Nephrocalcinosis secondary to exogenous Vitamin D intoxication - A case report

Nephrocalcinosis is characterized by abundant renal tubular and interstitial deposits of calcium phosphate. The calcium deposits are associated with chronic, irreversible scarring in the form of tubular atrophy and interstitial fibrosis. The main causes of nephrocalcinosis include conditions associated with hypercalcemia hyperparathyroidism, malignancy and excessive calcium intake. The main reason in the present case is vitamin D intoxication.A 18-year-old amateur weightlifter presented with symptoms of generalized tiredness and weakness, On evaluation at our institute he was diagnosed to have new onset hypertension with deranged renal function (serum creatinine of 3.1). He gave history of supplements in form of powder and over the counter multi-vitamin pills. Urine routine and microscopy showed presence of calcium oxalate crystals Blood urea and serum creatinine levels were 31 mgdL and 3.2mgdL, respectively. Serum calcium (corrected for albumin) was found to be elevated 12.6 mgdL. Serum phosphate 2.2mgdL (N 2.5-4.6mgdL) and alkaline phosphatase 80UL (N 39-117UL) levels were normal. 24 hour calcium was urine was 290mg (normal upper limit 4 mgkg). Serum parathormone was suppressed 14.80 pgmL (15.6-68.0pgml), the level of 25 hydroxycholecalciferol 25 (OH) D3 was estimated and found to be 70ngml (20- 40ngml). He undewent renal biopsy whichshowed chronic interstitial nephritis with foreign body granuloma around refractile and microcalcific material and tubular necrosis. Immunoflourescence was negative. He was treated conservatively and was advised to to increase hydration with no further ingestion of any supplementary compound his renal function came to normal serum creatinine of 1.2mgdL in 3 months duration.