Hypercalcemic Crisis

Presentation:
- severe dehydration
- hypotension,
- altered mental status
- dysrhythmias

Management:
- hydrate: normal saline at a rate of 300 ml/hr; rehydration promotes calcium excretion in proximal tubule which is associated with Na flux
- Loop diuretics: reduce fluid overload and inhibit calcium resorption in the loop of Henle, thus promoting increased renal calcium excretion. 
- Dialysis: Patients with renal failure should be dialyzed with low-calcium dialysate

Pharmacologic agents to be used after rehydration:
- Steroids: Glucocorticoids lower calcium by inhibiting effects of vitamin D, increasing renal calcium excretion, and inhibiting osteoclast-activating factor. 
- hydrocortisone is 200 to 400 mg IV per day for 3 to 5 days
- Bisphosphonates inhibit osteoclast activity, thus preventing bone resorption induced by PTH. 
- Pamidronate (90 mg IV) or zoledronic acid (4 mg IV initial treatment, 8 mg on retreatment) normalizes calcium levels in most patients
- Calcitonin acts quickly (within 24 to 48 hours) to lower serum calcium levels and is more effective when used in combination with glucocorticoids. It should not be used in patients with salmon allergies. 

After patients with PHPT and hypercalcemic crisis are stabilized and serum calcium levels have been reduced to acceptable levels, preoperative localization studies should be obtained expeditiously in anticipation of an urgent parathyroidectomy.

Cameron 9th ed