What is a Perilymphatic Fistula?

Do you or a patient of yours experience dizziness with coughing, loud sounds, or with sudden altitude changes? If so, the symptoms maybe due to a perilymphatic fistula.

Let’s cover the 5 W’s of what a perilymphatic fistula is. That way we will have a better understanding of what it is, what causes it, and treatment options.

What is a Perilymphatic Fistula?

A perilymphatic fistula is a hole or defect in one of the two thin membranes of the inner ear, being the round and oval window.

Function of the round and oval window

These two membranes allow for pressure changes in the inner ear. Specifically, the oval window allows for the vibration from the stapes (smallest bone in your body) in the air filled middle ear to pass into the fluid filled inner ear. The vibration causes pressure changes to the fluid in the inner ear. The inner ear then converts these pressure changes into neural impulses that are sent to the brain by the 8th cranial nerve. From there the brain interprets the impulses as sound. Now, as the inner ear is incased in bone it cannot expand and contract with the pressure changes. The round window, therefore, billows in and out to compensate for the pressure change.

Now, if there is a defect with either of the windows, the fluid from the inner ear will leak out.

Why does this occur?

A perilymphatic fistula is most commonly caused by head trauma (fracture, barotrauma, penetrating injury). Interestingly, penetrating injuries can include misuse of the common Q-tip. It can also be due to chronic ear infections, sudden altitude changes, childbirth, and less often with coughing, sneezing, or valsalva (i.e. heavy lift). It can also be iatrogenic (i.e. due to an ill fitted prosthetic stapes) or a congenital defect of the inner ear.

What does a perilymphatic fistula feel like?

Symptoms may include any of the following:

• dizziness,
• unsteadiness,
• motion intolerance,
• nausea/vomiting,
• hearing loss,
• sensitive hearing,
• ear pain, pressure, and/or fullness,
• tinnitus

associated with pressure changes such as with coughing, sneezing, blowing your nose, bending forward, heavy lifting, loud sounds, and sudden altitude changes (i.e. fast elevators, airplanes, driving into valleys).

Who can get a perilymphatic fistula?

Anyone, especially children. However, it is one of the more rare conditions to cause dizziness and hearing loss. According to Fiedler it has an incidence of 1.5/100,000 in adults, which is similar to that of vestibular schwannoma.

When should one seek medical treatment?

Immediately after the onset of symptoms.

Where should one seek medical treatment?

We would recommend that someone with a possible perilymphatic fistula see their family physician or nurse practitioner first.

How is a perilymphatic fistula diagnosed?

Unfortunately, given the location of the fistula, being deep in the ear and the leak being small, it is unable to be visualized even with a tympanotomy. Therefore, the history of the above noted symptoms with pressure changes, after a specific event is key to making its diagnosis.

If you are wondering about medical imaging such as MRIs, they  usually will not visualize the defect. They will, however, help determine if there is some other unidentified problem. With CT imaging there are mixed opinions as to whether it can visualize the defect.

Hearing tests may help determine the affected side. Infrared goggles, on the other hand, may demonstrate nystagmus with pressure changes, such as with performing a valsalva or tragal test. Sometimes the nystagmus can even be elicited with one’s own voice and music which is called Tullio’s Phenonenom. Note: If you click on this link make sure to see the video of the nystagmus elicited with sound.

How is a perilymphatic fistula treated?

The initial treatment is to limit pressure changes to the ear for 7-14 days by avoiding:

• Lifting, carrying, or any other exertion activity that causes exertion.
• Loud sounds.
• Coughing, sneezing, and blowing your nose.

Does perilymphatic fistula heal on its own?

By avoiding the above it usually heals on its own So, if there is no improvement within 14 days then consultation with an otolaryngologist is warranted. Patching of the defect may then be considered. The otolaryngologist will also determine if there are other causes for the symptoms.

Some more common questions:

1. Can a perilymphatic fistula make you feel dizzy? Yes.

2. Perilymphatic fistula and hearing loss - there can be both with this condition.

3. Perilymphatic fistula and flying - flying can definitely make the symptoms associated with this condition worse.

If you have further questions about perilymphatic fistula, please feel free to contact us at North 49.