Flashcards in Facial nerve palsy Deck (30):
Facial nerve palsy signs on inspection
Unilateral facial droop
Absent nasolabial fold
± absent forehead creases
Parotid scar or mass
Muscles affected in facial nerve palsy
Frontalis (raising eyebrows)
Orbicularis oculi (screwing up eyes)
Orbicularis oris (smiling)
What is Bell's phenomenon
AKA palpebral oculogyric reflex.
Normal reflex in most of population when cornea threatened or eyelids forcibly closed. But only becomes apparent if orbicularis oculi is weak.
Differentiating whether facial nerve palsy is LMN or UMN
UMN - sparing of frontalis and orbicularis oculi (upper spares the upper part of face)
Due to to bilateral cortical representation
Features of Millard-Gubler Syndrome
Lesion at pons: CN6, CN7, and corticospinal tract lesion.
Ipsilateral lateral rectus palsy
Ipsilateral LMN facial palsy
Cerebellopontine angle lesion features
Ipsilateral CN5,6,7,8 palsies + cerebellar signs.
Facial anaesthesia + absent corneal reflex
Lateral rectus palsy
LMN facial nerve palsy
Sensorineural hearing loss
Cranial nerves that pass through the auditory canal
Completion of facial nerve palsy exam
If UMN: likely stroke.
Examine limbs for ipsilateral spasticity, visual fields for ipsilateral homonymous hemianopia.
If LMN: likely Bell's palsy.
Examine PNS, CN and cerebellar function, test taste.
Causes of Bell's palsy
Supranuclear: vascular, MS, SOL
Pontine: vascular, MS, SOL
CPA: vestibular Schwannoma, meningioma, secondary met
Intra-temporal: Ramsay-Hunt, cholesteatoma, trauma
Infra-temporal: parotid tumour, trauma
Systemic: neuropathy (DM, Lyme, sarcoidosis), pseudopalsy (myasthenia gravis)
Causes of bilateral facial palsy
Pseudopalsy: myasthenia gravis, myotonic dystrophy
Specific history for facial nerve palsy
Symptoms: eye dryness, drooling, decreased taste, hyperacusis
Cause: onset (rapid in Bell's), rash or external ear pain (Ramsay-Hunt), Hx of DM, headache or nausea (SOL), other CN (vertigo, tinnitus, diplopia), limb weakness, rash, fever.
Pathophysiology of ageusia and hyperacusis in Ramsay-Hunt syndrome
Chorda tympani and nerve to stapedius arise just distal to geniculate ganglion within the temporal bone. Loss of these functions indicates a proximal lesion: Ramsay Hunt is VZV at geniculate ganglion.
Investigations for facial nerve palsy
Urine dip: glucose
Bloods: DM (glucose, HbA1c), serology (VZV and Lyme), antibodies (anti-ACh receptor)
Imaging: MRI posterior cranial fossa
Pure tone audiometry
Lumbar puncture to exclude infection
Nerve conduction studies (myasthenia gravis)
Management of Bell's palsy
1. Protect eye: dark glasses, artificial tears, tape closed at night
2. Prednisolone within 72 hours
3. Valganciclovir if VZV suspected
Prognosis in Bell's palsy
Incomplete paralysis: recovers completely within weeks.
Complete paralysis: 80% get full recovery. Remainder have delayed recovery or permanent neurological/cosmetic abnormalities.
Aberrant neural connections in Bell's palsy
Complication of resolved Bell's palsy.
Synkinesis: blinking causes up-turning of mouth.
Crocodile tears: eating stimulates unilateral lacrimation, not salivation.
Pathophysiology of Bell's palsy
75% of facial palsies
Inflammatory oedema leads to compression of CN7 in narrow facial canal. Probably of viral origin (HSV1).
Features of Bell's palsy
Complete LMN facial palsy
Ageusia: corda timpani
Hyperacusis: nerve to stapedius
Associated with other cranial nerve involvement in 8%
Cause of Ramsay Hunt symdrome
Reactivation of VZV in geniculate ganglion of CN7
Features of Ramsay Hunt syndrome
Preceding ear pain or stiff neck
Vesicular rash in auditory canal ± tympanic membrane, pinna, tongue, hard palate (no rash + 'zoster sine herpete')
Ipsilateral facial weakness, ageusia, hyperacusis
May affect CN8 - vertigo, tinnitus, deafness
Treatment of Ramsay Hunt syndrome
1. Protect eye
2. Valganciclovir + prednisolone within 72h
Prognosis for Ramsay Hunt syndrome
If treated within 72h: 75% full recovery
Otherwise, 1/3 full recovery, 1/3 partial, 1/3 poor.
Pathophysiology of cholesteatoma
Locally destructive expansion of stratified squamous epithelium within the middle ear.
Usually secondary to attic perforation in chronic suppurative otitis media.
Presentation of cholesteatoma
Foul smelling white discharge
Vertigo, deafness, headache, pain, facial paralysis
Appears pearly white with surrounding inflammation
Complications of cholesteatoma
Deafness due to ossicle destruction
Meningitis, cerebral abscess
Management of cholesteatoma
Causative organism in Lyme disease
Features of Lyme disease
Early local phase: erythema migrant + systemic malaise
CN palsy, esp. facial palsy
Examination of facial anaesthesia
Reduced or absent sensation in trigeminal distribution - note modality, note with branch(es)
Weak masseter and temporalis
Jaw jerk: brisk - UMN, absent - LMN
Loss of corneal reflex