PBL - Schwannoma Of Vetsibulocochlear Nerve Flashcards Preview

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Flashcards in PBL - Schwannoma Of Vetsibulocochlear Nerve Deck (62)
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1

Define the term tinnitus.

Perception of sounds in the absense of external auditory stimulus

2

What three things cause tinnitus.

Hearing loss
Sounds produced by adjacent structures
Other disease processes

3

What sounds can be produced by tinnitus

Ringing of the ears
Hissing
Roaring
Buzzing
Humming sound

4

Which two ways can tinnitus be defined?

Objective tinnitus
Subjective tinnitus

5

What is objective tinnitus?

Sound is potentially detectable by another observer

6

What are the causes of objective tinnitus?

Vascular abnormalities or neuromuscular disorders
- sounds generated by turbulent blood flow conducted into auditory system
- pulsatile

7

What is subjective tinnitus

Noise perception when there is no noise stimulation in the cochlear

8

What can cause transient tinnitus in normal people?

Aspirin
Nicotine
Coffee

9

Name some conditions associated with more persistent subjective tinnitus.

Noise induced hearing loss
Prebycusis - sensorineural hearing loss
Hypertension
Atherosclerosis
Cochlear of labyrinthine infection
Inflammation

10

What is the suggested pathophysiology of tinnitus?

Abnormal firing of auditory receptors
Dysfunction of cochlear neurotransmitters function or ionic balance
Alterations in central processing of the signal

11

Define vertigo.

Illusion of motion associated with disorders of vestibular function

12

Define objective and subjective vertigo?

Objective - person is in motion and environment is stationary
Subjective - person is stationary and environment is in motion

13

What are some differential diagnoses of vertigo?

Light-headedness
Syncope
Faintness

14

What can unstable gait be caused by?

Disorders of sensory input
Peripheral neuropathy
Gait problems

15

Vertigo can be caused by peripheral and central vestibular problems, what is the difference between them?

Peripheral - severe in intensity, and episodic
Central - mild and consistent

16

Describe motion sickness.

Normal physiological vertigo caused by repeated rhythmical stimulation of vestibular system

17

Symptoms of motion sickness

Vertigo
Malaise
Nausea
Vomiting
Autonomic symptoms
- lowered BP
- tachycardia
- sweating
Hyperventilation - can causes pooling of blood in lower extremities

18

What is the pathology of Ménière's disease?

Occurs due to distension of the endolymph compartment of the inner ear

19

What is the 'triad' of Ménière's disease?

Vertigo
Tinnitus
Hearing loss

20

What are the suggested mechanisms that may cause Ménière's disease.

Increased endolymph production
Decreased production of perilymph accompanied by compensatory increase in endolymph sac
Decreased endolymph absorption
- caused by malfunction of endolymph sac or blockage of endolymphatic pathways

21

Name five things which are thought to cause Ménière's disease.

Infection - syphilis
Trauma
Immunological
Endocrine - adrenal-pituitary insufficiency and hypothyroidism
Vascular disorders

22

What is Ménière's disease characterised by?

Fluctuating episodes of tinnitus, feeling of ear fullness, violent rotatory vertigo

23

What happens to hearing loss as Ménière's progresses?

Stops fluctuating and progressively worsens
Both ears become affected

24

What happens to the vertigo as the Ménière's progresses?

Episodes of vertigo diminish and disappear although the person may be unsteady

25

List the differential diagnoses of Ménière's disease

ENT causes
- acoustic neuroma
- otitis media
- earwax
- too toxic drugs
Intracranial pathology
- vertebrobasilar insufficiency
- tumours
- migraine
Systemic illness
- Anaemia
- hypothyroidism
- DM
- autoimmune disease
- syphilis

26

What is a schwanomma of the vestibulocochlear nerve?

Benign Schwann cell tumour affecting CN VIII

27

How does a schwanomma cause unilateral sensorineural hearing loss?

Compresses the cochlear nerve of interferes with the blood supply to the nerve and cochlear

28

What genetic problem is through to cause tumour growth?

Tumour suppressor gene abnormality on chromosome p22 (schwanomma protein)

29

How do patients with a schwannoma present?

Decreased hearing
Episodes of vertigo

30

What does unilateral hearing loss do to your hearing?

Leaves you unable to localise sound