Disorders Quiz 3 Flashcards
(177 cards)
1
Q
What are the four types of nerve functions?
A
Somatic motor, somatic sensory, visceral motor, visceral sensory
2
Q
What is a somatic motor nerve?
A
Innervates skeletal muscles
3
Q
What is a somatic sensory nerve?
A
Sensation from sensory organs, skin, muscles, connective tissues
4
Q
What is a visceral motor nerve?
A
Innervates smooth muscle
5
Q
What is a visceral sensory nerve?
A
Sensation from viscera – taste and smell
6
Q
What are the somatic motor functions of CN VII?
A
Facial expression, postauricular muscle, stapedius muscle
7
Q
What are the somatic sensory functions of CN VII?
A
Posterior EAC, concha, ear lobe, face sensation
8
Q
What are the visceral motor functions of CN VII?
A
Tear ducts and salivary glands
9
Q
What are the visceral sensory functions of CN VII?
A
Taste
10
Q
What is the origin of the facial nerve?
A
Facial motor nucleus on the anterior pons
11
Q
Where does the facial nerve insert?
A
Muscles in the face and the stapedius muscle
12
Q
From which pharyngeal arch is the facial nerve derived?
A
A mixed nerve from the second arch
13
Q
Where does the facial nerve exit the brainstem?
A
Pontomedullary junction, through the CPA, to the IAC
14
Q
What important structures does the facial nerve run alongside?
A
CN VIII (superior vestibular and cochlear nerves), AICA (anterior inferior cerebellar artery)
15
Q
Where does the facial nerve narrow to its lowest diameter?
A
Fallopian canal
16
Q
What is significant about the Fallopian canal?
A
It is a common site for facial nerve entrapment and disorders
17
Q
What are common issues in the labyrinthine segment of the facial nerve?
A
Temporal bone fracture, Bell’s palsy
18
Q
What are the common issues in the tympanic segment of the facial nerve?
A
Easily injured from pathologies or during ME surgery (located by the oval window)
19
Q
What are the common issues in the mastoid segment of the facial nerve?
A
Shows variable branching patterns in the face
20
Q
How can pediatric facial nerve paralysis be classified?
A
Congenital, prenatal acquired, postnatal acquired
21
Q
What is congenital facial paralysis?
A
Developmental errors during pregnancy – present at birth
22
Q
What are examples of prenatal acquired facial paralysis?
A
Intrauterine trauma, fetal exposure to teratogens
23
Q
What teratogen can cause facial nerve paralysis?
A
Rubella
24
Q
What are common causes of postnatal acquired facial paralysis?
A
Trauma and infections
25
What is osteopetrosis?
Congenital facial nerve disorder of bony dysplasia causing bone to harden and become dense
26
What is the treatment for osteopetrosis?
Facial nerve decompression
27
What is the inheritance pattern of osteopetrosis?
AD
28
What is Mobius syndrome?
Congenital facial nerve disorder resulting in underdevelopment of VI and VII nerve nuclei
29
What are signs and symptoms of Mobius syndrome?
Facial paralysis, CN VI paralysis, CN deficits, musculoskeletal deformities, intellectual disability
30
What teratogens can cause Mobius syndrome?
Cocaine, ergotamine, misoprostol
31
What are the treatments for Mobius syndrome?
Nerve reconstruction surgery
32
What is the most common cause of unilateral facial paralysis?
Bell’s Palsy
33
What is Bell’s Palsy?
Idiopathic facial nerve disorder causing unilateral facial paralysis that can be recurrent
34
What does idiopathic mean?
It is an exclusionary diagnosis – other conditions must be ruled out
35
What are risk factors for Bell’s Palsy?
Right side affected more often, pregnancy can increase risk
36
What are non-idiopathic etiologies of Bell’s Palsy?
Herpes simplex virus, otitis media, CPA/parotid gland/skull tumors, facial nerve schwannoma
37
What history and clinical examination results indicate Bell’s Palsy?
