Amy Stinson ENT PGY-2 Affinity Medical Center Bell’s Palsy Amy Stinson ENT PGY-2 Affinity Medical Center

Outline Anatomy Definition Differential Exam Electrophysiology Treatment Outcome

Anatomy: The Facial Nerve Motor and Sensory SVA fibers: taste ant 2/3 tongue Lingual & Chorda  geniculate  nervous intermedius  solitary nucleus SVE fibers: muscles of facial expression Facial motor nucleus  stylomastoid foramen GVA fibers: parasympathetics lacrimal, palatine, parotid, submandibular, sublingual glands Sup salivatory nucleus  GSPN/Sphenopalatine, lesser petrosal/otic, chorda/submandibular Sensory – concha and post auricular

Anatomy: The Facial Nerve Intracranial lateral for 12-14mm with CN8 to IAC Meatal 8-10mm ant/sup of IAC to meatal foramen Diameter changes from 1.2 mm to 0.68 mm Labyrinthine 2-4 mm to geniculate ganglion (GSPN exits) Tympanic First genu 11mm post/inf to 2nd genu Mastoid 12-14 mm inf (vertical seg) to SMF (chorda exits) Peripheral Pes anserus 20 mm then 5 terminal branches (upper and lower seg)

Anatomy: The Facial Nerve Favorite mnemonics Some Say Marry Money, But My Brother Says Big Breasts Matter More   To Zanzibar By Motor Car Ten Zebras Bit My Crotch Ten Zebras Beat My Cock Today Zoe Broke My Car

Anatomy

Anatomy

Bell’s Palsy Sir Charles Bell (1774-1842) Studied facial anatomy extensively during Battle of Waterloo Concluded that facial nerve controlled facial expression “Respiratory nerve of the Face”

Bell’s Palsy Idiopathic Facial Paralysis DIAGNOSIS OF EXCLUSION MC Diagnosis given >60% Unilateral Rapid Onset <48hrs Not progressive!

Bell’s Palsy 30/100,000 M = F 3.3x greater incidence in pregnancy 4-5x increased risk with DM Fam Hx 10% Recurrence rate 10%

Bell’s Palsy - etiology Exact etiology unknown Viral infection Herpes Simplex Vascular ischemia Autoimmune disorder Hereditary

Bell’s Palsy Reduced Stapedial reflex 71% Complete palsy @ presentation 69% Tear flow 67% Post-auricular pain 52% Dysgeusia 34% Hyperacusis 14%

Bell’s Palsy Complete Remission & Age Peitersen E. Acta Otolaryngol 2002;549:4–30.

Bell’s Palsy Peitersen E. Am. J. Otology. 1982

DIAGNOSIS OF EXCLUSION Bell’s Palsy DIAGNOSIS OF EXCLUSION

Differential Diagnosis Metabolic Diabetes Hypothyroidism Sarcoid Gullian Barre Autoimmune disorders Vascular Benign intracranial hypertension Neoplasm Facial neuroma Acoustic neuroma Cholesteatoma Menigioma Leukemia Metestatic Toxic Thalidomide Iatrogenic Infection Herpes Zoster Oticus (Ramsey Hunt Syndrome) Lyme disease Acute Otitis media +/- mastoiditis Malignant otitis externa TB AIDS Mono Congenital Treacher Collins syndrome Mobius syndrome Compression injury Trauma Temporal Bone fracture Barotrauma Penetration wounds, laceration, and contusions

Differential Diagnosis If nerve function had not returned or has gotten worse at the 6 month mark – You MUST revisit the previous list!

History Onset Degree of paralysis Associated symptoms Sudden, delayed, gradual Degree of paralysis Complete, incomplete Associated symptoms Numbness, otalgia, hyperacusis, diminished tearing, altered taste Intense ear pain and vesicles Sensorineural hearing loss, vertigo

Exam Quick and dirty facial nerve exam Raise eyebrows Tightly close eyes Wrinkle the nose Smile Pucker Grimace

Exam Complete Head and Neck exam Special attention to otoscopy and CNs Progressive segmental paralysis w/lesion Laceration, battle sign, hemotympanum Multiple CN deficits Compare motor function w/opposite side Bell phenomenon: visible vertical rotation of globe on closing affected eye Audiometry CT/MRI

Pathophysiology HSV viral reactivation leading to damage of facial nerve Neuropraxia– no axonal discontinuity Axonotmesis Wallerian degeneration (distal to lesion) Axoplasmic disruption, endoneural sheaths intact Neurotmesis Axon disrupted, loss of tubules, support cells destroyed

Electrophysiology Sunderland’s Classification Neurapraxia Axonotmesis Neurotmesis

Electrophysiology

Electrophysiology Nerve Excitation test (NET) Maximal Stimulation test (MST) Electroneurography (ENoG) Electromyography (EMG) Measure amounts of neural degeneration occurred distal to injury by measuring muscle response to electrical stimulus Able to differentiate nerve fibers undergoing Wallerian degeneration

Treatment Observation Medical Treatment Surgery Facial Rehabilitation Steroid Anti-viral agents Surgery Decompression Dynamic vs. static reanimation Facial Rehabilitation

Treatment Steroid vs. Steroid + Acyclovir Double-blind RCT 99 Bell’s palsy patients 53 treated with acyclovir- prednisone 46 with placebo – prednisone Prednisone dose 400 mg five times daily x 10 days Combined therapy is better in terms of: Return of muscle motion Prevention of partial nerve degeneration

Treatment Eye care Glasses/ Sunglasses/ avoid contact lens Artificial tears, lacrilube Taping Gold weight to upper eyelid Opthalmologic consultation

Treatment Surgical Decompression Middle Fossa Transmastoid Translabyrinthine Retrolabyrinthine Retrosigmoid

Outcome Complete Remission & Age

Outcome Return of Muscular function 85 %