[Hypercalcemia]

Hypercalcemia may develop as a consequence of a disturbance of one or more links within the feedback system of calcium homeostasis. Hypercalcemic diseases may be caused by the parathyroid glands as well as by their dependent end organs, the kidneys, the intestine, the skeleton. Partial parathyroid hormone activity can be produced by many tumour factors in a paraneoplastic way. Hypercalcemia induces the symptoms of the so-called hypercalcemic syndrome which should be familiar to the physician. Hints towards the cause may be the organ manifestation in case of primary hyperparathyroidism, in case of the other causal diseases they may present with typical components of their clinical picture. Diagnostics should start with the differentiation between parathyroid-related hypercalcemia (autonomous, primary hyperparathyroidism and variants) and the broad spectrum of non-parathyroid hypercalcemia, mainly accompanying malignancies. Symptomatic treatment of hypercalcemia often has to start before the definite diagnosis is confirmed. Later on, this merely symptomatic treatment may be replaced by causal treatment, as far as possible. Symptomatic treatment of hypercalcemia may follow the 'diuretic', the 'antiresorptive', or the 'antiabsorptive' way--the 'extractive' way by hemodialysis is the treatment of choice in case of hypercalcemic crisis accompanied by renal insufficiency.