Onset within 48 hours, stiffness and fever, no hearing loss or vertigo
38
What should you test if Bell’s Palsy is diagnosed?
Audiometric eval, HIV, and Lyme Disease
39
What will audiometric evaluation reveal in Bell’s Palsy?
Normal otoscopy, usually normal pure-tone audiometry, normal tympanogram
40
What happens if function does not return in 6 months with Bell’s Palsy?
Electroneurography to assess nerve fibers along with CT scan and MRI
41
What is the treatment for Bell’s Palsy?
Decompression of the nerve, steroids, eye care for dry eyes
42
What are differential diagnoses for Bell’s Palsy?
CPA/skull/parotid gland tumors, facial/vestibular nerve schwannoma, otitis media
43
What is the prognosis for Bell’s Palsy?
Function recovery typical within 3 to 6 months without intervention
44
What are positive factors for good prognosis in Bell’s Palsy?
Younger patients, early recovery, intact acoustic reflex thresholds
45
What are negative factors impacting prognosis in Bell’s Palsy?
Older patients, significant nerve degeneration, diabetic patients
46
What are traumatic causes of facial nerve disorders?
Temporal bone fractures, iatrogenic injury during surgery, lacerations, gunshot
47
What surgical site is most common for facial nerve injury?
The oval window
48
What infection of the ear canal can cause facial nerve disorder?
Malignant otitis externa
49
What is malignant otitis externa?
Pseudomonas pneumoniae bacteria penetrates soft tissue, cartilage, and bone
50
What is the treatment for malignant otitis externa?
Debridement, decompression of facial nerve, antibiotics
51
What two ME diseases can cause facial nerve disorder?
Acute suppurative otitis media, chronic otitis media with or without cholesteatoma
52
What causes acute suppurative otitis media?
Haemophilus influenzae
53
How does chronic otitis media cause facial nerve disorder?
Infection invades the facial canal through a dehiscence
54
What is the treatment for chronic otitis media?
Antibiotics, nerve decompression, removal of cholesteatoma
55
What viral infection can cause facial nerve disorder?
Herpes zoster oticus (Ramsay-Hunt Syndrome)
56
What virus causes Ramsay-Hunt Syndrome?
Varicella zoster virus
57
What are signs and symptoms of Ramsay-Hunt Syndrome?
Otalgia, rash of the concha or EAC, facial paralysis, hearing loss, vertigo
58
What portion of CN VII is the site for HZO?
Labyrinthine segment of the facial nerve
59
What is the treatment for HZO?
Antiviral meds, acyclovir
60
What is the prognosis for HZO?
Less chances of recovery of the nerve, even with steroids
61
What are facial nerve schwannomas?
Rare, benign neoplasms of SCHWANN cells
62
How does the location of a facial nerve schwannoma impact symptoms?
Closer to the brainstem may cause more severe hearing/balance problems
63
Do facial nerve schwannomas always cause facial nerve symptoms?
No; in 27% of patients, it is normal
64
What are symptoms of a facial nerve schwannoma?
Facial weakness, facial twitching, tinnitus, dizziness, hearing loss
65
What is the most common tumor location for facial nerve schwannomas?
Tympanic segment
66
What location might result in no facial symptoms from a schwannoma?
Internal auditory canal or cerebellopontine angle
67
How is a facial nerve schwannoma diagnosed?
Audiometric evaluation, ARTs, electroneurography, CT scan/MRI
68
What is the ART pattern for a facial nerve schwannoma?
Probe effect – abnormal response on affected side
69
How is a facial nerve schwannoma managed?
Monitoring, radiotherapy, decompression, tumor resection, grafting
70
What are differential diagnoses for facial nerve schwannomas?
Otitis media, cholesteatoma, glomus tumor, meningiomas, acoustic neuroma
71
What is ANSD?
Hearing disorder characterized by disruption of temporal coding of acoustic signals
72
What is disrupted in ANSD?
Neural synchrony
73
What are the difficulties associated with ANSD?
