CLINICAL Diving-related otological injuries Initial assessment and management Lyndon Nofz, Jemma Porrett, Nathan Yii, SCUBA DIVING, during which a diver uses pressure increases by 1 atm. For most Nadine De Alwis a self-contained underwater breathing purposes, atmospheric gas is made up of apparatus (scuba), is a popular recreational 21% oxygen and 79% nitrogen, similar to activity resulting in frequent presentations compressed gases found in a scuba tank. Background Scuba diving–related otological injuries to the general practitioner (GP). Two important laws of physics govern comprise the majority of diving-related Incorrect diagnosis and management the physiology associated with pressure incidents that present to general of otological diving injuries can lead to changes during scuba diving. Boyle’s practitioners (GPs). Correct diagnosis significant morbidity including chronic Law (P1V1 = P2V2) dictates that the and management are key to prevent vestibulopathy and hearing loss. As pressure and volume of a gas at a constant permanent hearing loss and vertigo. many patients present to the GP with temperature are inversely proportional. Objective diving-related concerns, it is pertinent As the diver descends, ambient pressure The aim of this article is to increase that treating clinicians are aware of the increases. The middle ear, being an awareness of the pathophysiology of common presentations, initial treatment air-filled space, correspondingly reduces its otological diving injuries and provide and prevention of such injuries. volume by 50% in the first 10 m of descent an approach to initial assessment and (Figure 1). If equalisation does not occur, treatment, as well as to highlight particular circumstances in which then a vacuum is created, placing pressure onward referral is required. Epidemiology on the tympanic membrane and round Diving-related otological injuries and oval windows (the flexible walls of this Discussion account for 65–72% of all diving- space). This accounts for direct pressure– Accurate diagnosis and treatment of related presentations to practitioners.1,2 related ear injuries during diving. diving-related otological injuries by GPs can have profound positive effects on a Middle ear barotrauma (MEB) is most As ambient pressure increases, so does patient’s long-term outcomes. Complete common, accounting for nearly 50% the partial pressure of each of the gases otolaryngological assessment in those of presentations.2 Decompression within the environment. Henry’s Law who have previously had a dive-related sickness (DCS) is one of the most severe dictates that as the partial pressure of a injury is critical to ensure patient safety diving-related complications and has gas increases, a greater amount becomes prior to recommencing scuba diving. an Australian incidence rate of 10 per dissolved in surrounding liquids. During 100,000 dives.3 Inner ear DCS (IEDCS) uncontrolled ascent, the reduction in is rare, with an estimated recreational pressure causes release of dissolved gas diving incidence rate of 0.01–0.03%.4 nitrogen bubbles within tissues or blood that can lead to cell injury and hypoxia, causing the symptoms of DCS. Pathophysiology – A lesson in physics Otological diving injuries occur as a External ear pathology result of the effect of ambient pressure Otitis externa changes on the ear structures. At sea Otitis externa is common among those level the atmospheric pressure is who spend considerable amounts of 1 atmosphere (atm). For every 10 m a diver time submerged underwater. Prolonged descends below this level, the ambient exposure of the ears to water results 500 | REPRINTED FROM AJGP VOL. 49, NO. 8, AUGUST 2020 © The Royal Australian College of General Practitioners 2020 DIVING-RELATED OTOLOGICAL INJURIES CLINICAL in a change in canal pH and skin volumes decrease, creating a vacuum. Symptoms include dullness or pain maceration, damaging the primary Serous or haemorrhagic effusion and in the ear and hearing loss. Tympanic skin barrier and promoting infection.5 tympanic membrane rupture can result membrane perforation during a dive Pseudomonas aeruginosa is the organism secondary to the negative pressure.10 can cause severe vertigo from caloric most responsible for acute otitis externa Conversely, during ascent, middle ear stimulation of cold water in the middle ear. following diving.6 The principles of volume expands as pressure decreases. If nausea and vomiting ensues, this can be treatment remain the same as for Normally this is passively released fatal because of obligate mouth breathing non-divers, with dry ear precautions, aural through a functional eustachian tube. during scuba diving.11 MEB can be graded toilet and topical antimicrobial therapy. However, with ETD, volume expansion