Vestibular and cerebellar disease Flashcards

1
Q

Classic signs - ataxia

A
  • overstep

- cross over legs

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2
Q

2 types of ataxia with alcohol

A
  • APPENDICULAR: jerky, uncoordinated limbs mvt, as though each mm were working independently from others
  • TRUNCAL: postural instability, gait instability - disorderly wide-based gait with inconsistent foot positioning
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3
Q

Define ataxia

A

neurological sign consisting of gross incoordination of muscle movements. It is an aspecific clinical manifestation

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4
Q

What to look at when observing ataxia. How to differentiate from MSK problems

A
  • limbs, head and how trunk moves during locomotion

- becomes better coordinated when running (MSK problems get worse with running

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5
Q

3 types of ataxia

A

sensory, vestibular and cerebellar

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6
Q

Define hypometria

A

shorter protraction phase of gait

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7
Q

Define hypermetria

A

longer protraction phase of gait

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8
Q

Define dysmetria - 3

A

ability to control teh distance, power and speed of an action in impaired. combination of hypo- and hypermetria

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9
Q

Neurolocalisation - sensory ataxia

A

General proprioceptive pathways:

  • peripheral nn
  • dorsal root
  • SC
  • brainstem
  • forebrain
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10
Q

CS - sensory ataxia

A
  • abnormal postural reactions

- limb paresis

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11
Q

Neurolocalisation - vestibular ataxia

A

Vestibular apparatus:

  • vestibular nuclei (central)
  • vestibular portion of CN 8
  • vestibular receptors (peripheral_
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12
Q

T/F vestibular system is a unilateral system

A

True - the RHS controls the RHS and vice versa

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13
Q

CS - sciatica

A

arched back as this provides greatest pressure relief on nn root.

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14
Q

How does the vestibular system affect the extensors?

A

Causes excitation/ tone to extensors –> head tilt and limp limbs if not working properly

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15
Q

CS - vestibular ataxia

A
  • head tilt
  • leaning, falling or rolling to one side
  • abnormal nystagmus (slow side always to side with lesion)
  • positional strabismus
  • normal (peripheral) or abnormal (central) postural reactions
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16
Q

Is prognosis of a vestibular problem affected by localisation (i.e. central/ peripheral)?

A

No

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17
Q

T/F: nervous system copes better with acute than chronic changes

A

False - oppositve

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18
Q

Why might you get reduced ear movement with vestibular disease?

A

lesion may spread and affect facial nerve –> paresis/ paralysis due to close proximity

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19
Q

CS - Cerebellar ataxia

A
  • wide based stance
  • intention tremors of head
  • loss of balance and truncal sway
  • delayed onset and dysmetric hopping
  • ipsilateral menace deficits with normal vision
  • no limb paresis OR conscious proprioception deficits
  • pendular nystagmus
20
Q

How do forebrain and cerebellum interact?

A

Forebrain - initiates movement

Cerebellum - coordinates movement

21
Q

How are the 3 types of ataxia differentiated (sensory, vestibular, cerebellar)?

A

CS

22
Q

Outline the neuro exam in terms of observation and hands-on examination parts

A
OBSERVATION:
mental status and behaviour
posture
gait
identification of abnormal voluntary movements
HANDS-ON EXAMINATION
postural reaction testing
cranial nerves assessment
spinal reflexes, mm tone and size
sensory evaluation
23
Q

2 components of inner ear

A

semicircular canals and cochlea (hearing)

24
Q

What part of the vestibular system detects head motion and angular acceleration?

A

semicircular canals

25
Q

What part of the vestibular system detects head position and gravity?

A

saccule and utricle

26
Q

Which nn does bulla disease affect?

A

facial and vestibulocochlear nn and SNS trunk (–> Horner’s)

27
Q

Where do vestibular nuclei receive input from? 3

A
  • semicircular canals
  • saccule and utricle
  • visual/ proprioceptive and tactile inputs
  • cerebellum: primarily inhibitory
  • spinal cord
  • potine reticular formation
  • contra-lateral vestibular nuclei
28
Q

With the occulovestibular reflex, turning the head causes what?

