R.N.

A patient is hypocalcemic when total serum calcium level is less than 8.5 mg/dL or the ionized calcium level is below 4.65 mg/dL. Possible causes of hypocalcemia include inadequate intake of calcium, hypomagnesemia (which can reduce PTH secretion or cause PTH resistance), malabsorption (as in celiac disease), hyperphosphatemia, or excessive renal excretion of calcium. Disorders often associated with hypocalcemia include renal failure, pancreatitis, and primary and surgical hypoparathyroidism. Pseudohypocalcemia is caused by hypoalbuminemia.²

The major signs and symptoms of hypocalcemia are related to increased neuromuscular excitability. Mild hypocalcemia may cause few if any signs and symptoms, but severe hypocalcemia, which can cause seizures, heart failure, and laryngospasm, can be life-threatening.⁷

During physical assessment, you may elicit a positive Chvostek sign or Trousseau sign.¹,³,⁷ See Two signs of trouble. For more signs and symptoms of hypocalcemia, see Comparing hypocalcemia and hypercalemia.