Decompression Sickness
(Caisson Disease, Altitude Sickness, The Bends)
Definition |
Causes |
Risk Factors |
Symptoms |
Diagnosis |
Treatment |
Prevention |
Organizations
Definition
Decompression sickness (DCS) occurs when the body is subjected to a sudden reduction in surrounding pressure. DCS occurs most frequently during deep sea diving, or when flying in a non-pressurized aircraft.
Causes
DCS is caused by the formation of gas bubbles in the blood and tissues. At normal altitudes, nitrogen and other gases are exhaled or dissolved in the blood and tissues. However, during severe changes in altitude and air pressure, nitrogen and other gases form gas bubbles. These bubbles block the flow of blood. This condition can be fatal if not treated quickly.
Risk Factors
A risk factor is something that increases your chances of getting a disease or condition. The only risk factor for decompression sickness is a sudden reduction in pressure. This occurs as a result of:
- Rising too quickly to the surface from deep sea scuba diving
- A fast ascent into a high altitude from a low altitude
- Sudden exit from a high pressure or hyperbaric chamber
Symptoms
The first and primary symptom of DCS is pain, often called "the bends." Although it may occur anywhere in the body, it is most common in or near an arm or leg joint. The pain may become more severe over time. Other symptoms include:
- Numbness or tingling in the extremities
- Weakness
- Fatigue
- Stomach discomfort
- Severe itching
- Mottled or blotchy skin rash
- Vertigo
- Chest pain and severe coughing (rarely)
Diagnosis
The doctor will ask about your symptoms and medical history, and perform a physical exam. Blood and other diagnostic tests are not usually helpful. Depending on the symptoms, DCS may be classified as Type I (mild) or Type II (serious). Type II DCS may result in paralysis, brain damage, heart attack, or death.
Treatment
If you experience symptoms of DCS, it is extremely important to get treatment immediately. In severe cases, delayed treatment may be fatal.
The treatment for DCS is oxygen therapy in a hyperbaric chamber. This device works by gradually increasing and then decreasing air pressure around the body, which forces gas bubbles to dissolve. Oxygen should be administered through an oxygen mask during transport to a hyperbaric chamber.
Treatment should be given even if initial symptoms are mild or disappear. Proper treatment administered quickly should cure all symptoms of DCS.
Prevention
Decompression sickness may be prevented by:
- Limiting the depth and duration of deep sea dives
- Following standard diving guidelines
- Avoiding diving if you are obese, pregnant, have heart or lung problems, or have had a recent joint or limb injury
- Avoiding excessive alcohol consumption within 24 hours before diving
- Avoiding flying within 24 hours after deep sea diving
- Avoiding repeated dives within a 12-hour period
- Avoiding flights in non-pressurized aircraft
Organizations
American College of Hyperbaric Medicine
http://www.hyperbaricmedicine.org
Undersea and Hyperbaric Medical Society
http://www.uhms.org
Divers Alert Network
http://www.diversalertnetwork.org/
SOURCE:
Office of Aerospace Medicine, Federal Aviation Administration
Last reviewed January 2002 by Medical Review Board
