**Question:** All are used in treatment of hypercalcemia, except:

A. Calcitonin
B. Aldosterone
C. Vitamin D
D. Thiazide diuretics

**Core Concept:**
Hypercalcemia is a medical condition characterized by abnormally elevated levels of calcium in the blood. Calcium is essential for various physiological processes, but excessive calcium can lead to complications. Treatment modalities aim to reduce calcium levels or address the underlying cause.

**Why the Correct Answer is Right:**
D. Thiazide diuretics are not utilized in hypercalcemia treatment because they primarily act as diuretics, increasing calcium excretion in the urine. However, in hypercalcemia, the body needs to retain calcium to reduce blood levels, so using diuretics would exacerbate the issue.

**Why Each Wrong Option is Incorrect:**
A. Calcitonin is a hormone that reduces calcium levels in the blood by inhibiting osteoclastic activity and promoting calcium reabsorption in the kidneys. Calcitonin is a suitable treatment option for hypercalcemia.
B. Aldosterone is a hormone that promotes sodium and water reabsorption in the distal nephron, leading to increased calcium reabsorption. Aldosterone is not a treatment for hypercalcemia as it exacerbates the problem.
C. Vitamin D is a hormone that regulates calcium absorption in the intestines. In hypercalcemia, reducing vitamin D levels is recommended to lower calcium absorption and blood levels.

**Clinical Pearl:**
Hypercalcemia treatment depends on the underlying cause. For example, in hyperparathyroidism, surgery or medical management with bisphosphonates is preferred, while in malignancy-induced hypercalcemia, bisphosphonates are the mainstay of treatment. In milder cases, hydration, diuretics, and calcitonin can be considered. Understanding the etiology is crucial when selecting appropriate treatment options.

**Correct Answer:** D. Thiazide diuretics are incorrect for treating hypercalcemia.