Which laboratory findings indicate hyperparathyroidism?

Which laboratory findings indicate hyperparathyroidism?

• A. Low blood calcium and PTH levels
• B. Normal calcium and elevated PTH levels
• C. High blood calcium and low PTH levels
• D. High blood calcium and elevated PTH levels

Answer: (D)

In hyperparathyroidism, the hallmark laboratory finding is elevated serum calcium levels due to increased release of calcium from bones, increased intestinal absorption, and increased renal tubular reabsorption of calcium. This elevation in blood calcium levels stimulates the parathyroid glands to produce more parathyroid hormone (PTH), which typically would help to regulate calcium levels. However, in cases of primary hyperparathyroidism, even though calcium levels are high, PTH levels are also elevated because the disease is driven by the parathyroid glands themselves rather than a response to low calcium levels, as would be seen in other conditions. The combination of high blood calcium and elevated PTH is therefore indicative of hyperparathyroidism. This finding distinguishes this condition from other scenarios, such as secondary hyperparathyroidism, where PTH levels may be elevated in response to low serum calcium levels, allowing for differentiation based on the associated calcium measurements.

In hyperparathyroidism, the hallmark laboratory finding is elevated serum calcium levels due to increased release of calcium from bones, increased intestinal absorption, and increased renal tubular reabsorption of calcium. This elevation in blood calcium levels stimulates the parathyroid glands to produce more parathyroid hormone (PTH), which typically would help to regulate calcium levels. However, in cases of primary hyperparathyroidism, even though calcium levels are high, PTH levels are also elevated because the disease is driven by the parathyroid glands themselves rather than a response to low calcium levels, as would be seen in other conditions.

The combination of high blood calcium and elevated PTH is therefore indicative of hyperparathyroidism. This finding distinguishes this condition from other scenarios, such as secondary hyperparathyroidism, where PTH levels may be elevated in response to low serum calcium levels, allowing for differentiation based on the associated calcium measurements.