Benign paroxysmal positional vertigo; Vestibular neuritis Flashcards
(22 cards)
Describe the pathophysiology of BPPV [2]
BPPV is caused by crystals of calcium carbonate called otoconia that become displaced into the semicircular canals. This occurs most often in the posterior semicircular canal.
- They may be displaced by a viral infection, head trauma, ageing or without a clear cause.
The crystals disrupt the normal flow of endolymph through the canals, confusing the vestibular system.
- Head movement creates the flow of endolymph in the canals, triggering episodes of vertigo.
Describe the features of BPPV [4]
Features
* vertigo triggered by change in head position (e.g. rolling over in bed or gazing upwards)
* may be associated with nausea
* each episode typically lasts 10-20 seconds
* positive Dix-Hallpike manoeuvre
Describe what is meant by a positive Dix-Hallpike manoeuvre [1]
It involves moving the patient’s head in a way that moves endolymph through the semicircular canals and triggers vertigo in patients with BPPV.
To perform the manoeuvre:
* The patient sits upright on a flat examination couch with their head turned 45 degrees to one side (turned to the right to test the right ear and left to test the left ear)
* Support the patient’s head to stay in the 45 degree position while rapidly lowering the patient backwards until their head is hanging off the end of the couch, extended 20-30 degrees
* Hold the patient’s head still, turned 45 degrees to one side and extended 20-30 degrees below the level of the couch
* Watch the eyes closely for 30-60 seconds, looking for nystagmus
* Repeat the test with the head turned 45 degrees in the other direction
Describe the results of a +ve Dix-Hallpike manoeuvre [1]
In patients with BPPV, the Dix-Hallpike manoeuvre will trigger rotational nystagmus and symptoms of vertigo. The eye will have rotational beats of nystagmus towards the affected ear (clockwise with left ear and anti-clockwise for right ear BPPV).
How do you tx BPPV? [1]
The Epley manoeuvre can be used to treat BPPV. The idea is to move the crystals in the semicircular canal into a position that does not disrupt endolymph flow.
Describe the Epley Manoeuvre [+]
- Follow the steps of the Dix-Hallpike manoeuvre, having the patient go from an upright position with their head rotated 45 degrees (to the affected side) down to a lying position with their head extended off the end of the bed, still rotated 45 degrees
- Rotate the patient’s head 90 degrees past the central position
- Have the patient roll onto their side so their head rotates a further 90 degrees in the same direction
- Have the patient sit up sideways with the legs off the side of the couch
- Position the head in the central position with the neck flexed 45 degrees, with the chin towards the chest
- At each stage, support the patient’s head in place for 30 seconds and wait for any nystagmus or dizziness to settle
Describe the structure of the inner ear [+]
Structure:
The inner ear contains the bony labyrinth, a complex bony structure containing fluids (perilymph and endolymph). The inner ear is comprised of three parts:
* Semicircular canals
* Vestibule (middle section)
* Cochlea
The semicircular canals and otolith organs within the vestibule (the utricle and saccule) are responsible for detecting movement of the head. Together they form the vestibular system:
* The semicircular canals detect rotation of the head
* The otolith organs detect gravity and linear acceleration
The cochlea is responsible for hearing.
* The vestibular nerve transmits signals from the vestibular system (the semicircular canals and vestibule) to the brain to help with balance. The cochlear nerve transmits signals from the cochlea to provide hearing. Together they form the vestibulocochlear nerve (the 8th cranial nerve).
Describe the pathophysiology of vesitbular neuronitis [2]
Vestibular neuronitis describes inflammation of the vestibular nerve. This is usually attributed to a viral infection.
Vestibular neuronitis refers to inflammation of the vestibular nerve. A viral infection may trigger this inflammation. It distorts the signals travelling from the vestibular system to the brain, confusing the signal required to sense movements of the head.
- This results in episodes of vertigo, where the brain thinks the head is moving when it is not.
Vestibular neuronitis refers to inflammation of the vestibular nerve. A viral infection may trigger this inflammation. It distorts the signals travelling from the vestibular system to the brain, confusing the signal required to sense movements of the head. This results in episodes of vertigo, where the brain thinks the head is moving when it is not.
Describe the presentation of vestibular neuritis [+]
Typically, the history involves the acute onset of vertigo. In addition, there may be a history of a recent viral upper respiratory tract infection.
Symptoms are most severe for the first few days.
