Postoperative Parathyroid Hormone Concentrations Research Articles

Permanent postoperative hypoparathyroidism: an analysis of prevalence and predictive factors for adequacy of control in a cohort of 260 patients.

Recent guidelines for the treatment of hypoparathyroidism emphasize the need for long-term disease control, avoiding symptoms and hypocalcaemia. Our aim has been to analyze the prevalence of poor disease control in a national cohort of patients with hypoparathyroidism, as well as to evaluate predictive variables of inadequate disease control. From a nation-wide observational study including a cohort of 1792 patients undergoing total thyroidectomy, we selected 260 subjects [207 women and 53 men, aged (mean ± SD) 47.2±14.8 years] diagnosed with permanent hypoparathyroidism. In every patient demographic data and details on surgical procedure, histopathology, calcium (Ca) metabolism, and therapy with Ca and calcitriol were retrospectively collected. A patient was considered not adequately controlled (NAC) if presented symptoms of hypocalcemia or biochemical data showing low serum Ca levels or high urinary Ca excretion. Two hundred and twenty-one (85.0%) patients were adequately controlled (AC) and 39 (15.0%) were NAC. Comparison between AC and NAC patients did not show any significant difference in demographic, surgical, and pathological features. Rate of hospitalization during follow-up was significantly higher among NAC patients in comparison with AC patients (35.9% vs. 10.9%, P<0.001). Dose of oral Ca and calcitriol were also significantly higher in NAC subjects. In a subgroup of 129 patients with serum parathyroid hormone (PTH) levels available, we found that NAC patients exhibited significantly lower postoperative PTH concentrations than AC patients [median (interquartile range) 3 (1.9-7.8) vs. 6.9 (3.0-11) pg/mL; P=0.009]. In a nation-wide cohort of 260 subjects with definitive hypoparathyroidism, 15% of them had poor disease control. These patients required higher doses of oral Ca and calcitriol, had higher rate of hospitalization during follow-up and showed lower PTH concentrations in the postoperative period.

Do Near-Infrared Intra-Operative Findings Obtained Using Indocyanine Green Correlate with Post-Thyroidectomy Parathyroid Function? the Icgpredict Study

Postoperative hypoparathyroidism (hypoPT) still remains a significant complication after thyroidectomy. Intra-operative imaging modalities, such as near-infrared fluorescence using indocyanine green (ICG), may assist in identifying and preserving the parathyroid glands (PGs). The purpose of this study was to test the association between the intra-operative ICG staining scoring system and 24-hour postoperative parathyroid hormone (PTH) levels, as well as its capability for intra-operative PG identification. This was a prospective study, recruiting patients scheduled for total thyroidectomy by the same surgical team, from December 2018 to April 2019. Intra-operative angiography was performed after infusion of ICG solution (5 mg). Two minutes later, images were acquired using the near-infrared system. Sixty patients fulfilled the eligibility criteria. The percentage of temporary postoperative hypoPT (defined as PTH <14 pg/mL) was 11.66%. No association between intra-operative ICG staining score (expressed as the number of PGs scoring <2 per patient) and 24-hour postoperative PTH (r = 0.011; P = .933) or serum calcium concentrations (r = 0.127; P = .335) was observed. There was also no correlation between the location of PGs scoring ≤2 and postoperative PTH (P = .257) or serum calcium levels (P = .950). Moreover, with regard to secondary endpoint, ICG correctly identified PGs in 98.3% of cases. ICG score was not affected by age, gender, duration of operation, or thyroid gland pathology. No allergic reactions attributed to ICG administration were observed. The intra-operative ICG staining scoring system did not predict 24-hour postoperative PTH and serum calcium levels. However, this modality may assist in intra-operative PG identification during a total thyroidectomy.

Role of routine frozen sections for parathyroid exploration in a resource poor setting

Removal of parathyroid is recommended for patients suffering from hypercalcemia due to excess parathyroid hormone levels. There are several causes for a hyperfunctioning parathyroid gland out of which parathyroid adenoma is the most common pathological entity. There is great variation in the number and location of parathyroid glands. Hence, intra-operative confirmation of parathyroid tissue makes it easier for the surgeon to be confident of the outcome of the procedure and assure the patient of a permanent cure. A descriptive cross sectional study was done in a cohort of 26 patients who presented with elevated total serum calcium and parathyroid hormone concentrations. Intra-operative frozen section diagnoses were correlated with routine histological studies and post-operative parathyroid hormone concentration. The majority of patients were diagnosed as having parathyroid adenoma (88.46%). Three out of 26 patients (11.53%) had parathyroid hyperplasia involving more than one gland. Sensitivity and specificity of intraoperative frozen section diagnosis was 100%. There was a statistically significant association (p In the light of the discussion on parathyroid surgery it is apparent that frozen sections play a pivotal role in resource poor settings, when facilities for novel intra-operative imaging studies such as sestamibi scan and single-photon emission computed tomography are limited. The participants of the study have been followed up during last 5 years with no evidence of residual disease or recurrence up to date.

