Making the diagnosis
Differential diagnosis
Because the symptoms are non-specific, the differential isthe diagnosis. Two mimics dominate: Ménière’s disease and superior canal dehiscence.
The two big overlaps
Several inner-ear problems cause vertigo with hearing loss. The questions that separate them are: was there a trigger? Is there an air–bone gap on the hearing test? Does pressure or sound bring on symptoms?
Ménière’s disease is the closest match — fluctuating hearing, vertigo and fullness — but it is spontaneous and recurrent, without a trigger or pressure sensitivity.2 Superior canal dehiscence is also pressure/sound-sensitive, but it is a fixed third window with a CT-visible bony defect and an air–bone gap.
The discipline is to require positive evidence for a fistula rather than diagnosing it by exclusion — the habit that drove decades of over-diagnosis.1 A trigger favours a fistula; an air–bone gap with enhanced VEMP favours SSCD; a spontaneous recurrent course with fluctuating low-frequency loss favours Ménière’s.
PLF against its mimics
Perilymphatic fistula is the reference row; tap a mimic to surface the discriminator. The trigger column is the quickest tell.
Tap a mimic to reveal the discriminator. A clear precipitant favours a fistula.
When to reconsider
Recurrent spontaneous spells with fluctuating low-frequency loss point to Ménière’s disease; an air–bone gap with preserved reflexes and a CT dehiscence to superior canal dehiscence; a single prolonged attack with spared hearing to vestibular neuritis. Sudden post-traumatic hearing loss without a demonstrable leak may simply be labyrinthine concussion or idiopathic sudden sensorineural hearing loss.
Key points
- Ménière’s is the key overlap — but it is spontaneous, recurrent and trigger-free.
- SSCD shares pressure/sound sensitivity but has an air–bone gap, enhanced VEMP and a CT dehiscence.
- Diagnose a fistula on positive evidence, not by exclusion.
- A clear precipitating event is the quickest discriminator in favour of a fistula.