Hypothalamic-pituitary-adrenal axis response to sustained stress after major burn injury in children.

The hypothalamic-pituitary-adrenal (HPA) axis is responsible for stress response after injury, yet its function after severe burn injury in children is unclear. The purpose of this study was to define the effects of burn injury on the HPA axis and to evaluate the utility of total serum cortisol in measuring adrenal function in children with major burns in the 2 months after injury. Children ages 0 to 17 years who were admitted within 72 hours to our pediatric burn center with 20% TBSA or greater full-thickness burns were eligible for the study. Serum total cortisol, adrenocorticotropic hormone (ACTH), dehydroepiandrosterone, vasopressin, Pediatric Risk of Mortality (PRISM) score, serum albumin level, and electrolytes were obtained on admission and weekly for 8 weeks. An ACTH stimulation test (250 microg for children >2 years, 125 microg for children < or =2 years) was administered weekly at 8:00 am. Total serum cortisol was measured before and 60 minutes after the administration of ACTH. Twenty-five children with mean age 7.6 +/- 1.1 years and TBSA burn 41.8 +/- 3.8% were enrolled in the study. Baseline total serum cortisol was 12.4 +/- 0.7 microg/dl in the 8 weeks after injury and increased to 24.4 +/- 0.8 microg/dl after the administration of ACTH. Cortisol level did not correlate with PRISM score, albumin, vasopressin, ACTH, or mortality. Although the adrenal response to acute and chronic stress is intact after severe burn injury, the ACTH/adrenal feedback loop is disrupted. Random total serum cortisol measurements overestimate adrenal dysfunction; thus, ACTH stimulation testing should be used to assess adrenal function before the administration of exogenous steroids.

Body composition and water compartment measurements in boys with Duchenne muscular dystrophy.

OBJECTIVE: Duchenne muscular dystrophy (DMD) patients have a lower percentage of total body water and higher extracellular water to intracellular water (ECW/ICW) ratio compared with normal subjects. However, it is not known whether this is due to increased fat mass or a decreased amount of ICW in muscle cells in DMD patients. The purpose of this study was to (1) determine the effect of increased fat mass and decreased lean mass on the ECW to ICW ratio in DMD patients and to (2) determine the validity of multifrequency bioelectrical impedance analysis (MFBIA) in assessing body composition in DMD patients. DESIGN: This study has a quasi-experimental, comparative design using nonequivalent groups. A total of 46 boys ranging from 6 to 13 yrs of age participated in this study. There were 12 nonobese able-bodied controls, 19 obese able-bodied children (obese), and 15 boys with DMD. Body composition was measured by dual-energy x-ray absorptiometry (DEXA). Body composition and body water compartment analysis were assessed by MFBIA. All measurements obtained using MFBIA were compared with those obtained using DEXA for validation. RESULTS: Both MFBIA and DEXA measures were strongly correlated in control (r = 0.99), obese (r = 0.92), and DMD subjects (r = 0.95). However, lean tissue mass measured by DEXA in the DMD subjects was only slightly higher (19.2 +/- 1.1 vs. 18.2 +/- 1.2, P < 0.02) than as measured by MFBIA. Mean percentage of body fat measured by DEXA in the DMD subjects (30.4 +/- 3.1%) was significantly lower than as measured by MFBIA (38.7 +/- 2.2%). The mean percentage of body fat measured by DEXA in the control group (23.2 +/- 1.8%) was significantly (P < 0.001) lower than as measured by MFBIA (28.6 +/- 1.6%). The mean percentage of body fat measured by DEXA in obese able-bodied controls (40.8 +/- 0.9%) was not significantly different from that measured by MFBIA (40.4 +/- 1.5%). Compared with the obese and control subjects, DMD subjects showed reduced ICW and ECW, with an increased ECW/ICW ratio, as expected. However, the percentage of fat for the DMD group was not different from the obese group. CONCLUSIONS: DMD patients have elevated ECW/ICW ratios compared with obese subjects and nonobese controls. However, obese subjects and nonobese controls had similar ECW/ICW ratios, despite the increased fat tissue mass in obese subjects. This suggests that the elevated ECW/ICW ratios in DMD subjects are not due to increased fat mass but rather some other mechanism, likely impaired cellular homeostasis due to muscle membrane instability. Although MFBIA slightly underestimates lean tissue mass in boys with DMD, it has a potential role as an inexpensive and easy to use measurement tool to measure changes in muscle mass in the clinical setting.

Saturday-morning television: do sponsors promote high-risk behavior for burn injury?

Television has become an important tool for learning and socialization in children. Although television violence has been associated with adverse effects, data on depiction of fire and burn injury are lacking. We sought to determine whether Saturday-morning television programming, viewed primarily by children, depicts fire and burn injury as safe or without consequence, thus potentially increasing the incidence of burn injury in children. This was a prospective observational study. Saturday-morning children's television programs were videotaped from 7 AM to 11 AM for eight different television networks during a 6-month period. Tapes were scored for scenes depicting fire or smoke by independent observers. Recorded items included show category, scene type, gender target, context of fire, and outcome after exposure to flame. Fire events were documented during programs and their associated commercials. A total of 108 hours of children's programs, 16 hours per network, were recorded. Scenes depicting fire or smoke were identified 1960 times, with 39% of events occurring during the program itself and 61% in commercials. Fire was depicted as either safe or without consequence in 64% of incidents. Action adventure stories accounted for 56% of flame depictions. Overall, one incident involving flame and fire was portrayed for each 3 minutes of television programming. Saturday-morning television programming frequently depicts fire as safe, empowering, or exciting. The incidence of flame use in programming varies between stations but is most prevalent in action/adventure stories. Television commercials, although brief, provide the majority of the misinformation regarding fire. Medical professional societies should alert the public to this potential hazard and recommend responsible portrayal of fire in children's television programming.