hypercalciemi

Hypercalcemia, or hypercalciemi, is a condition defined by higher-than-normal calcium levels in the blood. In adults, total serum calcium above about 10.5 mg/dL (2.62 mmol/L) or ionized calcium above roughly 1.3 mmol/L is considered elevated. Because calcium binds to albumin, corrected calcium may be used when albumin is abnormal.

Causes are typically divided into PTH-dependent and PTH-independent categories. PTH-dependent causes include primary hyperparathyroidism, familial hypocalciuric hypercalcemia, and, less commonly, tertiary hyperparathyroidism. PTH-independent causes include malignancy with PTH-related peptide (PTHrP) or local osteolysis, vitamin D intoxication, granulomatous diseases such as sarcoidosis, excessive vitamin D intake, certain medications (eg, thiazide diuretics, lithium), and immobilization.

Most cases are asymptomatic. When symptoms occur, they may include increased thirst and urination, dehydration, constipation, abdominal pain, nausea, weakness, confusion, or memory changes. Severe hypercalcemia can cause cardiorespiratory and renal complications and, if not treated, may be life-threatening.

Evaluation starts with measuring total and ionized calcium and albumin, followed by parathyroid hormone (PTH) level to distinguish PTH-dependent from PTH-independent causes. If PTH is suppressed, testing for PTHrP, 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D helps identify malignancy or granulomatous disease. Kidney function, phosphorus, and targeted imaging may be indicated based on the suspected etiology.

Management depends on severity and cause. Mild cases may require observation and treatment of the underlying condition. Moderate to severe or symptomatic hypercalcemia is typically treated with intravenous isotonic saline hydration, followed by agents that reduce bone resorption such as bisphosphonates or denosumab; calcitonin can provide rapid but short-term relief. Surgical treatment is considered for eligible cases of primary hyperparathyroidism, and cancer-related hypercalcemia requires oncologic therapy.