[Antenatal form of Bartter's syndrome].

Six cases of tubular disorder of antenatal onset responsible for biological manifestations characteristic of Bartter syndrome and severe hypercalciuria are reported. In all six cases, severe hydramnios occurred during pregnancy between the 26th and 28th week after the last menstrual period. All six patients were born prematurely; gestational age ranged from 20 to 35 weeks. Major polyuria with dehydration occurred immediately after birth. The amounts of water and sodium needed to compensate urinary losses ranged from 280 to 370 ml/kg/day and 25 to 43 mmol/kg/d, respectively, during the first two postnatal months. Decreased serum potassium levels and increased plasma levels of renin and aldosterone were seen in all six patients. Increased urinary excretion of calcium was evidenced during the first postnatal week in three cases. Urinary calcium excretion in the six patients ranged from 15 to 30 mg/kg/d. Nephrocalcinosis developed in all six patients and two patients developed urinary lithiasis. One patient died at one month of age from necrotizing enteropathy. The five remaining patients gradually developed severe growth failure with measurements between 4 and 5.5 SDs below the mean. These five patients had evidence of hyperparathyroidism including increased serum levels of parathyroid hormone (5/5), increased serum alkaline phosphatase activity (4/5), and roentgenographic bone changes (1/5). Ionized calcium assays performed in three of the five patients disclosed low values (range 1.25-1.47 mmol/l; mean = 1.35; normal values = 1.42-1.62), although total serum calcium levels were normal or high (range 2.16-2.98 mmol/l; mean 2.61; normal values = 2.45-2.65) probably as a result of chronic dehydration.(ABSTRACT TRUNCATED AT 250 WORDS)