Apparently what we generally diagnose as ‘viral labyrinthitis’ is actually far more likely to be BPPV or vestibular migraine. Very occasionally it might be vestibular neuritis, which is what we actually mean when we say ‘labyrinthitis’ (literal labyrinthitis is almost unheard of) but even vestibular neuritis is rare, and almost never recurs – incidence is approx 3.5/100 000.
(I’m editing this to question that last. I was suspicious of the figure as it simply doesn’t match what I’ve come across in primary care, and I couldn’t believe I was overdiagnosing it that much, so I checked the reference. Turns out that that figure comes from a survey in secondary care in Japan in the late ’80s. Well, that’s reliable as the final word on the matter.)
CVA can also be misdiagnosed as labyrinthitis (not a good mistake to make).
Genuine cases of vestibular neuritis, according to this editorial:
- present with vertigo that is constant over several days (even when the patient is completely still) with no periods of relief during that time.
- have unidirectional, primarily horizontal nystagmus on looking forward (spontaneous unidirectional nystagmus with no CNS symptoms or signs is usually an indication of a peripheral, rather than central, abnormality).
- have loss of vestibulo-ocular reflex (this is the one that causes the eyes to move in the opposite direction to the head). Normal vestibulo-ocular reflex is a red flag sign, as it implies a central rather than peripheral cause.
- have normal hearing and otoscopy
- can stay upright holding onto furniture (patients with cerebellar stroke can’t)
Red flag signs include:
- unilateral hearing loss
- new headache
- abnormal neurological symptoms or signs
- normal vestibulo-ocular reflex
In true cases of vestibular neuritis, bed rest and antiemetics are recommended for a maximum of three days. (Although, when told this by an ENT consultant in the past, I told him my policy was to recommend them only when needed for severe spinning feelings and not once the symptoms died down to an ‘off-balance’ feeling, and he felt that was fine.)