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Initial assessment and management
Background
Scuba diving-related otological injuries comprise the majority of diving-related incidents that present to general practitioners (GPs). Correct diagnosis and management are key to prevent permanent hearing loss and vertigo.
Objective
The aim of this article is to increase awareness of the pathophysiology of otological diving injuries and provide an approach to initial assessment and treatment, as well as to highlight particular circumstances in which onward referral is required.
Discussion
Accurate diagnosis and treatment of diving-related otological injuries by GPs can have profound positive effects on a patient's long-term outcomes. Complete otolaryngological assessment in those who have previously had a dive-related injury is critical to ensure patient safety prior to recommencing scuba diving.
SCUBA DIVING, during which a diver uses a self-contained underwater breathing apparatus (scuba), is a popular recreational activity resulting in frequent presentations to the general practitioner (GP). Incorrect diagnosis and management of otological diving injuries can lead to significant morbidity including chronic vestibulopathy and hearing loss. As many patients present to the GP with diving-related concerns, it is pertinent that treating clinicians are aware of the common presentations, initial treatment and prevention of such injuries.
Epidemiology
Diving-related otological injuries account for 65-72% of all divingrelated presentations to practitioners.1'2 Middle ear barotrauma (MEB) is most common, accounting for nearly 50% of presentations.2 Decompression sickness (DCS) is one of the most severe diving-related complications and has an Australian incidence rate of 10 per 100,000 dives.3 Inner ear DCS (IEDCS) is rare, with an estimated recreational diving incidence rate of 0.01-0.03%.4
Pathophysiology - A lesson in physics
Otological diving injuries occur as a result of the effect of ambient pressure changes on the ear structures. At sea level the atmospheric pressure is 1 atmosphere (atm). For every 10 m a diver descends below this level, the ambient pressure increases by 1 atm. For most purposes, atmospheric gas is made up of 21% oxygen and 79% nitrogen, similar to compressed gases found in a scuba tank.
Two important laws of physics govern the physiology associated with pressure changes during scuba diving. Boyle's Law (P1V1 = P2V2) dictates that the pressure and volume of a gas at a constant temperature are inversely proportional. As the diver descends, ambient pressure increases. The middle...