Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Clinical Trial
. 1999 Feb;229(2):237-45.
doi: 10.1097/00000658-199902000-00012.

Postoperative tetany in Graves disease: important role of vitamin D metabolites

H Yamashita  1 , T Murakami, S Noguchi, M Shiiba, S Watanabe, S Uchino, H Kawamoto, M Toda, N Murakami
Affiliations
Clinical Trial

Postoperative tetany in Graves disease: important role of vitamin D metabolites

H Yamashita et al. Ann Surg. 1999 Feb.

Abstract

Objective: To test the authors' hypothesis of the causal mechanism(s) of postoperative tetany in patients with Graves disease.

Summary background data: Previous studies by the authors suggested that postoperative tetany in patients with Graves disease occurs during the period of bone restoration and resulted from continuation of a calcium flux into bone concomitant with transient hypoparathyroidism induced by surgery.

Patients and methods: A prospective study was carried out to investigate sequential changes in serum levels of intact parathyroid hormone (iPTH), calcium and other electrolytes, 25-hydroxyvitamin D (25OHD), 1,25-dihydroxyvitamin D (1,25(OH)2D), and bone metabolic markers in 109 consecutive patients with Graves disease who underwent subtotal thyroidectomy.

Results: Preoperative serum iPTH levels negatively correlated with ionized calcium levels and positively correlated with 1,25(OH)2D or 1,25(OH)2D/25OHD. After the operation, there was a significant decline in levels of ionized calcium, magnesium, and iPTH. Serum iPTH was not detected in 15 patients after surgery. Four of these 15 patients, and 1 patient whose iPTH level was below normal, developed tetany. Preoperative serum ionized calcium levels were significantly lower, and iPTH levels were higher, in the 5 patients with tetany than in the 11 patients who did not develop tetany despite undetectable iPTH levels. The tetany group had significantly lower serum 25OHD levels and higher 1,25(OH)2D levels, and had increased 1,25(OH)2D/25OHD as an index of the renal 25OHD-1-hydroxylase activity than those in the nontetany group. These results suggest that patients with a high serum level of iPTH as a result of low serum calcium levels (secondary hyperparathyroidism) are susceptible to tetany under conditions of hypoparathyroid function after surgery.

Conclusions: Postoperative tetany occurs in patients with secondary hyperparathyroidism caused by a relative deficiency in calcium and vitamin D because of their increased demand for bone restoration after preoperative medical therapy concomitant with transient hypoparathyroidism after surgery. Calcium and vitamin D supplements may be recommended before and/or after surgery for patients in whom postoperative tetany is expected to develop.

PubMed Disclaimer

References

    1. J Clin Invest. 1976 Jul;58(1):61-70 - PubMed
    1. Proc Natl Acad Sci U S A. 1972 Jul;69(7):1673-6 - PubMed
    1. Lancet. 1977 Mar 19;1(8012):621-3 - PubMed
    1. Lancet. 1977 Apr 9;1(8015):806-7 - PubMed
    1. Acta Endocrinol (Copenh). 1977 Jul;85(3):515-25 - PubMed

Publication types