The ensuing hyperphosphatemia may induce potentially symptomatic hypocalcemia due to calcium-phosphate precipitation in the tissues. Calcifications can also be present in skin, soft tissue, and periarticular regions. Prolonged bone demineralization can lead to bone fractures.

Why does hyperphosphatemia lead to hypocalcemia?

By precipitating calcium, decreasing vitamin D production, and interfering with PTH-mediated bone resorption, hyperphosphatemia can cause hypocalcemia; in severe cases, hypocalcemia can be life-threatening.

Can hyperphosphatemia cause hypercalcemia?

Secondary hyperparathyroidism is due to diffuse hyperplasia of parathyroid glands in response to ongoing stimuli such as hypocalcemia or hyperphosphatemia. Secondary hyperparathyroidism can also cause hypercalcemia when severe due to increased bone resorption.