information about Frostbite

Frostbite occurs when the tissue in the extremities (hands, feet, nose ears etc) drops to below freezing (around -0.55C).  This results in ice crystals forming which in turn results and local tissue damage or death. 

To begin with the affected area becomes numb, has a waxy pale appearance and a woody feel. If recognised early enough, judicious rewarming will reverse the process- this is called frostnip.

If the situation continues to deteriorate, the injury becomes irreversible and is called frostbite. Frostbite can range from mild blistering (which should recover) to gangrene and loss of parts or all of finger(s) toe(s) or even limbs.

Prolonged exposures to sub-zero temperatures with inadequate thermal protection results is reduced blood flow, sludging of blood and subsequent cellular injury.

Frostbite is a potentially serious cold thermal injury of the extremities. 

Traditionally, management has been to re-warm and delay surgery for a couple of months. 

More recently, best management of the more severe injuries (Grade 2/3-4) is to consider in hospital thrombolysis/iloprost (Cauchy NEJM 2011), within 24 hours of the injury. This is potentially a limb saving intervention, but ‘time is tissue’ and delays to treatment significantly and adversely affect outcomes. 

Every year there are cases where there have been poor outcomes as a result of delayed access to treatment. There are cases where individuals have been flown by helicopter to a hospital that does not offer TPA/iloprost, despite the treatment being available a couple of miles down the road. .

Frostbite injuries can range in severity from minor and reversible (frostnip) to increasingly severe and irreversible. The field classification of frostbite divides the frostbite into either superficial (no or minimal anticipated tissue loss, corresponding to first- and second-degree injury) or deep (anticipated tissue loss corresponding to third- and fourth-degree injury).