In primary hyperparathyroidism, the defect primarily lies in the parathyroid glands.

In primary hyperparathyroidism, the defect primarily lies in the parathyroid glands.

• A. Parathyroid glands
• B. Pituitary gland
• C. Thyroid gland
• D. Adrenal glands

Answer: (A)

Primary hyperparathyroidism is driven by autonomous overproduction of parathyroid hormone from the parathyroid glands. PTH is the main regulator of calcium balance, acting on bone to release calcium, on the kidneys to reabsorb calcium and excrete phosphate, and on the gut indirectly by promoting activation of vitamin D to boost intestinal calcium absorption. When a parathyroid gland or glands become overactive (often due to an adenoma or hyperplasia), they secrete excess PTH regardless of the serum calcium level, leading to hypercalcemia. This makes the parathyroid glands the primary site of pathology in this condition, unlike the pituitary, thyroid, or adrenal glands, which are not the source of the excess PTH driving the disease.

Primary hyperparathyroidism is driven by autonomous overproduction of parathyroid hormone from the parathyroid glands. PTH is the main regulator of calcium balance, acting on bone to release calcium, on the kidneys to reabsorb calcium and excrete phosphate, and on the gut indirectly by promoting activation of vitamin D to boost intestinal calcium absorption. When a parathyroid gland or glands become overactive (often due to an adenoma or hyperplasia), they secrete excess PTH regardless of the serum calcium level, leading to hypercalcemia. This makes the parathyroid glands the primary site of pathology in this condition, unlike the pituitary, thyroid, or adrenal glands, which are not the source of the excess PTH driving the disease.