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Acquired Auditory Vestibular Disorders > Retrocochlear and CANS Pathologies > Flashcards

Retrocochlear and CANS Pathologies Flashcards

Lecture 10-11

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Preparativo Vestibular e ENEM flashcards
1
Q

Several conditions that affect the _____ and its connections to the ______?

A

Auditory nerve and Central auditory nervous system (CANS)

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2
Q

Retrocochlear disorders are?

A

several conditions that affect the auditory nerve and its connections to the central auditory nervous system

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3
Q

What are some common retrocochlear diseases and disorders?

A
  • genetic/congenital conditions
  • auditory processing disorders
  • intracranial neoplasms
  • trauma to auditory nerve and temporal lobe
  • cerebrovascular accidents
  • central auditory nervous system dysfunction
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4
Q

Neoplasia means?

A

new growth

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5
Q

neoplasm is?

A

Abnormal mass tissue

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6
Q

Neoplasm is a disorder of ?

A

the cell cycle

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7
Q

growth of neoplasm is?

A

uncoordinated, competes with normal cells/tissue for energy and nutrition

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8
Q

neoplasms are:

A

purposeless, prey on host, and autonomous

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9
Q

Intracranial neoplasms

A

-benign or malignant tumors
- mass lesions of brain parenchyma (functional tissue)
- meninge tumors
- tumors of structures near brain tissue (affect function of brain tissue)

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10
Q

intracranial tumors arise from?

A

neuroglia cells

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11
Q

Neuroglia cells are the _______ of central nervous system

A

non excitable; supporting cells

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12
Q

neuroglial cells are ____ than neurons; lack ___; and do NOT ____ with other cells

A

smaller, axons, synapse

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13
Q

what are the four type of neuroglial cells?

A

1) Astrocytes
2) Oligodendrocytes
3) Microglia
4) Ependymal cells

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14
Q

Astrocytes

A
  • star shaped
  • support nerve cells
  • function as electrical insulators
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15
Q

Astrocytes provide a barrier

A

at synapses that contain neurotransmitters or hormones such as dopamine
- lack implicated in Parkinsons

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16
Q

Astrocytes play a role in formation of:

A

Blood brain barrier

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17
Q

Oligodendrocytes are active in ?

A

formation of myelin sheath for central nerve fibers

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18
Q

Microglia are:

A

small glial cells

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19
Q

Microglia are activated in presence of?

A

inflammation and degenerative processes within the CNS

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20
Q

what kind of function does Microglia have?

A

Phagocytic function

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21
Q

microglia ingest and removes?

A

neural residue

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22
Q

Ependymal cells are ?

A

epithelial cells that line the cerebrospinal fluid filled brain cavities and spinal cord

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23
Q

Some ependymal cells facilitate

A

CSF circulation and are involved in production of CSF

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24
Q

Benign tumors

A
  • slow growing
  • well defined borders, surgical removal effective
  • DO NOT METASTASIZE
  • not life threatening
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25
Q

Malignant tumors

A
  • fast growing
  • invasion and destruction of other structures
  • life threatening
  • Metastasize
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26
Q

Intra-axial tumors

A

tumor resides in the brain tissue
ex: astrocytoma, glioblastoma

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27
Q

extra-axial tumors

A

resides outside brain, originates from brain tissue
- neither neuronal/glial
EX: meningiomas/ pineal & pituitary

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28
Q

Where is the temporal bone positioned between?

A

middle and posterior cranial fossa

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29
Q

4 segments of the temporal bone

A

1) Petrous
2) Squamous
3) Mastoid
4) Tympanic

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30
Q

What segment of temporal bone houses inner ear?

A

Petrous (hardest part of temporal bone)

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31
Q

What segment of the temporal bone forms the EAC?

A

Tympanic (matures by 3 years of age)

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32
Q

Most vascular tumors of the temporal bone are ?

A

Benign

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33
Q

Two categories of vascular tumors for classification?

A

1) Hemangiomas
2) Vascular malformations

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34
Q

Hemangiomas result in malformation of ?

