Hydroelectrolytic syndromes in neuroanesthesia and neurocritical care

Table 5 Calcium disorders correction

Disorder	Medication	Dosing/infusion	Route	Key notes
Hypocalcemia	Calcium gluconate	1-2 g (10-20 mL of 10% solution) over 10-20 min; repeat as needed	IV	Preferred for mild-moderate hypocalcemia; monitor ECG during infusion
	Calcium chloride	1 g (10 mL of 10% solution) over 5-10 minutes	IV (central line preferred)	Reserved for severe/acute hypocalcemia (e.g., tetany, arrhythmias); risk of tissue necrosis if extravasated
	Oral calcium	1-4 g elemental calcium daily (e.g., calcium carbonate 500-1500 mg TID)	PO	For mild/asymptomatic hypocalcemia; combine with vitamin D in chronic cases
	Calcitriol	0.25-2 µg/day	PO/IV	Enhances intestinal calcium absorption; used in chronic hypocalcemia or renal failure
	Magnesium sulfate	1-2 g over 1 h (if hypomagnesemic)	IV	Corrects hypomagnesemia to restore PTH function
Hypercalcemia	Isotonic saline	1-2 L bolus, then 150-300 mL/hour	IV	First-line for volume resuscitation and calciuresis; avoid in heart failure
	Furosemide	20-40 mg every 4-6 h (after rehydration)	IV	Enhances calcium excretion; avoid in hypovolemia
	Zoledronic acid	4 mg over ≥ 15 min	IV	Bisphosphonate for malignancy or severe hypercalcemia; peak effect at 48-72 h
	Pamidronate	60-90 mg over 2-24 h	IV	Alternative bisphosphonate; adjust dose for renal impairment
	Calcitonin	4-8 units/kg every 6-12 h	SC/IM	Rapid calcium reduction (4-6 h); tachyphylaxis limits use to 48 h
	Denosumab	120 mg weekly × 1-3 doses	SC	For refractory hypercalcemia (e.g., malignancy); inhibits RANKL
	Prednisone	20-40 mg/day	PO	For hypercalcemia due to vitamin D toxicity or granulomatous diseases

ECG: Electrocardiogram; IM: Intramuscular; IV: Intravenous; PO: By mouth; PTH: Parathyroid hormone; SC: Subcutaneous; TID: Three times a day; RANKL: Receptor activator of nuclear factor kappa-B ligand.