What is hypocalcemia?

Updated: Aug 08, 2019
  • Author: Manish Suneja, MD, FASN, FACP; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Hypocalcemia is defined as a total serum calcium concentration < 8.8 mg/dL (< 2.20 mmol/L) in the presence of normal plasma protein concentrations or as a serum ionized calcium concentration < 4.7 mg/dL (< 1.17 mmol/L). Reference ranges for serum calcium vary by age and sex; see Serum Calcium.

Hypocalcemia may be acquired or hereditary. Acquired causes include a variety of illnesses (eg, hypoparathyroidism, hepatic disease, kidney disease), diet, medication, and surgery (see Overview/Etiology).

The presentation of hypocalcemia varies widely, from asymptomatic to life-threatening. Hypocalcemia is frequently encountered in patients who are hospitalized. Depending on the cause, unrecognized or poorly treated hypocalcemic emergencies can lead to significant morbidity or death. [1] Symptomatic patients with classic clinical findings of acute hypocalcemia require immediate resuscitation and evaluation. However, most cases of hypocalcemia are discovered by clinical suspicion and appropriate laboratory testing. (See Presentation and Workup.)

The treatment of hypocalcemia depends on the cause, the severity, the presence of symptoms, and how rapidly the hypocalcemia developed. Most cases of hypocalcemia are clinically mild and require only supportive treatment and further laboratory evaluation. Oral calcium repletion may be indicated for outpatient treatment of mild cases. On occasion, severe hypocalcemia may result in seizures, tetany, refractory hypotension, or arrhythmias that require a more aggressive approach, including intravenous infusions of calcium. (See Treatment and Medication.)

For more information on hypocalcemia in children, see Pediatric Hypocalcemia.

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