RESUMO
In hyperprostaglandin E syndrome (HPS) renal wasting of electrolytes and water is consistently associated with enhanced synthesis of prostaglandin E2. In contrast to Bartter or Gitelman syndrome (BS/GS), HPS is characterized by its severe prenatal manifestation, leading to fetal polyuria, development of polyhydramnios, and premature birth. This disorder mimics furosemide treatment with hypokalemic alkalosis, hypochloremia, isosthenuria, and impaired renal conservation of both calcium and magnesium. Therefore the thick ascending limb of the loop of Henle seems to be involved in HPS. To characterize the tubular defect we investigated the response to furosemide (2 mg/kg) in HPS (n = 8) and BS/GS (n = 3) 1 week after discontinuation of long-term indomethacin treatment. Sensitivity to furosemide was completely maintained in patients with BS/GS. The diuretic, saluretic, and hormonal responses were similar to those of a control group of healthy children (n = 13), indicating an intact function of the thick ascending limb of the loop of Henle in BS/GS. In contrast, patients with HPS had a marked resistance to this loop diuretic. Furosemide treatment increased urine output by 7.5 +/- 0.7 ml/kg per hour in healthy control subjects but only by 4.4 +/- 1.2 ml/kg per hour (p < 0.5) in children with HPS. In parallel, the latter also had a markedly impaired saluretic response (delta Cl(urine) 0.14 +/- 0.04 mmol/kg per hour vs 0.85 +/- 0.09 mmol/kg per hour, p < 0.001; delta Na(urine) 0.23 +/- 0.06 mmol/kg per hour vs 0.77 +/- 0.09 mmol/kg per hour, p < 0.001). Furosemide therapy further enhanced prostaglandin E2 excretion in patients with HPS (54 +/- 17 to 107 +/- 28 ng/hr per 1.73 m2, p < 0.05), whereas no significant effect was observed in healthy children (20 +/- 3 to 12 +/- 3 ng/hr per 1.73 m2). We conclude that a defect of electrolyte reabsorption in the thick ascending limb of the loop of Henle plays a major role in HPS.
Assuntos
Dinoprostona/biossíntese , Diuréticos , Furosemida , Alça do Néfron/fisiopatologia , Síndrome de Bartter/tratamento farmacológico , Síndrome de Bartter/fisiopatologia , Síndrome de Bartter/urina , Dinoprostona/urina , Humanos , Indometacina/uso terapêutico , Nefropatias/tratamento farmacológico , Nefropatias/fisiopatologia , Nefropatias/urina , Alça do Néfron/efeitos dos fármacos , Síndrome , Equilíbrio HidroeletrolíticoRESUMO
Se expone un caso de síndrome de Bartter en un lactante menor de dos meses de edad con antecedente prenatal de polihidramnios y parto pretérmino. Con historia de vómito, diarrea y estreñimiento ocasional, asociado con retardo pondoestatural. Este paciente presentó cuadro de bronconeumonía viral la cual evolucionó en forma tórpida con aumento del síndrome de dificultad respiratoria (SDR) y deterioro del estado general por lo cual hubo necesidad de trasladarlo a la unidad de cuidado intensivo de pediatría. Allí se corroboró la presencia de alcalosis metabólica hipokalémica e hipoclorémica con aumento de la excreción urinaria de K, Na y Cl y defecto en la habilidad de concentrar la orina. Aunado a esto se detectó hiperreninemia, poliuria y aldosterona elevada. La tensión arterial fue normal con un percentil menor de cinco para el peso y de 10 para la talla. Con base en todo lo anterior se pudo confirmar el diagnóstico de síndrome de Bartter
Assuntos
Humanos , Lactente , Masculino , Alcalose Respiratória/classificação , Alcalose Respiratória/diagnóstico , Alcalose Respiratória/tratamento farmacológico , Alcalose Respiratória/enfermagem , Alcalose Respiratória/fisiopatologia , Síndrome de Bartter/congênito , Síndrome de Bartter/diagnóstico , Síndrome de Bartter/tratamento farmacológico , Síndrome de Bartter/enfermagem , Síndrome de Bartter/fisiopatologia , Síndrome de Bartter/urinaRESUMO
1. Different results concerning distal NaCl reabsorption have been reported for patients with Bartter's syndrome in tests of renal diluting ability. We describe clearance studies performed on 3 patients with Bartter's syndrome using different routes for body fluid content expansion: water was given orally and 0.45% NaCl solution intravenously. The impact of fluid composition was evaluated in one patient who additionally underwent a "reverse test": i.e., intravenous 5% glucose in water and an oral load of 0.45% NaCl solution. 2. Urine flow per ml glomerular filtration rate (GFR) reached higher levels when the iv route was used (20.6 +/- 1.8 vs 11.8 +/- 5.7%, P < 0.05). Fractional excretion of Na+, Cl- and osmoles increased during NaCl infusion but not during the oral load. Also, distal delivery of solute increased and was greater than that observed in the oral test (21.9 +/- 5.5 vs 11.4 +/- 2.1%, P < 0.05). 3. In contrast, fractional distal chloride reabsorption in the iv test reached subnormal values which were lower than in the oral load test (65.0 +/- 11.2 vs 86.8 +/- 11.0%, P < 0.05). A positive correlation was observed between distal delivery and Cl- fractional excretion (r = 0.87; P < 0.005). In one patient, the 5% glucose infusion resulted in greater urine flow and distal delivery when compared to distilled water or 0.45% NaCl taken orally (28.1 vs 13.3 ml/min and 27.3 vs 12.8%, respectively). These values were as high as those observed during iv administration of hypotonic saline. 4. The iv route was always associated with lower rates of fractional distal chloride reabsorption (70.7 vs 89.1%) regardless of the solute composition and should be recommended when testing the renal diluting ability of patients suspected of Bartter's syndrome.