"On my last dive trip I got bent. When is it OK for me to dive again, and are there any precautions I should take for my next dive(s)?"

ANSWER: With the information you have provided, my answer has to be “it depends”. There are different levels of seriousness to “getting bent.” One end of the spectrum includes simple joint pain that resolves completely with treatment or even symptoms that are vague and may or may not truly be decompression sickness (DCS). At the other end are serious cases of decompression sickness that include neurological symptoms like numbness or even paralysis. You also need to take into account whether the hit is explained by the dive profile.

What It's Like To Get An Unexplained Hit

The treatment for decompression sickness, while somewhat time and labor intensive, is relatively benign enough that all diving medical officers are certain that we have occasionally treated people who did not really have decompression sickness. There is no blood test or alternate method of making the diagnosis other than having an individual who recently completed a diver presenting with the right symptoms.

The U.S. Navy policy is for a return to diving after 30 days for severe decompression sickness or air embolism (AGE) that completely resolves with treatment. The time period is shorter for pain only DCS. Of course this recommendation is for professional divers who are paid extra to dive and are typically in excellent physical condition. The time period should be doubled for most recreational divers and a thorough medical evaluation prior to a return to diving is recommended. Diving more conservative profiles is a valid recommendation for the future and in cases of serious DCS or AGE without a provocative dive profile, the diver should consider being evaluated for a patent foramen ovale.

Traditionally decompression sickness (DCS) has been divided into two categories, Type I or mild DCS and Type II or severe DCS. Type I DCS has also been known as “pain only” DCS and, as the name implies, there is typically joint pain and/or muscle soreness and possibly even some perceived numbness/tingling but otherwise no neurological deficits. More severe DCS includes cases with significant neurological deficits such as bowel and bladder control issues, neurological issues that appear to have spinal cord involvement, and in extreme cases cardiovascular collapse (also known as “the chokes”).

While very minor symptoms of DCS may go away with just rest and over the counter pain medications, it is thought that treatment with recompression and oxygen is ideal to prevent any possible long term effects from the injury. For cases of severe DCS, recompression therapy using hyperbaric oxygen is critical and should not be delayed. Many clinical studies have demonstrated that a delay prior to treatment results in the need for more aggressive therapy and increases the chances of having incomplete resolution of symptoms.

Treatment of decompression sickness with hyperbaric oxygen (HBO) has few associated risks but is both time and labor intensive. Because of this, physicians who treat divers have a low threshold for initiating treatment. Distinguishing between pain due to trauma during the dive and pain from mild DCS can be very difficult. There is even a phenomenon that occurs when the weight belt presses on some nerves in the hips, giving the diver numbness down the thighs. The treating physician should take a very detailed history regarding the dive if time allows. Divers who present with symptoms of decompression sickness shortly after completing a dive will likely receive treatment as there is more concern for under-treatment than over-treatment.

If there is incomplete resolution of symptoms after treatment has been completed, a return to diving should be discouraged. Returning to diving after complete resolution of mild DCS is appropriate after a brief recovery period of a few weeks. With complete resolution of symptoms of severe DCS, a longer interval is recommended. It is highly recommended that a diver who suffers a severe “hit” discuss the dive profile and initial symptoms with an expert who can offer some insight on the incident. It should be mentioned however that decompression sickness can occur despite a dive profile that is well within table or computer no decompression limits. In cases where a diver suffers severe decompression symptoms after a seemingly very benign dive, further evaluation and possibly an echocardiogram to check out the heart anatomy would be worthwhile.