- Recurrent palsy
- Bilateral involvement
What is the managment for Bell’s Palsy?
- Prednisolone within 72 hours of onset (50mg for 10 days)
- Anti-viral treatment with corticosteroids (specialist decision)
- Eye care: lubricating drops and ointments, taping the eye when asleep, sunglasses outdoors
- Any patient with incomplete eye closure should be referred to ophthalmology
What are the complications of Bell’s Palsy?
- Majority of patients will make a full recovery within 4 months
- Refer:
1. develop eye symptoms (exposure keratopathy)
2. no improvement after 3 weeks
3. develop late problems with aberrant reinnervation (Marcus- Gunn Jaw-winking) - synkinesis
What is Synkinesis?
- Voluntary muscle contraction leading to involuntary contraction of another muscle
- It is due to regenerating collateral nerves that have inadvertently supplied another muscle
What is exposure keratopathy?
- Damage to the cornea that occurs primarily due to prolonged exposure of the ocular surface to the outside environment