Post-thyroidectomy hypocalcemia is related to parathyroid dysfunction even in patients with normal parathyroid hormone concentrations early after surgery

Hypocalcemia may develop even in the presence of normal postoperative parathyroid hormone (PTH) concentrations. We aimed to identify risk factors of hypocalcemia in patients with normal PTH concentration early after total thyroidectomy (TT). We included 1,504 consecutive patients who underwent TT between January 2012 and December 2013. Significant hypocalcemia was defined as serum calcium concentrations of <8.0 mg/dL. Overall, 333 patients had subnormal PTH 4 hours after surgery (4-hour PTH; <10 pg/mL) and received oral calcium (OC) and calcitriol supplementation. Among the 1,171 patients with normal 4-hour PTH (≥ 10 pg/mL; euparathyroid), 211 experienced hypocalcemia and required OC administration. Among the euparathyroid patients, no difference was found between normocalcemic and hypocalcemic patients in terms of age, hormonal status, preoperative PTH, 25-hydroxy vitamin D (25OH-VD), magnesium, and phosphate concentrations. On univariate analysis, euparathyroid hypocalcemic patients were more frequently females, had significantly lower preoperative serum calcium and 4-hour PTH concentrations, and greater decreases in PTH. Independent risk factors for hypocalcemia with normal 4-hour PTH were preoperative serum calcium concentration and PTH decline of ≥ 50%. Female sex, toxic goiter, and 25OH-VD deficiency are not risk factors for post-TT hypocalcemia. Relative parathyroid insufficiency seems to be the principal mechanism of post-thyroidectomy hypocalcemia, even in patients with normal postoperative PTH concentrations.

Determinants of postoperative hypocalcemia in vitamin D–deficient Graves’ patients after total thyroidectomy

Background The etiology of postoperative hypocalcemia after total thyroidectomy appears to be multifactorial, that is, postoperative transient hypoparathyroidism, low 25-hydroxy vitamin D (25-OHD) concentrations, aging, and hyperthyroidism with increased bone turnover. Our aim was to evaluate the factors responsible for postoperative hypocalcemia in euthyroid vitamin D–deficient/insufficient Graves patients who underwent total thyroidectomy at our institution. Methods Thirty-five consecutive patients with Graves disease treated by total thyroidectomy were included in the present study. All patients were vitamin D deficient/insufficient (ie, 25-OHD concentrations of <20/<30 ng/mL, respectively). Patients were divided into 2 groups according to postoperative serum albumin corrected calcium concentrations: group 1 (n = 13) patients had postoperative serum calcium concentrations of 8 mg/dL or less; group 2 (n = 22) patients had serum calcium concentrations greater than 8 mg/dL. Bone turnover markers (deoxypiridinoline, bone-specific alkaline phosphatase) and 25-OHD were determined the day before surgery. Results In group 1 patients, disease duration was significantly longer, 25-OHD and postoperative parathyroid hormone concentrations were significantly lower, and bone turnover markers were significantly higher. Logistic regression analysis revealed that a postoperative parathyroid hormone concentration less than 10 pg/mL was the most powerful parameter to predict postoperative hypocalcemia (odds ratio, 23; 95% confidence interval, 3.3–156). Conclusions In Graves patients with vitamin D deficiency/insufficiency, postoperative (transient) hypoparathyroidism is the most significant parameter to determine the development of postoperative hypocalcemia.

Determinación de paratirina en suero como factor predictivo de hipocalcemia tras tiroidectomía total

Introduction Postoperative parathyroid hormone (PTH) levels as a predictor of hypocalcaemia in patients subjected to total thyroidectomy is analyzed. Matherial and method Prospective study involving 67 patients who underwent total thyroidectomy due to a benign disease. Serum PTH and ionised calcium were measured 20 h after surgery. Sensitivity, specificity and predictive values of PTH and ionised calcium levels were calculated to predict clinical and analytical hypocalcaemia. Results A total of 42 (62.7%) patients developed hypocalcaemia (ionised calcium<0.95 mmol/l), but only 20 (29.9%) presented with symptoms. PTH concentration the day after surgery was significantly lower in the group that developed symptomatic hypocalcaemia (5.57±6.4 pg/ml) than in the asymptomatic (21.5±15.3 pg/ml) or normocalcaemic (26.8±24.9 pg/ml) groups (p=0.001). Taking the value of 13 pg/ml as a cut-off point of PTH levels, sensitivity, specificity, positive predictive value and negative predictive value were 54%, 72%, 76% and 48%, respectively. On the other hand, sensitivity for predicting symptomatic hypocalcaemia was 95% and specificity was 76%. The test showed a high incidence of false positives (11/30, 36%). Negative predictive value was 97% and positive predictive value was 65%. In multivariate analysis, PTH and ionised calcium were the only perioperative factors that showed an independent predictive value as risk indicators of symptomatic hypocalcaemia. Conclusions Normal PTH levels 20 h after surgery practically rule out the subsequent appearance of hypocalcaemia symptoms. On the other hand, low PTH levels are not necessarily associated to symptomatic hypocalcaemia due to the high number of false positives.

Transient rise in intact parathyroid hormone concentration after surgery for primary hyperparathyroidism.

Two-site immunometric assays for determination of the level of intact parathyroid hormone (PTH) in serum have enabled detailed clinical studies of PTH secretion. Fifty-one patients with primary hyperparathyroidism were studied before surgery and 2 years after operation. PTH levels dropped to low values after operation. A rebound increase in PTH concentration occurred from 10 days to 3 months after surgery. Abnormally raised postoperative PTH concentrations were noted in 31 per cent of the patients, who had lower serum concentrations of ionized calcium (Ca2+) than the rest (P < 0.003). Before operation these patients had a more pronounced hyperparathyroidism than the others. At 2 years after surgery there was still a positive correlation between PTH concentrations before and after surgery (P < 0.001). The rebound increase in the level of PTH was a general phenomenon probably caused by low Ca2+ concentrations at the time of remineralization of bone. This phenomenon was transient. The positive correlation between preoperative and postoperative PTH concentrations shows that effects of hyperparathyroidism can remain for a long time after surgical cure.