[Hypercalcemia, symptoms, differential diagnostics and treatment, or importance of calcium investigation].

UNLABELLED: The concentration of calcium is carefully maintained under physiological conditions with parathormone, calcitonin and 1,25-dihydroxyvitamin D at appropriate levels. There are multiple causes that may bring about increased concentrations of calcium which exceed physiological values. Increased production of parathormone in parathyroid glands is only one of the possible causes. Malignant diseases are a very frequent cause of hypercalcemia, due to their creating mediators which stimulate osteoclasts and thereby osteolysis. A less frequent cause is represented by granulomatous processes, a typical example of which is sarcoidosis, whose cells increasingly (independently of parathormone) hydroxylate 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D. However there are also hereditary forms of hypercalcemia. One of the causes of the hereditary form of hypercalcemia is mutations of the calcium sensing receptor. In order to locate the adenoma of parathyroid glands, essential apart from sonographic imaging is scintigraphy 99mTc-methoxyisobutylisonitrile (MIBI) and even more exact is PET-CT examination with a radio-pharmaceutical 18F-fluorocholine. PET-CT examinations are beneficial with regard to detecting a malignant cause of hypercalcemia in until then undetected malignancy or an undetected granulomatous process. The essential treatment procedures for malignant hypercalcemia include appropriate hydratation of ionic solutions without calcium, administering of bisphosphonates or denosumab. The text describes in detail the symptoms of hypercalcemia and diagnostics of causes of hypercalcemia.

KEY WORDS: bisphosphonates - cinacalcet - denosumab - granulomatous diseases - hereditary hypercalcemia - hypercalcemia - hypercalciuria - hyperparathyreosis - calcimimetics - calcitonin - multiple myeloma - malignant hypercalcemia - parathormone - sarcoidosis - 1,25-dihydroxyvitamin D.