Reelevation of parathyroid hormone level after parathyroidectomy in patients with primary hyperparathyroidism: importance of decreased renal parathyroid hormone sensitivity.
BACKGROUND
We hypothesized that impaired peripheral sensitivity to parathyroid hormone (PTH) may play a role in reelevation of PTH after successful operation for primary hyperparathyroidism (pHPT).


METHODS
Factors affecting reelevation of PTH were determined in 90 patients who underwent parathyroidectomy for pHPT. PTH/nephrogenous cyclic adenosine monophosphate ratio, as an index of renal resistance to PTH, was examined in relation to factors shown to influence reelevation of PTH.


RESULTS
Serum PTH levels were elevated above the upper limit of normal in 23 patients (26%) at 1 week and in 39 patients (43%) at 1 month after parathyroidectomy. These 39 normocalcemic patients with elevated serum PTH at 1 month after parathyroidectomy had a higher preoperative serum level of PTH and lower serum phosphate and 25-hydroxyvitamin D (25OHD) concentrations than those with normal PTH (n = 59). Elevated PTH and low 25OHD were shown by multivariate analysis to be significant predictors of reelevation of PTH. Renal resistance to PTH was higher in patients with vitamin D deficiency or renal insufficiency than in patients with normal serum vitamin D concentrations or normal renal function, and it increased according to increases in levels of PTH.


CONCLUSIONS
The mechanism of PTH reelevation in patients with pHPT after successful parathyroidectomy appears to be renal resistance to PTH.
Yamashita
Hiroyuki
H
Department of Surgery, Noguchi Thyroid Clinic and Hospital Foundation, 6-33 Noguchi-Nakamachi, Beppu Oita 874-0932, Japan. yama@noguchi-med-or.jp
Noguchi
Shiro
S
Moriyama
Taiki
T
Takamatsu
Yuji
Y
Sadanaga
Kyoko
K
Uchino
Shinya
S
Watanabe
Shin
S
Ogawa
Takahiro
T
D000236:Adenoma / Q000097:blood / Q000601:surgery*; D002117:Calcitriol / Q000097:blood; D000242:Cyclic AMP / Q000378:metabolism; D006801:Humans; D006961:Hyperparathyroidism / Q000097:blood / Q000601:surgery*; D015994:Incidence; D007668:Kidney / Q000503:physiopathology*; D010281:Parathyroid Hormone / Q000097:blood*; D010282:Parathyroid Neoplasms / Q000097:blood / Q000601:surgery*; D016105:Parathyroidectomy / Q000379:methods; D010710:Phosphates / Q000097:blood; D015995:Prevalence; D012016:Reference Values; D051437:Renal Insufficiency / Q000453:epidemiology / Q000209:etiology; D012189:Retrospective Studies
D010281:Parathyroid Hormone; D010710:Phosphates; D000242:Cyclic AMP; D002117:Calcitriol