Nephrocalcinosis



Nephrocalcinosis


Lynn D. Cornell, MD










Nephrocalcinosis, with purple-staining calcium phosphate image deposits in the interstitium, is associated with interstitial inflammation in this case.






A von Kossa stain reveals tubular basement membrane image and interstitial calcification image.


TERMINOLOGY


Definitions



  • Deposition of abundant calcium phosphate precipitates within renal tubules, tubular basement membrane, and interstitium


  • “Nephrocalcinosis” usually refers to calcium phosphate deposits in setting of hypercalcemia



    • Calcium oxalate deposits in other conditions (e.g., primary hyperoxaluria, usually termed “oxalosis”)


ETIOLOGY/PATHOGENESIS


Calcium Precipitation Within Kidney



  • Increased urinary concentration of calcium and phosphate that allows for precipitation


  • Almost all calcium (98%) filtered by glomerulus is reabsorbed by tubule


  • Randall plaques (calcium deposits at or near papillary tip) may be initial site of calcification, at least in some types of nephrocalcinosis



    • Randall plaques show deposits in interstitium, tubular basement membranes, and tubular lumens


Hypercalcemia Due to Various Conditions



  • Nephrocalcinosis usually in setting of chronic hypercalcemia


  • Sarcoidosis


  • Hypercalcemia of malignancy


  • Milk-alkali syndrome


  • Hypervitaminosis A or D


  • Hyperparathyroidism (primary)


Inherited Tubulopathies



  • Dent disease, cystinosis, and others


CLINICAL ISSUES


Epidemiology



  • Age



    • Childhood through older adulthood


    • Neonates, especially those receiving loop diuretics


Presentation

Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Nephrocalcinosis
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