Frostbite | Spoon Feed Version – In a Heat Wave :)

July 29, 2022

Written by Aaron Lacy

Spoon Feed
The incidence of frostbite is shifting from exploration to urban environments and requires prompt recognition and often presents with other disease processes. Standard treatment is supportive and conservative, but new therapies including direct and systemic thrombolysis, and anticoagulation may be the future.

Why does this matter?
In the past, most frostbite cases were limited to explorers and soldiers. However, epidemiology is shifting, and the disease is becoming one of urban environments. Most cases now occur in settings of social disadvantage, disability, unstable housing, and substance use disorder – meaning an ED near you. These injuries are expensive to manage and can be debilitating, so early recognition and correct management are essential.

What do you get when you cross a snowman and a vampire? Well, frostbite of course

Pathophysiology of frostbite

• Cold injury is a combination of direct cellular damage and cellular ischemia.
• Direct cellular damage is caused by ice-crystal formation and resulting injury to the cell membrane, leading to a host of local metabolic derangements.
• Cellular ischemia is a result of vasospasm and disruption of the endothelium, leading to thrombosis and inflammatory effects preventing reperfusion.

Prevention and pre-hospital care of frostbite

• Recognition and prevention are the best treatments for frostbite.
• Early recognition of systemic hypothermia (motor and cognitive impairment) can go unrecognized and develop into local tissue freezing and damage.
• Treatment with supportive management and active external rewarming should begin as soon as possible – but only if there is no risk of refreezing prior to definitive management – as freeze-thaw-refreeze injury is worse than prolonged freezing injury.

Standard Supportive Treatment for frostbite

• Actively and externally warm frozen body parts by placing in water or bathe with a warm washcloth with water temperature of 37-39°C for 20-30 minutes until thawed.
• Elevate the involved body part and keep it warm.
• Administer analgesia and perform conservative blister (tense blisters) drainage for comfort.
• Consider prophylactic LMWH and NSAIDs.

Promising, but not yet standard of care, options for treating frostbite

• Anticoagulation
  • Practices and duration of therapy vary widely.
  • Consider heparin after thrombolysis and prophylactic low-molecular-weight heparin in those who did not undergo thrombolysis.

• Iloprost
  • This synthetic prostacyclin analogue dilates small-vessel beds in the pulmonary and systemic circulation and inhibits platelet aggregation.
  • One trial showed that a group who received Iloprost had less tissue loss and digital amputation.
  • It’s not available in the United States at the present.

• Thrombolysis
  • t-PA for frostbite began in some programs in the early 2000s, with results showing that early thrombolysis reduced amputation of frozen hands and feet that failed to perfuse after rewarming.
  • A systematic review from 2019 showed all quality of evidence and data for thrombolysis in frostbite to be low.
  • Remember – thrombolysis cannot salvage tissue that is beyond salvaging (dead) and has multiple serious potential side effects.

• Direct angiography and directed thrombolysis
  • Data from controlled trials are lacking, but this makes more sense than systemic thrombolysis to me.
  • Vessels are dilated with intraarterial administration of nitroglycerin, and angiography is performed to determine if initiating of intra-arterial thrombolysis with t-PA should occur.

The big picture of modern frostbite

This were specifics on treating local tissue destruction from frostbite; however, it’s time to re-center. Unless you are an Everest expedition doctor, frostbite is becoming an urban disease process secondary to trauma, substance abuse, psychosis, and social determinants of health. When a patient presents with signs of frostbite, make sure to adequately treat comorbid overdose, psychosis, or traumatic injury. Conversely, after completing your primary and secondary survey and interventions in a patient brought in from the frigid streets, make sure to do a thorough tertiary exam looking for signs of freezing injury.

Source
Diagnosis and Treatment of Frostbite. NEJM. 2022;386(26):2213-2220. Doi:10.1056/NEJMra1800868