Despite the spontaneous resolution of post-dive neurological symptoms, the diver still needs urgent medical evaluation.
Reported Story
On a charter boat in a foreign country, a dive instructor was conducting drysuit training for two experienced divers. The training, which took place 50 minutes offshore on a nearby reef, involved a series of uneventful, repetitive, no-decompression air dives with a maximum depth of 66 fsw (20 msw) and specific buoyancy-control skills performed between 33 fsw (10 msw) and the surface.
Minutes after surfacing, a 50-year-old male student reported paralysis in his right leg. Another student aboard was a physician; his examination found that the diver was suffering from paresthesia of both legs and muscular weakness of the right leg.
The dive crew immediately administered surface-level oxygen via demand valve. Approximately 20 minutes after symptom onset with 15 minutes of oxygen breathing, all symptoms resolved, and muscular strength of the right leg returned to normal. The dive leader continued oxygen administration and called DAN.
DAN advised the continuation of oxygen first aid until the diver reached the next level of care, regardless of apparent spontaneous full recovery.
Comment
The symptoms reported in this case fit both decompression illness (DCI) and a stroke. Both presumptive diagnoses can have a similar natural course with an erratic evolution that initially fluctuates between clear and dramatic neurological impairment and an apparent full recovery. Both diagnoses need a timely intervention, but the diagnosis of stroke may be missed if a patient goes straight to a recompression chamber.
In this case, the patient was referred to an emergency care unit. The medical staff ruled out a cerebrovascular event, and the patient still reached the local recompression facility in time to receive all benefits of hyperbaric oxygen (HBO) treatment.
At the time this case report was written, it was too early to say whether it is safe for this individual to resume compressed-gas diving. Further studies might reveal the presence of known risk factors that could have explained such dramatic presentation. Considering the reportedly moderate exposure and the absence of provocative factors like breath-holding or rapid ascent, a paradoxical embolism through a patent foramen ovale (PFO) could have been a contributing factor. Whether or not the diver tests for PFO, if he resumes diving he should do so conservatively and avoid remote locations.
Dr. Matias Nochetto