Decompression sickness

Decompression sickness
Petty Officer 2nd Class Chelsy Alamina / U.S. Navy · Public domain · source
Name	Decompression sickness
Synonyms	Caisson disease, the bends
Specialty	Medicine
Symptoms	Joint pain, neurological deficits, rash
Complications	Stroke, pulmonary embolism
Onset	After rapid ambient pressure reduction
Causes	Inert gas bubble formation
Risks	Diving, aviation, hyperbaric exposure
Diagnosis	Clinical evaluation, imaging
Treatment	Recompression therapy, oxygen
Frequency	Variable by exposure and mitigation

Decompression sickness Decompression sickness is an acute condition caused by formation of inert gas bubbles in tissues and blood after rapid reduction of ambient pressure. It affects multiple organ systems and is a recognized hazard for divers, aviators, tunnel workers and astronauts. Management requires rapid recognition, supportive care, and definitive recompression therapy to reduce morbidity and mortality.

Overview

Decompression sickness was first described during the 19th century construction of caissons and became prominent in Crimean War-era engineering projects and later in military medicine during the World War I and World War II eras. High-profile cases in the history of exploration and sport diving involved participants associated with Jacques Cousteau, Sylvia Earle, Don Walsh, and Edmund Hillary-era high-altitude physiology research. The condition is clinically classified into cutaneous, musculoskeletal, cardiopulmonary and neurological forms and is managed in coordination with facilities such as the US Navy Experimental Diving Unit, Royal Navy hyperbaric units, and civilian hyperbaric centers affiliated with institutions like Mayo Clinic and Johns Hopkins Hospital.

Causes and pathophysiology

Rapid decompression causes dissolved inert gases, primarily nitrogen and sometimes helium, to come out of solution and form bubbles in tissues and blood. The underlying mechanisms were investigated by scientists associated with Royal Society, Max Planck Institute, and researchers like J. S. Haldane, Behnke, and Haldane's research-era physiology models. Bubble formation leads to mechanical obstruction, endothelial injury, and activation of inflammatory cascades mediated by pathways studied at National Institutes of Health laboratories and documented in research by investigators at Harvard Medical School and Stanford University School of Medicine. Vascular gas emboli can cause ischemia in territories analogous to events studied in Battle of Gallipoli-era field medicine, and biochemical effects mirror findings from investigations at the Scripps Institution of Oceanography.

Signs and symptoms

Presentation ranges from localized joint and limb pain to catastrophic neurological impairment. Typical musculoskeletal complaints resemble those reported by personnel in Panama Canal construction accounts and include "bends" affecting shoulders, elbows, and knees. Cutaneous manifestations, historically noted in accounts from Eiffel Tower-era caisson workers, include pruritus and mottled rashes. Cardiopulmonary involvement—"chokes"—can produce dyspnea and hemoptysis, paralleling pulmonary embolic events discussed in literature from Cleveland Clinic case series. Neurological signs, as described in reports linked to Antarctic expeditions and military diving units like United States Navy, can include paresthesia, paralysis, altered consciousness, and cranial nerve deficits similar to presentations encountered in stroke centers at Massachusetts General Hospital.

Diagnosis

Diagnosis is clinical, based on exposure history and symptom constellation, supported by imaging and laboratory tests when available. Dive logs and ascent profiles from training programs at PADI and NAUI are often crucial historical data points. Imaging modalities such as MRI and CT, performed at centers like Mount Sinai Hospital and Karolinska University Hospital, can identify ischemic lesions or gas emboli, though absence of imaging findings does not exclude the condition. Doppler ultrasound for venous gas emboli, a technique refined in studies at Duke University and University of California, San Diego, is used for screening and research. Differential diagnoses include arterial gas embolism, stroke syndromes managed at Cleveland Clinic and Mayo Clinic, musculoskeletal injuries treated by services at Hospital for Special Surgery, and decompression mimics seen in altitude illness cases documented by NASA and European Space Agency.

Prevention and dive planning

Prevention relies on conservative dive planning, adherence to decompression tables and computer models developed from work by Haldane, US Navy Experimental Diving Unit, and civilian agencies such as Divers Alert Network and PADI. Surface interval policies, staged decompression stops, and gas switching strategies used by NOAA and commercial operators in North Sea operations mitigate risk. Training programs at institutes like Royal Australian Navy diving schools and equipment standards from manufacturers cooperating with Underwriters Laboratories emphasize ascent rates, no-decompression limits, and altitude considerations. Operational protocols from Panama Canal Authority engineering projects and tunnel projects like those linked to Hoover Dam construction inform occupational exposure controls.

Treatment and management

Immediate management includes 100% oxygen, hemodynamic support, immobilization of affected limbs and rapid transport to hyperbaric facilities. Definitive treatment is hyperbaric oxygen therapy using recompression tables refined by the US Navy and employed at civilian centers such as Duke University Medical Center hyperbaric units and Royal Hobart Hospital. Adjunctive measures include intravenous fluids, analgesia, anticoagulation in selected cases per guidance from American College of Chest Physicians protocols, and rehabilitation services provided by institutions like Spaulding Rehabilitation Hospital and Walter Reed National Military Medical Center when neurological deficits persist. Experimental therapies and research have involved collaborations with National Aeronautics and Space Administration and university research centers including University of Oxford and Imperial College London.

Epidemiology and risk factors

Incidence varies by diving population, operational environment, and adherence to preventive measures. Recreational diving incidence figures derive from data collected by Divers Alert Network, PADI, and national health services such as NHS reporting systems, whereas commercial and military incidence data come from sources like the US Navy and Royal Navy occupational health records. Risk factors include rapid ascent, repetitive dives, dehydration, cold exposure, patent foramen ovale presence—investigated by cardiology centers at Cleveland Clinic and Mayo Clinic—and heavy physical exertion after surfacing, as documented in epidemiologic studies by Centers for Disease Control and Prevention and academic groups at University of British Columbia.

Category:Medical conditions