Decompression sickness

Decompression sickness is defined as a disorder induced by the in-situ formation of intravascular or extravascular gas bubbles resulting from decreased ambient pressure acting upon supersaturated tissues ^[1][2]. It constitutes a primary component of decompression illness, distinct from arterial gas embolism which involves the direct introduction of alveolar or venous gas into the arterial circulation rather than bubble nucleation from dissolved inert components ^[2]. The pathophysiology follows rapid pressure reduction after breathing inert gases under elevated conditions, or an upward shift from a saturated state, exceeding tissue solubility limits ^[1].

The predominant clinical presentation involves severe articular pain, most frequently localized to the shoulders, followed by the elbows, knees, and ankles, accounting for approximately sixty to seventy percent of reported altitude-related incidents ^[1]. Cutaneous manifestations such as pruritic rashes and mild discomfort commonly accompany musculoskeletal complaints, while neurological involvement remains less frequent in hypobaric exposures and tends to localize to cerebral structures rather than the spinal cord ^[1][2]. Symptom intensity exhibits substantial inter-individual variability, ranging from transient, barely perceptible disturbances to rapidly progressive paralysis, cardiovascular collapse, or death ^[1][2].

Occurrence patterns differ substantially between hyperbaric and hypobaric exposures, with hyperbaric cases typically presenting during descent to ambient pressure after tissue supersaturation, whereas hypobaric manifestations arise during upward excursions from surface or saturated conditions ^[1]. Altitude-related incidence is closely associated with unpressurized aviation operations, acute cabin depressurization events, aerial transit following submersion activities, and controlled hypobaric chamber testing ^[1]. Reported case distributions consistently identify articular pain as the primary clinical signal across these exposure categories, reflecting the widespread tissue distribution of dissolved gas bubbles ^[1].

Decompression sickness operates strictly as a physical injury mechanism driven by environmental pressure transitions rather than infectious transmission pathways ^[1]. Disease initiation necessitates prior respiration of metabolically inert gases under elevated ambient conditions, followed by rapid decompression that outpaces pulmonary elimination and forces dissolved gases beyond solubility thresholds ^[1]. Alternatively, upward atmospheric shifts from fully saturated physiological states trigger equivalent bubble nucleation when specific tissue compartments maintain maximal inert gas loads ^[1]. Theoretical risk profiles remain governed by the kinetic behavior of the tissue compartment exhibiting the highest dissolved inert gas concentration during pressure changes ^[1].

Operational risk mitigation centers on modulating known physiological and environmental stressors, specifically limiting prolonged immersion durations, regulating strenuous exertion levels, and maintaining thermal stability during pressure transitions ^[2]. Preventive frameworks consequently emphasize careful tracking of these variables to minimize supersaturation accumulation before decompression phases commence ^[2]. By controlling exposure intensity and environmental conditions, personnel can theoretically reduce bubble nucleation probabilities during ascent or altitude exposure ^[2].

1. 1 Wikipedia contributors. Decompression sickness - Wikipedia [Internet]. Wikipedia. cited 4 Sept 2026. Available from: https://en.wikipedia.org/wiki/Decompression_sickness
2. 2 Vann RD et al. Decompression illness. Lancet. 2011 Jan 8. PMID: 21215883. doi: 10.1016/S0140-6736(10)61085-9. PubMed: https://pubmed.ncbi.nlm.nih.gov/21215883/
3. 3 Sen S et al. Therapeutic effects of hyperbaric oxygen: integrated review. Med Gas Res. 2021 Jan-Mar. PMID: 33642335. doi: 10.4103/2045-9912.310057. PubMed: https://pubmed.ncbi.nlm.nih.gov/33642335/