Vestibular Disorders Flashcards
NOT IN BOOK: Explain the physiology of the vestibular organ
The inner ear is separated to the anterior cochlear part and the posterior vestibular part. The vestibular part is composed of 3 parts. 3 semicircular canals positioned 90 degress from each other responsible for angular acceleration (e.g. head rotation) and 2 otolith organs, the urticle and the saccule responsible for linear acceleration (Horizontal and vertical respectively).
NOT IN BOOK: How does the vestibular organ detect movement/acceleration and how is it interpreted?
The vestibular organ contains an endolymph which shifts on movement => shifting of Cuplia (semicircular canals) and Otoconia (linear) => hair cells stimulated => vestibular nerve => Vestibulocochlear nerve => Vestibular nuclei in brainstem
NOT IN BOOK: What is the meant by peripheral and central vestibular system?
Peripheral = 3 semicircular canals + urticle + saccule
Central = Cerebellum + spinal cord + Temporal love cortex
NOT IN BOOK What are the 2 main vestibular reflexes?
What tests are used to assess these reflexes?
Vestibulo-ocular -> Maintains optical fixation during head movement
Tested via Head Impulse Test
Vestibulospinal -> Senses head movement and position relative to gravity
Tested via Romberg or Unterberger/Fukuda Test
An individual’s balance depends on 3 sensory inputs. List them and state the one which the body is most dependent on.
1) Visual input (70%)
2) Proprioception (15%) - central
3) Vestibular input (15%) - Peripheral
2/3 are required for balance
Differentiate dizziness from vertigo
Then Differentiate Dysequilibrium from Dysmetria
Dizziness = encompasses vertigo, presyncope, dysequilibrium, dysmetria
Vertigo is the sensation that the environment is spinning around one’s self when no movement exists
Dysequilibrium = inability to balance one’s self or unsteady
Dysmetria is the inability to approximate
List the causes of vertigo/list vestibular disorders
Peripheral: BPPV, Meniere’s Disease, Viral Labyrinthitis, Acoustic Neuroma, Fistula from Cholesteatoma
Peripheral => ENT => not an emergency
Central: Migranous vertigo, Brainstem (TIA, Cerebellar stroke, Chiari malformations (spina bifida), Multiple Sclerosis)
Central => neuro => emergency
How can you differentiate between a central and peripheral cause of vertigo? Why?
HINTS Examination which involves the head impulse test, nystagmus test, and the test of skew to determine the cause. It is important to differentiate because central causes of vertigo are likely to be an emergency whereas peripheral causes are not
What is HINTS used for? What tests are involved in HINTS? What would be required according to the HINTS criteria to determine that the patient has a central cause of vertigo and requires immediate attention?
HINTS involves head impulse test, nystagmus test, and the test of skew to assess if the cause of sudden onset vertigo is central (hence requiring urgent attention) or peripheral
if 1/3 tests indicate a central cause then urgent attention with 98% specificity (super accurate)
Quick Hx for patient presenting with vertigo/dizziness
Episodical vs constant
Duration + frequency of episode (if episodical)
Triggering factors (rolling over, URTI, head injury, car, boat)
Associated Sx: headache, eye sx (red flag)!!!, Nausea/vomiting, palpitations, SOB, Syncope
Associated Ear sx: Tinnitus, hearing loss + type -> location of pathology
Neurological complaints (hemiparesis, cranial nerve…)
Past medical hx of cardio, neuro, opthalmo, rheumatological, migraines!
New medications!! (very good to specifically ask this in any hx)
Give the most likely diagnosis for a patient presenting with episodic vertigo, each lasting
seconds-minutes:
Minutes-hours:
days-weeks:
Constant and longstanding:
seconds-minutes: BPPV
Minutes-hours: Meniere’s or Vestibular neuritis
days-weeks: Viral Labyrinthitis
Constant and longstanding: Vestibular schwannoma
How would you describe an observed nystagmus to a consultant
Nystagmus observed on the right eye with right horizontal nystagmus. This would indicate that it is the right eye with the rapid phase being towards the right and slow to the left.
READ: You have a patient presenting with vertigo/dizziness. Imagine this is a long case station, now go through what you will do in the examination portion and then the main investigations you would order
1) Inspection head and neck with palpation of cervical lymph nodes…
2) ENT - Otoscopy, Hearing (Whisper, rinne, weber)
3) Neurological: Gait, Full Cranial Nerve Exam, Cerebellar testing including Past-pointing and Dysdiadokinesis, Fistula test, HINTS (Head impulse, nystagmus, and Test of Skew)
4) Vestibular: Dix-Hallpike Manouvre, Romberg Test, Unterberger test
Investigations:
1) Pure Tone Audiogram
2) Vestibular function tests
3) MRI of IAM!! and Brain !!
You can organize them how you will cuz many overlap. Whats important is that you are categorizing at all
What is the Fistula Test?
What pathology is this most important for?
Test for the presence of a fistula between middle and inner ear by applying pressure on the tragus and observe for nystagmus. This is particularly important for patients with cholesteatoma.
What is the Head Impulse Test and how would you conduct it and interpret your findings.
How would you interpret the findings in a patient with vertigo?
The Head impulse test is used to assess the vestibulo-ocular reflex involved in maintaining eye position on head movement. This is conducted by having the patient in front of you at eye-level and ask them to keep eyes open, looking at examiner’s nose. Move head to one direction quickly and observe for nystagmus or a !Corrective Saccade (eye returning to correct position). !!!Must state that it will be repeated on other side!!!
If patient maintains optical positioning => reflex preserved => -ve => Normal or central cause of vertigo in HINTS
If corrective saccade observed=> reflex not preserved => +ve => Peripheral cause of vertigo in HINTS
What is the Dix Hallpike Manouvre used for?
How will you explain this to a patient in order to obtain consent?
How is it performed?
The Dix Hallpike Test is used to diagnose BPPV
This is a routine manouvre with people experiencing this type of dizziness. I will ask you to cross your arms and look at me before lowering you down till you are lying down flat. This may make you dizzy but please try your best to keep your eyes open. !I will be holding your head in place during the entire manouvre!
Patient crossing arms looking 45 degrees towards examiner on asymptomatic side while seated on bed for 30s. Hold patient’s head in place with both hands throughout entire manouvre-> then lowered to supine and head extended 20 degrees off edge of bed. Hold in place and observe for nystagmus for 1 minute. !Then repeat test on other side!
