Abstract
Disclosure: R.M. Minns: None. A.N. Mukhtar: None. C.A. Koch: None. J.M. Chehade: None. Background: Hypocalcemia following total thyroidectomy is usually transient but can persist lifelong in rare cases, requiring chronic calcium and vitamin D supplementation. This challenge is exacerbated in patients with a history of gastric bypass surgery due to impaired calcium absorption, making calcium homeostasis difficult to maintain. We present a patient with recalcitrant hypocalcemia requiring multiple admissions who was eventually successfully treated with Teriparatide. Clinical Case: A 59-year-old woman with a history of multinodular goiter, osteoporosis, severe GERD on famotidine and gastric bypass surgery in 2020 presented for total thyroidectomy due to a Afirma suspicious nodule in May of 2024. Baseline corrected serum calcium was 9.2 mg/dL with a PTH of 58 pg/ml. Immediately after thyroid surgery, she had a serum calcium of 7.2mg/dl, however, this improved to 8.7 mg/dL the next morning with overnight infusion of calcium gluconate (10gm total) and was started on 1 mcg of calcitriol daily and 1500mg calcium carbonate TID with calcium level of 8.0 corrected at discharge. Patient was to continue this regimen but endorsed taking calcium 1500mg twice daily and calcitriol 0.5mcg daily. Labs two weeks postop were significant for corrected calcium of 5.5 mg/dL with a 25-OH vitamin D of 77ng/dl, magnesium of 1.6 mg/dl and a PTH of < 6 pg/ml. The patient denied muscle cramps, spasms, weakness, twitching, arrhythmias or seizures. She was advised to come to the hospital for inpatient treatment. On admission she had an EKG which showed a QTC of 435ms with a rate of 102 in sinus rhythm. After a prolonged course over six weeks with multiple admissions with trials of calcium citrate up to 2000 mg QID, calcitriol up to 2 mcg TID, and inability to get weaned off a calcium gluconate drip without decrease of calcium below 8mg corrected, the patient was started on PTH (1-34) teriparatide 20 mcg twice a day, before weaning to once a day with calcium citrate 2000 mg TID and calcitriol 0.5 mcg daily. After 6 months of therapy the patient was able to be weaned to teriparatide 20 mcg daily, calcitriol 0.5mcg daily, calcium citrate 2000 mg BID with a corrected calcium of 8.6 mg/dL as outpatient. The patient denied symptoms of hypocalcemia throughout her stay. Conclusion: While the hallmark of hypocalcemia is neuromuscular irritability our case demonstrates the importance of monitoring even in asymptomatic patients with low initial calcium and risk factors for decreased calcium absorption like gastric bypass and treated GERD with antacids. This case further supports use of teriparatide for refractory hypocalcemia. As new research emerges regarding the long-term safety of teriparatide, it may serve as a cost-effective alternative to recently approved but more expensive treatments like palopegteriparatide. Presentation: Saturday, July 12, 2025