In hypoparathyroidism with severely low calcium, which sign is expected?

In hypoparathyroidism with severely low calcium, which sign is expected?

• A. Unresponsive pupils
• B. Positive Trousseau's sign
• C. Negative Chvostek's sign
• D. Hyperactive bowel sounds

Answer: (B)

Low calcium levels increase the excitability of nerves and muscles, leading to tetany. A classic manifestation of this in severe hypocalcemia is a positive Trousseau's sign. When a blood pressure cuff is inflated above systolic pressure for a few minutes, the resulting ischemia triggers involuntary contraction of the hand and fingers (carpopedal spasm). This occurs because low extracellular calcium lowers the threshold for muscle fiber depolarization and nerve firing, so the hand spasms in response to the ischemic stimulus. In hypoparathyroidism, the lack of PTH reduces calcium and shifts the balance toward neuromuscular irritability, making Trousseau's sign a prominent and reliable clue. Chvostek's sign can also be positive, as tapping the facial nerve may elicit facial muscle twitch, but Trousseau's sign is the more specific and widely tested indicator of severe hypocalcemia. Unrelated signs like unresponsive pupils or hyperactive bowel sounds do not fit the typical picture of hypocalcemic tetany.

Low calcium levels increase the excitability of nerves and muscles, leading to tetany. A classic manifestation of this in severe hypocalcemia is a positive Trousseau's sign. When a blood pressure cuff is inflated above systolic pressure for a few minutes, the resulting ischemia triggers involuntary contraction of the hand and fingers (carpopedal spasm). This occurs because low extracellular calcium lowers the threshold for muscle fiber depolarization and nerve firing, so the hand spasms in response to the ischemic stimulus. In hypoparathyroidism, the lack of PTH reduces calcium and shifts the balance toward neuromuscular irritability, making Trousseau's sign a prominent and reliable clue. Chvostek's sign can also be positive, as tapping the facial nerve may elicit facial muscle twitch, but Trousseau's sign is the more specific and widely tested indicator of severe hypocalcemia. Unrelated signs like unresponsive pupils or hyperactive bowel sounds do not fit the typical picture of hypocalcemic tetany.