Key Tips for Interpreting Hypercalcemia
Hypercalcemia is often discovered during routine bloodwork. After malignancy is ruled out, asymptomatic or symptomatic patients with calcium concentrations >10.2 mg/dL should be evaluated for primary hyperparathyroidism.
Asymptomatic Hypercalcemia May Indicate Hyperparathyroidism
Hypercalcemia (serum calcium concentrations >10.2 mg/dL) is often detected during routine blood work. In over 90 percent of patients with hypercalcemia, the root cause is usually either malignancy or hyperparathyroidism.
Distinguishing between the two conditions is straightforward. Malignancy is usually clinically evident by the time hypercalcemia develops. These patients have higher (>13 mg/dL) and more rapidly increasing calcium concentrations and their PTH level is very low or undetectable.
Common symptoms of hypercalcemia include fatigue, bone pain, muscle weakness, memory loss or difficulty concentrating, constipation, nausea and vomiting, thirst, and frequent urination
Hyperparathyroidism should be suspected in asymptomatic patients who have chronic borderline or mild hypercalcemia (>10.2 mg/dL).
Physicians should first discontinue any calcium-elevating medications and repeat lab tests to confirm hypercalcemia. Those results should also be corrected for albumin abnormalities in patients with hypoalbuminemia.
Hyperparathyroidism Diagnosis: PTH >65 pg/mL
After hypercalcemia is confirmed, lab measurement of intact parathyroid hormone (PTH) is the gold standard for diagnosing hyperparathyroidism.
Elevated (>65 pg/mL) or high-normal (25 to 65 pg/mL) PTH concentrations likely indicate primary hyperparathyroidism.
Measurements of urinary calcium excretion and 25-hydroxyvitamin D may also be used to distinguish primary hyperparathyroidism from familial hypocalciuric hypercalcemia (FHH), secondary hyperparathyroidism, or other diseases.
After Diagnosis, Refer to an Endocrine Surgeon
Refer patients with hyperparathyroidism to an endocrine surgeon for further evaluation and treatment.
Imaging may be ordered by the surgeon to guide their operative management, but should not be used to determine who should be referred for surgical treatment.
Surgical removal of one or more parathyroid glands is recommended for patients with asymptomatic primary hyperparathyroidism. Parathyroidectomy helps preserve patients’ bone density, decreases the likelihood of cardiac events, and improves quality of life.
Patients with secondary hyperparathyroidism may be initially managed medically, but may require surgery if their disease is refractory to medical management. Patients with tertiary hyperparathyroidism are best treated surgically. Familial hypocalciuric hypercalcemia is not treated with surgery.
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