Interference with language comprehension, localization, binaural perception
74
What is the diagnostic criteria for ANSD?
Normal OAEs with absent or abnormal ABR response
75
Where are the site of lesions for ANSD?
Damage to synaptic junctions of IHCs, disordered release of neurotransmitters
76
What is the genetic code for ANSD?
DFNB9, AR
77
Common mutation associated with ANSD?
Nonsense mutation – early stop code
78
What protein is impacted in ANSD?
Otoferlin
79
What percent of the deaf population has ANSD?
10-15%
80
What is the etiology of ANSD?
Idiopathic, genetic, or environmental
81
What are common mutations in ANSD?
Connexin 26 and otoferlin
82
What metabolic disorder can cause ANSD?
Diabetic neuropathy
83
What immune disorder can cause ANSD?
Guillian-Barre syndrome
84
What are environmental causes of ANSD?
Viral infections like mumps and measles
85
What is a risk factor for babies related to ANSD?
Prolonged stay in the NICU
86
What is special about ANSD caused by hyperbilirubinemia?
Can be reversible
87
What vascular issue might complicate ANSD diagnosis?
Cut off blood supply from the cochlea
88
How do you diagnose ANSD?
Case history, OAEs, ABR, ARTs, audiometry, genetic evaluation
89
What are the ABR results for ANSD?
No amplitude or latency for waves I, III, or V
90
How is latency and amplitude related in a normal ABR vs. with ANSD ABR?
Normally, latency increases with decreasing amplitude; with ANSD, latency does not increase
91
How is ANSD diagnosed with click-evoked ABR?
Performed at high level stimulus using separate polarities
92
What does ABR stand for?
Auditory Brainstem Response
93
How does latency change with amplitude in normal conditions?
Latency increases with decreasing amplitude
94
In Auditory Neuropathy Spectrum Disorder (ANSD), how does latency behave?
Latency does not increase
95
What are two reasons why no CM might be present in ANSD?
Clinician error or use of alternating polarity
96
How is ANSD diagnosed with click-evoked ABR?
Performed at high level stimulus (75-90 dB nHL) using separate rarefraction and condensation polarities in separate trials
97
What indicates a true nerve response in ANSD diagnosis?
No reversal of the waveform with reversal of polarity
98
If latency does not increase with decrease in intensity, what is the response likely to be?
Cochlear Microphonic (CM)
99
Can ABR be used to estimate thresholds in ANSD?
No
100
How are thresholds estimated in ANSD?
Behavioral assessment
101
What is the typical hearing configuration of ANSD?
Can range from normal/mild to severe to profound SNHL
102
What impact does ANSD have on speech audiometry?
Significant impact on speech perception even with normal hearing thresholds
103
What might be the difference between speech in quiet and speech in noise for ANSD?
Speech in quiet might be normal, speech in noise might be very poor
104
How is ANSD managed initially?
Initially, amplification is used
105
What is the most successful treatment for ANSD, regardless of thresholds?
Cochlear Implants (CIs)
106
When are Cochlear Implants successful for ANSD?
When the etiology is a biochemical abnormality of neurotransmitter substances
107
How is gene therapy being used to manage ANSD?
Adeno-associated virus carrying a human version of the OTOF gene injected into the round window
108
Is ANSD pre- or post-lingual?
Both
109
What is the difference between ANSD and synaptopathy?
Both have the same site of lesion, but ANSD can occur along other places along the auditory brainstem
110
What are common audiologic findings of ANSD?
Present OAEs, abnormal ABR with CM present, poor WRS, audiogram can be any configuration
111
What is a neoplasm?
An abnormal mass of tissue
112
How is the growth of a neoplasm characterized?
Excessively and autonomously
113
What are brain tumors?
Intracranial lesions that are benign, malignant, or mass occupying
114
What type of cells do 45% of intracranial tumors arise from?
Neuroglia cells
115
What are the four main types of neuroglial cells?
