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

Exact etiology unknown Viral infection

Herpes Simplex

Vascular ischemia Autoimmune disorder Hereditary

Bell’s Palsy

Reduced Stapedial reflex 71% Complete palsy @ presentation69% Tear flow 67% Post-auricular pain 52% Dysgeusia 34% Hyperacusis 14%

Reduced Stapedial reflex 71% Complete palsy @ presentation69% Tear flow 67% Post-auricular pain 52% Dysgeusia 34% Hyperacusis 14%

Bell’s Palsy

Peitersen E. Acta Otolaryngol 2002;549:4–30.

Complete Remission & Age

Bell’s Palsy

Peitersen E. Am. J. Otology. 1982

Bell’s Palsy

DIAGNOSIS OF EXCLUSION

Differential Diagnosis 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

Metabolic

DiabetesHypothyroidism SarcoidGullian BarreAutoimmune disorders

VascularBenign intracranial

hypertension Neoplasm

Facial neuromaAcoustic neuromaCholesteatomaMenigiomaLeukemiaMetestatic

ToxicThalidomide

Iatrogenic

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

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 Wallerian degeneration (distal to lesion) 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

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

Steroid Anti-viral agents

Surgery Decompression Dynamic vs. static reanimation

Facial Rehabilitation

Observation Medical Treatment

Steroid Anti-viral agents

Surgery Decompression Dynamic vs. static reanimation

Facial Rehabilitation

Treatment

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

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

Steroid vs. Steroid + AcyclovirSteroid vs. Steroid + Acyclovir

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 %