Which condition involves freezing of tissue with potential permanent damage?

• A. Frostnip
• B. Frostbite
• C. Trench foot
• D. Hypothermia

Answer: (B)

Freezing of tissue with potential permanent damage occurs when tissue is exposed to freezing temperatures long enough for ice crystals to form inside cells and the spaces between them. This causes cellular injury and death, and the depth of freezing determines how much tissue damage may be permanent. Frostbite can affect just the surface (frostnip), which is usually reversible with warming, but when freezing penetrates deeper, permanent tissue damage can occur. This is different from frostnip, which is minor freezing without real tissue freezing; trench foot, caused by prolonged cold and moisture, leads to tissue injury from poor circulation rather than actual freezing of tissue; and hypothermia involves overall cooling of the body, not freezing of specific tissues.