Disorders · Introduction

Perilymphatic fistula

A tiny leak where the inner ear meets the middle ear — vertigo and hearing loss that start with a dive, a strain or a blow. Easy to suspect, genuinely hard to prove, and argued over for half a century.

What it is

Trainee

A perilymphatic fistula is an abnormal communication — typically at the round or oval window — that lets perilymph leak and pressure transmit abnormally, producing fluctuating sensorineural hearing loss and vertigo, often with pressure/sound sensitivity.1

By the numbers

The true incidence is unknown — a direct consequence of the diagnostic uncertainty. What is reliable is the pattern of triggers: a clear precipitating event is the single most useful clue.1

contestedtrue incidence — no non-invasive gold standard

roundwindow most often involved (vs oval)

1971Goodhill's explosive/implosive routes described

CTPcochlin-tomoprotein — a specific perilymph marker

Precipitating events

Barotrauma (diving / flying)34%
Heavy strain / Valsalva24%
Head / penetrating trauma20%
Post-ear surgery12%
Spontaneous / none10%

Illustrative proportions — a clear trigger (barotrauma, strain or trauma) is the most useful clue; the spontaneous category is the most contested.

How this chapter is organised

Mechanism & anatomy — the explosive and implosive routes, and the window sites.
Clinical features — the trigger, the hearing loss, the vertigo, and the fistula test.
Diagnosis & tests — why it is hard, what each test contributes, and a confidence checker.
Differential diagnosis — above all, Ménière’s and SSCD.
Treatment & repair — conservative first, surgical window repair for failure.

Key points

An abnormal leak between inner and middle ear, usually at the round or oval window.
Suspect it when vertigo and hearing loss begin after barotrauma, strain, trauma or ear surgery.
The diagnosis is contested — no non-invasive gold standard; objective markers (pneumolabyrinth, CTP) or surgery confirm it.
It overlaps with Ménière’s disease and SSCD — exclude them before labelling a fistula.
Conservative measures first; surgical window repair for persistent or progressive disease.