Hypercalcemia

Anesthesia Implications

Anesthesia Implications

Treatment – Hypercalcemia should be treated if calcium levels reach > 13 mg/dL or if the patient is symptomatic

Hydrate – Rehydrate prior to induction. Hypercalcemia is frequently associated with hypovolemia due to polyuria. Fluid replacement will help to drop calcium levels (dilution) and rehydrate. Loop diuretics to increase calcium excretion should NOT be used until after the patient has been fluid resuscitated.

Avoid Lactated Ringers – contains calcium.

Administration of calcitonin or biphosphonates – will inhibit bone resorption (further increases in calcium levels)

NO THIAZIDE diuretics – these actually stimulate renal tubule reabsorption calcium.

Watch hemodynamics – Fluid shifts caused by rehydration and diuresis may require monitoring central venous and/or pulmonary artery pressure

Careful positioning – these patients may have brittle bones due to calcium sequestration

Judicious paralytics – Hypotonia caused by hypercalcemia should prompt judicious use of paralytics and regular TOF monitoring

Hypokalemia – Hypercalcemia can cause hypokalemia due to transcellular shifts

Urine Output – Acute hypercalcemia will cause renal vasoconstriction and nephrogenic diabetes insipidus – so watch UOP

Pathophysiology

Defined as a blood calcium > 10.4 mg/dL

Hypercalcemia can happen for a number of reasons. Calcium is absorbed in the gut, excreted in the urine, and stored in bone as a reservoir. Disruptions in any of these can result in changes in calcium levels. In this case, excess intestinal absorption, decreased renal excretion, and increased bone breakdown/resorption would cause hypercalemia

Drugs/supplements responsible for this condition can include thiazide diuretics, lithium, estrogens, vitamin (D & A) toxicity, and calcium.

Signs and symptoms include confusion, hypotonia, depressed tendon reflexes, lethargy, abdominal pain, and N&V

The cardiac ST and QT segments are shortened

In essence, this condition raises the threshold of excitable cells and causes progressive depression of the central nervous system

Chronic hypercalcemia often leads to polyuria, hypercalciuria, and nephrolithiasis

Hyperparathyroidism is associated with a blood Ca LESS than 11 mEq. Cancer is associated with a blood Ca GREATER than 13 mEq.

Hyperparathyroidism and cancer are the most common causes. This is a poor prognostic indicator for cancer.

Treatment is aimed at reducing intestinal absorption, increased urinary excretion of calcium, and/or inhibiting bone resorption

Additional Notes:

Steroids reduce blood calcium by increasing the renal excretion of calcium and reducing the absorption of calcium from dietary sources

References

Hines. Stoelting’s anesthesia and co-existing disease. 7th edition. 2018. 416-417, 470-475, 593
Nagelhout. Nurse anesthesia. 5th edition. 2014. p. 388-389, 737, 846, 851
Nagelhout. Nurse anesthesia. 6th edition. 2018. p. 794