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Chapter 15 — 3
symmetrical and involves smaller joints, and local pressure application produces no relief.
These signs are uncommon in DCS.
In general, any pain in or near a joint after compressed air dives in excess
of 10 metres (or shallower with repetitive or prolonged dives) must be
assumed to be DCS until proven otherwise.
NEUROLOGICAL DCS
DCS can affect the
brain, spinal cord and/or peripheral nerves
. The clinical features are
due to disturbance of activity in the nervous system, interfering with one or more of its five
principal functions:
•
sensation
•
movement
(including balance and co-ordination)
•
consciousness
and intellectual functions
•
autonomic
functions
•
reflexes
(e.g. knee jerk, cough reflex).
Of these, the first four are easier for the layman to assess.
!
The Senses.
These include sight, hearing, smell, taste, pain and touch. Numbness and tingling
(paraesthesiae) are frequent symptoms. Other abnormal signs include loss of sensation.
!
Movement.
This includes the ability to move any muscle, the strength of the movement and the ability to
co-ordinate it.
!
Higher function of the brain.
The important intellectual functions are consciousness, orientation (awareness of time, person
and place), thinking, speech and memory. Epileptic fits (convulsions) and confusion are
possible. See the AMTS box at the end of this chapter for a rapid, simple method of assessing
higher function brain involvement.
!
Autonomic functions.
Interference with the control of breathing and heart function may cause shock and collapse.
Bladder and bowel malfunction usually causes progressive abdominal discomfort and
tenderness until the bladder or bowels are opened.
In
CEREBRAL (Brain) DCS
, the bubbles of DCS may be located in or near the blood
vessels supplying the brain, causing obstruction of blood flow and direct pressure on the
neurological tissues. The brain swells like any other tissue when injured, but because it is