Approach To Vertigo And Vestibular Function Test Flashcards
What is vertigo ?
Sense of spinning of oneself or their surroundings ; should be differentiated from hypoglycaemia and hypotension
What is the most common type / cause of vertigo?
Positional vertigo / BPPV ( Benign Paroxysmal Positional vertigo )
What is BPPV?
Paroxysmal episodes of vertigo occurring with change in position
What is the most common semicircular involved in BPPV?
Posterior semicircular canal
This is because the otolith(gets dislodged mostly due to idiopathic or trauma)gets easily deposited in the ampulla of the posterior scc due to gravity and causes irritation of the endolymph causing vertigo
Least affected is superior scc
Classical history given by patients with BPPV
Episodic vertigo on changing the position of head lasting for few seconds
What is DIX-HALLPIKE manoeuvre?
The head is turned towards the right and posteriorly to test the posterior semicircular canal in order to check whether BPPV is related to vertical semicircular canals
What is SUPINE ROLL?
To test whether the horizontal semicircular canal is affected or not
Nystagmus in both horizontal and vertical scc involvement
In horizontal scc involvement - horizontal nystagmus
In vertical scc involvement - vertical nystagmus
What is latency in peripheral nystagmus ?
The nystagmus will start 10-20 secs later after the stimulation of the scc . This delay in the onset of nystagmus is called LATENCY
What is the duration of nystagmus?
It lasts for 1-1.5 minutes and does not last for longer period of time
What is fatiguable in peripheral nystagmus?
Disappears with repetition (first time appears ; second time disappears)
With what the peripheral nystagmus disappears ?
With optic fixation (focusing on an object) peripheral nystagmus disappears
Prevented by wearing FRENZEL GLASSES - high diopter glasses=+20D ; also causes magnification of the eye
What are the components of peripheral nystagmus / jerk nystagmus ?
Slow component (because of disease) and fast component (corrective phase)
Direction of nystagmus is always the fast component since slow component can’t be appreciated
In which direction does the labyrinths tries to push the eye?
In the opposite direction
Right side labyrinth - pushes the eye to the left
Left side labyrinth - pushes the eye to the right
Normally both functions equally and in opposite direction and maintains the position of the eye in mid line
What happens in the case of hyperactive labyrinth ?
In case of hyperactive labyrinth , say the left, the eye is pushed to the right due to hyperactivity of left labyrinth(slow component)and brain senses this as abnormal and tries to correct the position back to normal (fast component)
In hyperactive labyrinth , the fast component (direction of nystagmus ) is toward the affected / diseased ear eg:BPPV
Direction of nystagmus in hypoactive labyrinth ?
The direction of nystagmus / fast component is toward the normal ear eg:Ménière’s disease
Always the direction of nystagmus is towards the more active ear
Characteristics of peripheral nystagmus
Latency
Fatiguable
Torsion present
Duration
Direction
Disappears with optic fixation
Direction of nystagmus is always the fast component
What is vestibular neuritis ?
It is the acute infection (viral) of the vestibular nerve
What to do if the vertigo is not suggestive of BPPV?
Whenever the vertigo lasts for longer period of time
Then we have to rule out whether the cause of vertigo is central or a peripheral cause
For ruling out peripheral causes of vertigo we have to ask for ?
Hearing loss (in vestibular neuritis there’s only vertigo and there’s no hearing loss)
Tinnitus
And confirm there’s no cranial nerve involved
For ruling out central causes of vertigo we have to ask for ?
Any cranial nerve involvement
Diplopia
Ataxia
Dysarthria
Motor weakness
Headache
What do to if none of the history is positive for the patient except for vertigo to rule between central and peripheral nystagmus ?
We have to look for characteristics of nystagmus
Characteristics of peripheral nystagmus - horizontal + torsion(complete destruction of one side labyrinth leads to horizontal nystagmus) ; disappears with optic fixation ; direction - fixed,doesn’t change
Characteristics of central nystagmus - pure horizontal/pure vertical/pure torsional component will be there ; doesn’t disappear with optic fixation ; direction does not change
Head impulse test asses what ?
Vestibulo - ocular - pathway
In this test , sudden movement of head is done to check if the patient is able to fix the gaze or not
Abnormality of this vestibulo - ocular pathway leads to rapid , ballistic movements of the eyes that abruptly try to come back to the point of fixation / gaze called as SACCADES
What is the other name for caloric test ?
Fitzgerald - hallpike manoeuvre or bithermal caloric test
