Here we have some very interesting information on diagnosing and reasons for some DCS examples.
There are no tests or imaging methods such as X-ray, CT scan or MRI that can diagnose DCS. The diagnosis of DCS is typically reached by a process of elimination. This can be more difficult when a preexisting condition mimics the symptoms of DCS. Three primary factors are associated with the diagnosis: provocative dive profiles, proximity of symptom onset to diving and symptoms consistent with DCS.
Some might argue that a preexisting musculoskeletal condition could predispose the individual to an increased risk of DCS in the affected area. There is some evidence that this is a possibility, but no such predisposition is statistically apparent; the case data about DCS do not support the idea that previously injured areas of the body are prone to DCS. DAN’s recommendation that the diver seek medical evaluation was to ensure review of all other possible signs and symptoms.
There is no substitute for a physical examination in person. A diagnosis cannot be made over the phone or based solely on signs and symptoms that appear in a particular list. None of the signs or symptoms listed for DCS is exclusive or unique to DCS; all factors need to be considered in their proper context. While one of the essential goals in the management of DCS is prompt initiation of treatment in a hyperbaric chamber, this should not supersede a thorough medical evaluation. Medical examinations that occur prior to treatment have not been associated with negative clinical outcomes, and they may uncover other important causes of symptoms that were erroneously associated with diving.
If a diver develops symptoms following a dive, encourage prompt evaluation by a medical professional, and do not hesitate to contact the DAN Emergency Hotline (+39 06 42115685).
As the popularity of scuba diving grows, so do the number of dives conducted each year and with them, a corresponding number of DCS cases. Though the number of exposed divers and the exact incidence of DCS is unknown, its occurrence is relatively rare, with rates ranging from 0.01–0.1% per dive; the higher end reflecting rates for commercial diving and the lower rates for technical, scientific, and recreational diving. Even so, the consequences can be dramatic.
Although, the exact pathogenic mechanism behind DCS is still open to debate there is widespread agreement that tiny circulating inert gas bubbles, called vascular gas emboli (VGE), are the principal culprit. Researchers also accept the fact that divers can have “silent” VGE, as measured by a Doppler monitor, without any DCS symptoms.
The current rules that govern the correct decompression procedures based on the hyperbaric exposure and the breathing gases used, are also well known and widely accepted, and therein lies the conundrum. The majority of cases of DCS are “unexpected,” meaning that they were not predicted by the current algorithms, and consequently considered ‘undeserved,’ i.e. divers got ‘bent’ though they correctly followed their tables or computers.
“The problem is that today’s decompression models are just considering saturation and desaturation of inert gas, and disregard the population of bubble micronuclei, the precursors of VGE, which we believe are primarily responsible for decompression bubbles,” study co-author Professor Costantino Balestra, DAN Europe’s Vice President of Research & Education explained.
According to Balestra, research suggests that an individual’s metabolic processes interacting with micronuclei may modulate the formation of VGE making a diver’s individual susceptibility and recent history such as life style, exercise and other predisposing and humoral risk factors all the more important in predicting the onset of DCS. “We are always trying to explain the why,” Balestra said.
Findings have led researchers to conclude that we have reached the reliable limit of current dive computing technology. The new frontier, according to researchers, is developing algorithms that can be customized for the user’s physiology, which may eventually lead to computers integrated with real-time physiological sensing technology.