Eponym
Differential Diagnosis
Comments
Perilymphatic fistulae are abnormal openings in the round and/or oval windows
that allow communication between the perilymph (the fluid surrounding the
membranous labyrinth) and the middle ear apace. They occur at any age and are
difficult to diagnose preoperatively; patients present with an "amazing array" of
signs and symptoms, and conclusive preoperative tests do not exist.1
Predisposing factors include prior otologic surgery, trauma, exertion/straining,
and upper respiratory infections. Roughly a third of cases are idiopathic or due
to congenital malformations.1
Hearing loss (involving any frequency), vestibular symptoms (of any kind),
tinnitus, and sensations of aural fullness may occur with any chronicity or may
not occur at all. Surgery eliminates or improves symptoms in 90% of patients.
Vertigo induced by straining (for example, during defecation) or by exertion
(even as little as vacuuming) is a classic symptom. Pressing on the tragus
causes vertigo by inducing a change in air pressure in the external ear canal:
The perilymphatic fistula allows transmission of this pressure change to the
endolymphatic space, wherein lie components of the vestibular apparatus.1
The Hennebert sign is eye deviation provoked by pneumatic otoscopy.1
References
(1) Laryngoscope. 94:37-49 (1986). 91 patients with proven PLFs.
(-) Ann Otol Rhinol Laryngol. 88:153-159 (1979). Perilymphatic fistulae with
vertigo and Hennebert sign, but without hearing loss.
(-) Ann Otol Rhinol Laryngol. 97:105-108 (1988). Seeks indications for
surgical exploration.
From:
Zebra Cards: An Aid to Obscure Diagnoses. JG Sotos. Philadephia: American College of Physicians, 1989. ISBN 0-943126-13-4. Copyright © 1989 American College of Physicians. All Rights Reserved. Phone: 1-800-523-1546. |