This disorder results from rapid changes in surrounding environmental pressures. The condition may be referred to as aerotitis, barotitis, bends, and caisson disease (decompression illness).

The cause of the condition is attributed to the formation of bubbles from dissolved gas in blood or tissue when external pressure on the body decreases. The disorder usually results from diving or hyperbaric exposure beyond no-stop limits, and without appropriate decompression stops or low-pressure exposure, such as loss of cabin pressure in an aircraft at altitude. The onset of the condition may be gradual or sudden. In addition, the onset may occur during decompression or excessive pressure up to 24 hours after dives greater than 30 feet. To determine the amount of external pressure exposed on the body, the weight of the water plus the barometric pressure is represented by the acronym, atm abs (atmospheres absolute). Atm abs is equal to the pressure sustained in increments of 33 feet of seawater, for example, the total pressure sustained at 1 to 33 feet is 1 atm, 33 to 66 is 2 atm, etc.

The signs and symptoms of the disorder are extremely variable. They include gas-bubble formation in the joints referred to as the bends which results in local pain in or near an arm joint for divers and leg joint for compressed-air workers. The pain may be sharp and clearly localized, or mild and intermittent, steadily becoming severe. Signs and symptoms of the disorder include respiratory distress (respiratory decompression sickness or the chokes), which is followed by circulatory collapse and death. The chokes are characterized by burning, pleuritic, substernal pain, cough, and difficulty in breathing. These symptoms constitute an extreme emergency. Other signs and symptoms include: neurological manifestations, such as mild paresthesia, headaches, confusion, visual disturbances, vomiting, loss of hearing, and weakness or numbness in the extremities; vertigo; arterial gas embolism; ear and sinus barotrauma; and death of a segment of bone (dysbaric osteonecrosis). Dysbaric osteonecrosis is characterized by chronic pain and severe disability. The most common sites are the shoulder and hip, and the disorder can damage the joints. Bone necrosis is insidious, or it may be detected months or years after the decompression episode.

Observation and history of being a flyer or diver are the most important diagnostic tools. Tests also include complete blood work, including arterial gas studies. X-rays are done to detect dysbaric osteonecrosis.

The major goal of decompression illness is recompression. Repeated treatment with hyperbaric oxygen therapy appears to help the disorder. Adequate fluid intake is maintained. Individuals with mild or moderate symptoms are treated immediately after the occurrence. Decompression illness is categorized as type I (which tends to be mild) and type II (which may be life-threatening and affect vital organs). 

Chronic pain and severe disability are noted residuals of dysbaric osteonecrosis. Osteonecrosis of the hip or shoulder may result in the need for surgical treatment such as arthroplasty or osteotomy. The degree of the residual will depend on the starting time frame of the treatment.

• The rating schedule for musculoskeletal was updated on February 7, 2021. Protection still does apply and should be considered with existing evaluations (38 CFR 3.951(a)).

• Rate manifestations under the appropriate diagnostic code within the affected body system, such as arthritis for musculoskeletal residuals; auditory system for vestibular residuals; respiratory system for pulmonary barotrauma residuals; and neurologic system for cerebrovascular accident residuals. 38 CFR 4.71a [Schedule of ratings-musculoskeletal system]

• May be entitled to special monthly compensation where the veteran has a single service-connected disability rated as 100% with additional service-connected disability or disabilities independently ratable at 60% or more, which are separate and distinct from the 100% service-connected disability and involves different anatomical segments or bodily systems. See  38 CFR 3.350(i)(1) – Special Monthly Compensation (SMC).

• None.