A

angioblastic fetal tissue

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35
Q

Hemangiomas are made of

A

extra blood vessels

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36
Q

Hemangiomas are characterized by

A
  • rapid growth (proliferation phase)
  • slow period of involution (decrease in size)
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37
Q

Vascular malformations are

A

abnormal development of blood vessels

38
Q

what is more common Hemangiomas or vascular malformations

A

Vascular malformations

39
Q

Vascular malformations are:

A
  • present at birth
  • grow in proportion with body w/o regression
  • present any time during life
40
Q

vascular malformations present either

A

in the IAC or geniculate ganglion of VII N located in the fallopian canal

41
Q

why is there tumor preference for the region of CN VII

A

extensive blood supply surrounding the geniculate ganglion

42
Q

For Vascular malformations and Hemangiomas when do patients typically present with symptoms

A

3rd decade of life

43
Q

For vascular malformations/ hemangiomas: when the geniculate ganglion is site of origin, what is almost always present

A

VII N dysfunction (weakness or twitch)

44
Q

Symptoms of vascular malformations and Hemangiomas

A
  • hemifacial spasm
  • tinnitus
  • Conductive HL (geniculate ganglion eroding into ME)
  • Progressive SNHL ( IAC site)
  • Vertigo (lesion affecting CNVIII)
45
Q

Diagnosis of vascular malformations and hemangiomas

A
  • case history and symptoms
46
Q

Diagnosis w/ Imaging for vascular malformations and hemangiomas ?

A
  • high resolution CT Scan
    -MRI with contrast
47
Q

Imaging for vascular malformations and hemangiomas: T2 weighted images

A

lesions appear hyperintense on T2
fluid is bright on T2

48
Q

Imaging for vascular malformation/ hemangiomas. Geniculate lesions

A
  • difficult to visualize on MRI, but can be detected on high resolution CT
49
Q

Differential diagnosis of vascular malformations/hemangiomas?

A
  • meningiomas
  • VII N schwannoma
  • Cholesteatoma
50
Q

Why is meningioma a DD of vascular malformations /hemangiomas

A

irregular margins and may contain specks of calcium

51
Q

Why is CN VII schwannoma a DD of vascular malformations/ hemangiomas

A

hemangiomas prodcues facial nerve symptoms when smaller in size compared to CN VII schwannoma

52
Q

Why are cholesteatoma DD of vascular malformations/ hemangiomas

A

vascular lesion seen in ME cavity or invades other nearby structures

53
Q

treatment of vascular malformation and hemangiomas

A

surgical removal

54
Q

myelin sheath covering myelinated axons in CNS is formed by

A

oligodendrocytes

55
Q

in peripheral nervous system the myelin sheath is formed by ?

A

connective tissue cells, schwann cells

56
Q

What are myelin sheath of schwann cells of all peripheral nerves referred to?

A

neurilemmal sheath of schwann

57
Q

What is the most common benign tumor of the temporal bone and cerbellopontine angle?

A

Schwannoma
- 6% intracranial tumors
- 91% of all tumors in and around the temporal bone

58
Q

Within the temporal bone, the anatomic location of schwannoma is typically in three sites

A

1) internal auditory canal from CN VIII N
2) Jugular foramen for CN IX and X
3) fallopian canal of the VII CN

59
Q

vestibular schwannomas arise from ?

A

Schwann cells

60
Q

Vestibular schwannomas are

A
  • benign extra axial tumors
    typically unilateral except for NF 2
61
Q

Incidence in vestibular schwannoma

A
  • rare before 30
  • 40 to 60 , 6th decade diagnosis
    higher incidence in females
62
Q

Vestibular schwannoma has two phases related to pressure:

A

1) otologic phase
2) neurologic phase

63
Q

The otologic phase of vestibular schwannoma

A

tumor compresses in the IAC
HL:
- compression of vascular supply of CnVIII
- direct compression of CN VIII in IAC

64
Q

neurologic phase of vestibular schwannoma

A

tumor compresses on other intracranial structures

65
Q

Signs and Symptoms of Vestibular schwannoma

A
  • hearing loss
  • headache
  • tinnitus
  • unsteady gait
  • imbalance/diziness
  • facial paralysis
66
Q

