Hypercalcemia in a Bariatric Surgery Patient Treated with Parathyroidectomy during the Second Trimester of Pregnancy

Presentation Number: MON 313
Date of Presentation: April 3rd, 2017

Pooja Rao*1 and Lori Barnett Sweeney2
1Virginia Commonwealth Univeristy, Richmond, VA, 2VCU Health System, Richmond, VA

Abstract

Background: Potential exists for the development of tertiary hyperparathyroidism in bariatric surgery patients who have chronically undertreated vitamin D deficiency. This can be difficult to discern from primary hyperparathyroidism. Symptomatic hyperparathyroidism can be successfully treated by parathyroidectomy during the second trimester of pregnancy. In these cases, postoperative hungry bone syndrome can occur and may relate to the degree of PTH reduction after surgery. Postoperative hypocalcemia in bariatric patients may be difficult to treat with calcium carbonate secondary to reduced gastric surface area and alterations in gastric pH.

Clinical Case: A 37 year old female with history of gastric bypass surgery presented for evaluation of hypercalcemia. Laboratory assessment revealed PTH elevation (322 pg/ml), vitamin D deficiency (13 ng/ml), and a low urine calcium in the setting of normal renal function. DXA revealed normal bone density. A parathyroid scan demonstrated increased tracer uptake inferior to the lower pole of the left and right thyroid lobes. While on vitamin D replacement with ergocalciferol her serum calcium trended up to 11.7 mg/dl and the patient complained of mild cognitive impairment and bone pain. She was referred to surgical oncology for discussion of potential parathyroidectomy but declined surgery. She was subsequently lost to follow-up and presented 18 months later during her second trimester of pregnancy with progressive PTH elevation (681 pg/ml) and worsening hypercalcemia. At this time she was experiencing muscle pain, fatigue, and refractory nausea thought to be related to intravascular volume depletion. Given the potential for hypercalcemia to exacerbate these symptoms, the patient elected for parathyroid exploration. Surgery was commenced and bilateral inferior parathyroid glands were resected. PTH declined from 221 to 2.8 pg/ml over twenty four hours and serum calcium remained in the normal range (9.1 mg/dl). Pathological evaluation of the bilateral parathyroid specimens revealed hypercellular parathyroid tissue. The patient was discharged to home on 1000 units vitamin D3 daily and was advised to take tums (two tablets twice daily). The patient experienced nausea after surgery and was unable to consistently adhere to the tums regimen. Four days after surgery she presented to her local ER with perioral numbness and was found to have a serum calcium of 6.3 mg/dl. She was admitted to the hospital and required IV calcium and high dose oral liquid calcium carbonate (20 ml of 1250 mg per 5 ml solution four times daily). Cinacalcet was not administered secondary to concern for potential teratogenic effects.

Conclusion: This case highlights important aspects in the classification of hyperparathyroidism and subsequent management of post-parathyroidectomy hypocalcemia in bariatric surgery patients.


 

Nothing to Disclose: PR, LBS