using the modified Teed classification,12 can create bulging of the tympanic which is useful in guiding flying and diving Exostoses membrane and perforation. restrictions post-injury (Table 1). Exostoses are bony outgrowths of the medial ear canal. They commonly occur in divers in response to chronic cold water or wind exposure that triggers refrigeration periosteitis.7 Bony canal stenosis can result in water and wax retention, predisposing to otitis externa. When severe, complete occlusion of the canal results in a conductive hearing loss. Furthermore, unilateral occlusion can lead to an asymmetric caloric stimulus underwater, leading to vertigo.8 Promoting the use of appropriately fitted wetsuit hoods can help to prevent this progression. Referral to an otolaryngologist for consideration of a canalplasty may be necessary in severe or symptomatic cases. External canal barotrauma External canal barotrauma can occur as a result of occlusion of the ear canal by exostoses, impacted cerumen and tight wetsuit hoods. An air-filled space between the occlusion and tympanic membrane is created, and negative pressure is Figure 1. Boyle’s law dictates that as pressure increases below the water surface, the volume generated on descent, leading to swelling of closed spaces decreases. and haemorrhagic blistering of the canal wall. Treatment consists of analgesia and topical steroid ear drops.9 External canal barotrauma can be reduced by avoiding Table 1. Modified Teed classification12 for middle ear barotrauma* tightly fitted hoods and cotton bud use for Grading Otoscopic findings Estimated return to dive wax removal. Aural toilet is recommended for persistent wax impaction. Grade 0 Normal tympanic membrane Seven to 10 days (complete resolution) Grade 1 Tympanic membrane erythematous/ inflamed Middle ear pathology Grade 3 Gross haemorrhage of the tympanic Six weeks (blood reabsorption) Middle ear barotrauma membrane MEB occurs when the diver cannot or does not regularly equalise on descent or Grade 4 Extensive free blood in middle ear ascent. This may be due to inexperience with bubbles visible behind tympanic membrane (haemotympanum) or eustachian tube dysfunction (ETD) secondary to rhinosinusitis, allergy or Grade 5 Perforation of the tympanic membrane Three months (healed perforation) nasopharyngeal obstruction. As external *Grade 2 has not been included in this modification pressures rise on descent, middle ear © The Royal Australian College of General Practitioners 2020 REPRINTED FROM AJGP VOL. 49, NO. 8, AUGUST 2020 | 501 CLINICAL DIVING-RELATED OTOLOGICAL INJURIES Management involves exclusion of inner present with vertigo, nausea and vomiting, is also not recommended within 24 hours ear barotrauma, short-term use of nasal although hearing loss and other central following diving.13 The use of oral or topical decongestants and/or intranasal steroid nervous system symptoms frequently decongestants is discouraged to treat ETD or sprays and antibiotics for any secondary occur.19 Examination usually reveals sinusitis prior to diving as their effects may infection.11 Diving should not recommence a normal external canal and tympanic wear off while underwater, leaving the diver until all symptoms have resolved, tympanic membrane. Tuning forks may reveal SNHL, in danger.13 membrane perforations have healed and nystagmus is usually present. Fitness to return to diving depends on and equalisation is possible. In cases of It is important for inner ear DCS to be residual symptoms and ongoing pathology. persistent tympanic membrane perforation, differentiated from inner ear barotrauma as Persisting neurology, especially affecting surgical repair may be necessary. treatment is markedly different (Table 2).20 the vestibular system, is associated with Treatment of inner ear DCS includes early high risk. An estimated 90% of patients recompression with hyperbaric oxygen, with previous diving-related vestibular Inner ear pathology preferably within five hours of symptom dysfunction have ongoing long-term Inner ear barotrauma onset. In the general practice setting, it deficits necessitating thorough assessment Rupture of the round or oval windows is recommended that administration of prior to continuing scuba diving.18 Some creates a perilymphatic fistula (PLF), 100% oxygen and intravenous saline or authors recommend full vestibulocochlear which can cause sensorineural hearing oral fluids be provided. Urgent referral assessment and exclusion of a right-to-left loss (SNHL), vertigo and tinnitus. Two to the nearest centre with a hyperbaric vascular shunt in those who have previously mechanisms have been postulated chamber is critical to long-term prognosis.4 had inner ear DCS.6,18 (Figure 2).13,14 If there is doubt regarding whether the Return