Idiopathic Hypercalciuria

See Table 15-5. The major indications for thiazide diuretics are (1) hypertension, (2) heart failure, (3) nephrolithiasis due to idiopathic hypercalciuria, and (4) nephrogenic diabetes insipidus. Use of the thiazides in each of these conditions is described in Clinical Pharmacology of Diuretic Agents. 

People with idiopathic hypercalciuria, characterized by hypercalciuria and nephrolithiasis with normal serum calcium and... 

Idiopathic hypercalciuria, a common cause of renal stone disease, may be reduced by thiazide diuretics... 

De Swart PM JR, Busemann Sokole E, Wilmink JM. The interrelationship of calcium and magnesium absorption in idiopathic hypercalciuria and renal calcium stone disease. J Urol 1998 159 669-72. 

Weisinger JR. New insights into the pathogenesis of idiopathic hypercalciuria role of the bone. Kidney Int 1997 49 1507-18. 

As intestinal absorption of calcium increases, urinary calcium excretion also increases. When the latter exceeds 300 mg/d, formation of calcium phosphate or calcium oxalate stones (urolithiasis) may occur. Hypercalciuria may result from decreased reabsorption of calcium due to a renal tubular defect or from increased intestinal absorption of calcium. Hypercalciuria may be due to an intrinsic defect in the intestinal mucosa or secondary to increased synthesis of 1,25-(OH)2D in the kidney. Disordered regulation of 1,25-(0H)2D synthesis is relatively common in idiopathic hypercalciuria. Treatment usually includes reduction in dietary calcium. Increased vitamin D intake, hyperparathyroidism, and other disorders can also cause hypercalciuria and urolithiasis. 

Vezzoli G, Caumo A, Baragetti I, et al. 1999. Study of calcium metabolism in idiopathic hypercalciuria by strontium oral load test. Clin Chem 45(2) 257-261. 

Coe, F.L. Treated and untreated recurrent calcium nephrolithiasis in patients with idiopathic hypercalciuria, hyperuricosuria or no metabolic disorders. Ann. Int. Med. 87 404-410 (1977). 

Table 1 shows the results of the basal metabolic study in 9 patients with RCN and hyperuricosuria and in the control group. Six patients had idiopathic hypercalciuria, one patient frank hyperoxaluria and 3 marginal hyperoxaluria. In four patients the results indicate renal leak of phosphates. 

Regarding the hypercalciuria, for lack of a defined etiology, we classify it for the time being with the socalled idiopathic hypercalciuria. If correct, this, to our knowledge, would be the first reported instance of hereditary familial idiopathic hypercalciuria. 

The association of idiopathic hypercalciuria, decreased bone density and renal hypouricernia in all the affected subjects distinguishes them from the two patients reported in the literature (4,5), having hypouricernia due to an isolated renal tubular defect. The family studied by us presents, to our knowledge, a hitherto undescribed syndrome. The etiological connection between the three components of this syndrome - renal hypouricernia, idiopathic hypercalciuria and decreased bone density - is not understood their relationships to one mutation are unclear. 

X-linked hypophosphataemic rickets Idiopathic hypercalciuria Familial hypocalciuric hypercalcemia Bartter syndromes Gitelman syndome... 

Finally, there is a rare, but extremely severe form of idiopathic hypercalciuria leading to progressive NC and renal failure X-linked hypercalciuric nephropathy with tubular proteinuria, also called Dent s disease (Lloyd et al. 1996). 

Stapleton FB (1983) Idiopathic hypercalciuria in children. Semin Nephrol 3 116-124... 

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