Hypercalcemia (calcium excess; synonyms: Hypercalcemia; hypercalcemia; hypercalcemia; hypercalcemia syndrome; ICD-10-GM E 83.5: disorders of calcium metabolism) occurs when the concentration of serum calcium in an adult rises above a value of > 2.5 mmol/l.
In mild hypercalcemia, the serum calcium level is 2.7-3.0 mmol/l and in severe hypercalcemia, it is > 3.0 mmol/l.
A special form of hypercalcemia is tumor-induced hypercalcemia (TIH; tumor hypercalcemia; tumor-associated hypercalcemia). This is accompanied by a serum calcium value > 3.5 mmol/l (= hypercalcemic crisis) and symptoms such as polyuria (increased urination), exsiccosis (dehydration), hyperpyrexia (extreme fever: higher than 41 °C), cardiac arrhythmias, weakness and lethargy as well as somnolence (drowsiness with abnormal sleepiness while maintaining responsiveness and wakefulness) up to coma.
Sex ratio: women are affected 3 to 4 times more often than men.
Peak incidence: incidence increases with age; after age 60, prevalence (disease frequency) increases.
Prevalence (disease incidence) is 1% and up to 3% in postmenopausal women. This is higher in hospitalized patients.
The incidence (frequency of new cases) of hypercalcemia is not known in the general population.
Course and prognosis: Since calcium homeostasis is very tightly regulated, deviations from the norm are rare. Therefore, any hypercalcemia should be clarified!First symptoms of hypercalcemia usually occur at a total serum calcium of > 2.8-2.9 mmol/l. Note: Mild hypercalcemia may be indicative of primary hyperparathyroidism (parathyroid hyperfunction with increased production of parathyroid hormone and resulting calcium excess) (= most common cause in a family practice; 25% of cases of hypercalcemia). In a clinic, hypercalcemia is due to malignancy in up to 65% of cases. Tumor-associated hypercalcemia is called tumor hypercalcemia (tumor-induced hypercalcemia, TIH).The course and prognosis of hypercalcemia depend on the type of disease.
