Perilymph fistula

Labyrinthine fistula
Cross-section of cochlea. Perilymph is located in the scala tympani and scala vestibuli - the aqua regions at the top and bottom of the diagram.
Classification and external resources
Specialty	otolaryngology
ICD-10	H83.1
ICD-9-CM	386.4
DiseasesDB	32218
eMedicine	emerg/414
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A labyrinthine fistula is an abnormal opening in the bony capsule of the inner ear, resulting in leakage of the perilymph from the Cochlea into the middle ear. This includes specifically a perilymph fistula (PLF), an abnormal connection between the fluid of the inner ear and the air-filled middle ear. This connection is caused by a rupture of the round window that separate the inner and middle ear. Another type of l.f. is a semicircular canal dehiscence, which allows the inner ear to be influenced by the intracranial pressure directly.

These can be both congenital or develop over time with the thinning of the otic capsule by the persistent pulsations of the intracranial pressures against the bones of the skull. Finally, disease conditions—for example cholesteatoma—can result in a labyrinthine fistula. Traumatic events, with excessive pressure changes to the inner ear such as in scuba diving, head trauma, or an extremely loud noise can lead to rupture and leakage.

PLF is a cause of dizziness, imbalance, and hearing loss—any or all of these symptoms can exist. Vertigo (an illusion of motion) is not common in this disorder. The most common cause of this fistula is head or ear trauma. Rapid increases of intracranial pressure can also result in a PLF. Rarely, these fistulas can be congenital, leading to progressive hearing loss and vertigo in childhood. It has also been a complication of a stapedectomy.

When diagnosing, PLF should be differentiated from Ménière's disease. Tympanostomy has been reported to be a way to diagnose and cure PLF.

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Wikipedia