What Causes a Perilymph Fistula?

Leak in the Inner Ear

Inner ear anatomy.
Inner ear anatomy. Stocktrek Images / Getty Images

A perilymph fistula occurs when there is a tear in the thin membrane called the oval or round window which separates the inner ear from the middle ear. The inner ear is filled with a fluid called perilymph, so when the tear occurs this fluid leaks into the middle ear space.

What Causes a Perilymph Fistula?

The most common cause of a perilymph fistula is head trauma. It can also be caused by barotrauma, a condition that usually occurs on an airplane or while scuba diving (when there are rapid changes it atmospheric pressure). More rarely perilymph fistulas can happen during childbirth, congenital (before birth), or other unknown causes.

Symptoms of Perilymph Fistula

Diagnosing a Perilymph Fistula

Diagnosis of a perilymph fistula can be difficult because symptoms overlap with other inner ear disorders such as Meneire's disease. There also is not a "gold standard" test for diagnosing a perilymph fistula, however you can sometimes make the diagnosis from a MRI or CT scan. The American Hearing and Research Foundation has specific recommendations on diagnosing a perilymph fistula particularly when barotrauma is not involved. Since the diagnosis can be so challenging and treatment can often involve surgical intervention, they recommend receiving a second opinion as well as the following tests to increase the likelihood of an accurate diagnosis:

  • fistula test
  • Fraser test
  • valsalva test
  • audiometry
  • Electrocochleography (ECOG) (a test that records the activity of the inner ear)
  • Electronystagmography (ENG)
  • Temporal bone CT scan, high resolution
  • MRI

A thorough history can be very important in helping your physician determine whether or not perilymph fistula is a possible problem that is causing your symptoms. It is common to have your symptoms get worse when you are sneezing, straining, or coughing, and you should share this with your doctor. Another common symptom is the Tullio phenomenon, which causes you to experience vertigo when exposed to loud sounds.

Of the tests listed above, there is some research that suggests that the best way to make a diagnosis of perilymph fistula is the medical history and a positive fistula or Fraser test.

Treating a Perilymph Fistula

Often strict bed rest is recommended to allow your body to repair the fistula on its own. As long as symptoms are improving your doctor may continue bed rest or strict activity restriction for up to six months before considering surgical repair of a perilymph fistula.

Certain medications may be helpful in treating symptoms but will not have any effect on the fistula itself. For example, medications like Zofran and Phenergen may be used to control nausea. Antivert is a medication used to treat different types of vertigo and may be beneficial in treating symptoms. Valium is another medication that is sometimes used.

Surgical repair involves a tissue graft to repair the tear in the round window. Unfortunately this approach is not always successful in treating a perilymph fistula. According to the American Hearing Research Foundation in a study of 160 persons about 90 percent of patients had stable or improved symptoms after surgery. None of the patients reported worsening of their symptoms.

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