Post-Chamber Joint Pain and Rash: Decompression Sickness Triage
A 35-year-old altitude-chamber technician completes a four-hour training profile with repeated exposures to 25,000 ft for 5 minutes and 35,000 ft for 3 minutes, including two rapid decompressions. Forty-five minutes after the final exposure he reports aching behind both knees, itching over the abdomen, and a mottled violaceous rash. He is alert, SpO2 97% on room air, lungs clear, no focal weakness, no confusion, and no chest pain. He wants to drive himself home, a two-hour trip. The chamber is at sea level and the nearest hyperbaric facility is 90 minutes away by ground. He has no prior decompression sickness and no recent flying or diving. The flight surgeon must decide diagnosis, immediate disposition, and return-to-duty criteria.
1. What is the working diagnosis and severity category, and why?
Read the worked answer
The working diagnosis is decompression sickness (DCS) until proven otherwise. Joint pain plus cutaneous mottling after repeated altitude exposure is highly suggestive. The case should not be dismissed as minor “niggles” because cutaneous signs can precede or accompany more serious manifestations, and joint pain may be the presenting feature of type I or evolve into type II. The absence of focal neurologic findings is reassuring but does not exclude spinal or cerebral involvement, especially with a rash. The severity is at least moderate because there are multiple symptom domains and the exposure was provocative. The flight surgeon should treat this as a time-critical disorder, stop further altitude exposure, and avoid allowing the technician to drive or remain unobserved. Ascribe the presentation to DCS while keeping alternative causes such as musculoskeletal strain or allergic reaction in mind; those alternatives do not justify delay in recompression when the exposure fits.
2. What is the immediate management and transport plan?
Read the worked answer
Give 100% oxygen by tight-fitting mask, place the technician at rest, and monitor airway, breathing, circulation, and neurologic status. Provide oral or intravenous fluids if clinically appropriate, but do not delay transport for paperwork. He must not drive himself because symptoms can progress to neurologic DCS and he could become incapacitated en route. Arrange ground ambulance transport to the hyperbaric facility, with oxygen continued. Avoid unpressurized air transport or any further altitude exposure; if air transport is unavoidable, use a pressurized aircraft at the lowest safe cabin altitude and coordinate with the hyperbaric physician. Do not give analgesics that could mask worsening symptoms before physician assessment unless needed for safety. Notify the receiving hyperbaric team, document the exposure profile, and arrange observation. The key judgement is that a benign-appearing rash plus joint pain still warrants urgent recompression evaluation, not home observation.
3. What return-to-duty and flying-after criteria should be applied?
Read the worked answer
Return to duty should wait until symptoms have completely resolved, hyperbaric treatment has been completed if indicated, and the flight surgeon has documented a normal neurologic examination. The technician should have no residual pain, rash, sensory change, or cognitive symptoms. Local DCS protocols should govern the interval before further altitude-chamber or compressed-gas exposure; a conservative approach is no altitude exposure or flying for at least 72 hours after complete resolution and treatment, with a longer interval if there was neurologic involvement. The return decision should include a review of the exposure profile, equipment, and procedures because this event may signal a training or oxygen-system problem. Recurrence or any new symptoms should trigger immediate grounding and re-evaluation. The technician should be counselled that “flying after” rules also apply to recreational diving and donated blood or plasma, and that clearance must be individualized rather than based on a fixed calendar alone.