A descriptive epidemiological analysis of isolated inner ear decompression illness in recreational divers in Hawaii.

Abstract

Inner ear decompression illness (IEDCI) was once thought to be relatively rare and seen predominantly in deep, mixed gas divers. The incidence of this type of injury is unknown, but IEDCI may be more common than previously thought and can be seen in recreational scuba divers using compressed air as their breathing medium. This study was conducted at the Hyperbaric Treatment Center (HTC) in Honolulu, Hawaii, to determine the frequency of occurrence of IEDCI and to evaluate some of the epidemiological parameters associated with these cases. Between 1983 and 2006, 28 presentations (2.8 percent of all cases of decompression illness treated) with a diagnosis of isolated IEDCI were identified in 26 divers. Presenting symptoms and physical findings included vertigo, nausea, postural imbalance, vomiting, nystagmus, hearing loss, and tinnitus. Most cases developed after multiple deep dives or after dives in which adequate decompression did not occur. All but two divers were breathing air. Symptoms developed on average 70 minutes after diving. The average delay to treatment was nine hours post injury. All but three cases were treated using the HTC deep treatment tables. Nineteen cases made a full recovery, with all cases achieving substantial improvement. Most cases required four to five treatments to obtain that level of recovery. Those with incomplete resolution of symptoms at the time of discharge were left with mild degrees of motion sickness and gait disturbance, and some were left with hearing loss. IEDCI warrants early and aggressive intervention to reduce the risk of permanent disability.