disodium, and zoledronic acid, which are available in intravenous forms. In burned children, acute intravenous pamidronate administration has been shown to help preserve bone mass, achieving a sustained therapeutic effect on bone [55]. An alternative treatment of the latter in burns includes anabolic agents such as oxandrolone [56]. The bisphosphonates have been advocated in the prevention of heterotrophic ossiÞcation, a complication that occurs in 1.2 % of burn patients.

6.3.8Bone Demineralization and Osteoporosis

Due to the substantial alterations of calcium and phosphorus metabolism, bone formation is reduced both in adults and children when burns exceed 40 % TBSA. Bone mineral density is signiÞcantly lower in burned children compared with the same age normal children. Girls have improved bone mineral content and percent fat compared with boys [6, 57, 58]. The consequences are increased risk of fractures, decreased growth velocity, and stunting. The bone is affected by various means: alteration of mineral metabolism, elevated cytokine and corticosteroid levels, decreased growth hormone (GH), nutritional deÞciencies, and intraoperative immobilization. Cytokines contribute to the alterations, particularly interleukin-1beta and interleukin-6, both of which are greatly increased in burns and stimulate osteoblastmediated bone resorption. The increased cortisol production in thermal injury leads to decreased bone formation, and the low GH levels fail to promote bone formation [59], further exacerbating the situation. Various studies suggest that immobilization plays a signiÞcant role in the pathogenesis of burn-associated bone disease. Alterations of magnesium and calcium homeostasis constitute another cause. Hypocalcemia and hypomagnesemia are constant Þndings, and ionized calcium levels remain low for weeks. The alterations are partly explained by large exudative magnesium and phosphorus losses. A close monitoring of ionized calcium, magnesium, and inorganic phosphate levels is mandatory, since burn patients usually require substantial supplementation by intravenous or enteral routes.

6.3.9Coagulation and Thrombosis Prophylaxis

The coagulation and hematologic system is profoundly affected by a burn, and the associated changes vary from depletion to overproduction. These acute phase responses are normal for a burn injury and usually require no major or only minor intervention. Hematological alterations observed after burns are complex and can last for several months and can be summarized as follows:

¥During the early phase after burns, Þbrin split products increase.

¥Dilution and consumption explain the early low PT values.

¥The coagulation cascade is activated.

¥Fibrin, factors V, and VIII increase as part of acute phase response.

¥Antithrombin deÞciency is frequent.

¥Thrombocytosis develops when wounds are closing.