Facial Nerve Tumors Flashcards
(34 cards)
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
