Exam 2: BPPV Lecture Flashcards
What are the 5 structures in the membranous labyrinth?
3 Semi Circular Canals (horizontal, posterior, anterior) and 2 Otolith Organs (saccule, utricle)
What type of acceleration do the SCCs detect?
Angular acceleration
What are SCCs filled with
Endolymph
What is the ampulla?
The enlarged end of each SCC
What is within the ampulla?
The gelatinous cupula that contains stereocilia and kinocilia
What are the two types of sensory hair cells?
Stereocilia and kinocilia
Where do the hair cells sit?
In the crista ampullaris
What causes the hair cells to move when the head is turned?
Head turning causes the endolymph to move, which causes the cupula to move, which causes the hair cells to move
What happens when stereocilia are deflected toward kinocilia?
Excitation
What happens when stereocilia are deflected away from kinocilia?
Inhibition
What is the Push-Pull Mechanism?
SCC on side that head is turned to is excited and opposite is inhibited
What is happening in the SCC at rest?
Tonic firing so that we know our head is still and balanced
What is the resting firing rate of a healthy vestibular system?
70-100 spikes/second
What type of acceleration do the otolith organs detect?
Linear acceleration
What type of acceleration does the utricle detect?
Horizontal acceleration and head tilt
What type of acceleration does the saccule detect?
Vertical acceleration
Where do the otoconia sit?
In the otolith organs
What is oscillopsia?
When stationary objects in the environment appear to be in motion when the patient is in motion causing blurred vision
What is diplopia?
Double vision
What is tinnitus?
Ringing in the ears
What does BPPV stand for?
Benign Paroxysmal Positional Vertigo
What is the general pathophysiology with BPPV?
Otoconia is dislodged from the otolith organs and float in the SCC that disrupt the vestibular signals to the brain
What is the most common type of vestibular disorder?
BPPV
What percentage of people spontaneously recover from BPPV after 1 month and 3 months?
20% and 50%
What does paroxysmal mean?
Rapid and sudden onset, short spell
What are possible causes of BPPV?
No known cause, but associated with aging, head trauma, migraine, diabetes, or lying in bed for long periods due to illness or surgical procedure
What canal is most commonly affected by BPPV?
Posterior
What canal is least commonly affected by BPPV?
Anterior
What is canalithiasis?
When the otoconia are free floating in the SCC
How long does vertigo last with a canalithiasis?
30-90 seconds and then fatigues