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Frostbite:
The
term "frostbite" refers to actual
localized of body parts to variable depth
depending on the temperature, length of
exposure, amount of insulation and other factors.
Frostbite requires temperatures of freezing or
below. The most commonly involved body parts
are on an exposed position (face, ears, hands,
and feet). In addition, the body's tendency to
protect itself from cold by restricting
peripheral circulation predisposes to
frostbite of the extremities.
Localized
cold injury results from local freezing and
interference with circulation. Intra-cellular
and extra-cellular ice crystals appear and as
they grow in size cause cellular damage.
Superficial
frostbite involves only the outer layers of
the skin and causes burning or tingling
followed by numbness. Inspection shows a
grayish-white patch of skin, usually on the
face or extremities. The deeper tissues remain
soft and pliable. After thawing, the area
becomes red and sensitive, and slight edema
with a few small blebs may appear. A few days
later, the skin may peel.
Deep
frostbite, a much more serious injury, usually
occurs in the hands and feet. Inspection shows
a cold, waxy, pale, or cyanotic member, solid
and unyielding, which resembles a piece of
chicken just out of the freezer. After
thawing, blisters of various sizes usually
develop. A relatively favorable sign is the
occurrence of huge blisters filled with
pinkish fluid, extending close to the tips of
the affected digits. In more severe frostbite,
the blisters tend to be smaller and filled
with a darker fluid, the part remains numb and
cool, and the joints remain stiff. In the most
severe cases, the frozen area is completely
numb, cold, and bloodless, without blisters or
edema, and gangrene develops rapidly. The
amount of damage tends to be overestimated in
the early stages, and amputation should be
delayed if possible until clear demarcation
occurs.
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