Hypocalcaemia
Hypocalcaemia means biologically active calcium in the blood is too low. It can increase nerve and muscle excitability, causing tingling or cramps, while a rapid or severe fall can provoke spasms, seizures or an abnormal heart rhythm.
Key points
- Total calcium can appear low when albumin is low, so corrected or ionised calcium may be needed for interpretation.
- Magnesium, vitamin D, kidney function and parathyroid hormone help identify the cause.
- Active vitamin D is useful for selected causes but can overshoot, so calcium and related minerals need monitoring.
A vitamin D medicine listing cannot establish the cause or urgency; symptoms, ECG findings and confirmed calcium level determine treatment.
What symptoms can low calcium cause?
Tingling around the mouth or fingertips, muscle cramps and twitching are common clues. Severity depends on how low calcium is and how quickly it fell; chronic mild abnormalities may cause few symptoms.
How is treatment selected?
Severe symptomatic hypocalcaemia may need monitored intravenous calcium. Calcitriol or alfacalcidol can support calcium absorption in hypoparathyroidism or selected kidney disease, but ordinary vitamin D deficiency may be managed differently. See bone health for related context.
When to seek urgent care
Seek emergency care for a seizure, breathing difficulty, sustained muscle spasm, fainting, confusion or a fast or irregular heartbeat. New tingling or cramping after thyroid or neck surgery also needs prompt assessment.