What causes decompression sickness in aircrew?

• A. Gas embolism from contaminated air
• B. Formation of inert gas bubbles in tissues and blood during rapid decompression
• C. Infection
• D. Oxygen toxicity

Answer: (B)

Decompression sickness occurs when a rapid drop in ambient pressure during ascent causes dissolved inert gas, mainly nitrogen, to come out of solution and form bubbles in tissues and blood. These bubbles disrupt microcirculation and trigger inflammation, producing symptoms such as joint pain, skin changes, dizziness, or neurological signs. This mechanism is specific to rapid decompression and is not caused by contaminated air, infection, or oxygen toxicity, which have different underlying processes.