Facial Nerve Tumors Flashcards
What are the 4 components of the facial nerve?
- Branchial motor
- Visceral motor
- Special sensory
- General sensory
Describe the branchial motor component of the facial nerve.
- Supplies the muscles of facial expression
- Posterior belly of digastic muscle
- Styohyoid
- Stapedius
Describe the visceral motor component of the facial nerve.
- Parasympathetic innervation of the lacrimal, submandibular, and sublingual glands
- As well as mucous membranes of nasopharynx, hard and soft palate
Describe the special sensory component of the facial nerve.
- Taste sensation from the anterior 2/3 of tongue
- Hard and soft palates
Describe the general sensory component of the facial nerve.
-General sensation from the skin of the concha of the auricle and from a small area behind the ear
What are the motor branches of the facial nerve?
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
Describe differential diagnosis for acute facial nerve paralysis.
- Polyneuritis
- Trauma (i.e. temporal bone, birth traum)
- Otitis media
- Sarcoiditis
- Malkersson-Rosenthal
- Neurologic disorders (i.e. HIV)
What are examples of polyneuritis?
- Bell’s palsy
- Herpes zoster
- Guillan Barre syndrome
- Autoimmune disease
- Lyme disease
- HIV
- Kawasaki disease
Describe differential diagnosis for chronic or progressive facial nerve paralysis.
- Malignancies (i.e. metastatic tumor)
- Benign tumors (i.e. schwannoma, glomus tumor)
- Cholesteatoma
Describe the examination of patient with facial paralysis/paresis.
-History (time of onset, precipitating factors, speed of progression, associated symptoms)
-PE (House-Brackmann classifications)
-Topodiagnostic tests
-Electrophysiologic tests
-Lab tests PRN
Imaging
Describe the House-Brackmann Scale.
- Grading of CN VII function
- Grade I: normal
- Grade II: mild
- Grade III: moderate
- Grade IV: moderately-severe
- Grade V: severe
- Grade VI: total paralysis
Describe Grade II of the House-Brackmann Scale
- Mild
- Gross: slight weakness noticeable on close inspection
- At rest: normal symmetry and tone
- Motion:
- Forehead: moderate to good
- Eye: complete closure with minimum effort
- Mouth: slight asymmetry
Describe Grade III of House-Brackmann Scale.
- Moderate
- Gross: obvious but not disfiguring asymmetry; may have hemifacial spasm
- At rest: normal symmetry and tone
- Motion:
- Forehead: slight to moderate movement
- Eye: complete closure with effort
- Mouth: slightly weak with maximum effort
Describe Grade IV of House-Brackmann Scale.
- Moderately-severe
- Gross: obvious weakness and/or disfiguring asymmetry
- At rest: normal symmetry and tome
- Motion:
- Forehead: no movement
- Eye: incomplete closure
- Mouth: asymmetric with maximum effort
Describe Grade V of House-Brackmann Scale.
- Severe
- Gross: only barely perceptible motion
- At rest: asymmetry
- Motion:
- Forehead: no movement
- Eye: incomplete closure
- Mouth: slight movement
What are some topodiagnostic tests of facial nerve function?
- Schirmer’s test of lacrimal function
- Stapedial reflex
- Electrogustometry
- Salivary flow
What are some electrodiagnostic tests of facial nerve function?
- Nerve excitability test
- Maximum excitability test
- Electromyography (EMG)
- Electroneuronography (ENoG)
What is the nerve excitability test?
- Transcutaneous stimuli delivered over stylomastoid foramen
- Electrical pulses delivered at increasing current levels until facial twitch is noticed
What is the maximum excitability test?
- Transcutaneous stimuli looking for twitch
- Increase current to get a maximum response
What is electromyography (EMG)?
- Recording of spontaneous and voluntary muscle potentials
- Needle electrodes in facial muscle groups
- May help to predict recovery
What is electroneuronography (ENoG)?
- Stimulating electrodes deliver suprathreshold electrical stimuli
- Recording electrode measures compound muscle action potential
- Reduction in response amplitude reflects number of damaged motor fibers
- Best 3 days to 3 weeks
What is Bell’s Palsy?
- Most common acute mono-neuropathy or disorder affecting a single nerve
- Most common diagnosis associated with facial nerve paresis or paralysis of unknown cause
- Causes partial or complete inability to voluntary move facial muscles on the affected side of the face
What may result from facial paresis/paralysis of Bell’s Palsy?
- Significant oral incompetence
- Eye injury
- Long term poor outcomes, which can be devastating to the patient
Describe the diagnosis of Bell’s Palsy.
- Diagnosis of exclusion
- Not every pt with facial paresis/paralysis will have Bell’s Palsy
- Rapid exclusion (<72 hours)
- Bilateral is RARE
- Currently, cause is unknown
- Can occur in anyone, but is most common in 15-45 y/o and those with risk factors
Describe the issues of testing/treating Bell’s Palsy.
- Variations in care; controversy over best treatment options
- Numerous tests available; many are of questionable benefit
- Typically, self-limiting
What are risk-factors for Bell’s Palsy?
- Pregnancy
- Severe pre-eclampsia
- Obesity
- Hypertension and chronic hypertension
- Diabetes
- Upper respiratory ailments
Describe the prognosis for Bell’s Palsy.
- Majority have spontaneous, good recovery at 3-6 months
- Best prognosis: never Grade VI, signs of recovery at 2 months, EMG evidence of voluntary activity, present acoustic reflex, <90 % degeneration on ENoG at 2 week point
- Worst prognosis: age 65+, diabetes, >90% degeneration on ENoG at 2 week point
Describe eye care for Bell’s Palsy.
- Very important for Grade III or worse
- Drying of eye secondary to decreased eye closure/lacrimation, leading to keratopathy and breakdown of the cornea
- Daytime: artificial tears every 2 hours
- Nighttime: opthalmic ointment and moisture chamber over eye
- Temporary tarsorrpaphy or gold weight
Describe medical treatment for Bell’s Palsy.
- Steroid Rx should be given in 72 hours for 16;0+ (i.e. prednisone)
- Antiviral therapy used in combination with oral steroid by some
Describe surgical treatment of Bell’s Palsy.
- Facial nerve decompression (transmastoid, MF)
- No clear evidence of efficacy (good outcomes for pts with incomplete paralysis, small Ns, variable surgical approaches, lack of efficacy compared to natural hx)
What is the presentation of Herpes Zoster Oticus aka Ramsay Hunt Syndrome?
- Severe pain
- Vesicles in cocha
- Severe facial paralysis (Grades V and VI)
- Frequently involves CN VIII giving hearing loss and vertigo
- May involve CN Ix, X, XI, and XII
What is the cause of Herpes Zoster Oticus?
-Varicella zoster virus
What is the prognosis for Herpes Zoster Oticus?
- Spontaneous recovery of CN VII function 22-31%
- ENoG prognostication-not so good
What is the presentation of facial neuroma?
- Facial weakness
- Hearing loss (50%)
- 10-15% have: tinnitus, ear canal mass, pain, vestibular sx, otorrhea
