Editing Decompression sickness (section)

== Signs and symptoms ==
{{See also|List of signs and symptoms of diving disorders}}

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 for altitude and bounce diving, and the knees and hip joints for saturation and compressed air work.{{r|Cronje 2014}} [[Neurological]] symptoms are present in 10% to 15% of DCS cases with [[headache]] and visual disturbances being 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.{{sfn|Powell|p=71}} The table below shows symptoms for different DCS types.{{sfn|Francis & Mitchell, ''Manifestations''|pp=578–584}}

{| class="wikitable"
|+ '''Signs and symptoms of decompression sickness'''
|-
! scope="col" | DCS type
! scope="col" | Bubble location
! scope="col" | Signs & symptoms (clinical manifestations)
|-
! scope="row" | Musculoskeletal
| Mostly large joints of the limbs

(elbows, shoulders, hip, wrists, knees, ankles)
|
* Localized deep pain, ranging from mild to excruciating. Sometimes a dull ache, more rarely a sharp pain.
* Active and passive motion of the joint may aggravate 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.
|-
! scope="row" | Cutaneous
| 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 (''[[cutis marmorata]]'')
* Swelling of the skin, accompanied by tiny scar-like skin depressions ([[pitting edema]])
|-
! scope="row" | Neurologic
| Brain
|
* Altered sensation, tingling or numbness ([[paresthesia]]), increased sensitivity ([[hyperesthesia]])
* Confusion or memory loss ([[amnesia]])
* Visual abnormalities
* Unexplained mood or behaviour changes
* [[Non-epileptic seizure|Seizures]], unconsciousness
|-
! scope="row" | Neurologic
| [[Spinal cord]]
|
* Ascending weakness or [[paralysis]] in the legs
* [[Urinary incontinence]] and [[fecal incontinence]]
* Girdling (also referred to as girdle, banding, or tightening feeling) around the [[abdominal]] region and/or [[chest]]
|-
! scope="row" | Constitutional
| Whole body
|
* Headache
* Unexplained fatigue
* Generalised malaise, poorly localised aches
|-
! scope="row" | Audiovestibular
| Inner ear {{r|pmid12562679}}{{efn|name=ICD}}
|
* Loss of balance
* [[Dizziness]], [[Vertigo (medical)|vertigo]], [[nausea]], [[vomiting]]
* Hearing loss
|-
! scope="row" | Pulmonary
| Lungs
|
* Dry persistent cough
* Burning chest pain under the [[Human sternum|sternum]], aggravated by breathing
* [[Shortness of breath]]
|}

=== Frequency ===
The relative frequencies of different symptoms of DCS observed by the U.S. Navy are as follows:{{sfn|Powell|p=70}}
{| class="wikitable" style="text-align: center;"
|+ Symptoms by frequency
|-
! scope="col" | Symptoms
! scope="col" | Frequency
|-
! scope="row" | local joint pain
| 89%
|-
! scope="row" | arm symptoms
| 70%
|-
! scope="row" | leg symptoms
| 30%
|-
! scope="row" | dizziness
| 5.3%
|-
! scope="row" | paralysis
| 2.3%
|-
! scope="row" | shortness of breath
| 1.6%
|-
! scope="row" | extreme fatigue
| 1.3%
|-
! scope="row" | collapse/unconsciousness
| 0.5%
|}

=== Onset ===
Although onset of DCS can occur rapidly after a dive, in more than half of all cases symptoms do not begin to appear for at least an hour. In extreme cases, symptoms may occur before the dive has been completed. The [[U.S. Navy]] and [[Technical Diving International]], a leading technical diver training organization, have published a table that documents time to onset of first symptoms. The table does not differentiate between types of DCS, or types of symptom.{{r|usn520-3.1 | TdiDpm}}
{| class="wikitable" style="text-align: center;"
|+ Onset of DCS symptoms
|-
! scope="col" | Time to onset
! scope="col" | Percentage of cases
|-
! scope="row" | within 1 hour
| 42%
|-
! scope="row" | within 3 hours
| 60%
|-
! scope="row" | within 8 hours
| 83%
|-
! scope="row" | within 24 hours
| 98%
|-
! scope="row" | within 48 hours
| 100%
|}