What does Trousseau's sign indicate?

Trousseau's sign is indicative of low calcium levels, also known as hypocalcemia. This sign is elicited by inflating a sphygmomanometer cuff around the upper arm to a pressure above the systolic blood pressure, typically for several minutes. A positive Trousseau's sign is characterized by the involuntary contraction of the hand and wrist, known as carpopedal spasm. This physiological response occurs due to increased neuromuscular excitability that happens when calcium levels are low in the bloodstream, highlighting the importance of calcium in muscle and nerve function.

In the context of the other options, low levels of magnesium may produce different clinical signs, but they do not specifically correlate with Trousseau's sign. Elevated blood pressure is related to several other health issues and is not directly linked to hypocalcemia or Trousseau's sign. Similarly, high potassium levels, or hyperkalemia, would manifest with different clinical symptoms and signs, such as cardiac changes, rather than the muscular response seen in Trousseau's sign. This clarity helps to confirm that the correct answer indeed represents the relationship between hypocalcemia and Trousseau's sign.