Type II Decompression Sickness After a Marginal-Procedure Dive
A 41-year-old commercial abalone diver surfaces after a 3-dive day: 22 m for 38 min, a 1-hour surface interval, 18 m for 31 min, a 2-hour interval, then 14 m for 45 min. He used air, made no decompression stops, and reports the last dive was 'easy.' Two hours after surfacing he has patchy numbness in both feet ascending to the umbilicus, mild low back pain, and unsteady gait. He is alert, has normal strength in the legs, and a normal urinalysis. He is 90 minutes from a chamber by road, or 25 minutes by helicopter that is currently grounded for weather with an estimated 3-hour clearance. He has no chest pain, no cough, and normal pulse oximetry on room air.
1. Classify the syndrome and state the urgency and rationale for recompression.
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This is Type II decompression sickness (neurological DCS) - ascending sensory level to the umbilicus plus gait ataxia and back pain constitutes spinal cord involvement, which is Type II regardless of symptom severity at presentation. Neurological DCS is treated as an emergency: recompression should begin as soon as safely possible because cord lesions can progress and outcome correlates with time to treatment.
The key judgment: do not be reassured by normal strength or a normal urinalysis. The sensory level signals a cord lesion that may evolve over hours. The back pain is not 'musculoskeletal' in this context - it is a recognized harbinger of spinal DCS.
2. Compare the two transport options and state your decision.
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Options:
- Road, 90 min - arrives now, but the patient is alone with a progressing neurological deficit and no monitoring en route.
- Helicopter, 25 min flight but 3-hour weather hold - faster once airborne but unacceptably delayed if the hold is real.
Decision: go by road now, with the helicopter as a contingency if the weather clears and the patient can be intercepted. A 90-minute drive beats an indeterminate 3-hour wait for a progressing cord lesion. Notify the chamber so it is ready on arrival and arrange a clinician or trained escort with the patient rather than sending him alone.
3. During transport the patient develops a cough and mild chest discomfort. What does this change, and how does it alter your chamber plan?
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New cough and chest discomfort after a dive raise concern for pulmonary barotrauma / pneumothorax or pneumomediastinum, and also for arterial gas embolism if there is any neurological worsening - though his deficits are already established. A pneumothorax is a barotrauma emergency that must be excluded before recompression, because a closed pneumothorax can tension under pressure.
Action: examine for unequal breath sounds and obtain chest imaging at the receiving facility before compression; if a pneumothorax is present, it must be treated (needle/tube) before hyperbaric treatment. This does not cancel recompression - it sequences it. Also consider that a cough with chest pain in a diver with neurological symptoms should prompt a search for a patent foramen ovale/right-to-left shunt as the mechanism for paradoxical embolism.