Which hormone is typically elevated in cases of hyperparathyroidism?

In cases of hyperparathyroidism, there is an elevated level of parathyroid hormone (PTH). Hyperparathyroidism is characterized by excessive secretion of PTH from the parathyroid glands, which can result from various conditions, including a primary disorder (such as a parathyroid adenoma) or secondary causes (such as chronic kidney disease or vitamin D deficiency).

PTH is crucial for regulating calcium and phosphate balance in the body. When PTH levels are elevated, it increases serum calcium levels by promoting the release of calcium from bones, increasing intestinal absorption of calcium (via activation of vitamin D), and decreasing renal excretion of calcium. This can lead to symptoms associated with hypercalcemia, including kidney stones, bone pain, and gastrointestinal disturbances.

In contrast, the other hormones listed—thyroid-stimulating hormone, insulin, and adrenaline—do not have a direct relationship with parathyroid hormone levels and are not elevated in hyperparathyroidism. Thyroid-stimulating hormone is involved in regulating thyroid hormone production, insulin is key in glucose metabolism, and adrenaline is part of the body's response to stress. Thus, the increase in parathyroid hormone levels is a hallmark of hyperparathyroidism.