Trousseau Sign and Post-Thyroidectomy Hypocalcemia
A 35-year-old woman is one day after total thyroidectomy for a large multinodular goiter. While the nurse inflates the blood pressure cuff on her arm, the wrist flexes and the fingers draw together into a painful spasm that persists for two minutes. She also reports tingling around the mouth and in the fingertips. Which of the following is the most appropriate next step in management?
- A.Administer intravenous analgesia
- B.Measure total and ionized serum calciumCorrect
- C.Repeat the blood pressure on the other arm
- D.Provide reassurance and observe
Explanation
Carpal spasm provoked by inflating a blood pressure cuff above systolic pressure is the Trousseau sign, a manifestation of latent tetany from hypocalcemia. One day after total thyroidectomy, the expected cause is iatrogenic hypoparathyroidism, because the parathyroid glands may be bruised, devascularized, or inadvertently removed during the dissection. Parathyroid hormone maintains serum calcium through bone resorption, renal reabsorption, and activation of vitamin D, so when it falls the ionized calcium falls with it. Low ionized calcium lowers the threshold for nerve and muscle depolarization, producing perioral and acral paresthesia, carpopedal spasm, and a positive Chvostek sign. The correct next step is to confirm the suspicion objectively by measuring total and ionized calcium, together with magnesium and phosphate, so that intravenous calcium gluconate can be started if the level is low or symptoms progress. This matters because severe hypocalcemia can cause laryngospasm with airway obstruction, seizures, a prolonged QT interval, and cardiac arrhythmia. Rechecking the blood pressure would simply reproduce the sign without adding information, and reassurance alone ignores a potentially life-threatening electrolyte disturbance. Analgesia treats a symptom rather than the underlying deficiency, which is why it is inappropriate here.
Why each option
- A.
- The problem is involuntary tetanic muscle contraction from low ionized calcium, not primarily a pain syndrome, so analgesia does not address the cause.
- B.
- Correct. Trousseau sign after thyroidectomy demands prompt measurement of total and ionized calcium so that calcium replacement can be started.
- C.
- Repeating the blood pressure would only re-elicit the spasm and delay the diagnostic test that changes management.
- D.
- Reassurance is not sufficient because the sign indicates a biochemical abnormality that can progress to laryngospasm, seizures, or arrhythmia.
Reference: Schwartz's Principles of Surgery, 11th ed., 2019; UpToDate 2025, Clinical manifestations of hypocalcemia
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