Factors that predispose to cast formation include the following: Low urine flow Radiocontrast agents Hyperuricemia Nonsteroidal anti-inflammatory drugs (NSAIDs) Elevation of luminal sodium chloride concentration (eg, due to a loop diuretic) Increased intratubular calcium due to the hypercalcemia that often occurs secondary to bone lysis in multiple myeloma Other types of tubulointerstitial lesions that occur with Bence Jones proteinuria include proximal tubular transport dysfunction, causing Fanconi syndrome, and light chain interstitial deposition with inflammatory infiltrates and active tubular damage, which can cause acute tubular necrosis.