PTH and hypercalcemia disease: Management of IIH is based on chronic restriction of dietary calcium and vitamin D. With this approach, hypercalcemia and hypercalciuria improves in some, but in many patients, elevated serum levels of 1,25(OH)2D, and the 1,25(OH)2D to PTH (1,25(OH)2D/PTH) ratio, (an index for PTH-independent accumulation of 1,25(OH)2D) providing evidence that the underlying pathophysiology remains active [7].