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of the body. Nitrogen will expand because of decreased atmospheric pressure at altitudes above 18,000
feet above mean sea level (MSL), forming bubbles in body tissues. The tissue affected by these bubbles
determines the severity of decompression syndrome (DCS). As DCS may be associated with ascent from
diving operations or with exposure to low ambient pressures during flight operations, see Diving Medicine
section also.
Subjective: Symptoms
"Bends" – musculoskeletal (primarily joint) pain
"Chokes" – shortness of breath, chest pain, non-productive cough
"Creeps" or "itches" – pruritus or feeling of insects crawling on the skin
Neurologic DCS – Any neurologic symptom is possible, including paralysis, paresis, paresthesia, loss of
consciousness, headache, fatigue, seizure, and personality changes.
Focused History: Do you have [each of the symptoms listed above]? (Answers provide insight to which body
tissues are affected, thus how severe DCS may be.) Are you taking any drugs, medications or "nutritional
supplements" of any kind? (Affirmative answer opens the possibility of allergic or idiopathic drug reaction.)
Have you flown over 18,000 feet, or been diving in the past 24 hours? (typical exposure)
Objective: Signs
Using Basic Tools: Conduct a normal physical exam since symptoms vary according to the area of the
body affected. Diffuse mottling of skin or central neurologic signs may indicate arterial gas embolism and are
ominous. Involvement of more than one joint is indicative of more serious DCS. Examiner must perform a
complete neurologic examination, to include mental status exam (see Appendix).
Assessment:
Differential Diagnosis
Acute hypoxia - indicated by immediate, complete resolution of symptoms with supplemental oxygen
Allergic or idiopathic reaction to prescription or OTC medications, including "nutritional supplements" - may
rule this out if not taking any of these substances
Seizure disorder - may be indicated by history of seizure disorder or head trauma involving loss of conscious-
ness within last 10 years
Arterial gas embolism (see Dive Medicine chapter) - may be indicated in Aerospace Medicine as a conse-
quence of catastrophic decompression of aircraft with loss of consciousness or sudden death less than 10
minutes following event
Plan:
Treatment
Primary: 100% oxygen until hyperbaric oxygen recompression can be accomplished
Alternative: Gamow bag or Hyperlite transport chamber
Primitive: 100% oxygen
Empiric: Return to sea level
Patient Education
General: DCS is a very serious condition. The threat of death or permanent neurologic injury is out of
proportion to the usually mild symptoms. Pre-existing acute musculoskeletal injuries, heavy intercurrent
exercise and alcohol use increase the risk of developing DCS.
Prevention and Hygiene: Allow at least 24 hours between diving operations and flying or other high altitude
operations. Avoid strenuous physical activity before high altitude operations.
Follow-up Actions
Return evaluation: Consultation with neurologist is indicated for any suspected neurologic DCS case.
Consultation Criteria: Consultation with Diving Medical Officer (DMO) is recommended. Aerospace medical
or Flight Surgeon consult may be helpful if DMO is not available.