Bell’s PalsyDr. Angelo Smith

WHPL

You wake up one morning, and your face feels stiff and odd. When you look in a mirror, half your face appears to droop. You can only manage half a smile, your eye is dripping tears and doesn't want to close. What in the world is going on?

Who is this Bell ? Charles Bell

› Well known for his studies on the nervous system and the brain

› In the 19th century discovered that lesions of the 7th cranial nerve causes facial paralysis

What nerve was that again?The 7th cranial nerve is

paired with thestructure that travels through a narrow, bony canal (called the Fallopian canal) in the skull

beneath the ear to the muscles on each

side of the face.The nerve is mostly

encased in this bony shell.

Facial NerveEach nerve controls:

› Eye blinking and closing› Facial expressions

Smiling and frowning› Tear glands› Saliva glands› Muscle of small bone in middle of ear

called the stapes› Taste sensations

Clinical Signs Suggesting Site of Facial Nerve Lesion

Upper facial territory is supplied by bilateral motor cortices

Lower facial territory is supplied only by contralateral motor cortex

Therefore, unilateral central lesions spare upper face

Lesions distal to geniculate ganglion› Mostly motor abnormalities

Lesions proximal to geniculate ganglion › Motor, gustatory & autonomic abnormalities

Classification

Sunderland classification of nerve injury

1° damage = Compression2° damage = Interruption of axoplasm3° damage = Disruption of myelin4° damage = Disruption of perineurium,

myelin and axon5° damage = Transection of nerve

Sunderland Classification of nerve injury

Bell’s Palsy

Characterized by:› Peripheral facial paralysis› Acute benign cranial polyneuritis

Acute disorder characterized by a disruption of the motor branches of cranial nerve VII on one side of the face. (in absence of stroke)

S/S Varies from person to

person› Comes on suddenly› Mild to total paralysis

Weakness, twitching on one of both sides of the face

› Facial and eyelid droop› Drooling› Dryness of eye or

mouth› Impairment of taste› Excessive tearing of

eye

Other S/S

Pain or discomfort in jaw and behind the ear

Ringing in one or both ears Loss of taste Headache Hypersensitivity to sound Impaired speech Dizziness Difficulty eating and drinking

Clinical manifestations

Often accompanied by an outbreak of herpes vesicles in or around the ear.

Pain around or behind the ear Fever, tinnitus, hearing deficits Flaccidity of the affected side of the

face with drooping of the mouth accompanied by drooling DT paralysis of the facial nerve (motor branches)

Clinical manifestations Inability to close the eyelids, with an upward

movement of the eyeball when closure is attempted; lower lid may turn out

Wide palpebral fissure (opening between eyelids)

Flattening of the nasolabial fold Inability to smile, frown, or whistle Unilateral loss of taste Altered chewing ability; loss of or excessive

tearing

House-Brackmann grading system

Grade I - Normal

Grade II - Mild dysfunction, slight weakness on close

inspection, normal symmetry at rest

Grade III - Moderate dysfunction, obvious but not disfiguring

difference between sides, eye can be completely closed with

effort

Grade IV - Moderately severe, normal tone at rest, obvious

weakness or asymmetry with movement, incomplete closure of

eye

Grade V - Severe dysfunction, only barely perceptible motion,

asymmetry at rest

Grade VI - No movement

Topographic Diagnosis

To determine the anatomical level of a peripheral lesion

Lacrimation Geniculate ganglion

Stapedius reflex motor nerve of stapedius muscle

Taste chorda tympani

Schirmer's Test Geniculate ganglion & petrosal nerve

function test Schirmer’s test +ve when

› Affected side shows less than half the amount of lacrimation seen on the normal side

› Sum of the lengths of wetted filter paper for both eyes less than 25 mm

Lesion at or proximal to the geniculate ganglion

Stapedius reflex

Nerve to stapedius muscle test Impedance audiometry can record

the presence or absence of stapedius muscle contraction to sound stimuli 70 to 100 dB above hearing threshold

An absence reflex or a reflex less than half the amplitude is due to a lesion proximal to stapedius nerve

Taste (Electrogustometry) Chorda tympani nerve test Solution of salt, sugar, citrate, quinine or

Electrical stimulation Compares amount of current require for a

response each side of tongue Normal : difference < 20 uAmp (thresholds

differening by more than 25%= abnormal) Total lack of Chorda tympani : No response

at 300 uAmp Disadvantage : False +ve in acute phase of

Bell’s palsy

What Causes This?

