Question

What is NOT likely to be the cause of stridor occurring 2 hours after a thyroidectomy?

• A. Hypocalcemia
• B. Wound hematoma
• C. Tracheomalacia
• D. RLN injury bilaterally

Hint:

Hypocalcemia after thyroidectomy takes a day or more to cause symptoms, not 2 hours.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
Stridor appears just 2 hours after a thyroidectomy, and we need the cause that is NOT likely to explain it at this early time point.

Step 2: Key Formula or Approach:
Post thyroidectomy stridor has several causes, and each has a different typical timing. Matching the cause to how soon it appears after surgery is the key to this question.

Step 3: Detailed Explanation:
Wound hematoma: bleeding into the closed neck space can build up within the first few hours after surgery, pressing on the trachea and causing sudden stridor. This fits a 2 hour timeline, it is an early, even immediate complication.
Bilateral recurrent laryngeal nerve (RLN) injury: if both nerves are cut or badly stretched during surgery, both vocal cords lie close to the midline right after extubation, and stridor from airway narrowing can show up as soon as the patient wakes up. This also fits an early timeline.
Tracheomalacia: a trachea long weakened by a large goiter can cave in once the supporting mass is removed, and this too can show itself early, in the recovery period soon after surgery.
Hypocalcemia: the parathyroid glands are often bruised or removed with the thyroid, and blood calcium drifts down gradually as parathyroid hormone falls after surgery. Symptoms like tingling, cramps, and laryngospasm from hypocalcemia usually appear from about 24 to 72 hours after surgery, not within the first 2 hours, since it takes time for calcium levels to fall low enough to cause symptoms.

Step 4: Final Answer:
Hypocalcemia takes a day or more to drop low enough to cause laryngospasm, so it is not a likely cause of stridor only 2 hours after surgery. \[ \boxed{\text{Hypocalcemia}} \]