Background:
Hypocalcemia is a frequent complication of parathyroidectomy for secondary/tertiary hyperparathyroidism. In patients with a history of prior Roux-en-Y gastric bypass (RYGBP), changes in nutritional absorption make management of hypocalcemia after parathyroidectomy difficult.
Case report:
A 41-old-year morbidly obese female with c-peptide negative diabetes mellitus and renal failure had RYGBP. Following significant weight loss she underwent simultaneous pancreas-kidney transplantation. She had excellent transplant graft function but developed tertiary hyperparathyroidism with calciphylaxis. She underwent resection of 3.5 glands leaving a small, physiologic remnant remaining in situ at the left inferior position. She was discharged on postoperative day one in good condition, asymptomatic with serum calcium of 7.6 mg/dL and intact PTH of 12 pg/mL. The patient had to be readmitted on postoperative day #14 for severe hypocalcemia of 5.0 mg/dl and ionized calcium 2.4 mg/dl. She required intravenous calcium infusion to achieve calcium levels of >6.5 mg/dl. Long-term treatment includes 5 g of elemental oral calcium TID, vitamin D, and hydrochlorothiazide. She remains in the long term on high-dose medical therapy with normal serum calcium levels and PTH levels around 100 pg/mL.
Discussion:
Our patient's protracted hypocalcemia originates from a combination of 3.5 gland parathyroidectomy, altered intestinal anatomy post-RYGBP, and potentially her pancreas transplant causing additional metabolic derangement. Alternative bariatric procedures such as sleeve gastrectomy may be more suitable for patients with renal failure or organ transplants in whom adequate absorption of vitamins, minerals, and drugs such as immunosuppressants is essential.