'The Bends'

A 36-year-old man was treated by paramedics after a diving mishap in Pt Lonsdale last week. It is believed that the diver 'swam down too fast' while scuba diving, and a short time later was suffering signs of decompression sickness, also known as 'the bends'. Here is some useful information on this common 'injury' suffered by scuba divers.

What is 'the bends'?

Decompression sickness (DCS; also known as divers' disease or the bends) describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurisation.

What are the symptoms of the bends?

While bubbles can form anywhere in the body, DCS is most frequently observed in the shoulders, elbows, knees, and ankles. Joint pain ("the bends") accounts for about 60% to 70% of all altitude DCS cases, with the shoulder being the most common site. Neurological symptoms are present in 10% to 15% of DCS cases with headache and visual disturbances the most common symptom. Skin manifestations are present in about 10% to 15% of cases. Pulmonary DCS ("the chokes") is very rare in divers and has been observed much less frequently in aviators since the introduction of oxygen pre-breathing protocols. The table below shows symptoms for different DCS types.

Signs and symptoms of decompression sickness

DCS type	Bubble location	Signs & symptoms (clinical manifestations)
Musculoskeletal	Mostly large joints(elbows, shoulders, hip, wrists, knees, ankles)	Localized deep pain, ranging from mild 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.
Cutaneous	Skin	Itching, usually around the ears, face, neck, arms, and upper torso Sensation of tiny insects crawling over the skin 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
Neurologic	Brain	Altered sensation, tingling or numbnessparasthesia, increased sensitivity hyperesthesia Confusion or memory loss (amnesia) Visual abnormalities Unexplained mood or behaviour changes Seizures, unconsciousness
Neurologic	Spinal Cord	Ascending weakness or paralysis in the legs Girdling abdominal or chest pain Urinary incontinence and fecal incontinence
Constitutional	Whole body	Headache Unexplained fatigue Generalised malaise, poorly localised aches
Audiovestibular	Inner ear	Loss of balance Dizziness, vertigo, nausea, vomiting Hearing loss
Pulmonary	Lungs	Dry persistent cough Burning chest pain under the sternum, aggravated by breathing Shortness of breath

Even when the change in pressure causes no immediate symptoms, rapid pressure change can cause permanent bone injury which can develop from a single exposure to rapid decompression.

How can I help to prevent getting the bends?

The potential severity of the bends is such that much research has gone into preventing it, and underwater divers use dive tablesor dive computers to set limits on their exposure to pressure and their ascent speed. Diving for too long, descending too quickly, or ascending too quickly without sufficient decompression stops to slowly reduce the excess pressure of inert gases dissolved in the body will increase the risk of the bends. Not flying straight after diving can also decrease the risk of getting the bends. Divers who ascend to altitude soon after a dive increase their risk of developing DCS even if the dive itself was within the dive table safe limits. Dive tables make provisions for post-dive time at surface level before flying to allow any residual excess nitrogen to outgas.

How is the bends treated?

Treatment is by hyperbaric oxygen therapy in a recompression chamber. If treated early, there is a significantly higher chance of successful recovery.