Symptomatische Hyperkalzämie und hyperkalzämische Krise

Biochemically, hypercalcemia can be classified as mild (< 3 mmol/L), moderate (3–5 mmol/L), or severe (> 3.5 mmol/L). Mild hypercalcemia is usually asymptomatic. Severe hypercalcemia can also be oligo- or asymptomatic if it has developed slowly. Symptomatic hypercalcemia is therefore usually at least moderate biochemically. Pronounced acute symptoms are accompanied by nausea, vomiting, exsiccosis, and a corresponding disturbance of vigilance. In chronic forms, fatigue, nephrolithiasis, and gastrointestinal complaints play a greater role.

In > 90% of cases, hypercalcemia is caused by primary hyperparathyroidism (pHPT) or malignant hypercalcemia (humoral hypercalcemia of malignancy: HHM). Elevated PTH and hypercalciuria are diagnostic for pHPT. In the case of HHM, the tumor disease is very often either known or obvious. If the PTH is then suppressed, further clarification is usually unnecessary. Calcitriol-dependent hypercalcemia, on the other hand, is already rare. In the case of calcium-induced exsiccosis, volume compensation is of decisive therapeutic importance. Inhibition of bone resorption by bisphosphonates or denosumab is then the most important pharmacological intervention. As a rule, the calcium can be normalized or at least reduced sufficiently well within 2–4 days. Patients requiring intensive care can also be stabilized well with these measures and therapy escalation is typically not necessary.