Bone/Parathyroid Case 1

A 34 year-old woman comes to the emergency department for evaluation and management of postsurgical hypoparathyroidism. Her serum calcium is 6.8 mg/dL (normal, 8.9 to 10.1 mg/dL) two days after undergoing subtotal thyroidectomy for a unicentric 2.5-cm right thyroid lobe papillary cancer, without evidence of metastatic lymph nodes. She tolerated her surgery without difficulty but developed mild symptoms of tingling paresthesias at her fingertips, toe tips, and lips, and muscle cramps, beginning about six hours after surgery. She was sent home on calcium carbonate 500 mg twice daily, but her tingling paresthesias worsened over the next 24 hours. Her laboratory studies during her emergency department evaluation showed her serum phosphate increased at 6.4 mg/dL (normal, 2.5 to 4.5 mg/dL), serum creatinine normal at 1.0 mg/dL, and parathyroid hormone (PTH) undetectable.

Question 1

What treatments should be offered acutely to this patient with newly diagnosed symptomatic hypoparathyroidism?

A. Infusion of calcium gluconate given by diluting 10 mL of 10% calcium gluconate solution in 100 mL D5W (5% dextrose in water) over 5-10 minutes and repeat as needed
B. Begin oral calcium citrate 600 mg elemental calcium two tablets twice daily as soon as she can begin oral intake
C. Begin magnesium oxide 400 mg twice daily
D. Begin calcitriol 0.25 mg twice daily
E. All of the above
Incorrect!
Correct!
Correct Answer
E. All of the above

Patients with new-onset postsurgical hypoparathyroidism commonly present to the emergency department within several days of surgery with hypocalcemia, hyperphosphatemia, normal serum creatinine, and a low or undetectable parathyroid hormone level. Most patients with acute hypoparathyroidism are symptomatic, like this patient, with tingling paresthesias around their fingertips, toe tips, and lips, and experience muscle cramps or tetany.

Chvostek's sign, Trousseau's sign, and prolonged QT interval on their electrocardiogram may be seen. Repletion of their deficiencies with supplementation of intravenous calcium followed by oral calcium, both active and nutritional vitamin D, and magnesium, if needed, is usually sufficient to minimize their symptoms and signs. Doses are titrated up every few days until serum calcium is in the 8.0 to 8.5 mg/dL range, with improved symptoms, serum 25-hydroxyvitamin D are in goal range, and serum magnesium is normal.

Patients with new-onset postsurgical hypoparathyroidism commonly present to the emergency department within several days of surgery with hypocalcemia, hyperphosphatemia, normal serum creatinine, and a low or undetectable parathyroid hormone level. Most patients with acute hypoparathyroidism are symptomatic, like this patient, with tingling paresthesias around their fingertips, toe tips, and lips, and experience muscle cramps or tetany.

Chvostek's sign, Trousseau's sign, and prolonged QT interval on their electrocardiogram may be seen. Repletion of their deficiencies with supplementation of intravenous calcium followed by oral calcium, both active and nutritional vitamin D, and magnesium, if needed, is usually sufficient to minimize their symptoms and signs. Doses are titrated up every few days until serum calcium is in the 8.0 to 8.5 mg/dL range, with improved symptoms, serum 25-hydroxyvitamin D are in goal range, and serum magnesium is normal.