Hypocalcaemia
Hypocalcaemia means calcium in the blood has fallen below the normal range. Calcium does far more than build bones: it controls how nerves fire and how muscles contract, so even a modest drop produces noticeable symptoms.
Key points
- Because calcium helps control how nerves fire and muscles contract, even a modest fall in blood levels can produce noticeable symptoms.
- Early signs such as tingling around the lips and fingertips, cramping or fatigue can progress to muscle twitching or spasms if calcium stays low.
- A parathyroid problem, low vitamin D or kidney disease often lies behind the condition, treated with synthetic active vitamin D such as calcitriol or alfacalcidol.
What low calcium feels like
Early signs are easy to miss. Tingling or numbness around the lips and in the fingertips, muscle cramps, or an unusual feeling of fatigue are the most common complaints. In more pronounced cases people notice muscle twitching (tetany) or spasms. A sudden jolt-like spasm, a change in heartbeat, or a seizure warrants urgent medical attention.
Why it happens and how it is treated
The most frequent causes are underactive parathyroid glands (often after thyroid surgery), vitamin D deficiency, and kidney disease that impairs the body’s ability to convert vitamin D into its active form. Because active vitamin D is what actually drives calcium absorption from food, treatment focuses there. Medicines such as calcitriol and alfacalcidol are synthetic forms of active vitamin D used to restore calcium levels when the body cannot produce enough on its own. Both are covered more fully under bone health.