Disorders Involving Calcium, Phosphorus, and Magnesium

Disorders of mineral metabolism are common in both the office and hospital setting. The diagnosis can be simplified by remembering the target organs involved—intestine, kidney, and bone—and by assessing the presence of kidney disease, levels of parathyroid hormone, and vitamin D status. Although the list of possible causes for these derangements is long, most patients who have hypercalcemia have hyperparathyroidism or malignancy; those who have hypocalcemia, hypophosphatemia, and hypomagnesemia have reduced gastrointestinal absorption, and those who have hyperphosphatemia and hypermagnesemia have increased intake in the setting of kidney disease.