Hyperglobulinemic Renal Tubular Acidosis

Abstract

Two cases of classical (distal) renal tubular acidosis (RTA), one in an 18 year old girl with idiopathic hyperglobulinemia and the other in a 76 year old woman with hyper-globulinemia and Sjogren''s syndrome. The relationship of the serum protein abnormalities to the renal tubular disease could not be determined. Fluorescein-labelled Coombs'' serum did not demonstrate gamma globulin localization in a renal biopsy specimen from the 1st patient. Both patients showed inability to lower urine pH normally in response to acid loading, hypokalemia, hyperchloremic acidosis, hypercalciuria without hypercalcemia, a renal concentrating defect with normal diluting capacity, decreased excretion of citrate, hyper-phosphaturia and increased uric acid clearance. Neither had glycosuria, proteinuria or significant aminoaciduria. A bicarbonate loading study in one patient showed a normal tubular ability to reabsorb bicarbonate. Unlike myeloma patients who may develop proximal renal tubular abnormalities characteristics of the Fanconi syndrome, non-myelamatous hyperglobulinemic patients develop distal tubular dysfunction which is indistinguishable from idiopathic RTA. Since long term alkali therapy is known to prevent progressive nephrocalcinosis and renal functional deterioration in that disease, patients with hyperglobulinemia should be screened periodically for development of RTA and treated appropriately if it occurs.