Facial Nerve Disorders Flashcards
1
Q
What is somatic motor?
A
Innervation of skeletal muscles
2
Q
What is visceral motor?
A
Innervation of smooth muscles
3
Q
What is visceral sensory?
A
Sensation from the viscera (includes taste and smell as they are associated with the digestive tract)
4
Q
What is somatic sensory?
A
Sensation from sensory organs, skin, skeletal muscles, and connective tissue
5
Q
What are the sensory nerves?
A
Olfactory
Optic
Vestibulocochlear
6
Q
What are the motor nerves?
A
Oculomotor
Trochlear
Abducens
Accessory
Hypoglossal
7
Q
What are the mixed nerves?
A
Trigeminal
Facial
Glossopharyngeal
Vagus
8
Q
Does the facial nerve have somatic motor, visceral motor, visceral sensory, and somatic sensory?
A
Yes
8
Q
What is the somatic motor innervation of the facial nerve?
A
Muscles of facial expression (furrowing the forehead, raising eyebrows, etc.)
Postauricular muscle
Stapedius muscle (MEMR)
9
Q
What is the postauricular muscle involved in?
A
Used to be involved in ear twitching like a rabbit
10
Q
What is the visceral motor innervation of the facial nerve?
A
Lacrimal (tear ducts) and salivary glands (submandibular and sublingual)
Paralysis can result in a lack of tears
11
Q
What is the visceral sensory innervation of the facial nerve?
A
Taste in the anterior 2/3 of the tongue (chorda tympani nerve)
12
Q
What is the somatic sensory innervation of the facial nerve?
A
Posterior EAC, concha, ear lobe, and deep parts of the face
13
Q
What is the origin of the facial nerve?
A
Facial motor nucleus in the anterior pons
14
Q
What is the insertion of the facial nerve?
A
Muscles of facial expression and the stapedius muscle
15
Q
Is the facial nerve a mixed nerve that is derived from the second pharyngeal arch?
A
Yes
16
Q
Does the facial nerve have multiple segments to it?
A
Yes
17
Q
What is the intracranial segment of the facial nerve?
A
Arises from the facial motor nucleus in the anterior pons
Exits the brainstem through the CPA
Goes to the internal auditory canal
18
Q
Once the facial nerve exits the brainstem, how close does it lie to the superior vestibular nerve and the cochlear nerve?
A
1.5 mm
19
Q
Does the AICA provide blood supply to the facial nerve after it exits the brainstem?
A
Yes
It runs between the VII and VIII nerves
20
Q
What is the chorda tympani?
A
It is a branch of the facial nerve
It lies between VII and VIII in the IAC
21
Q
After entering the IAC, where does the facial nerve go?
A
It travels 8 to 10 mm to the meatal foramen (opening of the IAC)
22
Q
In the meatal foramen, does the facial nerve and the facial canal narrow?
A
Yes
This is a common site for facial nerve entrapment and associated disorders
23
Q
Where is the facial canal?
A
It extends between the IAC and the stylomastoid foramen
24
Does the facial nerve have an intratemporal portion?
Yes
25
What are the three segments that fall in the intratemporal portion?
Labyrinthine segment
Tympanic segment
Mastoid segment
26
What is the labyrinthine segment?
Passes through narrowest part of the fallopian canal
Common site of pathology (temporal bone fractures and bells palsy)
27
What is the tympanic segment?
Forms the superior aspect of the oval window niche
Facial nerve is readily injured here in pathologic processes and during ME surgery
28
What is the mastoid segment?
Passes through this after passing between the stapes and the lateral semicircular canal
Exits the temporal bone via the stylomastoid foramen
Supplied by the stylomastoid artery
Shows variable branching patterns in the face
29
Is the course of the facial nerve vulnerable to many neoplastic, traumatic, and infectious conditions?
Yes
A lot of different parts of the nerve
30
What is the incidence of newborn facial paralysis?
About 0.2%
31
How can pediatric facial nerve paralysis develop?
Congenital
Prenatal acquired
Postnatal acquired
32
What is the cause of congenital pediatric facial nerve paralysis?
Development errors during embryogenesis
33
What is the cause of prenatal acquired pediatric facial nerve paralysis?
Intrauterine trauma (forceps compression during delivery or compression of the side of face against sacrum during labor)
Fetal exposure to teratogens (maternal rubella)
34
What is the time period of prenatal?
One month before and after birth
35
What is the cause of postnatal acquired pediatric facial nerve paralysis?
Many of the same conditions that can affect adults (trauma and infections)
36
Is osteopetrosis a congenital facial nerve disorder?
Yes
37
How is osteopetrosis inherited?
AD
38
Is osteopetrosis present at birth?
Yes
It has varying severity and is milder than the AR condition
39
Is osteopetrosis a bony dysplasia?
Yes
It causes the bones to harder and become denser
40
Does osteopetrosis result in multiple cranial neuropathies?
Yes
Because of bony obliteration of neural foramina with entrapment and compression of cranial nerves
41
Can osteopetrosis result in congenital facial paralysis and vision and hearing loss?
