Perilymph Fistula in Emergency Medicine

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. Markou et al reported on a patient who developed a perilymph fistula in the round window due to a whiplash injury.[6] In children, perilymph fistulas are associated with congenital anomalies of the middle or inner ear.

A study by Kim et al indicates that in patients with perilymph fistula, a third-window lesion may be involved. The report found evidence that in such cases, the existence of positional nystagmus associated with multiple semicircular canals and the occurrence of lower-frequency pseudoconductive hearing loss may be evidence of a third-window effect.[7]

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 of perilymph fistula 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.

History for perilymph fistula may include the following:

• Fluctuating sensorineural hearing loss that may be sudden or progressive

• Vestibular symptoms

  • Vertigo, with or without head position changes

  • Dysequilibrium

  • Motion intolerance

  • Nausea and vomiting

  • Disorganization of memory and concentration

  • Perceptual disorganization in complex surroundings such as crowds or traffic

• Tinnitus - May be roaring in nature

• Aural fullness

A retrospective study by Haubner et al of 69 patients who suffered unilateral sudden deafness (from sensorineural hearing loss) found that just a minority of these patients had a perilymph fistula. In the study, in which the patients underwent exploratory myringotomy, 18.8% of patients had a visible perilymph fistula, while possible, but doubtful, perilymph fistula was diagnosed in another 21.7%; no signs of fistulae were found in 59.4% of patients. Moreover, the investigators found themselves unable to predict the presence of a perilymph fistula, stating that intraoperative findings were not correlated to the patient’s history or the preoperative diagnosis of tinnitus or vertigo. (A typical history for a round window membrane rupture was not reported by 89.8% of the study’s patients.)[8]

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• Positive test results for vestibular dysfunction or hearing loss, while helpful, are not pathognomonic.

• Romberg (feet together) or tandem Romberg (heel-to-toe) test findings may be positive.

• Positional nystagmus and benign paroxysmal positional vertigo often are associated with traumatic perilymph fistula.

• Sensorineural hearing loss may be confirmed by audiograms.

See the list below:

• Prior stapes surgery

• Head trauma, including whiplash injuries

• Barotrauma

• Acoustic trauma

• Idiopathic or spontaneous, possibly related to episodes of valsalvae, nose blowing, or physical exertion (The existence of spontaneous perilymph fistula is still an area of controversy among otologists.)

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• No diagnostic test can be considered a criterion standard for perilymph fistula, and none are immediately useful in the emergency department.

• Clinical history and symptoms are more sensitive than radiographic studies for the assessment of perilymph fistula.

• A CT or MRI scan may be indicated with a history of head trauma if temporal bone fracture is considered, but its use as a diagnostic study for nontraumatic perilymph fistulas is questionable.

  • High-resolution CT scans are inadequate for evaluation of the round and oval window regions.

  • MRI with intrathecal gadolinium enhancement can detect inner and middle ear communication, but a more cost-effective modality is preferred.

See the list below:

• Otologists may use the following tests to diagnose perilymph fistulas:

  • Audiograms to detect hearing loss

  • Electrocochleography

  • Fistula tests (Hennebert sign): The subjective fistula test is performed by applying positive and negative pressure to the intact eardrum using a pneumatic otoscope. Positive results include the elicitation of nystagmus or onset of dysequilibrium with the sensation of motion or nausea. Some otologists administer the test with electronystagmography or by using platform posturography.

• Perilymph labeling methods

  • Initial studies used intrathecal or intravenous fluorescein, but these have been abandoned for perilymph-specific protein testing, such as beta-2 transferrin, apo D, and apo J.

  • Beta-2 transferrin, a protein found in perilymph and CSF but not in serum, has been the most actively studied. Initial enthusiasm for a Western blot assay for this protein has wavered due to low sensitivity. The presence of beta-2 transferrin in perilymph has been unreliable, possibly due to current collection methods or small sample volumes, and false-positive results may be secondary to CSF contamination during collection.

  • Focus has recently switched to the efficacy of apolipoprotein D (apo D) as a marker for perilymph with encouraging results.

  • Results of a study by Ikezono et al strongly suggest that cochlin-tomoprotein may be a specific marker of perilymph leakage. Additionally, cochlin-tomoprotein could be a potential marker, allowing definitive diagnosis of perilymph fistula related hearing loss and vestibular disorders.[9, 10]

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• The current criterion standard for confirmation of perilymph fistula is direct visualization either by operative middle ear exploration or by in-office endoscopy.

• The subjectivity of this diagnostic maneuver has been questioned because no universally accepted criteria exist for diagnosis during surgery. More objective tests are being developed, particularly those that identify compounds specific to perilymph upon the examination of the fluid contents.

The primary purpose of emergency evaluation is to seek other, more emergent causes of symptoms. However, consider the diagnosis with hearing loss and vertigo following head trauma. Vertigo suppressants, such as diazepam and meclizine, may be used, although their benefit remains unproven in this setting. Medical therapy is rarely reported. Some reports exist of spontaneous healing with bedrest, head elevation to 30°, and avoidance of lifting or middle-ear pressure–increasing activities.

Consult with an otolaryngologist.

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• Strict bedrest for 5-7 days or until reevaluation

• Elevation of the patient's head above the heart level

• Avoidance of straining

• Avoidance of nose blowing or Valsalva maneuver

• No lifting (>10 lb)

• Stool softeners

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• Bedrest with the head of the bed elevated to 30°

• Avoidance of lifting or pressure-increasing activities (ie, Valsalva maneuver)

• Surgical intervention is the principle approach to treatment when perilymph fistula is diagnosed. The site of perilymph leak is covered with some form of autologous tissue.

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• Both the patient and the physician should be prepared for no response to treatment, especially with regard to hearing improvement. Recurrence of postoperative signs and symptoms may occur in 21-47% of patients.

• Perilymph fistula may be associated with recurrent meningitis in children.

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• Because of the difficulty in making the diagnosis of perilymph fistula, the natural history of this disorder is unknown.

• Significant improvement in symptoms that are presumed to be from perilymph fistula may occur with conservative treatment.

• Surgery is more successful in relieving vertiginous symptoms than in improving hearing.