The term decompression illness (DCI) was coined to encompass both DCS and the related condition known as arterial gas embolism (AGE), the latter arising from barotrauma of the lungs that introduces gas into the systemic bloodstream. Some of the other conditions and circumstances that involve similar symptoms include inner-ear barotrauma; middle-ear or maxillary sinus overinflation; contaminated breathing gas; oxygen toxicity; musculoskeletal strains or trauma sustained before, during or after a dive; marine life envenomation; immersion pulmonary edema; water aspiration; and coincidental neurological disorders, such as stroke (Vann et al. 2011). Thermal stress — sometimes due to excessive heat, but usually due to cold exposure — can also be responsible for similar symptoms. In some cases, a careful medical history can easily rule out one diagnosis or another. For example, symptoms of immersion pulmonary edema often develop at depth. In such a case, a good history would rule out DCS, which only develops after significant decompression stress during ascent.
It is essential for divers with any of these symptoms to seek medical evaluation and support. While first responders are able to perform initial analysis of an injured individual, such as administering a field neurological assessment, the capabilities of nonphysicians do not come close to the clinical skills and insights held by experienced clinical specialists.