Primary hyperparathyroidism after Roux-en-Y gastric bypass

Abstract

Background: Primary hyperparathyroidism (PHPT) in the setting of previous roux-en-Y gastric bypass (RYGBP) is not well described. The diagnosis can be difficult, as secondary hyperparathyroidism (SHPT) commonly occurs in patients after RYGBP due to calcium malabsorption and vitamin D deficiency.

Methods: All patients from 2000 to 2012 who underwent cervical exploration for diagnosis of primary hyperparathyroidism with history of preceding RYGBP were identified and analyzed retrospectively.

Results: Ten patients were identified. The average age was 58.4 and all patients were female. Time interval between RYGBP and cervical exploration was 67 months with median follow-up of 19 months. Average preoperative calcium was 10.8 mg/dL, PTH 155 pg/mL, and 25-vitamin-D 32 ng/mL. Eighty percent of patients presented with symptoms and 90% underwent preoperative imaging. Seventy percent underwent initial focused parathyroidectomy with 20% being converted to four-gland exploration. Seventy percent of patients had a single adenoma with two patients having multi-gland disease. Intraoperative PTH was used in seven patients with successful drop to 50% of baseline in all. Ninety percent of patients had greater then 6-month follow-up without evidence of persistent or recurrent PHPT. Average 6-month calcium was 9.3 mg/dL, PTH 73 pg/mL, and 25-vitamin-D 44 ng/ML. Four patients had evidence of persistently elevated PTH despite normalization of calcium.

Conclusions: PHPT after RYGBP is rare but surgery with either a focused approach following successful localization or four-gland exploration is indicated when the biochemical diagnosis holds true. The presence of SHPT can make diagnosis and follow-up difficult and may predispose them to severe post-operative hypocalcemia.