Nephrocalcinosis in a systemic granulomatous disease is due to:
Nephrocalcinosis Calcification of the renal interstitium and tubules. Associated with hypercalcemia. Disorders associated with hypercalcemia, such as hyperparathyroidism, multiple myeloma, vitamin D intoxication, metastatic cancer, or excess calcium intake (milk-alkali syndrome), may induce the formation of calcium stones and deposition of calcium in the kidney (nephrocalcinosis). Extensive degrees of calcinosis, under ceain conditions, may lead to chronic tubulointerstitial disease and renal insufficiency. With fuher damage, a slowly progressive chronic kidney disease develops. Sarcoidosis and other granulomatous diseases can be cause of hypercalcemia and hypercalciuria owing to excess vitamin D production from extra renal conversion of 1,25 (OH)2D3.
Overproduction of 1,25 dihydroxy vitamin D
Dystrophic calcification
Mutation in calcium sensing receptors
Increased reabsorption of calcium
Chronic Inflammation