Inner ear barotrauma and inner ear decompression sickness: a systematic review on differential diagnostics

Introduction: Inner ear barotrauma (IEBt) and inner ear decompression sickness (IEDCS) are the two dysbaric inner ear injuries associated with diving. Both conditions manifest as cochleovestibular symptoms, causing difficulties in differential diagnosis and possibly delaying (or leading to inappropriate) treatment. Methods: This was a systematic review of IEBt and IEDCS cases aiming to define diving and clinical variables that help differentiate these conditions. The search strategy consisted of a preliminary search, followed by a systematic search covering three databases (PubMed, Medline, Scopus). Studies were included when published in English and adequately reporting one or more IEBt or IEDCS patients in diving. Concerns regarding missing and duplicate data were minimised by contacting original authors when necessary. Results: In total, 25 studies with IEBt patients (n = 183) and 18 studies with IEDCS patients (n = 397) were included. Variables most useful in differentiating between IEBt and IEDCS were dive type (free diving versus scuba diving), dive gas (compressed air versus mixed gas), dive profile (mean depth 13 versus 43 metres of seawater), symptom onset (when descending versus when ascending or surfacing), distribution of cochleovestibular symptoms (vestibular versus cochlear) and absence or presence of other DCS symptoms. Symptoms of difficult middle ear equalisation or findings consistent with middle ear barotrauma could not be reliably assessed in this context, being insufficiently reported in the IEDCS literature. Conclusions: There are multiple useful variables to help distinguish IEBt from IEDCS. Symptoms of difficult middle ear equalisation or findings consistent with middle ear barotrauma require further study as means of distinguishing IEBt and IEDCS.

Balloon Eustachian tuboplasty in a professional Navy SEAL diver: case report

Middle ear barotrauma due to dilatory Eustachian tube dysfunction (ETD) is probably the most common medical disorder related to diving. Moreover, ETD makes divers prone to other diving-related accidents, including inner ear barotrauma and alternobaric vertigo. Until the development of Eustachian tube balloon dilation no diving-compatible surgical options existed to effectively and safely prevent recurrence. We present a case of an Israeli Navy SEAL diver who dives in extreme strenuous combat-related closed-circuit rebreather (CCR) dives. Due to repeated middle ear barotrauma, the patient underwent Eustachian tube balloon dilation of the affected side. Following surgery, the patient returned to both CCR and scuba dives but still suffered from middle ear symptoms and repeated barotrauma hence was eventually disqualified from further combat diving.

Dysbarism

Dysbarism is defined as any medical condition that arises as a result of changes in ambient pressure. This review describes dysbarism with a focus on the undersea environment. Conditions discussed in this review include middle and inner ear barotrauma, pulmonary barotrauma, immersion pulmonary edema, decompression illness, and gas toxicities. For each, assessment and stabilization, treatment and disposition, and outcomes are presented. Figures show the AQUARIUS habitat for saturation diving; the anatomy of the external, middle, and inner ear; the Teed classification; the paranasal sinuses; and an example of a recompression chamber. Tables list the types of diving, gas laws relevant to diving, units of underwater pressure, compositions of typical breathing gas mixtures, decompression illness risk factors, symptoms of decompression illness (in order of frequency), signs and symptoms of decompression illness based on body system, maximum recommended depth to reduce the risk of central nervous system oxygen toxicity for various breathing gas mixtures, and progression of nitrogen narcosis symptoms with increasing depth. This review contains 5 highly rendered figures, 9 tables, and 120 references.

Investigations into Audiovestibular Manifestations in Patients with Psoriatic Arthritis

Objective.Although psoriatic arthritis (PsA) is a common chronic inflammatory rheumatic disease, little is known about audiovestibular impairment in this condition. We aimed to establish whether audiovestibular manifestations were present in patients with PsA.Methods.A set of 60 consecutive patients who fulfilled the Moll and Wright criteria for PsA and 60 matched controls were studied. During the period of recruitment, individuals were excluded who had a history of cardiovascular disease, cerebrovascular complications, peripheral artery disease, renal insufficiency, syphilis, Meniere disease and other vestibular syndromes, infections involving the inner ear, barotrauma, or were in treatment with ototoxic drugs.Results.Most patients with PsA were men (63%). The mean age at the time of our study was 52.9 years and the mean age at the onset of symptoms was 33 years. Thirty-six (60%) of the 60 patients showed abnormal hearing loss in the audiogram compared to only 5 (8.3%) of the 60 controls (p < 0.001). Values of audiometric tests (pure-tone average and speech reception threshold) yielded significant differences between patients and controls (p < 0.001). The audiogram disclosed a bilateral and symmetrical sensorineural hearing loss (SNHL) in PsA with predominant pattern of high frequency SNHL in patients with PsA (46.7%) compared to controls (8.3%, p < 0.001). Patients with PsA exhibited abnormal vestibular tests more commonly than controls. A significantly increased frequency of abnormal computerized dynamic posturography with a predominant vestibular loss pattern was also observed in patients (23.3%) compared to controls (0%, p < 0.001).Conclusion.Our current study demonstrates strong evidence for inner ear damage in patients with PsA.

Protective effect of edaravone in inner-ear barotrauma in guinea pigs

Objective: The purpose of this study was to determine the protective effect of edaravone, a free radical scavenger, on inner-ear barotrauma (IEB) in guinea pigs, based on a hypothesis implicating free radicals in the development of IEB.Materials and methods: One hundred and twenty-five guinea pigs were divided into a control group and a pretreatment group. After auditory brainstem response (ABR) testing, the pretreatment group received 9.0 mg/kg intraperitoneal edaravone. Animals were exposed to pressure loading and then to further ABR testing.Results: The incidence of IEB was 62.7 per cent in the control group and 42.9 per cent in the pretreatment group (p < 0.01). The distributions of threshold elevation in the control group were 37.3 per cent (for 10 dB or less), 21.3 per cent (for 20–30 dB), 18.0 per cent (for 40–60 dB) and 23.4 per cent (for 70 dB or more), and those in the pretreatment group were 57.1 per cent, 19.1 per cent, 14.3 per cent and 9.5 per cent, for the same respective decibel levels (p < 0.01).Conclusions: These results suggest that protective treatment with edaravone can significantly reduce both the incidence of IEB and the severity of the resultant ABR threshold elevation.