Frostbite!

Lindee Abe, APRN

Every November when the temperature starts dropping in the Midwest, I wonder why I live in an area that is so cold. There are people love the cold, but I am not one of them. Every extreme of temperature has its associated health risks, especially cold weather. The winter brings myocardial infarctions with the first snow, carbon monoxide poisoning, and hypothermia. It also brings frostbite.

The focus of this post will be frostbite and trench foot. If you work in an urgent care or emergency department in an area that has temperatures below freezing, then you will likely encounter these diagnoses.

Last year I was watching “A Christmas Story” with my family. Just like every year, as predicted, Fink licked the flag pole and his tongue got stuck. This led to the inevitable discussion of if that could really happen. The answer is yes! Your tongue cannot produce heat fast enough to offset the conduction of below freezing temps from the metal before the saliva freezes, thus causing your tongue to stick to metal pole. This. can also happen with animals as well.

Cold Weather

If we start thinking about the diagnosis of frostbite, we should be familiar with what the conditions necessary for frostbite in order to know when it is an appropriate differential diagnosis. Similar to the temperatures in the summer, there are also several factors beyond actual temperature that contribute to the conditions necessary to develop frostbite. Wind, just like during the summer, will cool a patient down. During the summer, this is a good thing to prevent heat injury. However, in the winter it increases the risk of cold weather injury. The National Weather Service issues a wind chill advisory when the weather become risky to the public. A wind chill warning is announced if weather conditions become life-threatening. The National Weather Service also has a convenient chart that shows the risk of frostbite based on outdoor temperature, wind chill, and length of exposure.

Frostbite is freezing of the skin and soft tissue, like a burn. There are four stages of frostbite, depicted below. There are several milder forms of frostbite that include chilblains, frostnip, and trench foot. Frostnip is the paresthesia that first accompanies exposure to the cold weather, like a warning sign that frostbite may occur. Chilblains occurs commonly on the face with exposure to wind and cold and results in red, swollen skin. Chilblains occur when temperature is above freezing, but involves moisture. Trench foot was a common condition in WWI and occurs as the result of submersion in cold, damp conditions.

Prompt diagnosis and treatment of frostbite are important for decreasing the severity of the frostbite and long-term sequelae. There are two main points of treatment: rewarming and pain control. The rewarming process is painful and the patient should have adequate analgesia.

Rewarming

Frostbite injuries often will require consultation with a burn center. With hypothermia and frostbite, dehydration should be considered and managed as part of the treatment protocol for frostbite.

There are several important points regarding the rewarming. Prior to starting rewarming, remove jewelry, clothing, and anything else that may restrict the area. Rewarming will cause the tissue to swell and constriction from clothing or jewelry can than affect blood flow to that area. Rewarming should be accomplished with moist (not dry) heat. Dry heat can cause thermal injury. It is also important not to rub the affected area in an attempt to rewarm.

One method for distal extremities is a warm water soak. One strategy is filling a bowl, trash can or sink with warm water between 100-105 degrees Fahrenheit. Essentially, if you touch the water and it is warm but not so warm that you feel like it is burning you or you have to remove your hand from the water, then the temperature is appropriate. Quick rewarming helps to save tissue and should done away from cold environments. Re-exposing warmed tissue to the cold can also lead to more damage. Rewarming is necessary for saving the tissue, but also causes damage to the cells.

The picture that comes to mind with cold weather is putting hands in front of an outdoor fire to warm them up…..which is exactly the opposite of what should be done if there is concern for frostbite and repeat exposure to below freezing conditions.

Thrombolytics

Thrombolytics are a significant advance in the treatment of frostbite in recent years. The cellular death caused by the freezing of tissue starts the coagulation pathway and the combination of vasodilation and vasoconstriction in the surrounding blood supply leads to thrombus formation. The thrombolytic will help to lyse the clots and restore circulation to the extremity. This can result in potentially saving the extremity. Previously, surgery would be delayed for months. It was thought this prevented the removal of too much tissue from the affected area. Burn centers can use thrombolytics if the injury is found within the first 24 hours. This intervention can also restore circulation to the extremity.

There are several other points worth noting regarding treatment. First, note that there are many similarities in treatment between thermal burns and frostbite. The general rule of thumb is to debride clear blisters while leaving hemorrhagic blisters intact. Blisters can develop anywhere between 12-48 hours after rewarming, depending on the depth of the injury. Tetanus immunization should be given, if applicable. Aloe vera can be used for burns, including frostbite. It has excellent anti-inflammatory properties. Hospitalization should be considered for patients with extensive frostbite. This allows for continued monitoring and rewarming.

Other Options

Consider splinting the extremity to avoid increased movement and further damage to tissue. Antibiotic treatment should be considered. This is especially true if there are open blisters. Frostbite can lead to amputation, chronic pain, and decreased sensation. It is important to treat this condition with the available resources to ensure the best outcome for these patients. This also is a good time to look up the nearest burn center phone number and save to your phone if you don’t already have it. With the advances in telehealth, many burn centers can also utilize video or pictures to help get a better picture of the extent of injury and provide better advice regarding the treatment plan.

One last note: Make sure to let your family and friends know that Flick’s tongue was stuck to flag pole because of thermoconduction. It can happen in real life! It is very painful to rip a tongue off a metal pole and I would not recommend that anyone try to test this to see if it really can happen. If they do, warm water will help to remove their tongue.

References

Limmer, D., O’Keefe, M., Grant, H., Murray, B., Bergeron, D., Dickinson, E. (2014).
Emergency Care (11th edition). Retrieved from https://www.pearson.com/content/dam/one-dotcom/one-dot-com/us/en/higher-ed/en/products-services/limmer-13einfo/pdf/EC13Chapter31.pdf.

Mayo Clinic. (2021). Frostbite. Retrieved from https://www.mayoclinic.org/diseasesconditions/frostbite/diagnosis-treatment/drc-20372661.

Pain, R., Turner, E., Kloda, D., Falank, C., Chung, B., Carter, D. (2020). Protocoled
thrombolytic therapy for frostbite improves phalangeal salvage rates. Retrieved from
https://academic.oup.com/burnstrauma/article/doi/10.1093/burnst/tkaa008/5818512.
Stoppler, M. (2021). Frostbite. Retrieved from
https://www.emedicinehealth.com/frostbite/article_em.htm#what_are_the_stages_of_frostbite.

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