What is Trousseau Sign?
Trousseau sign (also called Trousseau’s sign of latent tetany) is a clinical finding in which a sudden, involuntary contraction of the muscles of the hand and wrist occurs when a blood pressure cuff is inflated above systolic pressure for a few minutes. The hand adopts a characteristic “carpopedal spasm” – the fingers flex, the thumb adducts, and the wrist may extend, producing a look similar to a “claw.” The phenomenon reflects heightened neuromuscular excitability, most often caused by low levels of ionized calcium in the blood (hypocalcemia). The sign was first described by French physician Armand Trousseau in the 1860s and remains a bedside tool for detecting metabolic disturbances.
Common Causes
Although hypocalcemia is the classic trigger, many conditions can lower serum calcium or otherwise increase nerve‑muscle excitability, leading to a positive Trousseau sign. The most frequent causes include:
- Vitamin D deficiency – impairs calcium absorption from the gut
