Decompression Illness Decompression Illness
Wikipedia—The Free Encyclopedia

Caisson disease [decompression sickness] Classification and external resources Two United States Navy sailors inside a decompression chamber about to undergo training Decompression sickness (DCS; also historically or colloquially known as divers’ disease, the bends or caisson disease) describes a condition arising from the precipitation of dissolved gasses into bubbles inside the body on depressurisation.[1] DCS most commonly refers to a specific type of scuba diving hazard but may be experienced in other depressurisation events such as caisson working, flying in unpressurised aircraft and extra-vehicular activity from spacecraft. Although DCS is not a common event, its potential severity is such that much research has gone into preventing it and scuba divers use dive tables or dive computers to set limits to their exposure to pressure. Its effects may vary from joint pain and rashes, to paralysis and death. Treatment is by hyperbaric oxygen therapy in a recompression chamber. If treated early, there is a significantly higher chance of success. Classification DCS is usually classified by symptoms into Type I “the bends” which involves only the skin, musculoskeletal system, or lymphatic system and Type II which involves the other organs ( such as the central nervous system ) in addition to that potentially seen with Type I DCS.[2] Type II DCS thus usually has worse outcomes.[3] The usefulness of this classification in the initial assessment has been questioned as neurological symptoms may develop after the initial presentation and both Type I and Type II DCS are treated the same. Arterial gas embolism and DCS are treated very similarly because they are both the result of gas bubbles in the body.[4] Their spectra of symptoms also overlap, although those from arterial gas embolism are more severe because they often cause infarction and tissue death as noted above. In a diving context, the two are joined under the general term of decompression illness. Another term, dysbarism, encompasses decompression sickness, arterial gas embolism, and barotrauma. Signs and symptoms The symptoms of DCS are often summed up by “the bends”, “the chokes”, “the staggers”, and “the tingles” representing the musculoskeletal, pulmonary, inner ear, and skin / CNS involvement seen. While bubbles can form anywhere in the body, the bends are most frequently observed in the shoulders, elbows, knees, and ankles. This table gives symptoms for the different DCS types. The “bends” (joint pain) accounts for about 60 to 70 percent of all altitude DCS cases, with the shoulder being the most common site. These types are classified medically as DCS I. Neurological symptoms are present in 10 to 15 percent of all DCS cases with headache and visual disturbances the most common. DCS cases with neurological symptoms are generally classified as DCS II. The “chokes” are rare and occur in less than two-percent of all DCS cases. Skin manifestations are present in about 10 to 15 percent of all DCS cases. Signs and symptoms of decompression sickness. DCS Type Bubble Location Signs & Symptoms (Clinical Manifestations) Bends Mostly large joints of the body (elbows, shoulders, hip, wrists, knees, ankles) Localized deep pain, ranging from mild (a “tingle”) to excruciating. Sometimes a dull ache, but rarely a sharp pain. Active and passive motion of the joint aggravates the pain. The pain may be reduced by bending the joint to find a more comfortable position. If caused by altitude, pain can occur immediately or up to many hours later. Skin bends Skin Itching usually around the ears, face, neck, arms, and upper torso Sensation of tiny insects crawling over the skin (formication) Mottled or marbled skin usually around the shoulders, upper chest and abdomen, with itching Swelling of the skin, accompanied by tiny scar-like skin depressions (pitting edema) Neurological Brain Confusion or memory loss (amnesia) Headache Spots in visual field (scotoma), tunnel vision, double vision (diplopia), or blurry vision Unexplained extreme fatigue or behaviour changes Seizures, dizziness, vertigo, nausea, vomiting and unconsciousness may occur, mainly due to labyrinthitis Spinal Cord Abnormal sensations such as burning, stinging, and tingling around the lower chest and back Symptoms may spread from the feet up and may be accompanied by ascending weakness or paralysis Girdling abdominal or chest pain Peripheral Nerves Urinary incontinence and fecal incontinence Abnormal sensations, such as numbness, burning, stinging and tingling (paresthesia) Muscle weakness or twitching Inner Ear: “the staggers” Loss of balance Extreme vertigo Hearing loss Chokes Lungs Burning deep chest pain (under the sternum) Pain is aggravated by breathing Shortness of breath (dyspnea) Dry constant cough The observed frequency of symptoms of DCS are as follows: DCS symptoms by frequency. Percentage of cases Symptoms 89% local joint pain 30% leg symptoms 70% arm symptoms 5.3% dizziness 2.3% paralysis 1.6% shortness of breath 1.3% extreme fatigue 0.5% collapse/unconsciousness Onset Although onset of DCS can occur rapidly after a dive, in extreme cases even before a dive has been completed, in more than half of all cases symptoms do not begin to present until over an hour following the dive. The U.S. Navy and Technical Diving International, a leading technical diver training organisation, have published a table, which indicates onset of first symptoms: