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Background: Dysbaric osteonecrosis (DON) is defined as avascular bone necrosis, usually involving specific parts of the long bones, which is seen in divers or compressed-air workers due to exposure to pressure. We describe a case of DON in an artisanal diving fisherman working underwater for many years. Methods: A 48-year-old male case was admitted to the occupational disease outpatient with left shoulder and arm pain for 1-2 years. Since the age of 20, he has been artisanal diving fishing with a hookah at a depth of 20-25 meters in the sea. In 2011, he received hyperbaric oxygen therapy for widespread pain in the whole body due to decompression sickness (DCS). In the case's left shoulder joint x-ray and magnetic resonance imaging, degenerative changes in the acromioclavicular joint and signal changes consistent with osteonecrosis starting from the subcortical area of the humeral head and extending to the proximal shaft of the humerus were observed. Conclusions: DON is among the most common long-term pathologies in professional divers. In Turkey, as in our case, not applying safe decompression procedures and unsafe diving practices are common among diving fishers. In studies, the frequency of exposure to pressure, duration and depth of dive, insufficient decompression, formation of DCS and increasing age were associated with DON. Today, DON remains an occupational hazard with significant medical and social consequences. Diving fishers should be informed about the sequelae of DCS and trained on the safety measures to be taken.

Diving as a method of fishing is used worldwide in small-scale fisheries. However, one of the main causes of morbidity and mortality among fishermen is decompression sickness (DCS). We report the case of a 46-year-old male fisherman diver who presented with chronic inguinal pain that radiated to the lower left limb. Living and working in a fishing port in Yucatan, he had a prior history of DCS. A diagnosis of avascular necrosis in the left femoral head secondary to DCS was made via analysis of clinical and radiological findings. The necrosis was surgically resolved by a total hip arthroplasty. Dysbaric osteonecrosis is a more probable diagnosis. In this region fishermen undergo significant decompression stress in their daily fishing efforts. Further studies regarding prevalence of dysbaric osteonecrosis among small-scale fisheries divers are needed. In a community where DCS is endemic and has become an epidemic, as of late, the perception of this health risk remains low. Furthermore, training and decompression technique are lacking among the fishing communities., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Neurological decompression sickness (DCS) is a rare condition that commonly leads to spinal cord injury. We report the case of a 30-year-old man who developed left-sided weakness and numbness after diving to a maximum depth of 15 m with a total dive time of 205min (10 repetitive dives). To the best of our knowledge, only six cases diagnosed as Brown-Séquard syndrome caused by DCS have been reported in the literature. Divers should be aware of the risk factors of DCS before diving and clinicians should make the diagnosis of spinal cord DCS based primarily on clinical symptoms, not on magnetic resonance imaging findings., (© The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Purpose: The aim of this study is to investigate factors associated with residual symptoms after hyperbaric oxygen therapy (HBOT) in type I decompression sickness (DCS)., Basic Procedures: An HBOT registry, which includes patients with type I DCS, was analyzed retrospectively. We divided enrolled patients into two groups; complete resolution group and residual symptom (RS) group after a single HBOT session. We investigated factors associated with residual symptoms at discharge with univariable and multivariable analyses. Restrictive cubic spline curve and a test for trend analysis were used to show the trend of therapeutic response after HBOT based on time from symptom onset to HBOT., Main Findings: In a total of 195 patients, 131 (67.2%) patients were included in the RS group after single HBOT. Prolonged time from symptom onset to recompression was independently associated with residual symptoms (P = .004). When patients who underwent recompression within 24 hours from symptom were included in the reference group, the adjusted odds ratios (AOR) (95% confidence interval) of residual symptoms after HBOT were the following: 24 to 96 hours, 2.24 (0.75-6.65); 96 to 240 hours, 3.31 (1.08-10.13); more than 240 hours, 22.83 (2.45-231.43). In terms of sort of diving, commercial and recreational divers had higher probability of residual symptoms than military divers (AOR, 4.78 and 33.36, respectively)., Principal Conclusions: Early HBOT is associated with rapid symptom elimination after treatment in type I DCS. Military divers showed a more immediate response after recompression in comparison with commercial and recreational divers., (Copyright © 2015 Elsevier Inc. All rights reserved.)

