11/41. pseudoxanthoma elasticum and nephrolithiasis.We report the case of a 42-year-old man with pseudoxanthoma elasticum (PXE) and recurrent bilateral nephrolithiasis. diagnosis of PXE was made by yellow papules on the neck and ophthalmologic angioid streaks. This diagnosis was confirmed by a skin biopsy (Von Kossa stain) and by genotyping analysis of ABCC6 (homozygous mutation R1138Q). nephrolithiasis was recurrent and biological investigations showed hypophosphoraemia, hyperphosphaturia, hypercalciuria, normocalcaemia, normal serum parathyroid hormone value, high 1,25-dihydroxy vitamin d value and a renal calcium oxalate stone. ABCC6 encodes for MRP6, a multidrug resistant protein strongly expressed in the liver and kidney. The substrates of the MRP6 remain unknown. As PXE is characterized by calcification of elastic fibres and this patient presents important phosphocalcic anomalies, we discuss the possible implications of MRP6 in the phosphocalcic metabolism.- - - - - - - - - - ranking = 1keywords = hypercalciuria (Clic here for more details about this article) |
12/41. Idiopathic hypercalciuria causing osteoporosis and hypocalcemia.Idiopathic hypercalciuria, though a common cause of nephrolithiasis, has not been recognized to cause hypocalcemia and severe bone disease. We describe an adolescent with idiopathic hypercalciuria who presented initially with severe hypocalcemia and osteoporosis and this was later complicated by recurrent renal calculi formation after calcium and vitamin d supplement. After treatment with thiazide, hypercalciuria was controlled and serum biochemistry normalized. While idiopathic renal hypercalciuria may cause a negative calcium balance in adults, a variant of this syndrome with severe renal calcium leak occurring in a growing subject could lead to severe hypocalcemia and osteoporosis.- - - - - - - - - - ranking = 8keywords = hypercalciuria (Clic here for more details about this article) |
13/41. Stones, bones, and heredity.Genetic disorders of mineral metabolism cause urolithiasis, renal disease, and osteodystrophy. Most are rare, such that the full spectrum of clinical expression is difficult to appreciate. diagnosis is further complicated by overlap of clinical features. Dent's disease and primary hyperoxaluria, inherited causes of calcium urolithiasis, are both associated with nephrocalcinosis and urolithiasis in early childhood and renal failure that can occur at any age but is seen more often in adulthood. Bone disease is an inconsistent feature of each. Dent's disease is caused by mutations of the CLCN-5 gene with impaired kidney-specific CLC-5 chloride channel expression in the proximal tubule, thick ascending limb of Henle, and the collecting ducts. Resulting hypercalciuria and proximal tubule dysfunction, including phosphate wasting, are primarily responsible for the clinical manifestations. Low-molecular-weight proteinuria is characteristic. Definitive diagnosis is made by dna mutation analysis. Primary hyperoxaluria, type I, is due to mutations of the AGXT gene leading to deficient hepatic alanine-glyoxylate aminotransferase activity. Marked overproduction of oxalate by hepatic cells results in the hyperoxaluria responsible for clinical features. Definitive diagnosis is by liver biopsy with measurement of enzyme activity, with dna mutation analysis used increasingly as mutations and their frequency are defined.These disorders of calcium urolithiasis illustrate the value of molecular medicine for diagnosis and the promise it provides for innovative and more effective future treatments.- - - - - - - - - - ranking = 1keywords = hypercalciuria (Clic here for more details about this article) |
14/41. Antacid-induced phosphate depletion syndrome presenting as nephrolithiasis.A 29-year-old insulin-dependent diabetic woman developed phosphate depletion, nephrolithiasis and bilateral ureteric obstruction due to antacid abuse. Unlike previous descriptions of chronic phosphate depletion, myalgia, weakness and bone pain were absent. Biochemical features included hypophosphataemia, hypercalciuria, hypophosphaturia, elevated plasma, 1,25-dihydroxyvitamin D and low plasma intact parathyroid hormone. These abnormalities were corrected when antacid ingestion was reduced and phosphate intake supplemented. We propose that phosphate depletion secondary to antacid abuse caused 1 alpha-hydroxylase activation and elevation of the plasma 1,25-dihydroxyvitamin D level, leading to marked hypercalciuria. Once diagnosed, antacid abuse is a readily reversible cause of hypercalciuria and renal stones. Moreover, antacid-induced phosphate depletion may present with nephrolithiasis in the absence of musculoskeletal symptoms. This report is intended to draw attention to this important cause of renal stone disease.- - - - - - - - - - ranking = 3keywords = hypercalciuria (Clic here for more details about this article) |
