RESUMO
The objective of this study is to investigate the factors associated with serum phosphate concentrations in severely burned children and whether hypophosphatemia is associated with outcome. Seventy-eight children with a total body surface area of 24% (6.0-68.5) were retrospectively analyzed for serum phosphate concentrations during the first 10 days of stay in the intensive care unit (ICU). The method of generalized estimating equations was used to evaluate the effect of the exposure variables for serum phosphate concentrations during the study period. Outcome variables were the probability of ICU discharge at 30 days and time on mechanical ventilation. Potential explanatory variables for clinical outcome were hypophosphatemia (serum phosphate <3.8 mg/dL for children <2 years and <3.5 mg/dL for older children), age, sex, percent total body surface area burn, inhalation injury, and severe sepsis and/or septic shock. Competing-risk analysis was applied to calculate the probability of ICU discharge at 30 days, and death was assumed as the competing event. The rate of hypophosphatemia was 79.5%. Serum phosphate concentrations were associated with C-reactive protein (coefficient: -0.63; 95% confidence interval [CI]: -0.96 to -0.30; P = .001). Hypophosphatemia was independently associated with a 68% decrease in the probability of ICU discharge at 30 days (subhazard ratio: -0.32; 95% CI: 0.20, 0.53; P = .001) and an increase of 2.9 days in mechanical ventilation (coefficient: 2.91; 95% CI: 1.16, 4.66; P = .001). Serum phosphate concentrations in pediatric burn patients are associated with the magnitude of inflammatory response. Hypophosphatemia is associated with decreased probability of ICU discharge and increased time on mechanical ventilation.
Assuntos
Queimaduras/sangue , Queimaduras/complicações , Mortalidade Hospitalar , Hipofosfatemia/etiologia , Hipofosfatemia/terapia , Adolescente , Análise de Variância , Superfície Corporal , Brasil , Queimaduras/diagnóstico , Queimaduras/terapia , Criança , Pré-Escolar , Estado Terminal/terapia , Bases de Dados Factuais , Feminino , Humanos , Hipofosfatemia/mortalidade , Hipofosfatemia/fisiopatologia , Escala de Gravidade do Ferimento , Unidades de Terapia Intensiva Pediátrica , Estimativa de Kaplan-Meier , Tempo de Internação , Masculino , Monitorização Fisiológica/métodos , Análise Multivariada , Prognóstico , Respiração Artificial/métodos , Estudos Retrospectivos , Medição de Risco , Índice de Gravidade de Doença , Resultado do TratamentoRESUMO
A 60-year-old Caucasian woman with a 1-year history of pain at the ribs, spine, and pelvis consulted at our Institute in March 1999. She brought a bone densitometry performed using a Lunar DPX densitometer that showed bone mineral density (BMD) measurements in the osteoporotic range at both the lumbar spine and the femoral neck. As a child she had had bowed legs and had been treated with ultraviolet radiation. Results of the laboratory test performed at our institute showed normal total serum calcium, repeated low serum P levels, and a low renal phosphate threshold with elevated total and bone fraction of alkaline phosphatase with normal intact parathyroid hormone (PTH). A diagnosis of hypophosphatemic osteomalacia due to renal phosphate leak was made. She began treatment with neutral sodium phosphate at 1.5 g/day and calcitriol 0.5 microg/day. Her serum P levels normalized, and there was a progressive decrease in alkaline phosphatase levels. The densitometry showed a very rapid increase in BMD values with normalization at the lumbar spine after 10 months of treatment. This case shows the importance of bone densitometry in the follow-up of patients with suspected osteomalacia.
