What is a common cause of stridor following a parathyroidectomy when the drain is empty?

Laryngospasm due to hypocalcaemia is indeed a common cause of stridor following a parathyroidectomy, particularly when the drain is empty. During this surgical procedure, the removal of one or more parathyroid glands may lead to a significant drop in serum calcium levels, resulting in hypocalcaemia. One of the physiological responses to low calcium levels is laryngospasm, which is a sudden closure of the vocal cords. This can present as stridor, a high-pitched wheezing sound resulting from turbulent airflow through narrowed airways.

In the context of the post-operative setting, the empty drain indicates that there is no immediate concern regarding fluid accumulation or ongoing bleeding, which could obstruct the airway. While excessive bleeding could lead to airway complications, the specific challenge presented by stridor in this scenario points to the physiological response triggered by hypocalcaemia.

Airway obstruction might suggest a different cause of stridor, such as swelling, infection, or foreign body, rather than the biochemical changes associated with hypocalcaemia. Vocal cord paralysis is a potential consequence of surgical trauma or nerve injury during the procedure but is less commonly the immediate cause of post-operative stridor compared to laryngospasm due to hypocalca