An elderly patient enters your room appearing unsteady, ‘No, I haven’t had too much to drink, Doc!’. You probably already have a differential diagnosis in your head, labyrinthitis being one of them. But, as this BMJ editorial reminds us, not all vertigo is labyrinthitis (BMJ 2012; 345:e5809).
The authors stress that the terms vertigo and labyrinthitis are not synonymous. Vertigo simply refers to an illusion of movement, whereas labyrinthitis (or more correctly vestibular neuritis) is actually rare with an incidence of 3.5/100,000/y. In one study, only 15% of patients referred to neuro-otology service with vestibular neuritis had the diagnosis; most of the others had benign paroxysmal positional vertigo (BPPV) or vestibular migraine. So, how can we get the diagnosis right?
In BPPV, vertigo is triggered by movement. Typically, this occurs when getting out of bed or turning over and settles when the patient is still. In 90% it involves one of the posterior semi-circular canals. Hallpike’s manoeuvre is useful in diagnosing BPPV and helps differentiate it from vestibular migraine.
Here, the history is similar to BPPV without the association with movement but perhaps with stress instead. Hallpike’s manoeuvre will not trigger an attack.
This presents with a sudden acute unrelenting attack of continuous rotational vertigo, nausea +/- vomiting and imbalance, usually lasting several days. These patients can rarely get to the surgery and may be bed-bound. Examination reveals unilateral, usually horizontal nystagmus to one side with some rotational element, not altered by the direction of gaze. Patients will have lost their vestibulo-ocular reflex on one side. This reflex allows you to fix on a point even if your head is moving and can be tested with the headthrust test:
- Ask the patient to look at your nose.
- Turn their head rapidly to one side (you only need to move it by about 5-10⁰ but speed is important).
- In normal individuals they will remain looking at your nose.
- If the vestibulo-ocular reflex fails, the patient’s eyes will move as their head moves before jumping back to fix on your nose.
Examination will otherwise be normal, and patients are unlikely to have a headache or deafness. The condition rarely recurs and you should reconsider your diagnosis if it does.
Could this be a cerebellar stroke?
An important differential diagnosis. The authors suggest this presents similarly to vestibular neuritis with vertigo and severe imbalance. Hearing loss may precede the imbalance, patients are usually unable to stand and may or may not have nystagmus (which can be vertical). Other cranial nerve deficits and up-going plantars may be present.
Treatment options for vestibular neuritis
- Bed rest and anti-emetics for a maximum of 3d, then encourage increasing activity. Symptoms usually resolve over a week.
- A Cochrane review in 2011 found no evidence to support the use of oral steroids.
- The authors suggest that correctly diagnosing and managing these acute cases may reduce long-term dizziness and subsequent handicap.
This article first appeared in The Sessional GP Magazine August 2015
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