DAN Medical Frequently Asked Questions
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Inner-Ear Barotrauma (IEBT)
>Inner-ear barotrauma is damage to the inner ear due to pressure differences caused by incomplete or forceful equalization. A leak of inner-ear fluid may or may not occur.
The inner ear is separated from the external world by the middle ear. It is the organ for hearing and balance. When the pressure in the middle-ear space is properly equalized, the risk of inner-ear barotrauma is extremely low.
>If the pressure in the middle ear is not equalized during descent, the water pressure on the eardrum transfers inward through the middle-ear ossicles to the oval windows, and the round window bulges outward. The pressure itself may damage sensitive inner-ear structures. If the pressure is excessive, either the oval window or, more commonly, the round window may tear, and the inner-ear fluid (perilymph) may leak into the middle ear (perilymph fistula).
>The Valsalva maneuver increases the pressures in cranial tissues and circulation, which may transmit to the cochlear fluid, causing an outward movement of the round window. Pressure waves alone can cause damage to the inner ear without window rupture. If the rupture occurs, the loss of fluid from inner ear leads to damage of the hearing organ and sometimes of the balance organ. If the leak is not stopped soon by spontaneous healing or surgical repair, permanent hearing loss may occur.Divers may experience:
Symptoms of middle-ear barotrauma are almost always present. Vertigo is usually severe and accompanied by nausea and vomiting. Hearing loss can be complete, instant and permanent, but divers usually lose just the higher frequencies. The loss becomes noticeable only after a few hours. You may not be aware of the loss until you have a hearing test. In case of vertigo underwater, abort the dive, and obtain assistance to reach the surface safely. Begin surface oxygen if decompression illness is suspected. First aid providers should conduct a complete neurological exam and note any deficits.It is important to distinguish between these two conditons, because their treatments differ. The standard treatment for DCS of any kind is hyperbaric oxygen treatment in a recompression chamber; recompression or any pressure change is contraindicated when inner-ear barotrauma is likely. While the symptoms are similar in both conditions, barotrauma is preceded by failed equalization of middle-ear pressure and usually occurs at the beginning of dive, while DCS occurs due to failed decompression at the end of the dive.
- Severe vertigo
- Hearing loss
- Ears roaring/ringing (tinnitus)
- Involuntary eye movement (nystagmus)
- Fullness of the affected ear
>Urgently seek an evaluation by a physician to rule out DCS. If your physician determines it is not DCS, consult an ENT specialist with experience treating divers. For a referral in your area, email email@example.com, or call the DAN Medical Information Line at +1-919-684-2948.
>Avoid any exertion, middle-ear equalization, altitude or diving exposure, sneezing or nose blowing. Do not take aspirin, nicotinic acid (vitamins), other vasodilators or anticoagulants. Conservative treatment includes bed rest in a sitting position and avoiding any strains that can increase intracranial or middle-ear pressure. If symptoms do not improve, surgery may be necessary. Healing of the tear (fistula) usually occurs within a week or two. Hearing loss may become permanent.Evaluation of fitness to dive requires an expert diving physician and depends on the degree of permanent damage as well as the probability of repeated injury.In many cases, complete healing occurs spontaneously. If fistula presents and does not heal soon spontaneously, surgery may be recommended. In some cases, the inner ear may be damaged permanently; the body may adapt to one side not working properly. If injury occurs to the other ear, the situation can be serious and may involve incapacitating balance problems.Learn gentle but effective equalization techniques, and avoid aggressive employment of the Valsalva maneuver. Do not dive when congested.