PAEA Surgery End Of Rotation (EOR) Practice Exam

Which of the following can cause hypercalcemia?

1. Hypoparathyroidism

2. Primary hyperparathyroidism

3. Chronic kidney disease

4. All of the above

The correct answer is: Primary hyperparathyroidism

Primary hyperparathyroidism is a condition characterized by an overproduction of parathyroid hormone (PTH) from one or more of the parathyroid glands. This condition leads to an increase in calcium levels in the blood (hypercalcemia) through several mechanisms: it increases renal tubular reabsorption of calcium, stimulates the conversion of vitamin D to its active form (calcitriol), and induces increased intestinal absorption of calcium. Additionally, PTH mobilizes calcium from the bones, contributing to elevated serum calcium levels. In contrast, both hypoparathyroidism and chronic kidney disease typically do not lead to hypercalcemia. Hypoparathyroidism results in low PTH levels, which causes decreased calcium levels. Chronic kidney disease often involves a complex interplay of renal function and calcium metabolism but is usually associated with lower calcium levels due to the impaired capacity of the kidneys to excrete phosphate, which, in turn, can lead to secondary hyperparathyroidism. Thus, the presence of primary hyperparathyroidism stands out as the primary cause of hypercalcemia among the provided choices.