Frostbite

• • Frostbite involves freezing of tissues

  • Ice crystals form between cells and grow at expense of extracellular fluid

  • Cellular dehydration and ischemia due to vasoconstriction and increased viscosity are mechanisms of tissue injury

  • Caused by cold exposure; effects can be amplified by moisture or wind

Symptoms and Signs

• • Frostbitten parts are numb, painless, and white or waxy in appearance

  • Superficial frostbite is compressible with pressure (unfrozen deep tissues)

  • Deep frostbite is woody (frozen deep tissues)

• • Evaluate for endocarditis

  • Evaluate for secondary LV dysfunction

  • After rewarming, frostbitten area becomes mottled blue or purple and painful and tender

  • Blisters appear that may take weeks to heal

  • Affected part becomes edematous and painful

  • Must evaluate for other associated injuries as suggested by history

• • Nuclear medicine scans may be useful to delineate tissue viability

• • Frostbitten part should be rewarmed in a water bath at 40-42.2 °C for 20-30 min

  • Thawing should not be attempted until the victim can be kept permanently warm and at rest

  • After thawing, patient should be kept recumbent and with thawed part exposed to air

  • Blisters should be left intact

  • Skin gently debrided by immersion in whirlpool for 20 min twice daily

  • Vasodilating agents and sympathectomy are NOT helpful

Surgery

Indications

• • Constricting eschar

Contraindications

• • Expectant management is the rule

  • Tissue usually sloughs spontaneously

  • Amputation rarely indicated before 2 months

Prognosis

• • Excellent if appropriate treatment is provided

  • Recovered patients will have increased susceptibility to future frostbite

References