Monday, 15 August 2016

Vertigo

Vertigo is a very difficult topic. Although typically the diagnosis is split into central vs peripheral, it's probably better to think of it as
- investigate now
- investigate later
- No investigations needed.


Peripheral does not equal benign -> eg acoustic neuroma
Central does not equal life threatening -> migraine. Central rarely occurs in isolation, is less intense than peripheral, not possitional, hearing loss and tinnitus are rare and nystagmus is not inhibited by ocular fixation.It normally persists for more than 48 hours. Mild nausea and vomiting.

There are a few great flow charts, and lots of things to think about to work out what the cause is.

1. How long does it last for?
Seconds (psychogenic), Less than 1 min (BPPV), Minutes (Vascular/Ischaemic), Hours
(Meniere's or vestibular migraine), Hours to days (vestibular neuronitis, central causes, MS), Recurrent with headaches (Vestibular migraines).

2. Is it central or peripheral?

3. Dix - Hallpike to see if it's BPPV (peripheral cause)
Don't do it if there's any neck pathology that would make the procedure harmful - like arthritis. If patient dizzy on turning over in bed, BPPV is possible.

Patient in middle of bed. Looks towards one end of bed. Quickly lie flat.
Then over and up to the other side of the couch
Look for nystagmus
Nystagmus is diagnostic.

5. Treat the BPPV with Epley manueuvere:
Lie patient down
Head over couch
Look to side
Quickly turn head to other side - look for nystagmus. Stay there for 30 - 6o sec
Prepare to look at the floor - keep head still and roll onto side
Quickly look at floor
Stay for 30 - 60 seconds
Then sit up and put head down to keep looking at the floor

6. If it's central, HINTs
HI – Head impulse test: This test is a test of the patient vestibulo-occular reflex
Ask patient to look at a fixed target. Rapidly rotate head and look at eyes. A patient with an intact vestibulo-occular reflects will be able to maintain their gaze on the fixed target. The patient who has a defect with one of the vestibules will not be able to maintain gaze and as the head is rotated the eyes will rotate with the head away from the target, after a brief pause will then saccade back to the target. This can be subtle and some people have suggested that it can help
to use a phone with a slow motion app to capture the eye movements.

N - Nystagmus: Nystagmus mixed in peripheral, horizontal in central.
Peripheral vertigo decreases with fixation. Central vertigo persists with fixation.
Peripheral fatigues, central doesn't.
Horizontal, unidirectional never vertical in peripheral vertigo. Any direction for central vertigo.
In peripheral nystagmus resolves within 48 hours, and in central persists beyond 48 hours.


TS- Test of skew: Cerebellum and midbrain are required to allow the eyes to maintain fixed on their target during binocular vision. Cover each eye in turn and when an eye is uncovered looking for vertical deviation of the uncovered eye suggesting the presence of a central lesion.

7. Central Causes
Need ongoing referral and investigation. MRI in the first 48 hours misses 10 - 30% Posterior Circulation Strokes.

8. Treatment
Betahistine is for Meniere's disease only. Seak secondary care advice before starting.

9. Other Investigations
Arrhythmias are rarely the cause of dizziness, but it's worth having a look just incase.
ECG Abnormalities suggestive of arrhythmic syncope
Bifascicular block
Prolonged QRS
Mobitz 1
Brady <50bmp
Sinus pause >3sec
Pre-excited QRS
Long QT
RBBB with ST elevation (Brugada)

10. Look for red flag features
Headache 40% posterior circulation stroke
Gait ataxia May be only non‑vertiginous manifestation of cerebellar stroke
Hyperacute onset Suggests vascular origin
Vertigo and hearing loss AICA or urgent ENT problem
Prolonged symptoms (greater than 4 days) Floor of fourth ventricle problem
Symptoms on valsalva Perilymphatic fistula

References
https://vertigoed.wordpress.com/
http://www.londonscn.nhs.uk/wp-content/uploads/2016/04/neuro-adult-with-dizzy-spells-edu-videos-042016.pdf
http://www.rcemlearning.co.uk/modules/vertigo-will-it-make-your-head-spin/ 

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