Audiometric findings of vestibular schwannoma: PURE TONE

A
  • unilateral high frequency SNHL
    asymmetrical more profound at higher frequencies

Brainstem lesions show flat unilateral SNHL

67
Q

Audiometric findings of vestibular schwannoma: TONE DECAY

A

positive tone decay

68
Q

Audiometric findings of of vestibular schwannoma: OAES

A

Normal OAES
-decreased contralateral suppression

69
Q

Audiometric findings of vestibular schwannoma: SPEECH

A

WRS worse than pure tone thresholds, WRS worse in noise
- positive rollover ratio

70
Q

Audiometric findings of vestibular schwannoma: IMMITTANCE

A
  • tympanogram normal
  • ARTS = abnormal/absent (VIII lesion)
    -abnormal ipsilateral/contralateral for affected side (right ipsi right contra)

brainstem lesion = cross over pathways affected normal ipsi, absent contra

71
Q

positive retrocochlear sign
RD +++

A

reflex amplitude declines >50% in 5 sec at 500 and 1000 Hz

72
Q

questionable retrocochlear sign
RD ++

A

reflex amplitude declines >50% in 5 sec at 1000 HZ but not 500 Hz

73
Q

not a significant retrocochlear sign
RD +

A

reflex amplitude declines <50% in 5 sec at 500 and 1000 Hz

74
Q

ABR findings with vestibular schwannoma

A

increased wave V latency
increased I-V inter wave latency
- absent/abnormal wave V on affected size

75
Q

Treatment for Vestibular schwannoma

A
  • observation
    -stereotactic radiosurgery (radiation)
  • surgery
76
Q

Meningioma

A

tumor that grows from membranes that surround the brain and spinal cord called the meninges

77
Q

Meningioma Incidence

A

later decades of life
more common in females
- associated with progesterone and breast cancer

78
Q

Meningioma etiology

A
  • association with NF2
  • radiation therapy to head
  • genetics
  • chromosomes 1,7,10, and 14 and telomerase activation
  • Di George syndrome is AD caused by deletion parts 22q
79
Q

Audiometric S/S of meningiomas

A
  • progressive unilateral SNHL
    -vertigo
  • tinnitus
  • nausea/vomitting
80
Q

Audiometric findings of meningiomas

A
  • VIII CN involvement
  • abnormal ARTS affected side
  • normal tymp
  • positive acoustic reflex decay
  • positive roll over and poorer scores of speech in noise
  • abnormal ABR
    NORMAL OAES
81
Q

Differential Diagnosis of Meningioma

A
  • otitis media
  • Paraganglioma (glomus tumor)
  • Facial VII nerve involvement
  • Vestibular schwannoma
82
Q

Treatment of Meningioma

A

Surgical excision
complete resection

83
Q

Benign Tumors of the temporal bone

A
  • osteoma (tumor in the EAC)
  • paraganglioma (glomus tumor)
  • neurofibromatosis 2
  • Facial nerve schwannoma
84
Q

Cortical tumors affecting the auditory cortex may show normal results for

A

peripheral auditory tests
- Pure tone audiometry, ARTs, OAES
WRS poorer in noise

85
Q

Cortical tumors with ABR

A

ABR will be normal if periphery is normal because ABR measures responses up to brainstem level

86
Q

Cortical tumors what signs are common

A

headaches and diziness

87
Q

Malignant tumors tumors of temporal bone examples:

A

adenocarcinoma and osteosarcoma

88
Q

Malignant tumors are often diagnosed at late stages of disease and present with dismal prognosis

A

symptoms similar to chronic suppurative otitis media

89
Q

Malignant tumors audiologic signs and symptoms are

A
  • aural discharge with or without blood
  • otalgia
  • hearing loss
  • tinnitus
90
Q

Malignant tumors signs and symptoms of cranial neuropathies

A
  • facial paralysis
  • headache
  • cochleovestibular deficits (SNHL and vestibular symptoms)
91
Q

Metastatic tumors of the temporal bone is metastasis from other sites to temporal bones, include:

A

breast cancer
lung cancer
renal carcinoma
lymphoma and leukemia
thyroid cancer
osteoblastoma
melanoma

Acquired Auditory Vestibular Disorders (3 decks)

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