Lower Urinary Citrate Excretion Research Articles

Clinical significance of hypocitraturia in kidney stone patients.

Although a low concentration of urinary citrate is cited as one of the risk factors promoting stone formation or recurrence among patients with urinary stones, its clinical significance remains obscure. We studied 62 kidney stone patients with a low urinary citrate excretion (hypocitraturia) of less than 320 mg/day, without any apparent cause. The incidence of hypocitraturia in 722 kidney stone patients followed up at our stone clinic was 14.6%. Among the 62 patients, 37 had an uncomplicated hypocitraturia as the sole abnormality, while 25 had other associated stone risk factors, including hypercalciuria in 11% (7/62), hyperuricosuria in 24% (15/62), hyperoxaluria in 5% (3/62) and hypomagnesuria in 24% (15/62). The rate of urinary stone recurrence was 38% (14/37) in uncomplicated hypocitraturia, and 52% (13/25) in complicated hypocitraturia, but no statistical difference was observed. Regarding the outcome of stones, more stones were managed with lithotripsy and more passed spontaneously in the hypocitraturic patients than in the control patients with normal urinary citrate excretion. The diagnosis of hypocitraturia complicated with additional stone risks urged us to treat patients more vigorously with lithotripsy and medication, resulting in a prompt cure.

Urinary citrate excretion in primary aldosteronism.

Urinary citrate output was studied in 5 cases of primary aldosteronism, in 3 of Addison's disease and in 8 of normal subjects. The urinary citrate output was decreased in 4 of 5 cases of primary aldosteronism, and the citrate output could not be normalized by removal of adrenocortical adenoma. In patients with primary aldosteronism citrate excretion was somewhat increased by admini-stration of potassium chloride, but rather decreased by spironolactone. In these patients urinary citrate output could not be correlated with either plasma CO2 content or plasma potassium concentration. The low urinary citrate excretion in primary aldosteronism may not be satisfactorily explained either by direct action of aldosterone on the kidney or by intracellular acidosis.