Figure 114

Nephrocalcinosis in type I (distal) renal tubular acidosis. Nephrocalcinosis and nephrolithiasis are common complications in distal renal tubular acidosis (RTA-1). Several factors contribute to the pathogenesis. The most important of these factors are a reduction in urinary excretion of citrate and a persistently alkaline urine. Citrate inhibits the growth of calcium stones; its excretion is reduced in RTA-1 as a result of both systemic acidosis and hypokalemia. The high urine pH favors precipitation of calcium phosphate (CaPO4). Thus, RTA-1 should be suspected in any patient with pure calcium phosphate stones [4]. Systemic acidosis also promotes hypercal-ciuria, although not all patients with RTA-1 have excessive urinary calcium excretion [5]. Hypercalciuria results from resorption of bone mineral and the consequent increased filtered load of calcium as acidosis leads to consumption of bone buffers. Acidosis also has a direct effect of inhibiting renal tubular calcium reabsorption. Conversely, nephrocalcinosis from other causes can impair urinary acidification and lead to RTA in some patients. The mainstay of therapy for RTA-1 is potassium citrate, which corrects acidosis, replaces potassium, restores urinary citrate excretion, and reduces urinary loss of calcium [5]. (From Buckalew [5]; with permission.)

51 Tips for Dealing with Kidney Stones

51 Tips for Dealing with Kidney Stones

Do you have kidney stones? Do you think you do, but aren’t sure? Do you get them often, and need some preventative advice? 51 Tips for Dealing with Kidney Stones can help.

Get My Free Ebook

Post a comment