TY - CHAP M1 - Book, Section TI - Frostbite A1 - Nemer, Jacqueline A. A1 - Juarez, Marianne A. A2 - Papadakis, Maxine A. A2 - McPhee, Stephen J. A2 - Rabow, Michael W. A2 - McQuaid, Kenneth R. PY - 2023 T2 - Current Medical Diagnosis & Treatment 2023 AB - Frostbite is injury from tissue freezing and formation of ice crystals in the tissue. It can be divided into four tiers, or “degrees” of injury, which can be established by differences in imaging after rewarming. Alternatively, a two-tier classification may be used in the field after rewarming and before imaging. First-degree frostbite results in numbness and erythema; injured areas may show mild epidermal sloughing without gross tissue infarction. Second-degree injuries exhibit superficial skin vesiculation with clear or milky fluid filled blisters surrounded by erythema and edema. Third-degree frostbite results in deeper hemorrhagic blisters, extending beneath the dermal vascular plexus. Fourth-degree injuries extend completely through the dermis with necrosis extending into muscle and bone. The two-tier classification (similar to thermal burns) includes superficial (first- and second-degree injuries) with no or minimal anticipated tissue loss; and deep (third- and fourth-degree injuries) with anticipated tissue loss. Most tissue destruction follows reperfusion of the frozen tissues, with damaged endothelial cells and progressive microvascular thrombosis resulting in further tissue damage. In mild cases, only the skin and subcutaneous tissues are involved. Symptoms include numbness, prickling, itching, and pallor (eFigure 37–1). With increasing severity, deeper structures become involved; the skin appears white or yellow, loses elasticity, and becomes immobile. Edema, hemorrhagic blisters, necrosis, gangrene, paresthesias, and stiffness may occur (eFigure 37–2). SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/29 UR - accessmedicine.mhmedical.com/content.aspx?aid=1193138301 ER -