Decompression sickness, commonly known as “the bends,” is a condition that arises from rapid changes in ambient pressure. This typically occurs in underwater diving when dissolved gases, primarily nitrogen, form bubbles within the body’s tissues and bloodstream. When a diver ascends too quickly, the nitrogen, which has been absorbed under higher pressure, does not have sufficient time to safely exit the body through respiration. These gas bubbles can then cause a range of physical effects, from mild discomfort to severe, life-threatening complications.
Common Manifestations
One of the most frequently observed signs of decompression sickness is joint pain. This pain typically affects major joints such as the shoulders, elbows, knees, and ankles. It can manifest as a deep, dull ache, or sometimes as a sharp, intense sensation, and while movement does not typically worsen the pain, adjusting the joint might offer some temporary relief.
Muscle aches and discomfort can also accompany joint pain. Skin manifestations are another common indicator, presenting as itching. A distinctive mottled or marbled rash, known as cutis marmorata, may appear on areas like the chest, abdomen, or shoulders. Unusual fatigue or malaise can also be a subtle but meaningful sign of decompression sickness. While these symptoms are generally less severe, their presence warrants careful attention.
Serious Indicators
More severe forms of decompression sickness can involve the central nervous system, respiratory system, or circulatory system. Neurological symptoms are particularly concerning and can include dizziness, persistent headache, or visual disturbances such as blurred vision or double vision. Individuals might also experience numbness, tingling, or weakness in their limbs.
In some cases, neurological involvement can progress to impaired coordination, difficulty walking, or even paralysis. Changes in mental status, such as confusion, disorientation, or a reduced level of consciousness, are serious indicators. Slurred speech, seizures, or problems with bladder and bowel control can also point to significant neurological compromise.
Respiratory symptoms involve breathing difficulties like shortness of breath, a persistent dry cough, or chest pain behind the breastbone. These signs suggest that bubbles are affecting the lungs. In the most severe instances, decompression sickness can lead to circulatory collapse or shock, underscoring the need for immediate medical intervention.
Symptom Onset Timeline
The appearance of decompression sickness symptoms can vary in timing after exposure to pressure changes. Many individuals experience symptoms within minutes to a few hours following a dive. Approximately half of all cases show symptoms within one hour of surfacing, and about 90% manifest within six hours.
In some instances, however, symptoms can be delayed, occasionally appearing up to 24 to 48 hours later. This delayed onset is more common if an individual ascends to a higher altitude shortly after diving. A shorter time between surfacing and symptom onset generally indicates a more severe presentation of the condition.
Responding to Suspected Cases
If someone exhibits signs of decompression sickness, immediate medical attention is necessary. Contacting emergency medical services or a specialized dive medical network, such as the Divers Alert Network (DAN). While awaiting professional help, certain first aid measures can be implemented to support the affected individual.
The person should be placed in a comfortable, flat position. If available, administering 100% oxygen through a tight-fitting mask can help reduce the size of the nitrogen bubbles. The primary treatment for decompression sickness is recompression therapy in a hyperbaric chamber.
This treatment involves placing the individual in a high-pressure environment to shrink the bubbles, followed by a gradual reduction in pressure to allow the gases to be safely eliminated. Even mild or transient symptoms warrant medical evaluation, as they can sometimes precede more serious issues if left untreated.