Decompression Sickness Symptoms

Regular aches and pains can for many be a part of every day life.  It is easy to see how a diver can then put symptoms after a dive down to this, other than the possibility of a bend. A good example is joint pain following a dive. The use of heavy scuba equipment and exertion getting in and out of the boat, or after a long walk up a beach, is understandably used to explain any joint pains or generalised aches that someone feels.

DCI is a complicated medical problem and can manifest itself anywhere in the body at any time during or up to 48 hours after a dive. A diver doesn’t even have to do anything “wrong” to get a bend. If you have dived and are displaying signs or symptoms, or feeling generally “unwell” – you must consider the possiblity of DCI and seek medical advice.

Even a so called “mild” symptom, such as a skin rash or joint pain, could be indicating that your body has not adequately decompressed. More serious symptoms may well follow.

Immediate recompression is essential and will remove the excess gas load and promote the healing of damaged tissue. Delayed recompression will aid the healing of damaged tissue.

Where oxygen has been breathed on the surface, via a mask, symptoms may improve. If so, it is a sign that you should be assessed and medical advice sought as soon as possible. Re-entering the water with symptoms is not recommended.

Source: US Navy Diving Manual, Rev. 6

Source: MOON, RE Assessment of patients with decompression illness SPUMS Journal volume 28 no. 1, March 1998

Pain in or near one of the muscles or tendons around the joints is the most common symptom of decompression illness. The shoulder is most often the joint affected followed by elbows, wrists, hand, hips, knees and ankles. It is often explained away as being a general ache or pain – dci denial is a real danger.  If onset of symptoms follows a dive then assume it is a bend until proven otherwise.
Symptoms may begin with discomfort or an strange feeling in or around the joint which can then develop into what is commonly described as a deep, dull ache – sometimes throbbing.

Gas bubbles can form a physical obstruction of the lymphatic system which controls fluid exchange in body tissues. In these cases the diver will see localised swelling of tissue, typically around the upper arm or chest area. The skin can often be slow to return to normal shape when pressed, not unlike memory foam mattresses.

Skin bends, or subcutaneous marmorata, have often been dismissed as trivial by divers on account that they will often spontaneously disappear.  This gives the diver a false sense of security, however, as we regularly see people with serious decompression illness who then go on to report skin bends acquired earlier in the dive season.

The skin rash can appear marbled or blotchy in appearance and is sometimes accompanied by itching or may even feel warm to the touch.  It occurs when nitrogen bubbles obstruct the skin blood supply and is a demonstration that the diver has not decompressed sufficiently.  Most common areas that we see affected are the shoulders, arms, chest and stomach.

This covers more general symptoms and is harder to pin down.  Divers often report some of these symptoms in combination with other more obvious symptoms of decompression illness.  During the course of treatment they find that these resolve as well, a clear sign that gas bubbles are implicated.  Unusual degrees of fatigue, headache or reporting not feeling 100% without being to specify exactly why – all can be subtle symptoms of constitutional decompression illness.

Gas bubbles present in sufficient number and size in the brain or the spinal cord can lead to a host of symptoms. Forming in the brain can lead to (partial) paralysis and/or numbness, difficulties with speech, headache, visual disturbances, vertigo, cognitive or brain function difficulties and loss of consciousness.

More commonly affected is the spinal column, sometimes preceded with girdle or abdominal pain.  Areas of tingling/altered sensation are common, weakness, loss of co-ordination and bladder or bowel problems.  Examination by the Diving Doctor can often determine which nerves are affected and give further insight into the type of decompression illness a diver has.

In cases where the sheer number and position of gas bubbles overwhelm the gas filtering capability of the lungs, blood flow can be impaired leading to a sensation of struggling for breath.  This type of decompression illness is known as ‘chokes’ or pulmonary decompression sickness.

A diver may report chest tightness or pain, difficult and rapid
breathing.  Such cases can frequently deteriorate very rapidly.

If sufficient gas bubbles form in the inner-ear, particularly the hearing (cochlea) or balance organs (vestibular), then inner-ear or vestibular decompression illness may result. Symptoms can include hearing loss, tinnitus or ringing in the ear(s), vertigo, nausea and vomiting. Divers often want to lay down without moving the head in particular, which can minimise what can often be very significant vertigo and dizziness.

Often associated more frequently with deeper, repetitive dives, sometimes using trimix, it is very unpleasant for the diver and can require more than one treatment to resolve. A pressure injury, or barotrauma, of the ear can cause some similar symptoms and can be ruled out by the examining Doctor.

The presence of shock in a diver is often an indication of serious, evolving decompression illness.  One potential cause is hypovolaemia, where fluid imbalance results from gas bubbles affecting the ease with which body fluids can pass through cell walls.  Depending on the specific cause, typical symptoms include anxiety, bluish lips, chest pain, confusion, dizziness or faintness, pale clammy skin, profuse sweating.

If a diver surfaces rapidly and either does not exhale, or exhales insufficiently, then air that is present in the lungs can expand on ascent.  This is particularly apparent in the last 10 metres to surface.  If the air expands enough it can rupture lung tissue – called pulmonary barotrauma – which releases gas bubbles into the arterial circulation.

This then carries the bubbles around the body in the blood stream and since the brain has a high blood flow it is the main organ where bubbles may interrupt circulation if they become lodged in small arteries.  This is known as an arterial gas embolism, or AGE.  Symptoms are instantaneous or within minutes.

An AGE can occur from very shallow depths – even from swimming pools!  Very little pressure difference is needed to provide a dangerously large expansion of gas in the lungs if a diver breathe holds.  Pulmonary disease such as obstructive lung disease may increase the risk of AGE.  The most obvious presentation of an air gas embolism is the diver who surfaces unconscious and remains so, or the diver who loses consciousness within minutes of surfacing. Rapid evacuation to a treatment facility is essential.