[Hypercalcemia]

The most common cause of hypercalcemia is primary hyperparathyroidism. The level of parathyroid hormone (PTH) is the starting point of differential diagnosis. Other basic investigations include plasma phosphorus level, vitamin D, and calculated creatinine clearance. PTH-dependent hypercalcemia is mainly caused by primary hyperparathyreosis. If PTH is suppressed, malignant disease must be concidered carefully. Signs of severe hypercalcemia or hypercalcemic crisis are nausea, worsening general condition and impairment of renal function, whereby symptomatic treatment will be initiated without delay. Calcium drugs, thiazide diuretics and lithium are terminated. After taking care of sufficient rehydration, loop diuretics and bisphosphonates can be used as first line treatment of severe hypercalcemia.