A

Increased firing on the side where the head is turning to and decreased firing on the side the head is turning away from.

29
Q

Where do vestibular nuclei communicate with?

A
  • forebrain, perceived orientation
  • SC and cerebellum
  • oculomotor system, eye movements
30
Q

Outline head tilting

A
  • rotation of median plane of head
  • one ear lower than other
  • often indicates a vestibular disorder (i.e. a disorder of the balancing system)
31
Q

Outline head turning

A
  • where the median plane of the head remains perpendicular to the ground, i.e. nose turned to one side
  • may indicate a forebrain disorder
32
Q

Describe pendular nystagmus

A
  • siamese, birman, himalayan (melanin disorder and more fibres cross over)
  • congenital abnormality (larger # fibres cross chiasma)
  • cerebellar disorders and visual deficits
  • jerk nystagmus: horizontal, vertical and rotary
33
Q

Name different types of nystagmus

A
  • physiological
  • pendular
  • searching
  • jerk (horizontal, vertical, rotary)
34
Q

Name the 5 features of Horner’s syndrome (SA)

A

= loss of sympathetic innervation to eye:

  • enopthalmos
  • TE protrusion
  • ptosis
  • miosis
  • (congested BVs)
35
Q

Features of Horner’s syndrome in horses

A
  • ptosis - examine eyelashes closely
  • miosis
  • enophthalmus
  • prominent TE
  • conjunctival and nasal hyperaemia
  • sweating
36
Q

Name 4 important CS to determine whether a vestibular lesion is central or peripheral

A
  • conscious proprioceptive deficit
  • consciousness
  • cranial nerve deficits
  • vertical nystagmus (will often improve with time)
37
Q

Outline difference in CS between central and peripheral nystagmus

A

CENTRAL: possible conscious proprioceptive deficit, consciousness (normal, obtunded, stupor, coma), cranial nerves (5-8 may be affected), vertical nystagmus (yes)
PERIPHERAL: no conscious proprioceptive deficit, consciousness (alert, disorientation possible), cranial nerve deficits (8 only), no vertical nystagmus

38
Q

What is the first Q that should be asked when examining a pupil for a peripheral vestibular proble?

A

Ototoxic drugs

39
Q

What is a myringotomy?

A

sx procedure, penetration of TM, remove fluid from middle ear, relatively safe, very diagnostically helpful

40
Q

CS - bilateral vestibular problem

A
  • no nystagmus
  • no occulovestibular response
  • head swaying from left to right
41
Q

3 parts - cerebellum

A
  • vestibulo-cerebellum (central)
  • spino-cerebellum (central)
  • cerebro-cerebellum (peripheral)
42
Q

3 functions - cerebellum

A
  • maintain equilibrium
  • regulate mm tone (–> preserves mm position at rest and mvt)
  • coordinate mvt
43
Q

If the head tilt is away from the sign of the proprioceptive deficit, what should you consider?

A

paradoxical vestibular problem (head tilt usually towards lesion but may be away from it and thus also away from the proprioceptive deficit)

44
Q

Name different regions of the cerebellum 5

A
  • rostral lobe
  • caudal lobe
  • flocculonodular lobe
  • caudal cerebellar peduncle
  • cerebella nuclei fragment
45
Q

CS - cerebellar syndrome

A
  • spastic, dys- or hyper-metric ataxia (goose-stepping)
  • intention tremor
  • ipsilateral menace deficit + normal vision
  • broad-based stance
  • postural reactions delayed with exaggerated responses
  • menace deficit (ipsilateral) with normal vision
    +/- anisocoria (pupil dilate contralateral to side of lesion)
    +/- opisthotonus (rare)
    +/- vestibular signs
46
Q

Define opisthotonus

A

tetanic spasm in which the body is bent back and stiffened, head will be in an extended position