Hypothermia & Paradoxical Undressing
Recently in the news, there was a tragic event where a family got caught out in deep snow while driving through the mountains. Eventually, the father decided to leave his family in their car and go for help on foot. Unfortunately, through his valient effort, he didn’t survive that cold, harsh winter environment, and died of hypothermia.
One of the discussions in the news was that even though he succumbed to the cold and hypothermia, at some point he had taken off some of his clothes. This is a phenomenom associated with hypothermia known as paradoxical undressing.
Pathophysiology:
The supposition as to the cause of paradoxical undressing is that the primary defense against the cold and hypothermia is vasoconstriction of the peripheral circulation. This shunts the blood into the warm core and the skin now becomes a more effective layer of insulation. The problem is that vasoconstriction of the smooth muscles in the vasculature requires glucose and energy consumption. Vasodilation, on the other hand, is a passive process that simply requires the smooth muscles that make up the blood vessels to relax. Over time, the vasoconstricted vessels begin to run out of energy (glucose) because of the poor circulation, and they fatigue and relax, thus vasodilating. This now allows the warm core-blood to re-perfuse the skin, causing a sensation of warmth. This results in the hypothermia victim feeling warm, so, they now begin to shed layers, thus the paradoxical undressing. Between the peripheral vasodilation and the loss of layers of protective clothing, their core temperature now begins to plummet and this hastens death from hypothermia.
I spoke with Dr. Murray Hamlet about parodoxical undressing and hypothermia and his experience and expertise with this phenomenom is the same as ours, in that we do not know of any cases where a hypothermia victim that underwent paradoxical undressing survived.
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