NEPHROCALCINOSIS AND URINARY CALCULI ASSOCIATED WITH INCOMPLETE RENAL TUBULAR ACIDOSIS

Abstract

In 1959 Wrong and Davies reported on three patients with an inability to lower urine pH in response to ammonium chloride loading test in the absence of systemic acidosis. This is the first description of incomplete renal tubular acidosis. Twenty-seven cases of this condition have been reported in the literature since the presentation by Wrong and Davies. Though Miyake et al. (1964) and Hirooka et al. (1965) observed a similar tubular acidification defect, the following case is the first to be reported as incomplete renal tubular acidosis in Japan.
A 41-year-old man was admitted to the hospital on March 2, 1974 with recurrent urinary calculi. He passed numerous stones repeatedly since 1952. X-ray films showed bilateral nephrocalcinosis and upper urinary calculi with no evidence of excretion from the right kidney and with left pyeloureterectasis. Laboratory examinations revealed slightly infected urine with pH 6.5 or over but no systemic acidosis was indicated. The ammonium chloride loading test showed an acidification defect leading to diagnosis of incomplete renal tubular acidosis. A left ureteral stone was extracted on July 7 and right pyeloureterolithotomy was performed on August 9, 1974. The patient has had no recurrent calculus since he started alkali therapy.
Light microscopic examination from the biopsy specimen revealed evidence of chronic pyelonephritis i. e. atrophy and degeneration of tubules with thickened basement membrane, increase of fibrous elements in interstitium and occasional accumulation of lymphocytes, pericapsular fibrosis of glomeruli which remained with minimal changes.
Fine granular deposits are occasionally observed in subepithelial spaces in capillary loops and rare dense amorphous deposits in subendothelial spaces by electron microscopic observation.