15/41. Heritable syndrome of pseudoxanthoma elasticum with abnormal phosphorus and vitamin d metabolism.A patient with pseudoxanthoma elasticum was documented to be hyperphosphatemic and mildly hypercalcemic for six years. Complications included metastatic calcification, absorptive hypercalciuria, and renal insufficiency. The 1,25-dihydroxyvitamin D value was elevated, despite normal serum parathyroid hormone values, high serum phosphate levels, and renal insufficiency. Either increased dietary calcium or prednisone seemed to suppress the 1,25-dihydroxyvitamin D value. nephrolithiasis or abnormalities suggestive of pseudoxanthoma elasticum occurred in the patient's father, daughter, and several siblings, suggesting a distinct familial syndrome in which connective tissue changes are accompanied by abnormalities of phosphorus and vitamin d metabolism that may resemble those in the syndrome of familial tumoral calcinosis. Nine similar cases were described before 1970.- - - - - - - - - - ranking = 1keywords = hypercalciuria (Clic here for more details about this article) |
16/41. Gouty diathesis and sarcoidosis in patient with recurrent calcium nephrolithiasis.We describe a patient who initially formed calcium-containing renal stones owing to gouty diathesis and hypocitraturia. On therapy with 300 mg. allopurinol and 60 mEq. potassium citrate daily serum uric acid decreased from 9.2 to 5.8 mg. per dl., urinary pH increased from less than 5.5 to 6.6 and urinary citrate increased from 223 to 1,005 mg. per day. Four months later while still on this medical regimen, the patient presented with hypercalcemia (13.4 mg. per dl.), high serum 1,25-dihydroxyvitamin D (65 pg. per ml.) and hypercalciuria (598 mg. per day), which subsequently were found to result from sarcoidosis. prednisone therapy normalized the disturbances in calcium metabolism. During 33 months of combined treatment with 7.5 to 10 mg. prednisone a day, allopurinol and potassium citrate, the patient was free of stones and he had normal urinary calcium, pH and citrate. However, a calcium stone formed 1 month after discontinuation of prednisone therapy, although treatment with allopurinol and potassium citrate was continued. The patient had marked hypercalciuria of 447 to 465 mg. per day, despite normal urinary pH, citrate and uric acid. This case represents calcium stone formation in a patient with 2 separate etiologies for stone disease, that is gouty diathesis and sarcoidosis. Therapeutic regimens directed at the correction of both metabolic disturbances were required to control renal stone formation.- - - - - - - - - - ranking = 2keywords = hypercalciuria (Clic here for more details about this article) |
17/41. hypercalciuria and renal stones in a sarcoidosis patient treated by extracorporeal shockwave lithotripsy.A case of chronic pulmonary sarcoidosis and hypercalciuria complicated by bilateral renal stones is reported. Urinary stones were pulverized by extracorporeal shockwave lithotripsy (ESWL) as the patient had declined any surgical procedure. The use of ESWL in conjunction with corticosteroids appears to be the treatment of choice in the management of renal stones secondary to abnormalities of calcium metabolism in sarcoidosis.- - - - - - - - - - ranking = 1keywords = hypercalciuria (Clic here for more details about this article) |
18/41. Mild metabolic hyperoxaluria and its response to pyridoxine.Three cases of mild metabolic hyperoxaluria (with glycollaturia) are described. They showed different types of response to pyridoxine. One responded to low dose, one responded at first to low dose but became resistant, and the third showed temporary response to high dose. One case also had primary hyperparathyroidism and one had medullary sponge kidneys and hypercalciuria. It is important to measure urinary oxalate (and glycollate) in all cases of calcium oxalate urolithiasis.- - - - - - - - - - ranking = 1keywords = hypercalciuria (Clic here for more details about this article) |
19/41. Percutaneous ultrasonic lithotripsy of symptomatic renal calculi in children.Percutaneous ultrasonic lithotripsy of upper urinary tract lithiasis is a well-established procedure in adults. We successfully applied this technique to completely remove symptomatic renal calculi in two children with idiopathic hypercalciuria. The procedure was well tolerated and no complications occurred. Both patients were discharged within 4 days of the lithotripsy. This method is an alternative to surgery for the removal of large or impacted calculi from the upper urinary tracts of pediatric patients.- - - - - - - - - - ranking = 1keywords = hypercalciuria (Clic here for more details about this article) |
20/41. Complete distal renal tubular acidosis in systemic lupus: clinical and laboratory findings.We report two patients with systemic lupus erythematosus (SLE) who were found to have complete (acidotic) distal renal tubular acidosis (DRTA). One patient had nephrocalcinosis and renal magnesium wasting with tetany; the other patient had nephrolithiasis and nephrotic syndrome secondary to membranous glomerulopathy. Both patients had decreased urinary citrate excretion but neither had hypercalciuria. We discuss the association of DRTA with immunologic disorders and the possible role of hypocitraturia in promoting renal calcification in these patients. We suggest that patients with renal calcification be evaluated for DRTA, and that patients found to have DRTA be further evaluated for signs, symptoms, and laboratory evidence of immunologic disorders.- - - - - - - - - - ranking = 1keywords = hypercalciuria (Clic here for more details about this article) |
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