Symptoms in humans which result from a sudden reduction in atmospheric pressure. It is also called dysbarism, caisson disease, the bends, and compressed-air illness. It is most commonly seen in two groups of subjects, (1) those who rapidly ascend in nonpressurized air-planes to altitudes in excess of 18,000 ft (5500 m), and (2) divers, scuba divers, sandhogs, and professional workers in hyperbaric chambers who work under increased ambient pressures and are decompressed. See also Diving.
This condition is caused by the formation of nitrogen bubbles in the tissues and blood vessels. These bubbles plug vessels and expand in tissue spaces producing the characteristic symptoms and signs of this illness. Helium, when present in high concentrations utilized by divers or found in some spacecraft, can also produce a similar condition.
The onset of symptoms may occur at any time from a few minutes to several hours after decompression. The most common manifestation is pain in the joints and muscles. However, skin, respiratory, and neurologic symptoms are not uncommon. The skin manifestations are itching, discoloration, and edema (swelling). Respiratory symptoms are coughing and dyspnea (difficulty in breathing). The neurologic symptoms vary from mild paresthesia (sensations of tingling, crawling, or burning of the skin) and weakness to total paralysis; loss of bladder and rectal sphincter control is common. The severe forms of this illness are followed by circulatory failure, paralysis, coma, and death.
Treatment is recompression, followed by gradual decompression to normal atmospheric pressure. Prognosis is generally good except in those subjects who show central nervous system damage.
