453 SALT WASTING WITH POSTERIOR URETHRAL VALVES

Abstract

Clinical manifestations of posterior urethral valves (PUV) may vary widely. Biochemical abnormalities have not been emphasized. Seven male infants (mean age 6 weeks, range 9 days to 6 months), seen over a ten year period, presented with laboratory evidence of salt wasting suggesting adrenal insufficiency. Admission sodium, potassium, BUN, creatinine, serum pH, and urine pH and specific gravity were recorded. When available simultaneous urine and serum electrolytes were noted. In all cases PUV were confirmed by voiding cystourethrogram. The mean sodium on admission was 117 ± 11 mEq/L (range 95-127) while the mean potassium was 7.9 ± 1.3 mEq/L (range 6.5-9.6). The BUN and creatinine were 76 ± 42 mg/dl (range 27-136) and 3.7 mg/dl (range 2.2-5.8) respectively. The mean specific gravity of the urine was 1.007 ± .004 (range 1.005-1.017). In four patients simultaneous serum and urine electrolytes were determined. The mean serum sodium was 132 while the mean urine sodium was 9.25 mEq/Kg/L. All of the patients manifested an impaired ability to conserve water and sodium. In addition, an impaired ability to excrete acids into the urine resulted in acidosis and hyperkalemia. The sodium, potassium, water and acid imbalance is not due to aldosterone deficiency but reflects a glomerulus-tubular dysfunction.Infants presenting with hyponatremia and hyperkalemia who have a very high BUN should have a urethral catheter implaced and a diagnosis of PUV ruled out.