Which sign may be present in hypocalcemia?

Trousseau's sign is a clinical finding indicative of hypocalcemia. It occurs when there is involuntary contraction of the muscles, typically in the hand, after inflation of a blood pressure cuff around the arm. This phenomenon is due to increased neuromuscular excitability that results from low levels of calcium in the blood. The mechanism is related to the effect of calcium on nerve and muscle function; insufficient calcium leads to heightened thresholds for depolarization, causing muscles to react too strongly to stimuli.

In contrast, while bradycardia may relate to other electrolyte imbalances or other medical conditions, it is not specifically indicative of hypocalcemia. The other options, including jaundice and ecchymosis, also relate to different pathophysiological processes—jaundice is typically associated with liver dysfunction or hemolysis, while ecchymosis involves bleeding or bruising and can be linked to clotting disorders or trauma rather than low calcium levels. Thus, Trousseau's sign is a hallmark clinical indicator specifically associated with hypocalcemia.