RESUMEN
OBJECTIVE: The objective of this study was to test the hypothesis that hepatomegaly in burned children can be attenuated or reversed by blocking lipolysis and reducing free fatty acids delivered to the liver. SUMMARY BACKGROUND DATA: Accelerated lipolysis in severely burned children has been shown to play an important role in the accumulation of hepatic TGs. Severely burned children who survive 10 days or more after injury commonly have enlarged livers often twice or more normal size for their sex, age, and weight. METHODS: Ninety-eight children, 2 to 18 years of age, with burns covering more than 40% of their body surface and who received either propranolol (beta-adrenergic blockade) or placebo were studied. Liver weights were measured by ultrasonic scanning. Body composition changes were identified by dual-image x-ray absorptiometry and validated by whole-body potassium-40 scintillation counting. Discarded abdominal cutaneous adipose tissue was collected before and after propranolol or placebo for microarray analysis. RESULTS: In 80% of severely burned children studied not receiving propranolol, liver sizes increased by 100% or more while 86% of burned children receiving propranolol showed a decrease or no change in liver size over the same period of time after injury. Gene expression patterns of adipose tissue after propranolol treatment showed that all of the identified genes related to lipid metabolism were down-regulated. CONCLUSIONS: Data reported here support the hypothesis that beta-adrenergic blockade can reduce delivery of fatty acids to the liver and hepatic congestion commonly found in severely burned children by inhibiting lipolysis and reducing hepatic blood flow.
Asunto(s)
Antagonistas Adrenérgicos beta/uso terapéutico , Quemaduras/tratamiento farmacológico , Hepatomegalia/prevención & control , Propranolol/uso terapéutico , Quemaduras/complicaciones , Quemaduras/terapia , Niño , Nutrición Enteral , Femenino , Hepatomegalia/etiología , Humanos , Masculino , Trasplante de Piel , Procedimientos Quirúrgicos Operativos , Resultado del TratamientoRESUMEN
Hepatomegaly is a common postmortem observation in severely burned children, with the liver often tripling in size when compared with normal livers for age, weight, and sex. Lesions identified at autopsy include deposition of large and small fat droplets in the hepatocyte, congestion, centrilobular necrosis, and cholestasis. The present study was designed to identify the primary causes of hepatomegaly in severely burned children postmortem. For this purpose, 41 autopsies were reviewed and, when available, blood and tissue samples were studied. Histopathologic findings showed that large intrahepatocytic fat droplets within hepatocytes and cholestasis were important contributors to hepatomegaly. Liver density and wet/dry weight ratios significantly decreased with increasing liver size. Hepatocyte volume increased with increasing liver size (P < 0.001) as did total fat content (P < 0.001). The liver enzymes, alanine aminotransferase and aspartate aminotransferase, remained normal except within 5 to 10 days of injury and 5 to 10 days of death. Triglycerides made up 4% to 70% of the total fat, with the percentage of triglycerides increasing with the severity of hepatomegaly. Saturated fatty acids represented about 85% of the total fatty acids in normal-sized livers, whereas in the largest livers (400% of predicted), only 25% of the fatty acids were saturated. This study provides evidence that 85% to 90% of the hepatomegaly observed in severely burned children postmortem is associated with hepatocyte enlargement, which includes up to 19% intracellular fat. Increases in extracellular protein, intracellular glycogen, and fluid accumulation may make a minor contribution to postburn hepatomegaly.
Asunto(s)
Quemaduras/patología , Citoplasma/patología , Hepatocitos/patología , Hepatomegalia/patología , Hígado/patología , Factores de Edad , Alanina Transaminasa/metabolismo , Aspartato Aminotransferasas/metabolismo , Quemaduras/complicaciones , Quemaduras/enzimología , Niño , Preescolar , Citoplasma/enzimología , Femenino , Hepatocitos/enzimología , Hepatomegalia/enzimología , Hepatomegalia/etiología , Humanos , Hígado/enzimología , Masculino , Necrosis/enzimología , Necrosis/patología , Tamaño de los Órganos , Factores Sexuales , Índices de Gravedad del Trauma , Triglicéridos/metabolismoRESUMEN
Several studies have noted gender differences in adult mortality related to thermal injury, however, little is published on gender-related outcomes of burn patients 17 years of age or less. The aim of this study was to evaluate the relationships between mortality, gender, prepubertal and during puberty, ethnic origin, and age, with or without identified sepsis in severely burned children. Seven hundred forty-seven children admitted to our burn hospital from March 1985 to January 2005 with burns greater than 40% total body surface area were studied. Mortality associated with identified sepsis, gender, age, and ethnic origin were outcomes of interest. Two hundred sixty (35%) of the patients studied were girls and 487 (65%) were boys. No significant difference could be shown between girls and boys for the number of operations, time from burn to hospital admission, or the presence of identifiable inhalation injury. Nearly 60% of the male nonsurvivors and 48% of the female nonsurvivors in this study had identifiable sepsis at postmortem. The mortality rate was higher in infants and toddlers, age 0 to 2.9 years, compared with children and adolescents, age 3 to 17 years; however, there was no significant difference in rate of mortality between genders, prepuberty versus puberty, those with septic episodes, or ethnic origin. Burn mortality among infants and toddlers, children, and adolescents with greater than 40% total body surface area burns with or without identified sepsis could not be shown to be gender or ethnic origin dependent.
Asunto(s)
Quemaduras/epidemiología , Quemaduras/mortalidad , Adolescente , Población Negra , Niño , Preescolar , Estudios de Cohortes , Etnicidad , Femenino , Hispánicos o Latinos , Humanos , Lactante , Recién Nacido , Masculino , Factores Sexuales , Resultado del Tratamiento , Población BlancaRESUMEN
BACKGROUND: Pulmonary failure has emerged as one of the leading causes of mortality in burned children due, in part, to the success in reducing the incidence of sepsis, early surgery and fluid resuscitation, and new advances in nutritional support. To evaluate the effect of pulmonary injury, age, gender, race, and burn size on mortality, the records of 3179 burned children admitted to our burn center from 1985 to 2001 were reviewed. In this population, 1246 were admitted within 14 days of injury with burns greater than 20% of their total body surface area (TBSA). METHODS: Lethal burn areas (LAs) for a thermal injury only or burn plus inhalation injury were estimated from best fit probit curve within 95% confidence limits. Data analysis was by chi(2)-test, t-test, or Fisher's exact test where appropriate. RESULTS: The lethal burn area for a 10% mortality rate with and without concomitant inhalation injury was a 50 and 73% TBSA burn, respectively. Children up to the age of 3 with >/=20% TBSA burns had a higher rate of mortality (9.9%) compared to those 3-12 years of age (4.9%) and 13-18 years of age (4.2%). Children with 21-80% TBSA burns showed a significant difference in mortality (P<0.05) between those with burn plus inhalation injury (13.9%) and burn only (2.9%), while those with 81-100% TBSA burns showed no significant difference between burn only and burn plus inhalation injury. CONCLUSION: Inhalation injury remains one of the primary contributors to burn mortality. Children under the age of 3 years, however, are at a higher risk both with and without inhalation injury.