SHM Converge Scientific Abstract ePoster Gallery-Hypocalcemia Following Total Thyroidectomy in a Patient With Roux-en-Y Gastric Bypass

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This case describes severe, persistent hypocalcemia after total thyroidectomy in a 63-year-old woman with a prior Roux-en-Y gastric bypass (RYGB). Although transient hypocalcemia occurs in up to 30–60% of patients after thyroidectomy, her course was unusually refractory. She presented four days after surgery with facial flushing, dysphagia, paresthesias, and tetany. Exam showed a positive Chvostek sign and bilateral hand tetany. Labs demonstrated marked hypocalcemia (serum calcium 6.5 mg/dL, ionized calcium 0.76 mmol/L), hypomagnesemia (1.5 mg/dL), low PTH (4 pg/mL), and normal vitamin D.<br /><br />She received IV calcium gluconate, magnesium replacement, oral calcium carbonate, and calcitriol, but calcium levels remained low despite repeated treatment. Pathology showed intact parathyroid glands, making surgical removal less likely. Hungry bone syndrome was considered but felt unlikely because she did not have preoperative hyperthyroidism or prolonged PTH excess. The most important contributing factors were thought to be her prior RYGB, which reduces calcium absorption, and hypomagnesemia, which can suppress PTH secretion and worsen hypocalcemia.<br /><br />Because oral tablet calcium may be poorly absorbed after RYGB, endocrinology switched her to liquid calcium suspension with meals. Her symptoms resolved, and calcium improved from 6.5 to 7.9 mg/dL at discharge and to 8.3 mg/dL at follow-up.<br /><br />This case highlights the multifactorial nature of hypocalcemia after thyroidectomy, especially in patients with malabsorptive bariatric surgery. It emphasizes the need to consider magnesium deficiency, altered calcium absorption, and individualized treatment strategies, including liquid calcium formulations and close outpatient monitoring.

Asset Subtitle

Jennifer Zhan

Meta Tag

Author List Emmanuel Mensah, Fenghan Zhang, Frank Duan, Gurkirat Bhangu, Jennifer Zhan, Matthew Burday, Zahra Manji

Category Clinical Vignettes

Concept Hypocalcemia

Concept Roux-en-Y Gastric Bypass

Concept Malabsorption

Concept Thyroidectomy

Concept Intravenous Calcium

Distinguished Non-Finalist

Presenter Organization SKMC

Presenting Author Jennifer Zhan

Track Adult

Keywords

hypocalcemia

total thyroidectomy

Roux-en-Y gastric bypass

hypomagnesemia

parathyroid hormone

calcium gluconate

calcitriol

liquid calcium suspension

tetany

calcium malabsorption

Hypocalcemia

Roux-en-Y Gastric Bypass

Malabsorption

Thyroidectomy

Intravenous Calcium