* Astrocytes
* Oligodendrocytes
* Microglia
* Ependymal cells
116
What are astrocytes?
Star-shaped support cells that function as insulators
117
What do oligodendrocytes do?
Form the myelin sheath in central nerve fibers
118
What is the role of microglia?
Ingest and remove neural residue during inflammation
119
What happens if there is a lack of astrocytes?
Implication in Parkinson's disease
120
What are characteristics of benign tumors?
* Slow growing
* Encapsulated
* Do not metastasize
* Not life-threatening
121
When can a benign neoplasm become dangerous?
If it is locally destructive or located in areas controlling vital functions
122
What are characteristics of malignant neoplasms?
* Faster growing
* Can invade and destroy contiguous structures
* Life-threatening
* Can metastasize
123
What are intra-axial tumors?
Tumors that originate in the brain tissue
124
What are examples of intra-axial tumors?
* Astrocytoma
* Glioblastoma
* Cerebral metastases
125
What are extra-axial tumors?
Tumors that originate from tissue that is neither neuronal nor glial
126
What is the most common extra-axial tumor in the brain?
Meningiomas
127
What are characteristics of hemangiomas?
* Present in the first month of life
* Initial rapid growth followed by slow involution
128
What are characteristics of vascular malformations?
* Always present at birth
* Grow in proportion with the body
* Do not regress
129
Where are most vascular malformations in the temporal bone present?
In the IAC or fallopian canal
130
What are signs and symptoms of vascular malformations and hemangiomas?
* CN VII dysfunction
* Hemifacial spasm
* Tinnitus
* Conductive hearing loss
* Progressive SNHL
* Vertigo
131
What is the reason most patients seek medical care regarding vascular malformations?
Facial nerve dysfunction
132
How are vascular malformations and hemangiomas diagnosed?
Case history, CT, MRI with contrast
133
What type of MRI is best for diagnosing vascular issues?
T2 MRI
134
What are differential diagnoses for vascular malformations?
* Meningioma
* VII N schwannoma
* Cholesteatoma
135
What is the treatment for vascular malformations?
Surgical removal
136
What are schwann cells responsible for?
Forming myelin sheath in the PNS
137
What is the most common benign tumor of the temporal bone?
Schwannoma
138
What are the three common locations of schwannomas in the temporal bone?
* Medial portion of IAC (CN VIII)
* Jugular foramen (CNs IX and X)
* Fallopian canal (CN VII)
139
What are characteristics of vestibular schwannomas?
* Unilateral
* Benign
* Slow growing
* Extra-axial
140
What happens if vestibular schwannomas are not treated?
Coma, Hydrocephalus, and death
141
What are the two phases of vestibular schwannoma?
* Otologic phase
* Neurologic phase
142
What side do signs and symptoms of vestibular schwannoma occur?
Ipsilateral to the lesion
143
What are symptoms of vestibular schwannoma?
* Hearing loss
* Headache
* Tinnitus
* Unsteady gait
* Facial paralysis (rare)
144
What are pure-tone findings of vestibular schwannomas?
Unilateral high frequency SNHL
145
What do OAEs look like in vestibular schwannomas?
Likely normal with decreased contralateral suppression
146
What will speech audiometry show for vestibular schwannomas?
WRS will be very poor and worse in noise
147
What is reflex decay?
Adaptation that occurs because of reduction of neural response over time
148
What is normal reflex decay?
No decay for 10 seconds at 10 dB above the reflex
149
What is tone decay?
When a tone dies out during listening
150
What tone decay is considered positive for retrocochlear pathology?
>30 dB for 60 seconds
151
What is the ABR result for retrocochlear pathology?
Abnormal in vast majority of CN VIII tumors
152
What is the gold standard for definitive diagnosis for vestibular schwannoma?
T1 MRI with gadolinium contrast-enhanced MRI
153
What is an indirect sign of a vestibular schwannoma?
Trumpeted internal acoustic meatus
154
What are differential diagnoses for vestibular schwannoma?
