Regarding Caisson’s disease which
statement among the following is
CORRECT?
a) Lung damage is caused by air embolism
b) Pain in the joints is due to nitrogen bubbles
c) Tremors are seen due to nitrogen narcosis
d) High pressure Nervous syndrome can be prevented by using
mixtures of Oxygen & Helium
Correct Answer - B
Ans. is. B. ain in the joints is due to nitrogen bubbles
[REF: Ganong 22ed chapter
37, http://en.wikipedia.org/wiki/Decompression_sickness]
Decompression Sickness:
As a diver breathing 80% N2 ascends from a dive, the elevated
alveolar PN2 falls. N2 diffuses from the tissues into the lungs along
the partial pressure gradient. If the return to atmospheric pressure
(decompression) is gradual, no harmful effects are observed; but if
the ascent is rapid, N2 escapes from solution. Bubbles form in the
tissues and blood, causing the symptoms of decompression
sickness (the bends, caisson disease). Bubbles in the tissues cause
severe pains, particularly around joints, and neurologic symptoms
that include paresthesias and itching
Lung damage causes air embolism and not vice versa. The problem
of nitrogen narcosis can be avoided by breathing mixtures of 02 and
helium, and deeper dives can be made. However, the high-pressure
nervous syndrome (HPNS) develops during deep dives with such
mixtures. Tremors are symptoms of high pressure Nervous
syndrome
Signs and symptoms of decompression sickness
DCS type Bubble
location
Signs & symptoms (clinical
manifestations)
MusculoskeletalMostly large
joints
Localized deep pain, ranging from
mild to excruciating. Sometimes
(elbows,
shoulders, hip,
wrists, knees,
ankles)
a dull ache, but rarely a sharp pain,
Active and passive motion of
the joint aggravates 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.
Cutaneous Skin Etching, 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, Swelling
of the skin, accompanied by
tiny scar-like skin depressions
(pitting edema)
Neurologic Brain Altered sensation, tingling or
numbness paresthesias, increased
sensitivity hyperesthesia, Confusion
or memory loss (amnesia),
Visual abnormalities, Unexplained
mood or behaviour changes,
Seizures, unconsciousness
Neurologic Spinal cord Ascending weakness or paralysis in
the legs, Girdling abdominal or
chest pain, Urinary incontinence and
faecal incontinence
Constitutional Whole body Headache, Unexplained fatigue,
Generalised malaise, poorly
localised aches
AudiovestibularInner ear Loss of balance, Dizziness, vertigo,
nausea, vomiting, Hearing loss
Pulmonary Lungs Dry persistent cough, Burning chest
pain under the sternum,
aggravated by breathing, Shortness
of breath