Postoperative hungry bone syndrome in patients with secondary hyperparathyroidism of renal origin

Background Hungry bone syndrome (HBS) is a postoperative condition of severe hypocalcemia that can be seen in patients who have undergone parathyroidectomy (PTX) for secondary hyperparathyroidism (2HPT) of renal origin. This study examines HBS in patients after PTX for 2HPT. Methods Prospectively collected data was retrospectively reviewed in patients who underwent PTX for 2HPT of renal origin at a single institution. HBS was defined as the need for additional days of hospitalization or readmission for intravenous calcium supplementation due to clinical symptoms of hypocalcemia, including tingling, muscle spasms, and bone pain and/or immediate postoperative low serum calcium ≤7.5 mg/dl. Results Of 79 patients who underwent PTX for 2HPT, 27.8% (n = 22) experienced HBS. Young age (≤45 years, p = 0.02) was the only preoperative variable that predicted HBS. Most patients developed HBS within 18 h after surgery and required a prolonged hospital stay (19/22) compared to those requiring hospital readmission within the first 7 days (3/22). Initial postoperative serum calcium levels within 18 h of surgery were significantly lower in those patients who developed HBS (7.1 vs. 8.3 mg/dl, p = 0.001), and those patients also had a greater absolute decrease in serum calcium (2.8 vs. 3.5 mg/dl, p = 0.04). Conclusion HBS develops in a significant proportion of patients generally within the first 18 h after subtotal PTX for 2HPT. The only identifiable preoperative risk factor for HBS was young age. Additionally, low initial calcium levels and greater absolute decrease in serum calcium may help identify those patients that will develop HBS requiring judicious calcium supplementation.