Evaluation of a patient with an apparent freezing cold injury
Evaluation of a patient with an apparent freezing cold injury (1)
History
- obtain information on how and when the cold injury occurred
- focus on factors which affects the severity e.g. - likely temperature, wind chill, and duration of exposure
- additional information should focus on finding predisposing factors e.g. - patient’s premorbid state, particularly history of peripheral vascular disease and smoking status
Examination
- early features
- affected parts feel cold and possibly painful
- continued freezing produce a paraesthesia or numbness (or both)
- areas of blanching blending into areas of apparently uninjured skin
- late features
- white and waxy skin with distinct demarcation from uninjured tissues
- woody, insensate tissue
- progression to bruising and blister formation (usually on thawing)
Note
- full extent of the injury may not be visible initially for few days. Therefore close observation is required
In true freezing cold injury, clinical appearance of the tissue can be used to identify the degree of injury:
| mild frostbite injury | severe frostbite injury | ||
first degree | second degree | third degree | fourth degree | |
depth of tissue freezing | partial thickness skin freezing | full thickness skin freezing | freezing of the skin and subcutaneous tissue | freezing of the skin, subcutaneous tissue, muscle, tendon, and bone |
colour of tissues | erythematous or hyperaemic | erythematous | blue or black | initially deep red and mottled; eventually black and mummified |
blistering or necrosis | none | blisters containing clear fluid | haemorrhagic blisters and some tissue necrosis | profound necrosis |
oedema | minor | substantial | substantial | little or none |
Note - frostbite is a clinical diagnosis. Using additional laboratory testing may be helpful in determining the extent to which comorbid conditions may be contributing to tissue ischemia.
Technetium-99 (Tc-99) triple phase scanning and magnetic resonance angiography (MRA) may help to determine extent of amputation in the first few days after injury (2,3)
Reference:
- McIntosh SE, Freer L, Grissom CK, et al. Wilderness Medical Society clinical practice guidelines for the prevention and treatment of frostbite: 2024 update. Wilderness Environ Med. 2024 Jun;35(2):183-97.
- Cauchy E, Marsigny B, Allamel G, Verhellen R, Chetaille E. The value of technetium 99 scintigraphy in the prognosis of amputation in severe frostbite injuries of the extremities: A retrospective study of 92 severe frostbite injuries. J Hand Surg Am. 2000 Sep;25(5):969-78.
- Barker JR, Haws MJ, Brown RE, Kucan JO, Moore WD. Magnetic resonance imaging of severe frostbite injuries. Ann Plast Surg. 1997 Mar;38(3):275-9.
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