Medical Minute: Frostbite

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February 12, 2015 by dailybolusoflr

By Marrissa Baker, MD
Frostnip is a superficial non-freezing cold injury associated with intense vasoconstriction on exposed skin and ice crystals may form on the surface of the skin. No long-term damage occurs.
Frostbite occurs when there is some freezing of the tissue and may be classified based on the extent of damage
Frostbite Treatment (Wilderness Medical Society practice guidelines):
  • Protect the frozen body part from further damage
  • Immersion of frozen body part in 37-39ºC water bath until the area becomes red/purple and is soft and pliable to the touch followed by air drying or gentle blotting (do not rewarm if there is a possibility of refreezing as refreezing thawed tissue will cause further damage). If rapid rewarming is not possible, spontaneous or slow thawing should be allowed
  • Pain control with NSAIDs or opiate analgesics PRN
  • Non-hemorrhagic bullae/blisters may be aspirated but should not be debrided. Hemorrhagic bullae should not be aspirated or debrided
  • Topical aloe vera may improve frostbite outcomes (reduces prostaglandin and thromboxane formation) and has low risk
  • May apply loose bulky dry dressings for protection
  • The thawed body part should not be used directly after if avoidable 
  • Elevate the extremity
  • Keep patient hydrated to assist with perfusion
  • Low molecular weight dextran can be given (decreases blood viscosity and prevents red blood cell aggregation and microthombi formation)
  • Apply supplemental oxygen especially if hypoxic or at high altitude
  • Antibiotics if there is evidence of significant trauma or signs/symptoms of infection
  • Surgical consultation if signs/symptoms of sepsis attributed to frostbite infection
  • Tetanus prophylaxis

Advanced Treatment:
  • For deep frostbite injury with potential significant morbidity consider angiography and IV or intra-arterial tPA within 24 hours of thawing to reduce microvascular thrombosis taking into consideration the risk/benefit analysis. Heparin may be used as an adjunct in certain protocols
  • Imaging such as MRA or bone scan can be used at an early stage if there is delayed presentation (greater than 24 hours) to predict the likely levels of tissue viability for amputation
  • Vasodilators (nitroglycerin, nifedipine, iloprost, reserpine, pentoxifylline) have potential to improve outcomes but data is limited and many are not available for use in the United States
  • Fasciotomy for compartment syndrome in the setting of reperfusion injury

Disposition is determined on a case by case basis depending on severity of injury, other injuries, co-morbidities, and treatments given
Long-term management includes hydrotherapy, surgical debridement/amputation after definitive demarcation, and possibly hyperbaric oxygen therapy and sympathectomy
Reference:
McIntosh et al. Wilderness Medical Society practice guidelines for the prevention and treatment of frostbite. Wilderness Environ Med. 2011 Jun;22(2):156-66. doi: 10.1016/j.wem.2011.03.003.

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