Question

a 33 - year - old woman presents to your office with the following lab findings: elevated alkaline phosphatase, elevated calcium, and low phosphorus. what is the most likely diagnosis? a) bone breakdown b) hyperparathyroidism c) kidney disease d) hepatitis

Explanation:

• Hyperparathyroidism: In hyperparathyroidism, the parathyroid glands over - secrete parathyroid hormone (PTH). PTH acts on the bones (increasing bone resorption, which can increase alkaline phosphatase as it is a marker of osteoblast activity during bone turnover), on the kidneys (decreases phosphate re - absorption leading to low phosphorus), and on the intestines (increases calcium absorption). Overall, this leads to elevated calcium levels.
• Bone breakdown (a): While bone breakdown can cause elevated alkaline phosphatase and calcium to some extent (from bone mineral release), it does not typically cause the characteristic low phosphorus seen in hyperparathyroidism.
• Kidney disease (c): In chronic kidney disease, there is often hyperphosphatemia (high phosphorus) due to decreased renal excretion of phosphorus, which is the opposite of what is seen here.
• Hepatitis (d): Hepatitis primarily affects liver - related enzymes (such as alanine aminotransferase, aspartate aminotransferase) and may cause some changes in alkaline phosphatase (if there is biliary involvement), but it does not cause the triad of elevated calcium and low phosphorus.

Answer:

B. hyperparathyroidism