Hypercalcemia can be produced by a variety of disorders, but primary hyperparathyroidism and malignancy account for most cases. (See "Etiology of hypercalcemia".) It may be associated with a spectrum of clinical manifestations (table 1), ranging from few if any symptoms if the hypercalcemia is mild and/or chronic to obtundation and coma if it is severe and/or acute . The symptoms and signs associated with hypercalcemia are typically independent of the etiology .
Patients with mild hypercalcemia (calcium <12 mg/dL [3 mmol/L]) may be asymptomatic, or they may report nonspecific symptoms, such as constipation, fatigue, and depression. A serum calcium of 12 to 14 mg/dL (3 to 3.5 mmol/L) may be well-tolerated chronically, while an acute rise to these concentrations may cause marked symptoms, including polyuria, polydipsia, dehydration, anorexia, nausea, muscle weakness, and changes in sensorium. In patients with severe hypercalcemia (calcium >14 mg/dL [3.5 mmol/L]), there is often progression of these symptoms [1,2].
This topic will review those symptoms directly associated with hypercalcemia. The clinical manifestations more directly associated with hyperparathyroidism and the diagnostic approach to and treatment of hypercalcemia are discussed separately. (See "Clinical manifestations of primary hyperparathyroidism" and "Diagnostic approach to hypercalcemia" and "Treatment of hypercalcemia".)
A number of mild neuropsychiatric disturbances have been associated with hypercalcemia, mostly in patients with primary hyperparathyroidism. The most common symptoms have been anxiety, depression, and cognitive dysfunction. Improvement in some or all of these symptoms has been described after correction of the hyperparathyroidism, but these reports are of uncontrolled cases and therefore difficult to evaluate. (See "Clinical manifestations of primary hyperparathyroidism", section on 'Neuropsychiatric disturbances' and "Management of primary hyperparathyroidism", section on 'Neuropsychiatric'.)
More severe symptoms, including lethargy, confusion, stupor, and coma may occur in patients with severe hypercalcemia (calcium >14 mg/dL [3.5 mmol/L]) from any cause . These symptoms are more likely to occur in the elderly and in those with rapidly rising calcium concentrations [2,3].