Chicago midwinter – a user’s guide for preventing frostbite

(Robert Kozloff/The University of Chicago)

(Robert Kozloff/The University of Chicago)

The forecast for the next few days may remind people of last year’s Polar Vortex. The high temperatures for the week, according to the National Weather Service, should top out at around 14 degrees Fahrenheit, with nighttime lows well below zero. There will be strong winds and fresh snow. This makes some people think about cross-country skiing. More often, they think about hot chocolate. In the University of Chicago Medicine’s burn unit, they will be fretting about frostbite.

Last winter, between November 2013 and March 2014, the number of people admitted to the UCM burn unit for frostbite injuries was more than five times that seen during the same period in each of the previous seven years. In a typical winter, there are only a few patients who require hospitalization. During that period in 2013-14 there were 53. One quarter had frostnip, the early stages of frostbite, which can usually be treated outside the hospital. About half of them had superficial frostbite—a partial thickness injury which can require hospital care. Ten patients had deep, or full-thickness, frostbite. One of them also had significant hypothermia.

Frostnip can cause fluid-filled blisters. Superficial frostbite results in swelling, redness, loss of sensation, and white plaques on the skin. In the most extreme cases, full-thickness freezing damages muscles, blood vessels and even bone, resulting in tissue death and reconstructive surgery.

FB blister 1

Blistering from frostbite (click to enlarge–warning: graphic)

Most people, especially those who have been to a late-season Bears game, have experienced the discomfort of really cold fingers and toes. If the skin freezes, it hurts even more. But the real ache, a throbbing, stinging or burning pain, often comes when it thaws. That’s when the body recognizes how much damage has been done. Body parts most susceptible to frostbite—fingers and toes, exposed skin on the face, the ears, even the corneas of the eyes—tend to be tissues with the most nerve endings.

In the winter of 2013-14, most of the cold-weather injuries involved fingers or toes. Thirty-nine of the frostbite patients had a total of 337 damaged digits. About one out of five patients had at least one finger or toe surgically removed. Four more had larger tissues blocks removed or reconstructed, a process that requires multiple operations and about two weeks, on average, in the hospital.

There is, especially on the South Side of Chicago, a sad social component to frostbite injuries. Patients in an inner-city setting tend to “present in a delayed fashion,” the researchers report. Often, they have sustained repeated cold injuries, further complicated by psychological issues or intoxication. Three of the 10 patients with deep frostbite were homeless. Six had profound psychiatric issues.


Swelling from frostbite (click to enlarge–warning: graphic)

“It’s a shame whenever anyone gets a frostbite injury,” said Lawrence Gottlieb, MD, professor of surgery at the University of Chicago and director of the Burn and Complex Wound Center. “People need to be aware of it and take precautions when the temperature drops, like it has this week. Be especially cautious when temps fall below zero, especially when there is a strong wind. Obviously, wear warm clothes. If you are driving a long way, especially at night, make sure you have enough extra clothes to cover up effectively if you get stuck somewhere. And don’t get stuck. Put enough gas in the car.”

Pointers for people who go out in the cold:

  • If the temperature is below zero you could sustain a cold injury in less than 15 minutes.
  • Mittens are warmer than gloves.
  • Insulate the affected body part to prevent additional heat loss and damage.
  • Immobilize and protect the frostbitten tissues from further injury.
  • Prevent thaw-refreeze cycles. Do not begin rewarming until there is no risk of further exposure.
  • Once in the hospital, physicians recommend rapid rewarming in a water bath at 104°-107.6°F (40°- 42°C) for 15-30 minutes until thawing is complete.
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