* Meningiomas
* Neurofibromatosis type 2
* Facial nerve schwannomas
* Hemangiomas
* Epidermoid cysts
* Endolymphatic sac tumors
155
What is the treatment for vestibular schwannoma?
Surgery or stereotactic radiosurgery
156
What is a meningioma?
Single, vascular, benign, lobulated brain tumors arising on the meninges
157
What is the incidence of meningiomas?
Appears later in life and more in females
158
What are risk factors for meningiomas?
* NF2
* Radiation therapy
* Genetics
159
What is the relation of size and symptoms with meningiomas?
Can be large without causing symptoms if growing in a spacious location
160
What are audiometric signs and symptoms of meningioma?
* Progressive unilateral SNHL
* Vertigo
* Tinnitus
* Abnormal ARTs
161
What is the treatment for meningioma?
Surgery and radiation
162
What are some benign tumors of the temporal bone?
* Osteoma
* Paraganglioma
* Neurofibromatosis 2
* Facial nerve schwannoma
163
What is the impact of cortical tumors on audiometric results?
Can have normal results for pure-tones, ARTs, OAEs
164
What are other symptoms of cortical tumors?
* Headaches
* Dizziness
165
What is the recurrence rate for meningiomas?
High recurrence, especially since resection is not always possible
## Footnote
Meningiomas are known for their tendency to recur after treatment.
166
Name some benign tumors of the temporal bone.
* Osteoma
* Paraganglioma
* Neurofibromatosis 2 (NF2)
* Facial nerve schwannoma
## Footnote
These tumors are typically non-cancerous and can affect hearing and balance.
167
What is the impact of cortical tumors on audiometric results?
Can have normal results for pure-tones, ARTs, OAEs, and possibly ABR. The only test that will probably be abnormal is WRS, especially SIN.
## Footnote
This highlights the complex relationship between tumor presence and audiometric testing outcomes.
168
What are other symptoms of cortical tumors?
* Headaches
* Dizziness
## Footnote
These symptoms may vary depending on the tumor's location and size.
169
On which side will symptoms show in relation to a cortical tumor?
The opposite side of the lesion
## Footnote
This is due to the contralateral nature of symptom presentation in neurological conditions.
170
What are audiologic signs and symptoms of malignant temporal bone tumors?
* Aural discharge
* Bloody discharge
* Pain
* Hearing loss
* Tinnitus
## Footnote
These symptoms are similar to those of suppurative otitis media.
171
What are signs and symptoms of cranial neuropathies?
* Facial paralysis
* Headache
* SNHL
* Vestibular issues
## Footnote
These symptoms indicate potential dysfunction in cranial nerves.
172
Which cancer is most commonly associated with spreading to the temporal bone?
Breast cancer
## Footnote
Other cancers that can spread include lung cancer, renal carcinoma, GI and liver adenocarcinoma, and thyroid cancer.
173
Where is the facial nerve located?
Facial Nerve CN VII
## Footnote
The facial nerve is responsible for facial expressions and is involved in taste sensations.
174
What happens in the case of a proximal lesion to the stapedius nerve?
Abnormal ARTs
## Footnote
This can indicate dysfunction in the auditory reflex pathways.
175
What happens in the case of a distal lesion to the stapedius nerve?
Normal ARTs
## Footnote
This suggests that the distal portions of the auditory pathway are intact.
176
What are some common cancers that can spread to the temporal bone?
* Breast cancer
* Lung cancer
* Renal carcinoma
* GI and liver adenocarcinoma
* Thyroid cancer
* Osteoblastoma
* Melanoma
## Footnote
Understanding the origins of metastases can aid in diagnosis and treatment planning.
177
What are the auditory results from a pure tone threshold test at 95 dB nHL?
Wave I: 1.44 ms, Wave III: 3.84 ms, Wave V: 6.02 ms
## Footnote
These latencies are essential in evaluating auditory processing and identifying potential abnormalities.
