Thus, neurologic dysfunction is the major feature of hypercalcemic states. Table 2: Clinical Manifestations of Hypercalcemia Symptoms and SignsĪ normal extracellular calcium concentration is necessary for normal neuromuscular function. Symptoms of underlying diseases-malignancy, sarcoidosis, and tuberculosis, for example-causing hypercalcemia may dominate the clinical picture. Patients with a chronic calcium level as high as 12 to 14 mg/dL may tolerate those levels well whereas sudden development of hypercalcemia in this range or higher may lead to dramatic changes in a patient's mental status. Symptoms are more severe with acute changes than with chronic calcium level elevation. Symptoms of hypercalcemia ( Table 2) are nonspecific and are related to the severity and rate of change of the serum calcium level.
These and other causes are summarized in Table 1. Measuring ionized calcium avoids issues with binding proteins.Īpproximately 90% of all cases of hypercalcemia in the outpatient setting are caused by either primary HPT or hypercalcemia of malignancy. The remainder is ionized calcium that is biologically active.
A small amount of calcium (about 6%) is also complexed to anions such as citrate and sulfate. Thus, this formula estimates the actual total plasma calcium level:Ĭorrected = Total + (0.8 × )Īcidosis decreases the amount of calcium bound to albumin whereas alkalosis increases the bound fraction of calcium. The calcium concentration usually changes by 0.8 mg/dL for every 1.0-g/dL change in plasma albumin concentration. Normal calcium levels range from 8.5 to 10.5 mg/day, assuming an albumin level of 4.5 g/dL. The total plasma calcium level, therefore, must be corrected for the albumin level. Although rare, this can result in pseudohypercalcemia-for example, in patients with hyperalbuminemia secondary to dehydration and in some patients with multiple myeloma. The total calcium level is low in patients with low levels of binding proteins (hypoalbuminemia) and higher in those with high levels of binding proteins. Approximately 50% of total calcium is protein bound, and the total calcium level will vary with protein-binding capacity. Hypercalcemia is usually detected initially as an elevation of total plasma calcium levels rather than ionized calcium levels. Treatment depends on the cause of the disorder. Symptoms are nonspecific and are related to the severity and rate of change of the serum calcium level, although neurologic dysfunction is an uncommon feature with mild hypercalcemia-patients can experience slight difficulties in concentrating but also experience depression, confusion, and coma as the condition becomes more severe. The condition can affect almost every organ system in the body. Most cases are caused either by primary hyperparathyroidism (HPT) or malignancy. Hypercalcemic emergencies are possible but uncommon. Hypercalcemia is a common clinical problem that typically leads to a chronic and mild elevation of calcium blood levels.
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