Yes
Due to the progressive and fluctuating involvement of CN II, V, VII, and VIII
42
What is the treatment for osteopetrosis?
Symptomatic
Facial nerve decompression if nerve entrapment and associated facial dysfunction
43
Is mobius syndrome a congenital facial nerve disorder?
Yes
44
What is mobius syndrome?
Rare congenital disorder associated with hypoplasia of CB VI and VII nuclei
45
What is the etiology of mobius syndrome?
Genetic with multiple genes and modes of inheritance (multifactorial)
46
What can cause mobius syndrome?
Exposure in utero to teratogens like cocaine, ergotamine (used as a vasoconstrictor to treat migraine, induce child birth, and prevent post-partum hemorrhage), and misoprostol (vasodilator to prevent stomach ulcers and tinnitus)
47
What are the signs and symptoms of mobius syndrome?
Congenital facial diplegia (bilateral facial paralysis)
Associated CN VI unilateral or bilateral paralysis
Other CN deficits
Deformities of extremities
Musculoskeletal deformities
Intellectual disability
48
What is the treatment for mobius syndrome?
Ophthalmologic consultation
Nerve reconstructive therapy
49
Is bell's palsy an idiopathic facial nerve disorder?
Yes
50
Is bell's palsy the most common cause of acute unilateral facial paralysis?
Yes
Accounting for approx 60 to 75% of these cases
51
Can bilateral facial paralysis occur?
Yes
But it is much less common than unilateral
52
Can bell's palsy be recurrent?
Yes, in about 4 to 14% of affected individuals
53
What side is generally more affected by bell's palsy?
The right
54
Does bell's palsy affect both sexes equally?
Yes
Although the condition is more frequent in younger women (10-19) compared to the same age group of men
55
Can pregnancy increase the risk of bell's palsy threefold?
Yes
Most commonly during the third trimester
56
Can preeclampsia increase the risk of occurrence of bell's palsy?
Yes
57
What is preeclampsia?
Disorder of pregnancy with high blood pressure and proteins in the urine
58
What is the etiology of bell's palsy?
We don't know the cause
Diagnosis of exclusion (rule out other conditions)
Herpes simplex virus
Begins with the sensory fibers and then involves motor fibers
59
Why can herpes simplex virus cause bell's palsy?
Causes inflammatory response leading to compression of the nerve at the meatal foramen and the labyrinthine segment
Nerve degeneration can occur
60
What rarely causes bell's palsy?
Otitis media
CPA, parotid gland, or skull-based tumors
Metastatic lesions
61
How is bell's palsy diagnosed?
Exclusionary diagnosis, but misdiagnosis is rare
62
What are some of the things that suggest bell's palsy?
Onset of partial/total unilateral facial paralysis during a 48-hour period
Fever and neck stiffness at onset
No hearing loss and vertigo
No other CN neuropathy
Normal head and neck examination
Drying of eye due to decreased eye closure and lack of lacrimation
Rare cases of recurrence
Some spontaneous recovery within 3 to 6 months in all patients
63
What is needed to diagnose within 3 to 6 months of onset of bell's palsy?
Audiometric evaluation
Testing for HIV and lyme disease (if appropriate)
64
What does an audiometric evaluation look like for bell's palsy?
Normal otoscopy
Hearing loss is rare for pure tones
Normal tymps
Reflexes normal or abnormal
Abnormal ARTs indicate lesion proximal to the stapedius nerve
Normal ARTs indicate lesion distal to the stapedius nerve
65
What is done if there is no return of function after 6 months of bell's palsy?
Electroneurography (ENoG) to assess degeneration of nerve fibers
CT scan and MRI (for differential diagnosis of VII N tumors)
66
What is the treatment of bell's palsy?
Decompression of the nerve (indicated when over 90% degeneration occurs within 2 weeks of onset)
Steroids early in disease
Acyclovir (antiviral) with steroids (inconsistent data)
Eye care to prevent permanent damage due to dryness
67
What is the differential diagnosis of bell's palsy?
CPA or skull-based tumors
Vestibular schwannoma
Otitis media
Parotid gland tumors
68
Do majority of patients recover from bell's palsy within 3 to 6 months with no medical or surgical intervention except eye care needed?
Yes
69
Is there a good prognosis for recovery of function from bell's palsy?
Yes
Especially for younger patients, partial paralysis and recovery of function within 2 months, intact ARTs (distal to stapedius nerve), electromyographic evidence of voluntary activity, and ENoG shows less than 90% of degeneration of electrically evoked muscle action potential after about 2 weeks on onset
70
What are some indications of poor prognosis of bell's palsy?
Over 65 years old
Greater than 90% nerve degeneration within the first 2 weeks
Diabetic patients (affects circulation and could affect blood vessels to VII N)
71
What is the most common site of temporal bone fractures?
Adjacent to the geniculate ganglion
72
What is a common result of temporal bone fractures?
Hearing loss (CHL, SNHL, or mixed)
73
What is iatrogenic injury?
Injury during surgical procedures
74
What is the incidence of iatrogenic injury?
0.5 to 4%
Most common site of injury is the tympanic segment over the oval window
75
What are some other traumas to the facial nerve?
