Excerpt from Perilymph Fistula

Please click here to view the full topic text: Perilymph Fistula

Background

A perilymph fistula (perilymphatic fistula [PLF], labyrinthine fistula) is a pathologic communication between the fluid-filled space of the inner ear and the air-filled space of the middle ear, most commonly occurring at either the round or oval window. The primary manifestations of perilymph fistulization are sudden or progressive fluctuating sensorineural hearing loss and vertigo. Other symptoms that may be present include tinnitus, disequilibrium, and aural fullness.

This clinical entity was proposed more than a century ago, yet it remains a topic of controversy, especially regarding the occurrence of spontaneous PLF. Trauma and poststapedectomy are etiologies proven to cause PLFs and must be considered in the appropriate settings. A PLF should be considered in pediatric patients with recurrent meningitis, and the option of middle ear exploration should be pursued. It is likely that most pediatric patients with PLFs will have an anatomic abnormality of their middle ear or labyrinth. It is also known that although several potential pathways exist between the perilymphatic space and the middle ear, actual leaking of fluid can be difficult or impossible to prove.

There is no agreed upon diagnostic test with enough sensitivity and specificity to identify the presence or absence of perilymph fistula. This has made it difficult to establish criteria to determine when surgical exploration might be indicated. Additionally, there are no universally accepted criteria to confirm diagnosis at surgery; the determination of the presence or absence of PLF is the subjective decision of the surgeon. Additionally, the presence of clear fluid in the middle ear at the time of surgery may represent perilymph or may be CSF, serum, or local anesthetic. No reliable and accurate test is currently available to reliably distinguish these fluids from one another. No studies have been reported to account for the substantial placebo effect of a surgical procedure for vertiginous symptoms in patients with suspected PLF, and no appropriate long-term follow up of patients after surgery has been reported.

The presenting complaint and symptoms of perilymph fistula are often consistent with Ménière syndrome. Therefore, in the absence of prior surgery or definite traumatic event, distinguishing a perilymph fistula from Ménière syndrome may be difficult.

Pathophysiology

Most commonly, a tear in the round or oval window leads to loss of perilymph into the middle ear. This condition may be the result of stapes prosthesis surgery, trauma, barotrauma, or bony erosion due to infection or neoplasm, or it may be idiopathic. In children, perilymph fistulas are associated with congenital anomalies of the middle or inner ear.

Mortality/Morbidity

In children, the condition may be associated with recurrent meningitis. Acute or chronic perilymph fistulas may significantly affect quality of life.

Sex

Prevalence is higher in females than in males.

Age

Perilymph fistulas occur in young children with congenital abnormalities; otherwise, the condition is not known to be age specific.

Please click here to view the full topic text: Perilymph Fistula