What imbalance is observed in hyperparathyroidism?

In hyperparathyroidism, there is an increased secretion of parathyroid hormone (PTH) from the parathyroid glands, leading to significant alterations in calcium and phosphorus levels in the body. This condition is characterized by hypercalcemia, which means that calcium levels in the blood are elevated. The increased PTH stimulates the bones to release calcium into the bloodstream, enhances intestinal absorption of calcium, and reduces renal excretion of calcium.

In addition to the elevated calcium levels, hyperparathyroidism is also associated with increased levels of PTH itself as a direct result of the parathyroid glands overactivity. Interestingly, alongside the increase in calcium, phosphorus levels tend to decrease due to the action of PTH, which promotes renal excretion of phosphate. As a result, the classic laboratory findings in hyperparathyroidism include increased calcium levels, elevated PTH levels, and decreased phosphorus levels.

These physiological changes are reflective of the body's attempt to maintain calcium homeostasis despite the underlying disorder, demonstrating the impact of parathyroid hormone on calcium and phosphorus metabolism.