**2. Overview of mechanistic considerations**

Burn management begins with a complete history and physical examination, known as the "burn patient evaluation" (BPE), which is intended to quantify and classify the thermal injury [7, 8]. Burns are typically described and classified by etiologic cause, extent of body surface area involved, and depth [9–11]. There are three broad categories of etiologies associated with burn injuries—thermal, chemical, and electrical [12–14]. Thermal mechanisms can be further broken down into flame burns, scald burns, contact burns, steam burns, or flash burns [15, 16]. This chapter focuses primarily on thermal injuries, although many of the concepts discussed herein also apply to other burn types.

The understanding of mechanistic considerations and associated tissue injury patterns is of critical importance when evaluating and treating burn victims [17, 18]. For example, thermal injury causes coagulative necrosis of the affected tissue, and the depth of injury is directly dependent on temperature and duration of exposure, which will vary widely across different types of thermal exposures and injured tissue characteristics [19, 20]. The extent of chemical-induced tissue injury will vary with substance type (acids, alkalis, or hydrocarbon-based organic solvents), concentration, and duration of exposure, but all require expedited clinical management and lavage (when appropriate) of affected areas [21–25]. Electrical injuries will vary in nature between high and low voltage exposure, and depending on exact circumstances, involved victims may be at an increased risk of presenting with cardiovascular and neurologic manifestations, as well as associated traumatic injuries from falling or violent muscle contractions [26–30].
