Which condition is caused by overproduction of parathyroid hormone leading to hypercalcemia?

• A. Hyperparathyroidism
• B. Hypoparathyroidism
• C. Insulinoma
• D. Pancreatitis

Answer: (A)

Overproduction of parathyroid hormone causes hypercalcemia because PTH raises blood calcium through three main actions: it increases calcium release from bone, enhances calcium reabsorption in the kidneys, and stimulates active vitamin D production to boost intestinal calcium absorption. When PTH is chronically elevated, calcium levels rise, which is the hallmark of hyperparathyroidism. This condition is usually due to a parathyroid adenoma or gland hyperplasia. Symptoms often relate to high calcium, such as fatigue, bone pain, kidney stones, increased urination, abdominal discomfort, and mood changes.

The other conditions don’t fit this scenario: hypoparathyroidism results in low calcium from insufficient PTH; insulinoma is a pancreatic tumor causing low blood sugar; pancreatitis is inflammation of the pancreas and isn’t driven by excess PTH.