What causes tetany and involuntary muscle spasms?

Tetany is a condition characterized by involuntary muscle spasms and rhythmic cramping, particularly in the hands, feet, and larynx. It is primarily caused by a metabolic imbalance, most notably a deficiency of calcium in the bloodstream, known as hypocalcemia.123

In addition to low calcium, tetany can be triggered by:
* Abnormal levels of potassium or magnesium in the circulation.1
* Alkalosis, which is an over-alkaline condition of the body's blood and tissues.12

These imbalances often stem from underlying health issues, such as hypoparathyroidism—frequently caused by the accidental removal of the parathyroid glands during surgery—renal disorders, vitamin D deficiency, or malabsorption syndromes. Treatment focuses on restoring metabolic balance, often through the administration of calcium.134

It is important to distinguish tetany from tetanus, a separate condition involving continuous muscle spasms caused by toxins from the bacterium Clostridium tetani.2