Inner Ear Barotrauma

Inner Ear Barotrauma in diving is rare but can lead to significant consequences.

It occurs most commonly during descent and is usually associated with difficulty in equalizing.

In over half of cases, it is associated with middle ear barotrauma and occurs through the same mechanisms.

However, there is a significant percentage of cases where inner ear barotrauma occurs without injury to the middle ear. The mechanisms behind this are not well understood.

Hypotheses on the origin of inner ear barotrauma:

a) The inner ear may be injured by an increase in intracranial pressure, which occurs when attempting to equalize through forced Valsalva maneuver when the Eustachian tube does not function properly during descent (explosive mechanism).

b) The inner ear may be injured by a sudden increase in pressure in the middle ear, caused by a forced Valsalva maneuver overcoming the resistance of the Eustachian tube. This could happen during descent or ascent (implosive mechanism).

In all cases, these pressure changes, transmitted to the inner ear, can damage its delicate structures, including those involved in hearing and those related to balance, and may even result in the rupture of the membranes separating the middle ear from the inner ear, leading to a perilymphatic fistula.

Dibujo esquemático de las distintas partes del oído.

 

Main symptoms of acute inner ear barotrauma:

The main symptoms are hearing loss, tinnitus, and vertigo with a spinning sensation, often accompanied by nausea or vomiting, but they can also be associated with all the symptoms of middle ear barotrauma. However, when there is injury to the inner ear, the hearing loss is usually more significant than in middle ear barotraumas, and unlike middle ear barotrauma, it is often irreversible.

If the hearing loss fluctuates or if vertigo occurs with positional changes, changes in pressure in the ear due to sneezing, coughing, or the Valsalva maneuver, or due to intense sound stimulation (Tullio phenomenon), a perilymphatic fistula should be suspected.

Following inner ear barotrauma, it is necessary to refrain from underwater activities for a variable period depending on the severity of the injury. Treatment should be initiated as soon as possible; most often, medical treatment (corticosteroids, anti-vertigo medication, etc.) will be advised, along with postural measures (bed rest with elevated head) if a perilymphatic fistula is suspected. If the condition does not resolve spontaneously, surgical treatment may be necessary. Despite treatment, residual auditory or vestibular sequelae are common.

Prevention of otic barotraumas, both in the middle and inner ear, involves preventing the blockage of the Eustachian tube: diving with nasal congestion (cold, allergies, etc.) should be avoided, attempting gentle and gradual equalization, avoiding sudden maneuvers or too rapid descents or ascents. In some cases, the use of nasal decongestants to improve Eustachian tube permeability prior to dives may be advisable.