7 Cold injuries

Question 1

Causes of Frostnip & Frostbite

Answer 1

Low air temperature
• Windchill
• Exposed skin
• Moisture on skin & in clothing
• Poor insulation
• Direct skin contact with supercooled metal or liquid
• Reduced blood circulation
• Tight clothing or shoes
• Dehydration
• Localised pressure

Question 2

Frostnip:

Answer 2

• Only outer layer of skin
• like a 1st degree burn
• Rewarm instantly, no long term damage

Question 3

Superficial Frostbite:

Answer 3

• Some underlying skin tissue frozen
• White or grey, hard on surface, soft below, blisters.
• Rapid rewarming required

Question 4

Severe Frostbite:

Answer 4

• Crystalisation of fluids in skin, tissue death
• Pale, hard, numb
• Extreme pain, swelling and blisters
• Take to A&E without thawing

Question 5

Non-Freezing cold injuries:

Answer 5

• Trench/Immersion Foot
• Chilblain
• Pernio

Question 6

Trench/Immersion Foot:

Answer 6

• Prelonged exposure to 0-20(C)
• Reduced CIVD response
• Damage caused by prolonged intense vasoconstriction
• Should be rewarmed slowly

Question 7

Phases of Non-Freezing Cold Injury

Answer 7

Phase 1: During cold exposure:
• Cold, pale, numb

Phase 2: Following cold exposure / rewarming:
• Swollen, mottled pale blue, numb

Phase 3: Hyperaemia
• Red, hot, flushed, intense pain, swelling, blistering &
ulceration

Phase 4: Following hyperaemia
• Cold sensitivity, pain, loss of sensation, hyperhydrosis

Question 8

Treatment of Non-Freezing Cold Injury

Answer 8

-Rewarm slowly
-Rewarming of injured tissues increases metabolic demand above the supply capability
of injured blood vessels
-Alleviate pain in early stage

Question 9

Mechanisms of frostbite:

Answer 9

Local vasoconstriction -> Reduced blood flow -> Clot

Freezing of tissue (ice crystals) -> cell damage and dehydration

Question 10

Mechanisms of Non-Freezing Cold Injury

Answer 10

Local vasoconstriction -> Reduced blood flow -> Clot

Local nerve cooling -> Local nerve damage