Renal tubular acidosis in children. Diagnosis, treatment and prognosis

Abstract

To delineate the spectrum of clinical expressions of distal, type 1 renal tubular acidosis in children and to update progress in diagnosis, therapy, and prognosis, the medical records of 14 girls and 10 boys, seen over a 7 year period, who met the following criteria, were examined: persistent urinary pH more than 6, net acid excretion less than 70 microEq/min/1.73 m2, simultaneous serum total CO2 less than 17.5 mEq/1, and normal or mild impairment of the glomerular filtration rate. The mean age at diagnosis was 8 months. The presenting signs and symptoms were failure to thrive (50%), vomiting and/or diarrhea (37.5%), dehydration (12.5%), and poor feeding (8.3%). Mean values +/- SD of serum calcium (9.8 +/- 0.8 mg/dl), inorganic phosphate (5.6 +/- 0.8 mg/dl), and alkaline phosphatase (222.6 +/- 96.1 U/l) were normal. Hyperkalemia (serum potassium above 5.0 mEq/l) was present at diagnosis in 13 children. Type 4 renal tubular acidosis was ruled out by the inability to achieve a minimum urine pH. With a mean follow-up period of 28.1 +/- 25.3 months, after alkali therapy at 3.3-3.5 mEq/kg/day had been administered for at least 12 months, the growth parameters improved as follows: the percentile weight (mean +/- SD) increased from the initial 11.8 +/- 7.5 to the final 27.6 +/- 31.3 (p less than 0.003), and the length/height percentile increased from 11.5 +/- 7.3 to 29.7 +/- 24.2 (p less than 0.03). The relationship between urine calcium/creatinine ratio and serum total CO2 showed poor correlation.(ABSTRACT TRUNCATED AT 250 WORDS)