45a - Balance, Dizziness, Vertigo Flashcards

1
Q

What is the vasovagal reaction?

A

common fainting.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

If patient says room is spinning to the left, which way is the nystagmus?

A

fast beat of the nystagmus is also to the left and slow is to the right.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

If patient says room is spinning to left, which side is the lesion on?

A

if room is spinning to the left, nystagmus is to the left so slow phase is to the right, meaning right side is lesioned.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is rotation around the z axis called?

A

yaw

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many degrees of freedom are there in standard human motion?

A
  1. 3 translational and 3 rotational
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What structure is responsible for detecting angular movements?

A

semicircular canals with the ampulla (cupula)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What structure is responsible for detecting translational movement in the horizontal axis?

A

utricle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What structure is responsible for detecting translational movement in the vertical axis?

A

sacculus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are otholiths/otoconia?

A

crystals of calcium carbonate stuck in the membrane that distort the matrix when linear force movments occur.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the action potential of stereocillia in the vestibule

A

force can either open or close K+ on the kinocilium by moving them. If gravity opens the channels, K will flow in and depolarize the cell membrane, opening Ca channels, increasing intracellular Ca. Calcium will open Ca-dependent K channels that leak K into the perilymph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the midline of the kinocilium called?

A

striola. This is the midline that the kinocilium of the utricle all face. In the sacculus they face away from it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a major difference between the sacculu/utricle and the cupula inside the ampulla?

A

the kinocilia of the cupula always point in one direction only, whereas the utricle and saccule have mirror images across the striola (pointing in opposite directions).There are also no otoliths in the hair cells of the semicircular canal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

If you suddenly turn your head to the left, which vestibular canal will be stimulated and which direction should your eyes turn?

A

left horizontal semicircular canal will be stimulated and right canal will be inhibited. This will mediate a reflex movment of the eyes to the right to maintian visual fixation. AKA vestibulo-ocular reflex (VOR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What side should you administer cold water irigation to to ease the symptoms of a perosn with left beating nystagmus?

A

if it’s left beating nystagmus, eyes are slowly moving to right, so lesion is on the right. If you administer cold water to left, the eyes will pull back towards midline and symptoms will abate temporarily

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does ice-water caloric testing differentiate psychogenic coma?

A

In true coma, there is a disconnect from the brainstem. When you do ice-water caloric testing, eyes will deviate towards irrigated side with no nystagmic corrections. If patient is in psychogenic coma, cortex recognizes mismatch between vestibular info and other sensory input so it directs eys back to midline with a nystagmus.TLDR: if ice water induces nystagmus = psychogenic coma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are Frenzel lenses

A

Nichols’ everyday glasses.20+ diopter lenses that block visual fixation and unmask compensated nystagmus.

17
Q

Which way is the eye moving if on fundoscopic exam you see the optic disc moving down?

A

eye is moving up if the disc is seen moving down.

18
Q

What is Dix-Hallpike maneuver?

A

turn head to right and fall back from sitting to lying position to maximally stimulate right posterior canal and maxiamlly inhibit left anterior canal.

19
Q

What is Nylan-Barany maneuver?

A

same as Dix hallpike except head is turned AS you lay donw. Tests the exact same information.

20
Q

How will a peripheral vertigo present on Dix-Hallpike maneuver?

A

nystagmus has 5-20 sec latency of onset after maneuver and subsides after 1-2 minutes.Nystagmus increases with gaze away from lesionUsually mixed horizontal.Repeated motion Habituates (gets better)

21
Q

How will central vertigo with nystagmus present on Dix-hallpike maneuver?

A

no latency of onsetsustained wihth positionno increase with change of gazeusually singl eplane nystagmusDoes NOT habituateprobably have other brainstem deficits

22
Q

What is pathology of bening paroxysmal positional vertigo?

A

calcium carbonate crystals called otoconia or otholiths that are usually embedded ina gelatinous membrane overlying the hair cells break free and enter semi-circular canals. During sleep they fall into posterior canal and plug it up, causing increased pressure and vertigo when laying down

23
Q

What is Epley maneuver?

A

??

24
Q

Which way will nysatgmus go if a person has BPPV in their right ear and they are doing a right Dix-hallpike?

A

normally right posterior canal would be activated and push eyes down so that field of vision remained fixed. However, BPPV will cause posterior canal to OVERREACT and will push eyes too far down. Nystagmus upward will result.

25
Q

What pathology can present in almost an identical manner as vestibular neuritis?

A

acute cerebellar stroke. You need to do a CT and MRI to exclude it. Head thrust will be normal, whereas it shoudl have catch-up saccades if it were vestibular neuritis