Clinical vestibular system Flashcards
State the two perceptual mechanisms that are the basis of symptoms
- Vestibular-motion perception. (sensation of motion)
- Seeing environmental motion… i.e. oscillopsia which indicates a nystagmus
This is like when sitting on the train and you think you’re moving because you see the other train next to you moving
i.e.
did they feel like they were moving (i.e. falling like a stone, going round a carousel) and did they see the world move
Commenest causes of emergency room vertigo
- BPPV – 35%
- Vestibular Neuritis – 15%
- Migrainous Vertigo – 15%
- Stroke – 5%
- Mixed (syncope, anxiety…) – 30%
Meniere’s is less than 1%
Possible causes of acute vertigo outside of neurological diagnosis
How to rule these out
PRESYNCOPE
PULMONARY EMBOLISM &; CARDIAC DYSRHYHMIA
do
postural blood pressure.
arterial saturation
ECG
Which system (visual or auditory) is better placed in spatial locatilsation and temporal differences
Auditory system is not so good at localising in space, but eyes are
Auditory system detects changes over time much quicker than the visual system
Which examinations can you do for vertigo
EYES: • Gaze • VOR • Hallpike • Fundoscopy
• EARS: • Otoscop
LEGS: – Gait (+ tandem)
Outline the two phases of a saccade
Fast and slow phase
Slow is due to the nystagmus and then the fast beating back because of the brainstem
T/F a vetibular problem relates to the inner eatr
F…. vestibular problem could involve anywhere in the system… brainstem, ear, cerebellum etc
How can the gaze test on a nystagmus patuent help distinguish between a central and pheripheral vision
This test involves blinding both eyes (by covering one and shining bright light in the other so you can see the nystagmus still)
If it is a peripheral systagmus problem (I.e. with the inner ear) then the nystagmus will be worsened when the patient is blinded. This is because visual system helps to suppress the nystagmus, so when this is removed it increases the nystagmus
If it is central then there will be no worsening when the blindness happens, because the visual input does not help to suppress anyway because of problem with CNS
How can the VOR be tested
doll’s head impulse test (eyes will not remained fixed on you when head turned to the lesioned side)
How can fundoscopy help in the vestibular diagnosis
- Retina 2. Spontaneous nystagmus? 3. Effect of visual fixation on nystagmus?
How can otoscopy help in vestibular diagnosis
Rarely informative in acute vertigo (except for looking for VZV vesicles in acute unilateral peripheral vestibular loss or suppurative infection in meningitis)
t/f/ oral antibiotics are never indicated for actue vertigo
T…. I think because usually viral (VZV/meningitis)
What is BPPV
Benign paroxysmal positional vertigo
What does paroxysmal mean
Sudden onset/attack
When does BPPV commonly occur
Positional – lying back in bed • Brief – seconds [beware prolonged malaise]
Why would you specifically ask about dizziness with movement in bed in BPPV
Because it takes away any BP stress….
I,e, rules out postural hypertension
What are the red flags in BPPV
Red flags:
• Headache
• Atypical nystagmus
What is the onset of a vestibular neuritis.
Distinguish pattern of vestibular neuritis from BPPV
Subacute onset (minutes – hours)
It is continuous vertigo rather than brief/positiona
What is vestibular neuritis
Inflammation of the 8th CN
Symptoms for vestibular neuriris
• Obvious ‘vestibular’ nystagmus • Positive head impulse test • Normal gai
Treatment for vestibular neuritis
Vestibular sedatives for 24-36 hours
Mobilise at day 3
Treat any BPPV or migraine
What are the red flags for BPPV and why
Headache (•40% posterior circulation stroke)
Gait ataxia (may be only non-vertiginous manifestation of cerebellar stroke)
Hyperacute onset (suggests vascular origin)
Vertigo + hearing loss (AICA stroke or urgent ENT problem)
Prolonged symptoms (> 4 days) – •Floor of 4th ventricle problem.
Think HELP HELP HELP, GP!
(hhh gp)
What is the main differential diagnosis for acute vestibular migraine
cerebellar stroke
What are the hallmarks of a cerebellar stroke
Thunderclap onset vertigo (?Valsalva) • Difficulty walking • Headache
Differentiate the sings of a peripheral vs central vestibular problem
CENTRAL: gait, headache
PERIPHERAL: loss of VOR (so +ve head impulse test, obvious ‘vestibular nystagmus’)
What mediates vertigo sensation and why do some people with nystagmus not sense vertigo
a brain network mediates this
In tramatic brain injury patients, the speed of ocular nystagmus was the same as control when being spun, but the perception of being spun was much less.
they are less sensitised to vertigo
What is the hallpike maneuvre
Movement to shift the otoconia in the SCC and see if the patient feels busy after… will feel dizzy in BPPV
T/f you must have a headache to expericne migraine
F… can occur without headaches
What is a significant drop in BP to perhaps cause dizziness
At least 15mmHg