Assuntos
Densidade Óssea/efeitos dos fármacos , Hipofosfatemia/fisiopatologia , Osteomalacia/diagnóstico , Fosfatase Alcalina/sangue , Fosfatase Alcalina/efeitos dos fármacos , Cálcio/farmacologia , Colecalciferol/uso terapêutico , Feminino , Humanos , Hipofosfatemia/complicações , Hipofosfatemia/tratamento farmacológico , Pessoa de Meia-Idade , Osteomalacia/tratamento farmacológico , Osteomalacia/etiologia , Endopeptidase Neutra Reguladora de Fosfato PHEX , Fosfatos/uso terapêutico , Fósforo/sangue , Proteínas/genéticaRESUMO
BACKGROUND: Acyclovir (ACY) is a useful therapeutic agent for the systemic treatment of herpes virus infection. An increase in urinary phosphate excretion and polyuria has been described. The objective of this study was to analyze the exact mechanism of the urinary-concentrating dysfunction and the increase in phosphaturia associated with ACY. METHODS: We first analyzed 7 (adult and pediatric) non-AIDS cases of encephalitis receiving 15 mg/kg bw/d of intravenous ACY. Fractional phosphate and sodium excretion, urinary potassium volume, and plasma phosphate concentrations were analyzed. Additional studies in rats treated with intraperitoneal ACY (100 mg/kg bw) were also conducted. Animals were maintained in metabolic cages and 24-hour urine samples were collected to measure volume, osmolality, and sodium/potassium/phosphate excretion. Treated rats were also evaluated after 24 hours and 48 hours of water deprivation. Northern hybridization and semiquantitative immunoblotting were performed to evaluate (in both control and treated animals) expression of the cotransporters Na-Pi type IIa (Na-Pi-IIa) and Na-K-2Cl (NKCC2). Semiquantitative immunoblotting was carried out in the kidneys of ACY rats and control rats in order to analyze aquaporin 2 (AQP2) protein expression. RESULTS: Patients started on ACY developed polyuria and hyperphosphatemia after 48 hours. In rats, ACY-induced hyperphosphaturia and hypophosphatemia were accompanied by increased excretion of sodium, potassium, and magnesium, increased urine output, lower urinary osmolality, and a partial urinary concentrating defect. Concurrent downregulation of Na-Pi-IIa and NKCC2 expression was observed. There was also a decrease in medullar expression of the AQP2 collecting duct water channel. CONCLUSION: Downregulation of Na-Pi-IIa appears to play a crucial role in the downregulation of ACY-induced hyperphosphaturia. The accompanying polyuria and urinary-concentrating defect can in part be explained by the downregulation of NKCC2 and AQP2.
Assuntos
Aciclovir/efeitos adversos , Antivirais/efeitos adversos , Aquaporinas/metabolismo , Hipofosfatemia/metabolismo , Poliúria/metabolismo , Simportadores de Cloreto de Sódio-Potássio/metabolismo , Adulto , Animais , Aquaporina 2 , Aquaporinas/genética , Cálcio/sangue , Criança , Regulação para Baixo , Expressão Gênica/efeitos dos fármacos , Humanos , Hipofosfatemia/induzido quimicamente , Hipofosfatemia/fisiopatologia , Capacidade de Concentração Renal/efeitos dos fármacos , Túbulos Renais Proximais/metabolismo , Magnésio/sangue , Masculino , Concentração Osmolar , Fosfatos/sangue , Fosfatos/urina , Poliúria/induzido quimicamente , Poliúria/fisiopatologia , Potássio/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Sódio/metabolismo , Simportadores de Cloreto de Sódio-Potássio/genética , Membro 1 da Família 12 de Carreador de Soluto , Urina , Água/metabolismoRESUMO
Bajo el término de síndrome de realimentación se agrupan una serie de trastornos metabólicos como hipofosfatemia severa entre otros, observados en pacientes desnutridos sometidos a diferentes terapias de repleción nutricional, bien por vía parenteral o enteral. Se presentan dos casos con manifestaciones similares luego de iniciar la terapia de realimentación, uno parenteral y otro enteral, que mostraton cifras bajas de fósforo con trastornos de la conciencia y neuromusculares que cedieron con la suplementación de este anión. El propósito de la actual revisión es ampliar la definición del síndrome y clarificar los otros trastornos, además de la hipofosfatemia encontrados con la repleción nutricional, así como tipificar los diferentes pacientes en quienes es posible que aparezca esta complicación y por último hacer recomendaciones para su reconocimiento y más importante aún; para su prevención.