Primary Distal Renal Tubular Acidosis in Children

ABSTRACT

PURPOSE: This study was designed to examine the clinical characteristics and the effect of treatment in children with primary distal renal tubular acidosis (dRTA). METHODS: Medical records of 4 children diagnosed as dRTA at Seoul National University Children's Hospital were reviewed, and the clinical manifestations, laboratory findings, diagnostic criteria and effects of treatments were investigated. RESULTS: All cases presented with growth retardation. Polyuria, polydipsia and secondary enuresis from urinary concentrating defect were observed in three. All patients showed hyperchloremic metabolic acidosis with normal anion gap. All had hypercalciuria determined by spot urine calcium/creatinine ratio over 0.2. Radiological studies revealed nephrocalcinosis in three and rickets in the other one. With administration of alkali, three patients reached mean height of their age. The other one with rickets failed to reach the mean height despite rapid catch-up growth. Rapid catch-up growth occurred in the first two years of alkali therapy in all patients. 8 cases previously reported in Korea were also discussed. CONCLUSIONS: dRTA should be included as an etiology of growth retardation in children and it can be easily diagnosed by routine measurement of serum electrolytes concentrations and the urine pH. Adequate alkali therapy will correct the growth retardation as well as the other symptoms. The prognosis for final height can be determined at 2 years after initiation of therapy. Patients with rickets will have poor prognosis for growth. Early recognition and continuous administration of alkali are mandatory not only to prevent the impairment of renal function associated with nephrocalcinosis but to achieve the normal growth.