While recovering on the surgical floor 24 hours after a total thyroidectomy for a large, s… — USMLE Step 2 CK

While recovering on the surgical floor 24 hours after a total thyroidectomy for a large, symptomatic multinodular goiter, a patient reports the onset of a "crawling" sensation around her lips and fingertips. Vital signs show a temperature of 38.2°C (100.8°F), pulse of 92/min, respirations of 16/min, and blood pressure of 115/75 mm Hg. Examination of the neck reveals a clean, dry, and intact surgical incision without any surrounding swelling, fluctuance, or erythema. The patient's voice is normal and there is no stridor. Tapping the area just anterior to the earlobe results in brief twitching of the ipsilateral facial muscles. Laboratory results drawn earlier this morning reveal:

Test	Result	Reference Range
Calcium, total	7.2 mg/dL	8.4-10.2 mg/dL
Albumin	4.0 g/dL	3.5-5.0 g/dL
TSH	1.8 µU/mL	0.5-5.0 µU/mL
Free T4	1.3 ng/dL	0.9-1.7 ng/dL

Which of the following is the most appropriate next step in the management of this patient?

Intravenous administration of calcium gluconateAnswer
B
Initiation of empiric broad-spectrum antibiotics
C
Immediate bedside opening of the cervical incision
D
Administration of oral levothyroxine therapy
E
Obtaining a computed tomography scan of the neck

Answer

Intravenous administration of calcium gluconate

The correct answer is the intravenous administration of calcium gluconate. This patient is presenting with classic signs of acute, symptomatic hypocalcemia, including perioral numbness, tingling in the extremities, and a positive Chvostek sign (ipsilateral facial muscle twitching when tapping the facial nerve). In the context of a recent total thyroidectomy, this is overwhelmingly likely due to inadvertent removal or devascularization of the parathyroid glands. Because she is actively symptomatic, she requires immediate intravenous calcium replacement (typically calcium gluconate) to prevent severe complications such as laryngospasm, tetany, seizures, and QT-prolongation leading to arrhythmias.

Step-by-Step Solution

Analyze the physical examination findings and vital signs.

The patient exhibits perioral numbness, paresthesias of the fingertips, and a positive Chvostek sign (facial muscle twitching upon tapping the facial nerve). Fever is present, but the incision is benign and the airway is secure.

Identifying these classic neurologic signs establishes a clinical suspicion for neuromuscular irritability.

Correlate physical findings with laboratory data.

The total serum calcium is significantly low at 7.2 mg/dL with a normal albumin, confirming true hypocalcemia. Thyroid labs are within normal limits.

Laboratory confirmation is necessary to differentiate hypocalcemia from other causes of postoperative parasthesias or neurological changes.

Determine the etiology based on the surgical history.

The patient is 24 hours post-total thyroidectomy. The most common cause of acute hypocalcemia in this setting is transient or permanent hypoparathyroidism due to inadvertent parathyroid gland removal or devascularization.

Connecting the surgery to the metabolic derangement guides targeted therapy.

Select the appropriate therapeutic intervention.

Because the patient is symptomatic (positive Chvostek sign, paresthesias), immediate intravenous calcium gluconate is required to prevent progression to tetany, seizures, or cardiac arrhythmias.

Symptomatic hypocalcemia is a medical emergency; oral calcium is insufficient for acute, symptomatic presentation.

Key Concept

Post-thyroidectomy symptomatic hypocalcemia recognition and management

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