Metabolic abnormalities in patients with caliceal diverticular calculi

Purpose: We determined the incidence and spectrum of metabolic abnormalities in patients with caliceal diverticular calculi. Materials and Methods: Five men and 9 women with caliceal diverticular calculi underwent metabolic evaluation, including determination of serum electrolytes, calcium, phosphate and uric acid, and 24-hour urinary volume, creatinine, calcium, oxalate, uric acid and citrate. Results: Of the 14 patients 7 (50%) had urinary excretion abnormalities promoting stone formation, including hypercalciuria in 3, hyperoxaluria in i, hypercalciuria combined with hyperuricosuria in 1 and hyperoxaluria combined with hyperuricosuria in 2. Two patients had a history of gout while another had radiographic evidence of medullary sponge kidney. Of the patients 9 (64.3%) had a history of synchronous or metachronous calculi distant from the involved caliceal diverticular stone and 5 (55.6%) of these 9 had definable metabolic disorders. However, there was no statistically significant difference in urinary excretion values between patients with or without a history of additional extra diverticular stones. Conclusions: Urinary stasis alone does not explain stone formation in a significant number of patients with caliceal diverticular calculi. Rather, the local physiological environment of the urine likely has a predisposing role and evaluation for metabolic abnormalities should be considered. In some patients cure may be effected by treating the stone and any associated metabolic disorders rather than the diverticulum.