- Initially, vertigo may be constant, after which it is triggered or worsened by head movement. It is often associated with:
* Nausea and vomiting (may be severe)
* Balance problems
Features:
* recurrent vertigo attacks lasting hours or days
* nausea and vomiting may be present
* horizontal nystagmus is usually present
* no hearing loss or tinnitus
What is important to distinguish with a patient who presents with vertigo? [1]
How do you do this? [1]
It is essential to differentiate between peripheral (inner ear) and central (brain) causes when a patient presents with vertigo.
Any neurological signs or symptoms should make you consider a central cause of vertigo rather than vestibular neuronitis. This may require urgent management, particularly if posterior circulation infarction (stroke) is suspected.
TOM TIP: [2] are not features of vestibular neuronitis.
If these are present, consider [2] disease as differential diagnoses.
TOM TIP: Tinnitus and hearing loss are not features of vestibular neuronitis, as the cochlea and cochlear nerve are not affected.
If tinnitus and hearing loss are also present, consider labyrinthitis or Ménière’s disease as differential diagnoses.
TOM TIP: Tinnitus and hearing loss are not features of vestibular neuronitis, as the cochlea and cochlear nerve are not affected.
If tinnitus and hearing loss are also present, consider labyrinthitis or Ménière’s disease as differential diagnoses. You can remember this with [2]
Labyrinthitis – Loss of hearing
Neuronitis – No loss of hearing
The [test] can be used to diagnose peripheral causes of vertigo, resulting from problems with the vestibular system (e.g., vestibular neuronitis or labyrinthitis).
The head impulse test can be used to diagnose peripheral causes of vertigo, resulting from problems with the vestibular system (e.g., vestibular neuronitis or labyrinthitis).
The head impulse test can be used to diagnose peripheral causes of vertigo, resulting from problems with the vestibular system (e.g., vestibular neuronitis or labyrinthitis).
Describe how this occurs [+]
The head impulse test involves the patient sitting upright and fixing their gaze on the examiner’s nose. The examiner holds the patient’s head and rapidly jerks it 10-20 degrees in one direction while the patient continues looking at the examiner’s nose. The head is slowly moved back to the centre before repeating in the opposite direction. Ensure they have no neck pain or pathology before performing the test.
A patient with a normally functioning vestibular system will keep their eyes fixed on the examiner’s nose.
In a patient with an abnormally functioning vestibular system (e.g., vestibular neuronitis or labyrinthitis), the eyes will saccade (rapidly move back and forth) as they eventually fix back on the examiner.
The head impulse test helps diagnose a peripheral cause of vertigo but will be normal if the patient has no current symptoms or a central cause of vertigo.
Describe the mx of vestibular neuritis [+]
Patients may need admission if they are becoming dehydrated due to severe nausea and vomiting.
For peripheral vertigo, short-term options for managing symptoms include:
* Prochlorperazine (buccal / IM)
* Antihistamines (e.g., cyclizine, cinnarizine and promethazine)
NICE advise that symptomatic treatment can be used for up to 3 days. More extended use may slow down the recovery.
When do you refer onwards for vestiublar neuritis? [1]
NICE also recommend referral if the symptoms do not improve after 1 week or resolve after 6 weeks, as they may require further investigation or vestibular rehabilitation therapy (VRT).
[1] may develop after vestibular neuronitis.
Benign paroxysmal positional vertigo (BPPV) may develop after vestibular neuronitis.
How do you distinguish ?vestibular neuronitis from posterior circulation stroke? [1]
posterior circulation stroke: the HiNTs exam can be used to distinguish vestibular neuronitis from posterior circulation stroke
PoCS is a central cause of vertigo, whereas vestibular neuronitis is a peripheral cause of vertigo.
* In peripheral causes you have abnormal head impulse and none or unidirectional nystagmus, and no findings on test of skew. I always think abnormal, normal, normal = peripheral.
* In central you have a normal head impulse (which is actually a really bad finding), a bidirectional or vertical nystagmus, and a vertical skew.
So, normal abnormal, abnormal = central.
Central causes are worse than peripheral and require acute, time-sensitive management.
HiNTS exam is composed of which three tests? [3]
HiNTS exam is composed of 3 tests: head impulse test + assess nystagmus + test of skew
Describe the results of HiNTS exam [3]
Peripheral vertigo:
- abnormal head impulse test (catch-up saccade)
- no/unidirectional nystagmus
- no vertical skew
Central vertigo:
- normal head impulse test
- vertical/saccadic/bidirectional nystagmus
- vertical skew