To investigate the magnetic resonance imaging (MRI) features of spinal cord decompression sickness (DCS) on compressed-air divers, we hereby report seven cases diagnosed with spinal cord DCS. Only two patients out of seven showed positive MRI findings: A detailed case report will be provided on each. In one of the cases, the MRI revealed extensive high signal within the central gray matter of the spinal cord. The other one showed patchy high signal on T2-weighted images as well as diffusion-weighted images (DWI) in the dorsal column white matter of the spinal cord. The findings in our collective suggest that the MRI focused on the spinal cord is not always appropriate for obtaining a quick diagnosis. The discrepancy between MRI findings and clinical evolution leads to the conclusion that MRI focused on the spinal cord does not always correlate with neurological improvement. Decision for hyperbaric oxygen (HBO2) treatment should not be based primarily on MRI findings.

Background: Diving is associated with long-term effects on several organ systems., Aim: The objective was to investigate the impact of decompression sickness (DCS) and diving exposure on health-related quality of life (HRQL) in former Norwegian North Sea divers., Methods: HRQL was recorded by a questionnaire in the cohort of 375 Norwegian North Sea divers registered before 1990. Demographic data, relevant health data and data on diving education, history of DCS and SF-36 were recorded in 230 divers., Results: All SF-36 sub-scores were significantly reduced compared with Norwegian norms. Reduced scores were seen for all scales among divers who reported previous DCS compared to those without DCS. A decreasing trend in scores was seen when comparing no DCS, skin or joint DCS and neurological DCS. There was a decreasing trend in scores related to number of days in saturation and maximal depth. Stratification on DCS showed that the impact of saturation diving was present only in divers with DCS., Conclusions: HRQL was reduced in this study sample of divers. Having had DCS during the diving career contributed significantly to the reduction in all SF-36 scales, and apparently neurological DCS has the most pronounced impact. Cumulative diving exposure including days in saturation and maximal depth contributed to a reduced HRQL.

A 44-year-old tunnel worker was studied who suffered from several unexplained decompression illness events for almost 15 years. This caisson worker was affected after standard pressure profiles that did not cause symptoms of decompression illness in his colleagues on the same shift. Transesophageal echocardiography revealed an atrial septal defect (grade II) in this otherwise healthy man. Cranial magnetic resonance imaging showed ischemic brain lesions. Among divers, patent foramen ovale, the most common cause of cardiac right-to-left shunts, was shown to increase the risk for decompression illness events by a factor of 4.5 and to double the risk of ischemic brain lesions. Hyperbaric workers with symptoms of unexplained decompression illness, even if they are only slight, should immediately be transferred to a cardiologist so that a cardiac right-to-left shunt will not be overlooked.

This case report describes a 20-yr-old man who presented with retro-orbital pain and blurred vision in his left eye 3 wk after an altitude exposure in a hypobaric chamber. He was found to have significant deficits in color vision and visual fields consistent with an optic neuropathy in his left eye. The patient was diagnosed with decompression sickness and treated with hyperbaric oxygen with a U.S. Navy Treatment Table VI. All signs and symptoms resolved with a single hyperbaric oxygen treatment but recurred. A head MRI revealed a left frontoethmoid sinus opacity. A concomitant sinusitis was diagnosed. The patient had full resolution of symptoms after a total of four hyperbaric oxygen treatments and antibiotic therapy at 6-wk follow-up. Although a para-infectious etiology for this patient's optic neuropathy cannot be excluded, his history of altitude exposure and significant, rapid response to hyperbaric oxygen treatment strongly implies decompression sickness in this case.

Multinational experience over many years indicates that all current air decompression schedules for caisson and compressed air tunnel workers are inadequate. All of them, including the Occupational Safety and Health Administration tables, produce dysbaric osteonecrosis. The problem is compounded because decompression sickness (DCS) tends to be underreported. Permanent damage in the form of central nervous system or brain damage may occur in compressed air tunnel workers, as seen on magnetic resonance imaging, in addition to dysbaric osteonecrosis. Oxygen decompression seems to be the only viable method for safely decompressing tunnel workers. Oxygen decompression of tunnel workers has been successfully used in Germany, France, and Brazil. In Germany, only oxygen decompression of compressed air workers is permitted. In our experience, U.S. Navy tables 5 and 6 usually prove adequate to treat DCS in caisson workers despite extremely long exposure times, allowing patients to return to work following treatment for DCS. Tables based on empirical data and not on mathematical formulas seem to be reasonably safe. U.S. Navy Exceptional Exposure Air Decompression tables are compared with caisson tables from the United States and Great Britain.

