In a patient with bone pain and recurrent kidney stones, laboratory results show hypercalcemia with increased urinary calcium and phosphate excretion. The likely cause is:

Prepare for the CAMLPR Chemistry Test. Enhance your understanding with interactive quizzes, flashcards, and detailed explanations. Boost your confidence and readiness for exam success!

Hyperparathyroidism best explains this pattern. When the parathyroid glands are overactive, they raise parathyroid hormone, which drives bone resorption (causing bone pain) and increases calcium reabsorption and vitamin D activation in the kidney and gut. The net result is hypercalcemia with calcium and phosphate being lost in the urine (calciuria and phosphaturia). The combination of bone pain, kidney stones, and a hypercalcemic state with increased urinary calcium and phosphate excretion points to PTH-driven hypercalcemia from hyperparathyroidism, most often primary hyperparathyroidism due to an overactive gland. Hypercalcemia of malignancy typically involves different patterns (often with suppressed PTH), and hypoparathyroidism would cause low calcium rather than high.