Table 2.

Potential risk factors for hungry bone syndrome.

Potential risk factors for hungry bone syndrome	Explanation
High preoperative PTH level	Sudden removal of the effect of high circulating levels of PTH on osteoclastic resorption leads to increased influx of calcium into bone (new remodeling sites) (94)
Large volume (weight and mass) of parathyroid adenoma	Positive correlation between PTH levels and volume of adenoma (93, 95)
High preoperative calcium levels	Explained as increased calcium resorption from bone and calcium reabsorption from renal tubules in case of preoperatively elevated PTH levels (95)
Radiological evidence of PHPT-related bone disease	Brown tumors, multiple fractures, osteitis fibrosa cystica as an effect of long-lasting high circulating levels of PTH on the skeleton (91, 94)
Significantly elevated alkaline phosphatase	Reflects osteoblast activity and bone formation, thus overall the state of bone turnover (91, 94)
Preoperatively low 25(OH)D concentrations	HBS develops indirectly by skeletal demineralization due to low circulating levels of 1,25(OH)2D with postoperative increased skeletal calcium requirements (95)

1,25(OH)₂D, 1,25-dihydroxyvitamin D; 25(OH)D, 25-hydroxyvitamin D; HBS, hungry bone syndrome; PHPT, primary hyperparathyroidism; PTH, parathyroid hormone.