The next morning the patient complains his feet are worse–more painful–and he is unable to walk. The patient’s feet are red, warm, and swollen with good capillary refill. The white patch on his right big toe is gone. There are no blisters or other soft tissue wounds or rash. The patient can feel light touch on the ends of all the toes and wiggle his toes. He denies itching, numbness, or pins and needles sensations, but says his feet hurt worse. He is only able to hobble around camp on his heels and he cannot wear his shoes.
Assessment (day 2)
Pt has a possible non-freezing cold injury
Plan (day 2)
- We will continue to keep the feet elevated and warm and arrange for support to carry this patient from the field.
- We will again carefully inspect everyone’s feet to check for local cold injury and dry socks, boots, and clothing.
Comments
The progression from pins and needles to numbness, to pain, to inability to walk is an unwanted but expected sequence. After warming the cool tissue often becomes red and swollen and very painful (called the hyperemic phase), surprising people who thought their feet were just a bit cold.
We used to think sleeping with warm dry feet prevented injury, no matter how cold they were during the day. This is probably true in many cases, but we’ve seen immersion foot develop over a day and in a cold multi-hour river crossing, events which were likely the tipping point after several days of exposure--an afternoon of lapsed attention that undoes days of diligent prevention.
Footwear isn’t a panacea, although today’s plastic boots are a godsend compared to the leather we used to wear. You can get a non-freezing cold injury from sweat-dampened socks, neoprene socks, and other vapor barrier systems. It happens to novices and experts, in summer and winter, in the deserts and mountains, and even in the jungle. It’s a consequence of how cool and damp your extremities are, no matter what you wear on your feet.
The adage that “cold injuries are a leadership challenge long before they are a medical problem” is certainly true. Prevention starts by looking at your feet, and the feet of those you lead. Don’t assume. This injury surprises people.
The prevention toolbox is deep with advice: wool or synthetic socks; keeping the body warm; massaging the feet twice a day; sleeping with dry and warm feet; drying wet socks against your skin; warming feet during the day; keeping feet out of water or mud as much as possible; watching carefully and reacting promptly if you experience numbness or tingling; keeping footwear loose to allow for circulation.
I’ve tried vapor barrier, and anti-perspirants for my sweaty feet, both with mixed success. I’m partial to changing my socks in the middle of the day, which makes me look at my feet. They surprised me once years ago. I’m sure they can do it again. I don’t tolerate numb toes, and my threshold for dealing with cold toes is low. Changing my socks gives my students permission to do the same and shows that cold, damp socks is not a sign of toughness; rather, it’s a bad habit.