Rex was on the plane headed home and didn’t understand why his left arm felt so strange. It felt odd after his last dive but had felt normal within an hour or two. But now, the numb feeling in his arm was worse and seemed to be moving.

THE DIVER

Rex was 41 and had recently gotten his open-water certification at a local lake.

During training, Rex booked a Caribbean dive trip and was excited about it.

THE DIVE

Rex made nine dives during four days, but he never went deeper than 70 feet. On every dive, he performed safety stops and used his new dive computer. He never entered decompression status.

Rex’s last dive was to a shallow reef at 42 feet. He didn’t note any problems. Within 30 minutes of surfacing, his left hand and forearm were numb. He thought his arm was asleep. He also had some numbness around his right index finger, but it lasted only about five minutes. About an hour and a half later, everything seemed normal. He went sightseeing and then relaxed. He didn’t fly home until the next afternoon.

THE ACCIDENT

Twenty-six hours after his last dive, Rex boarded a commercial flight to go home. Just after takeoff, Rex’s left arm felt numb again. This time the unusual feeling extended to his upper arm. His entire arm felt heavy, and he had pain in the joints in that arm.

On his second flight, the pain in his joints and the numbness in his arm didn’t change. Rex was tired, so he took some over-the-counter pain relievers.

The next morning, Rex woke up feeling lightheaded, and his elbow continued to hurt. Rex quickly got an appointment with his personal physician. His doctor ordered an ECG and a chest X-ray. When both came back normal, Rex was referred to a local hyperbaric physician, who determined it was likely Rex had decompression sickness.

Approximately 55 hours after his last dive, Rex was treated with a U.S. Navy Treatment Table 6 with two extensions. His symptoms gradually resolved, and he was symptom-free at the end of the six-hour treatment. He was advised not to dive for a month.

ANALYSIS

Decompression sickness happens when bubbles form in tissues or blood after diving. Typically these are nitrogen bubbles, but they can also be helium bubbles if the diver is diving on a specialized breathing gas. How the body reacts, or what problems they cause, depend on the size of the bubbles, their quantity and the locations where they form. Symptoms of decompression sickness might appear within 30 minutes or take as long as 24 hours to appear.

The only way to completely eliminate the risk of decompression sickness is to not dive. Most dive tables and computer algorithms are designed with approximately 1 percent of risk of decompression illness, so even if you stay within the tables, you have a small risk of decompression sickness on every dive. Also, tables and dive computers can’t take human variables into account, such as how rested the diver is, hydration levels, alcohol use or other factors that might increase the risk. They do not monitor heart rate, oxygen uptake or exercise levels, or even a diver’s fitness.

When a diver reports symptoms of a dive-related injury, a physician trained in diving medicine performs a neurological assessment to see if there are any other signs of weakness, numbness or tingling. It is likely the doctor would have found other problems during a detailed physical exam that Rex didn’t notice.

Rex had some symptoms and then flew home. The standard recommendation about flying or ascending to altitude after multiple days of diving is to wait 18 hours after the last dive, as long as no symptoms are present. Any ascent to altitude after diving can cause problems for a diver. The reduced pressure on the body allows more nitrogen to come out of the blood or body tissues. While commercial airliners are pressurized, they are not pressurized to sea-level pressure. In Rex’s case, the reduced cabin pressure of the airplane made his symptoms worse.

Rex’s symptoms resolved completely. While decompression sickness is rare, it often takes multiple treatments to resolve or sometimes, it might never resolve completely. Recognizing common symptoms, reporting them and seeking treatment are all crucial.

Often, divers are embarrassed by decompression illness. They think they’ve done something wrong or violated a rule, but that’s not always the case. If a runner sprains his or her ankle, it requires rest and treatment to return to active training. Decompression sickness is no different.

Lessons for Life

Understand the common signs and symptoms of decompression sickness.

Immediately report any symptoms of decompression sickness.

Seek training in diving-accident first-aid care.

The most frequently reported signs and symptoms of decompression illness, according to Divers Alert Network, are:

• Pain, especially joint or muscle
• Numbness/paresthesia
• Fatigue/malaise, nausea
• Vertigo/dizziness
• Muscular weakness
• Altered mental status
• Bowel and bladder problems