Trousseau sign indicates hypocalcemia.

• A. Chvostek sign
• B. Trousseau sign
• C. Kernig sign
• D. Babinski sign

Answer: (B)

Low calcium makes nerves more excitable, so muscles can start contracting stubbornly (tetany) when the system is irritated. The Trousseau sign tests for this latent tetany by inflating a blood pressure cuff above systolic pressure for a few minutes. The ischemia in the forearm triggers a reflex carpopedal spasm with the hand and fingers curling inward, which is a classic positive finding in hypocalcemia. This bedside test directly demonstrates the heightened neuromuscular excitability caused by low calcium.

Chvostek sign, another marker of hypocalcemia, arises from tapping the facial nerve and causing facial muscle twitching—also due to increased nerve irritability but via a different mechanism. Kernig sign and Babinski sign are not related to calcium status; they indicate meningeal irritation and upper motor neuron pathways, respectively. So the Trousseau sign is the most specific bedside indicator of hypocalcemic tetany.