FACIAL NERVE, PALSY AND PAIN & TRIGEMINAL NEURALGIA
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Transcript of FACIAL NERVE, PALSY AND PAIN & TRIGEMINAL NEURALGIA
Origin - Nucleus in the pons
Exit → Stylomastoid foramen
Upper part of VIIth nucleus supply upper face (principally frontalis) bilaterally
Largely motor
Supplies muscles of facial expression
Chorda tympani◦ Motor fibres to the stapedius muscle◦ Sensory taste fibres from the anterior two-thirds
of the tongue
Upper motor neuron (UMN lesions)◦ Facial Nucleus and above
Lower motor neuron (LMN) lesions◦ Below facial nucleus
Upper motor neurone (UMN lesions)
Lower motor neurone (LMN) lesions
Contralateral IpsilateralLower part Entire faceFrontalis (frowning) spared Frontalis (frowning) affectedEye closure/blinking present Eye closure/blinking absentNo corneal exposure and ulceration
Corneal exposure and ulceration
Angle of the mouth falls; unilateral dribbling
Relative preservation of spontaneous emotional movement
Taste sensation is frequently also impaired
UMN-◦ Cerebrovascular accident (stroke)
LMN
LMN-◦ Pons
Tumours (e.g. glioma) Multiple Sclerosis Infarction
◦ Cerebellopontine angle (CPA) – V+VI+VII+VIIIA Acoustic neuroma Meningioma Metastasis Cholesteatoma
◦ Petrous temporal bone Bell’s palsy Trauma Middle ear infection Herpes zoster
LMN-◦ Beyond the skull
Skull base tumours Paget’s disease of bone Parotid gland tumours Sarcoidosis Trauma.
Acute isolated facial palsy Why?
?Viral infection (often herpes simplex) Lyme disease HIV seroconversion
Nerve swollen - petrous bone facial canal Unilateral LMN
Evolves over 24–48 hours Taste on the tongue may be lost/altered Hyperacusis Pain behind the ear is common at onset Suspect a stroke Vague altered facial sensation Examination of facial sensation - normal.
Prognosis good Recurrence unlikely Recovery-
◦ 3–8 weeks◦ At least 85%◦ Complete/near complete
Eye care◦ Lubricants◦ Taping, lateral tarsorrhaphy, gold weight
Drugs◦ Steroids early◦ Prednisolone 1mg/kg/day X 7 days
Rare Often less obviously apparent - no facial asymmetry Causes:
◦ Infections: Lyme (bilateral in 25% – Bannwarth’s syndrome) Viral: HIV seroconversion, EBV Mastoiditis (bilateral) Diphtheria and botulism (rare)
◦ Sarcoidosis◦ Skull base trauma and tumours◦ Pontine lesions, e.g. gliomas◦ Neuromuscular disorders:
Guillain–Barré syndrome Myasthenia Myotonic dystrophy and facioscapulohumeral dystrophy
◦ Congenital and genetic causes
Teeth Gums Paranasal sinuses Temporomandibular joints Jaw Eyes Neurological conditions
Trigeminal◦ Autonomic cephalgias◦ Neuralgia
Migraine Carotid dissection Giant cell arteritis (temporal arteritis) Atypical facial pain (somatisation?)
6th and 7th decades Hypertension - main risk factor
Compression At or near the pons Ectatic vascular loop High res MRI
Younger patients Multiple sclerosis CP angle tumours
◦ Acoustic schwannomas◦ Meningiomas◦ Epidermoids
Paroxysms pain Knife-like/electric shock-like Lasting seconds Vth nerve distribution Starts in mandibular division (V3) →
maxillary (V2) → occasionally ophthalmic divisions (V1).
Bilateral ◦ Rare (3%)◦ Intrinsic brainstem pathology (demyelination)
Many times a day Trigger
◦ Trigger zones in the face◦ Washing, shaving, cold wind, chewing
Drugs:-◦ Carbamazepine (600–1200 mg daily)◦ Oxcarbazepine, lamotrigine, gabapentin
Surgical:-◦ Percutaneous radiofrequency selective ablation of
the trigeminal ganglion◦ Microvascular decompression
Spontaneous remissions◦ Months or years
BUT almost invariably recur