a. Definition/Characteristics. Both trench foot and immersion foot result from
prolonged exposure of the feet to wet cold. Trench foot results from exposing the foot
to wet conditions in cold weather (50 to 32F) for an extended period of time, usually
over 12 hours. Immersion foot results from the foot being immersed in water--with or
without socks and/or boots--for an extended period of time, the water temperature being
50F or below. Both cold injuries are local, nonfreezing injuries manifested by vascular
and superficial tissue changes. There are two classification stages: ischemic and
hyperemia. In the ischemic stage, there is tissue anemia due to obstruction of the
inflow of arterial blood. In the hyperemia stage, there is an excess of blood in a body
(a) Feeling. The person experiences coldness and wetness, often
from the waist down. There is numbness and loss of sensation in the affected part.
The feet are stiff and the person has a wooden feeling in the feet. Walking is difficult
(b) Color/appearance. The skin of the affected part is mottled with
cyanotic (blue) splotches, and there is swelling.
(c) Examination. When the area of injury is examined by touch, there
is no resilience and no pulse.
(a) Feeling. The injured area is hot, and there is constant burning pain.
(b) Color/appearance. The skin of the area is red and swollen, and
blisters and blebs commonly occur.
Examination. When touched, the area feels woody and there is a
(d) There is massive edema (fluid in the cells) and extravasation of
blood (diffusing through the surrounding tissues).
(e) Gangrene, the death of tissue caused by lack of blood supply, may