Objectives: To explore the use of 99technetiumm-hexamethyl propylene amine oxime single photon computed tomography (HMPAO-SPECT) of the brain as a means of detecting nervous tissue damage in divers and to determine if there is any correlation between brain image and a diver's history of diving or decompression illness (DCI)., Methods: 28 commercial divers with a history of DCI, 26 divers with no history of DCI, and 19 non-diving controls were examined with brain HMPAO-SPECT. Results were classified by observer assessment as normal (I) or as a pattern variants (II-V). The brain images of a subgroup of these divers (n = 44) and the controls (n = 17) were further analysed with a first order texture analysis technique based on a grey level histogram., Results: 15 of 54 commercial divers (28%) were visually assessed as having HMPAO-SPECT images outside normal limits compared with 15.8% in appropriately identified non-diver control subjects. 18% of divers with a history of DCI were classified as having a pattern different from the normal image compared with 38% with no history of DCI. No association was established between the presence of a pattern variant from the normal image and history of DCI, diving, or other previous possible neurological insult. On texture analysis of the brain images, divers had a significantly lower mean grey level (MGL) than non-divers. Divers with a history of DCI (n = 22) had a significantly lower MGL when compared with divers with no history of DCI (n = 22). Divers with > 14 years professional diving or > 100 decompression days a year had a significantly lower MGL value., Conclusions: Observer assessment of HMPAO-SPECT brain images can lead to disparity in results. Texture analysis of the brain images supplies both an objective and consistent method of measurement. A significant correlation was found between a low measure of MGL and a history of DCI. There was also an indication that diving itself had an effect on texture measurement, implying that it had caused subclinical nervous tissue damage.

Background: For many years there has been a widely held but largely unsubstantiated belief that pain in the upper limb in decompression sickness (DCS) is associated with bounce diving, whereas compressed air workers, saturation divers and high altitude aviators are more susceptible to involvement of the lower limbs., Hypothesis: The hypothesis of counter current exchange of inert gas, modulated by changes in tissue temperature, has been evaluated as a possible mechanism to explain the reported distribution of limb pain in DCS., Methods: An extensive review of over 19,000 cases of limb pain decompression illness has been undertaken from case reports stored in the diving accident database at the Institute of Naval Medicine, in the published literature, and from unpublished clinical and experimental reports., Results: There was a predominance of upper limb involvement in bounce divers and, in contrast to traditional teaching, in aviators. By contrast, the lower limbs were more commonly involved in compressed air workers and saturation divers., Conclusion: Each of the occupational exposures has been discussed individually with reference to counter-current exchange and other factors as potential influences on the distribution of disease. We conclude that counter-current exchange of inert gas may be implicated in the distribution of limb pain in DCS.

A report is given on dispensary investigations of professional divers. In 32 of a control group consisting of altogether 41 scaphander divers radiologically were found changes in the sense of aseptic bone necroses. 18 of the examined persons showed polyostotic affection and 14 had a monostotic localisation of the foci. Divers with no extensive findings could further work in their profession with a limitation of depth up to 13 depth of water. On the other hand examined persons with severe changes had temporarily to leave their profession. Relevant problems of the clinical symptomatology and the radiological differential diagnostics of aseptic bone necroses are discussed.

Abalone divers are subject to considerable decompression stresses and could be at risk of progressive cognitive impairment. A sample of abalone divers was compared with a sample of fishermen, by means of a battery of neuropsychological tests. No evidence of cognitive impairment was found in the divers, in spite of evidence of their exposure to decompression stress. The implications for other professional divers and for recreational underwater divers who follow standard decompression protocols are reassuring.

Dysbaric osteonecrosis was found in 259 cases among 2260 examined hyperbaric workers from several occupations. No positive cases were found in the divers in shipyards and diving experiments. Naval divers showed the lowest incidence (2.1%) and fishery divers the highest (19.8%). Distribution of long bone lesions was 46.0% in upper humerus, 37.7% in upper femur, 8.3% in lower femur, and 8.0% in upper tibia. We classify long bone lesions into three radiographic stages, the first two on the basis of size of the bone lesions as projected on the radiographs, and the third stage on the basis of extension of the lesion toward articular destruction. The three-stage classification system correlates with the clinical symptoms, and the working capacity of the individual patients tends to correlate with the severity of dysbaric osteonecrosis and can be understood by the general public.