Editing Decompression sickness (section)

===Differential diagnosis===
{{See also|Inner ear decompression sickness#Diagnosis}}

Symptoms of DCS and arterial gas embolism can be virtually indistinguishable. The most reliable way to tell the difference is based on the dive profile followed, as the probability of DCS depends on duration of exposure and magnitude of pressure, whereas AGE depends entirely on the performance of the ascent. In many cases it is not possible to distinguish between the two, but as the treatment is the same in such cases it does not usually matter.{{r|Cronje 2014}}

Other conditions which may be confused include skin symptoms. ''[[Cutis marmorata]]'' due to DCS may be confused with [[Barotrauma#In divers|skin barotrauma]] due to [[Dry suit#Suit squeeze|dry suit squeeze]], for which no treatment is necessary. Dry suit squeeze produces lines of redness with possible bruising where the skin was pinched between folds of the suit, while the mottled effect of ''cutis marmorata'' is usually on skin where there is subcutaneous fat, and has no linear pattern.{{r|Cronje 2014}}

Transient episodes of severe neurological incapacitation with rapid spontaneous recovery shortly after a dive may be attributed to [[hypothermia]], but may actually be symptomatic of short term CNS involvement due to bubbles which form a short term gas embolism, then resolve, but which may leave residual problems which may cause relapses. These cases are thought to be under-diagnosed.{{r|Cronje 2014}}

[[Inner ear decompression sickness]] (IEDCS) can be confused with [[inner ear barotrauma]] (IEBt), [[alternobaric vertigo]], [[caloric vertigo]] and [[reverse squeeze]]. A history of difficulty in equalising the ears during the dive makes ear barotrauma more likely, but does not always eliminate the possibility of inner ear DCS, which is usually associated with deep, mixed gas dives with decompression stops.{{r|Cronje 2014}} Both conditions may exist concurrently, and it can be difficult to [[Inner ear decompression sickness#Differential diagnosis|distinguish whether a person has IEDCS, IEBt]], or both.

Numbness and tingling are associated with spinal DCS, but can also be caused by pressure on nerves (compression [[neurapraxia]]). In DCS the numbness or tingling is generally confined to one or a series of [[Dermatome (anatomy)|dermatomes]], while pressure on a nerve tends to produce characteristic areas of numbness associated with the specific nerve on only one side of the body distal to the pressure point.{{r|Cronje 2014}} A loss of strength or function is likely to be a medical emergency. A loss of feeling that lasts more than a minute or two indicates a need for immediate medical attention. It is only partial sensory changes, or [[paraesthesia]]s, where this distinction between trivial and more serious injuries applies.<ref name="Cronje 2009" />

Large areas of numbness with associated weakness or paralysis, especially if a whole limb is affected, are indicative of probable brain involvement and require urgent medical attention. Paraesthesias or weakness involving a dermatome indicate probable spinal cord or spinal nerve root involvement. Although it is possible that this may have other causes, such as an injured intervertebral disk, these symptoms indicate an urgent need for medical assessment. In combination with weakness, paralysis or loss of bowel or bladder control, they indicate a medical emergency.<ref name="Cronje 2009" />