It occurs when the facial nerve is swollen, inflamed, or compressed

So what causes the damage? Mostly unknown May be caused by a viral infection

› Viral meningitis› Herpes simplex

Influenza Headaches Chronic ear infections High blood pressure Diabetes Sarcoidosis Tumors Lyme disease trauma

Who can get this?

Affects 40,000 Americans each year› Men and women equally affected› Can occur at any age

Mostly after 15 and before 60 y/o Occurs more often in people who:

› Are pregnant› Are diabetic› Have an upper respiratory infection

Complications

Psychological withdrawal DT changes in appearance, malnutrition or dehydration, mucous membrane trauma, corneal abrasion, muscle stretching, and facial spasms and contractures.

Diagnosed

There are no specific lab tests to confirm diagnosis

Will exam for upper and lower facial weakness

Electromyography› Confirm presence of damage and determine

severity MRI and CT

› r/o causes of pressure on nerve

Treatment

No real Treatment› Symptoms usually subside

Anti-inflammatory and an antiviral › Prednisone and acyclovir

Increases the chance of recovery Acupuncture and surgery

› For long term paralysis

Treatment Cont.

Hard to close eye› Use and eye patch› Eye drops› Tape eye shut when sleeping

Therapeutic Management

Corticosteroids- drug of choice Prednisone may be started

immediately!› Best if initiated before paralysis is

complete› Taper off over 2 weeks› Decrease edema and painAnalgesics may be needed for painAntivirals : Acyclovir (Zovirax) and Famvir

because HSV is implicated in 70% of cases.

When does it go away?

Outcome is good!!! Total recovery depends on amount of damage to

nerve Improvement is gradual Usually start to get better after 2 weeks of onset

and most recover completely within 3 to 6 months.

In a few cases, the symptoms may never completely disappear.

In rare cases, the disorder may recur, either on the same or the opposite side of the face.

Atypical Bell’s Palsy

Clinical features› Slower onset of symptoms› Bilateral› Recurrence

Numbness is not unusual Progression beyond

seven days suggests another cause

Lyme Disease

Lyme disease (borreliosis)› Endemic areas (Northeast USA, central

Europe, Scandinavia, Canada)› Consider in children w/atypical facial palsy

Imaging: small white matter lesions similar to multiple sclerosis, enhancement of facial & other cranial nerves

Bilateral facial paralysis: 25% Important to make diagnosis early

because it is curable early w/antibiotics

Ramsay Hunt Syndrome Caused by reactivation varicella zoster virus

(herpes virus type 3) Facial paralysis + hearing loss +/- vertigo

› Herpes zoster oticus Two-thirds of patients have rash around ear Other cranial nerves, particularly trigeminal

nerves (5th CN) often involved Worse prognosis than Bell’s (complete recovery:

50%) Important cause of facial paralysis in children

6-15 years old

Infectious causes

Acute facial paralysis may result from bacterial or tuberculous infection of middle ear, mastoid & necrotizing otitis externa

Incidence of facial paralysis with otitis media: 0.16%› Infection extends via bone dehiscences to nerve

in fallopian canal leading to swelling, compression & eventually vascular compromise & ischemia

Immune compromised patients are at risk for pseudomona infection

Poor prognosis (complete recovery is < 50%)

Trauma

Most acute post traumatic facial palsies are due to t-bone fractures

Historically fractures classified as longitudinal or transverse with transverse carrying risk of permanent paralysis› Longitudinal fracture usually leads to temporary

paralysis from concussion & swelling of nerve› Transverse fracture can lead to transection of nerve

In all types of paralysis due to fracture, usually the region of geniculate ganglion is involved

Neoplasms

27% of patients with tumors involving the facial nerve develop acute facial paralysis

Most common causes: schwannomas, hemangiomas (usually near geniculate ganglion) & perineural spread such as with head and neck carcinoma, lymphoma & leukemia

Other neoplasms can also involve the facial nerve› Adults: metatstatic disease, glomus tumors,

vestibular schwannomas & meningiomas› Children: eosinophilic granuloma & sarcomas

Other Causes Guillain-Barre Syndrome

› Ascending paralysis Iatrogenic

› Temporal bone surgery Excision of vestibular schwannoma

has <10% chance of paralysis Middle ear surgeries

› Babies who required forceps delivery >90% recovery

Melkersson-Rosenthal Syndrome

Acute episodes of facial paralysis› Facial swelling› Fissured tongue

“Scrotal” tongue Very rare Familial but sporadic

› Usually begins in adolescence Leads to facial disfigurement No definite therapy