The contribution of acidosis to renal osteodystrophy

Abstract

A 5-year-old boy was admitted to the hospital 19 years ago for repair of primary hypospadias. The serum creatinine was 1.2 mg/dl; the BUN, 33 mg/dl; and the bicarbonate concentration, 23 mEq/liter. The creatinine clearance, determined from a 24-hour urine collection, was 75 mI/mm/I .73 m2. An intravenous pyelogram demonstrated a faint nephrogram on the right and no nephrogram on the left. Renal function was markedly diminished bilaterally with dysplastic pelvicalyceal systems and renal dysplasia affecting the left renal parenchyma more than the right. A voiding cystourethrogram demonstrated a distended and irregular bladder with massive bilateral reflux, distended calyces and pelves, and tortuous, dilated ureters. After voiding and standing, most of the contrast medium was drained from the upper collecting system; however, the bladder contained 500 ml of residual urine. A urologist advised against surgery because the patient had never had a urinary tract infection. Over the next several years, the patient's renal function progressively declined. Thirteen years ago, the serum creatinine was 3.9 mgldl; phosphate, 5.5 mgldl; calcium, 8.8 mg/dl; and bicarbonate, 22 mEq/liter. Aluminum hydroxide was administered, as was vitamin D. Six months later, the serum creatinine was 4.9 mgldl; phosphate, 6.1 mg/dl; calcium, 8.6 mg/dl; and bicarbonate, 20 mEq/liter. Oral sodium bicarbonate was given and the aluminum hydroxide was increased. In spite of marked increases in oral aluminum hydroxide and sodium bicarbonate, the serum phosphate level ranged from 5.2 to 7.4 mgldl (mean, 6.2 mg/dl over 2 years) and the bicarbonate ranged from 16 to 23 mEq/liter (mean, 20.7 mEq/liter) as the serum creatinine increased to 9.8 mg/dl over the next 18 months. Approximately ii years ago, peritoneal dialysis was begun. The patient was evaulated for transplantation at 3 major university centers, but each required that bilateral nephrectomy be performed prior to transplantation; the patient and his family refused. Nine years ago, the patient's mode