Lacerations
Gunshot wounds
76
Is facial nerve grafting done after penetrating trauma to the nerve?
Yes
77
Is malignant otitis externa an infectious facial nerve disorder?
Yes
78
What is the etiology of malignant otitis externa?
Invasion of pseudomonas pneumoniae and other bacteria into the soft tissue, cartilage, and bone
79
What is the treatment of malignant otitis externa?
Debridement of infected tissue
Decompression of facial nerve
Antibiotics
80
Can facial paralysis be secondary to inflammatory ME disease?
Yes, like acute suppurative otitis media
81
What is acute suppurative otitis media caused by?
Gram-positive bacteria and haemophilus influenzae
82
Can acute suppurative otitis media invade into facial canal?
Yes, through a dehiscence and may evoke an inflammatory response with edema, compression, and ischemia resulting in facial weakness
83
What is the treatment of acute suppurative otitis media?
Myringotomy
Appropriate antibiotics
Trans-mastoid decompression if nerve degeneration is progressive
84
Is facial nerve paralysis secondary to chronic otitis media common?
Yes
Can occur with or without cholesteatoma
85
What is the treatment for chronic otitis media?
Urgent indication for surgical intervention
Tympano-mastoidectomy is appropriate followed by decompression of facial nerve
Removal of cholesteatoma adherent to the nerve
86
Can herpes zoster oticus also cause facial nerve problems?
Yes
87
What is herpes zoster oticus caused by?
Varicella zoster virus (shingles)
88
What is another name for herpes zoster oticus?
Ramsey-hunt syndrome
89
What are some signs and symptoms of herpes zoster oticus?
Otalgia and severe pain
Vesicular eruption on the concha and/or external canal
Sensory disruption of CN VII
Facial paralysis
Hearing loss
Vertigo
Higher frequency of complete degeneration of the facial nerve
90
What is the characteristic site of pathology for herpes zoster oticus?
Labyrinthine segment of the facial nerve
Can involve CNs V, IX, X, and XI
Herpes zoster cephalicus (rare and involves cervical dermatomes)
91
What is the treatment of choice for herpes zoster oticus?
Acyclovir (antiviral medication)
92
What is the prognosis for herpes zoster oticus?
Less chances of complete spontaneous recovery
Chances of recovery low even with steroid
93
What are primary facial neuromas or schwannomas?
Rare benign neoplasms of schwann cells
94
Are metastatic tumors 16 times more common than primary ones?
Yes
They come from different places in the body
95
What are some presenting signs/symptoms of facial neuroma?
Facial weakness (2/3 of all cases)
Hearing loss (50% of all patients) - can be SNHL, CHL, or mixed depending on tumor location
Other symptoms in 10 to 15% of cases including tinnitus, otorrhea, ear canal mass, otalgia, and vestibular symptoms
96
Is the tumor location of facial neuroma variable?
Yes
Could be in the tympanic segment (most common), vertical segment (lesion proximal to stapedius nerve), labyrinthine segment and geniculate body, IAC, CPA, and in the stylomastoid foramen
97
Do many facial nerve tumors involve multiple segments?
Yes
98
If the facial neuroma is confined to IAC or CPA, can no facial symptoms be present?
Yes
Misdiagnosis is common with vestibular schwannoma
99
How is facial neuroma diagnosed?
Audiometric evaluation
Electroneurography
CT and MRI
ABR
100
What is the audiometric findings for facial neuroma?
Generally SNHL due to cochlear nerve compression
Normal tymps
Abnormal ARTs indicates lesion proximal to the stapedius muscle
Normal ARTs indicated lesion distal to the stapedius nerve
101
Where is the lesion likely for facial neuroma?
In the mastoid or extratemporal segment of the facial nerve
102
What are the electroneurography findings for facial neuroma?
Can be normal in cases of VII N tumors located primarily in the CPA that may cause hearing loss but do not affect affect facial function
103
What are the CT and MRI findings of facial neuroma?
Differential diagnosis from VIII N tumors and other conditions
104
Can ABR determine if a tumor is a facial or acoustic neuroma?
Yes
105
Does facial nerve pathology cause a distinct ART pattern?
Yes
ARTs are abnormal whenever measured on the affected side (when the probe is in the affected ear)
106
Is there controversy over whether to surgically remove small facial neuromas?
Yes
107
If a facial neuroma is slow growing, what is the management?
Conservative
Mostly observation unless VII N paralysis or other symptoms
108
What are other management methods of facial neuromas?
Radiotherapy to decrease tumor size before surgery
Decompression of facial nerve
Tumor resection if warranted with facial nerve grafting
109
What is often used to harvest the graft?
The greater auricular or sural nerve
110
Does grafting result in excellent facial muscle tone post-surgery?
Yes after 6 to 8 months but often some weakness remains
111
What are the differential diagnoses of facial neuroma?
Otitis media with CHL
Cholesteatoma (requires prompt decompression of VII N and resection)
Glomus tumor
Meningiomas (tumor of meninges)
Acoustic neuroma (vestibular schwannoma - both VII and VIII nerve schwannomas have been reported in NF2
