Primary hyperparathyroidism: Dynamic postoperative metabolic changes

Summary Objective Little is known about the natural changes in parathyroid function after successful parathyroid surgery for primary hyperparathyroidism. The association of intact parathyroid hormone ( iPTH ) and calcium (Ca) with “temporary hypoparathyroidism” and “hungry bone syndrome” ( HBS ) was evaluated. Design Potential risk factors for temporary hypoparathyroidism and HBS were evaluated by taking blood samples before surgery, intra‐operatively, at postoperative day ( POD ) 1, at POD 5 to 7, in postoperative week ( POW ) 8 and in postoperative month ( POM ) 6. Patients Of 425 patients, 43 (10.1%) had temporary hypoparathyroidism and 36 (8.5%) had HBS . Measurements The discriminative ability of iPTH and Ca on POD 1 for temporary hypoparathyroidism and HBS . Results Intact parathyroid hormone (IPTH) on POD 1 showed the highest discriminative ability for temporary hypoparathyroidism (C‐index = 0.952), but not for HBS . IPTH was helpful in diagnosing HBS between POD 5 and 7 (C‐index = 0.708). Extending the model by including Ca resulted in little improvement of the discriminative ability for temporary hypoparathyroidism (C‐index = 0.964) and a decreased discriminative ability for HBS (C‐index = 0.705). Normal parathyroid metabolism was documented in 139 (32.7%) patients on POD 1 and in 423 (99.5%) 6 months postoperatively, while 2 (0.5%) patients had persistent hyperparathyroidism, one diagnosed between POD 5 and 7 and another at POW 8. No patients suffered from permanent hypoparathyroidism. Conclusions The necessity for Ca and vitamin D3 substitution cannot be predicted with certainty before POD 5 to 7 without serial laboratory measurements. Based on the results, a routine 8‐week course of Ca and vitamin D3 treatment seems reasonable and its necessity should be evaluated in a follow‐up study.