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Flashcards in Vertigo Deck (20):
1

When does Syncope occur?

When cardiac output falls

2

True vertigo is a disease of

the vestibular system

3

The clinical sign of vertigo

Nystagmus- fast ans slow phase. Fast phase consists of corrective saccades from the frontal eye field of the contralateral hemisphere. Person is blind during the fast phase because the brain suppresses the visual info. During the slow phase the person feels dizzy.

4

How many degrees of freedom are there and what detects positional change in these six degrees of freedom in humans?

The Vestibular apparatus

5

Translational motion

linear along x,y,z

6

Rotational Motion

angular around x,y, z

7

Linear motion and the effects of gravity are sensed by two specialized organs called

Sacculus and Utricle

8

What detects angular movements

The semicircular canals, detect rotational acceleration or deceleration within the plane of the canal

A specialized organ called a corpula located inside the amupulla transduces this info

9

Cellular structure of the utricle and saccule

Sensory Hair cells with Cilia are embedded in a gelatinous matrix. On top of this matrix filled with hair cells, tiny crystals of calcium carb called otoiths are stuck to the membrane and are sufficiently heavy to distort the matrix by a linear force during movement and gravitational pull.

10

The nerve fibers whose cell bodies lie in Scarpa's ganglion have afferent and efferent sides

The Efferent axons project to the brainstem via the vestibular nerve

11

Remember that each vestibular apparatus acts as a pushing muscle...that is, if you turn your head suddenly to the left but want to keep your eyes fixed on a point, the left semicircular canal is stimulated while the right is inhibited

ok....This is the vestibulo-occular reflex

12

How would you reveal a centrally compensated vestibular dysfunction

Frenzel lenses ....keep the eyes from focusing on distant objects

13

Head Thrust maneuver does what

can detect a decrease in the vestibular-ocular reflex by the presence of a catch up saccade

14

Semi-circular canals work in a push-pull manner

when head rotation stimulates one the other part is inhibited

15

BPPV

Benign Paroxysmal Positional Vertigo-
Caused when otoliths break off with age or trauma and enter the semi-circular canals. They tend to collect in the posterior semi-circular canals due to head dependency during sleep. THey can form a sludge which produces greater pressure in the affected canal and send signals to the brain via the ampulla that the head has rotated posteriorly much quicker and to a greater extent that it really has. Vertigo occurs 5-10 seconds after head movement and lasts about 45 secs

16

BPPV is the most common cause of vertigo in who>

Elderly

17

More on BPPV

usually goes away in about two weeks, can be protracted with nausea and vomitting
Can recur in about 10%

18

What immediately cures pts of symptoms

Canalith maneuver (EPley)

19

The two mechs for BPPV

1) Canalithiasis- sludge in the canal
2) Cupulolithiasis- sludge in the cupula, rare

20

Vestibular Neuritis

Postulated viral infection...entire vestibular apparatus is inflamed hence movement in any direction is poorly tolerated