PAEA Surgery End Of Rotation (EOR) Practice Exam

What results from calcium wasting due to renal failure and is associated with low calcium levels?

1. Primary hyperparathyroidism

2. Secondary hyperparathyroidism

3. Hypoparathyroidism

4. Tertiary hyperparathyroidism

The correct answer is: Secondary hyperparathyroidism

Secondary hyperparathyroidism occurs in response to low calcium levels, which can be a direct consequence of calcium wasting caused by renal failure. In chronic kidney disease, the kidneys are less able to convert vitamin D into its active form, leading to decreased intestinal absorption of calcium. This results in persistent hypocalcemia. As a compensatory mechanism, the parathyroid glands begin to secrete more parathyroid hormone (PTH) to help increase calcium levels in the blood. The increased PTH secretion works to mobilize calcium from bones, enhance renal tubular reabsorption of calcium, and stimulate the production of active vitamin D. However, in the context of renal failure, even with elevated PTH levels, the calcium levels often remain low due to the kidneys' impaired ability to handle calcium and phosphate properly. In contrast, primary hyperparathyroidism is characterized by hypercalcemia due to overactivity of the parathyroid glands. Hypoparathyroidism leads to low levels of PTH and is typically associated with hypercalcemia rather than low calcium levels. Tertiary hyperparathyroidism refers to a state where the parathyroid glands are autonomous and overproducing PTH, usually following long-standing secondary hyperparathyroidism,