Delayed Off-Gassing

Q: After a week of very conservative diving in Roatan, I waited about 25 hours before flying home. A day or two later I had pain in my neck, which I have had intermittently for years, but this time it included a feeling of pins and needles, numbness, and weakness in my right arm. I didn’t have any symptoms while on the plane or shortly afterward. The intensity peaked about two weeks ago and now is getting better, but the symptoms are still present about 50 percent of the time. Could a pre-existing injury delay offgassing, and why wouldn’t any symptoms appear earlier? Would radiculopathy in my right arm prevent me from diving to shallow depths (less than 40 feet)?

DAN medical information specialists cannot render a diagnosis via the phone, internet or email. Arriving at a diagnosis is a complex process that requires a physician using clinical judgment, the patient’s medical and dive history, symptom evolution and findings on a physical exam.

We can only comment based on our limited insight and index of suspicion. Based on your description, it seems unlikely that your right arm symptoms could be the result of any form of decompression sickness (DCS) — especially in the absence of symptoms for a day or two post-flight. Recreational divers tend to offgas any excess inert gas within the first 24 hours following the final dive. A condition or injury that compromises the blood supply to tissues may theoretically impair inert gas uptake and elimination.

For this reason, some researchers think that DCS may be more likely at previous surgical or injury sites, but no data support this claim. Regarding fitness-to-dive guidelines with pre-existing spinal radiculopathy, physicians trained in dive medicine generally agree that if there are no neurological, physical or functional impairments, you can consider diving. They also agree, however, that because the similarity between neurological deficits (related to the radiculopathy) and possible DCS can cause confusion when diagnosing a symptomatic diver, a detailed neurological examination is helpful.  

Knowledge of pre-existing neurological deficits comparedwith a current neurological exam with previously documented results may help a diver avoid the need for an unnecessary hyperbaric chamber treatment. Please discuss with your physician your interest in scuba diving. Your doctor can contact DAN for a physician-to-physician consultation. We can also refer you to a doctor in your area who is trained in dive medicine.
— Daniel A. Nord, EMT-P, CHT