A 54-year-old female is awakened in the OR after thyroidectomy and develops severe stridor two days later. The most likely cause of airway obstruction is

A 54-year-old female is awakened in the OR after thyroidectomy and develops severe stridor two days later. The most likely cause of airway obstruction is

• A. Damage to the recurrent laryngeal nerve
• B. Damage to the superior laryngeal nerve
• C. Tracheomalacia
• D. Hypocalcemia

Answer: (D)

Hypocalcemia after thyroidectomy is the likely cause. The parathyroids (which regulate calcium) can be damaged or removed during thyroid surgery, leading to low calcium levels. Calcium stabilizes nerve and muscle membranes; when calcium falls, nerves become hyperexcitable and muscles can spasm (tetany). In the larynx, this can trigger laryngospasm, causing severe stridor and potential airway obstruction. The timing—within the first couple of days after surgery—fits this scenario. Damage to the recurrent laryngeal nerve would mainly cause hoarseness from vocal cord paralysis, not sudden stridor from a laryngospasm. Injury to the superior laryngeal nerve affects voice quality more than acute airway obstruction. Tracheomalacia involves dynamic airway collapse from long-standing tracheal compression and is not the typical cause of an abrupt post-op stridor like this.

Hypocalcemia after thyroidectomy is the likely cause. The parathyroids (which regulate calcium) can be damaged or removed during thyroid surgery, leading to low calcium levels. Calcium stabilizes nerve and muscle membranes; when calcium falls, nerves become hyperexcitable and muscles can spasm (tetany). In the larynx, this can trigger laryngospasm, causing severe stridor and potential airway obstruction. The timing—within the first couple of days after surgery—fits this scenario.

Damage to the recurrent laryngeal nerve would mainly cause hoarseness from vocal cord paralysis, not sudden stridor from a laryngospasm. Injury to the superior laryngeal nerve affects voice quality more than acute airway obstruction. Tracheomalacia involves dynamic airway collapse from long-standing tracheal compression and is not the typical cause of an abrupt post-op stridor like this.