The clinical and histologic signs of invasive burn wound infection include which of the following?

A. Focal dark red or dark brown discoloration of the eschar.

C. Conversion of an area of partial-thickness burn to full-thickness necrosis.

D. The presence of micro-organisms in the unburned subcutaneous tissue in a burn wound biopsy specimen

DISCUSSION: It is essential to examine the entire burn wound at the time of the daily cleansing to identify invasive burn wound infection at the earliest possible time. The appearance of focal areas of dark red or dark brown discoloration are the most common changes indicative of burn wound infection, but similar changes may be caused by hemorrhage due to local trauma or maceration. Accelerated separation of the eschar is often produced by burn wound infections, but delayed separation of the eschar is indicative of effective control of the microbial population in the burn wound. Conversion of an area of partial-thickness burn to full-thickness necrosis is the most reliable clinical sign of invasive burn wound infection. Identification of such a change mandates histologic examination of a burn wound biopsy, which is the only reliable means of differentiating the colonization of nonviable tissue from the invasion of viable tissue. Identification of micro-organisms in the unburned viable tissue of a burn wound biopsy confirms the diagnosis of invasive burn wound infection. Microbial migration along the skin appendages, terminal nerve radicles, and thrombosed capillaries in the eschar and heavy growth of micro-organisms in the subeschar space are manifestations of the colonization of nonviable tissue and represent the mechanisms by which eschar separation occurs.