[Role of parathyroid hormone measurement in prediction for symptomatic hypocalcaemia after total thyroidectomy].
OBJECTIVE
To evaluate the role of parathyroid hormone (PTH) and serum calcium in prediction for hypocalcaemia after total thyroidectomy.


METHODS
One hundred and sixty-five patients undergoing total or complete total thyroidectomy were reviewed retrospectively. The indications included bilateral carcinoma, undifferential carcinoma, surroundings invasion, distant metastasis and huge benign lesions. Preoperative and postoperative PTH, calcium concentrations and their decline levels were compared between Jan. 2005 and May 2009. The role of PTH value and decline level predicting for symptomatic hypocalcaemia were analyzed by receiver operator characteristics (ROC) curve.


RESULTS
After total thyroidectomy, 85 patients (51.5%) developed hypocalcemia. Symptoms were reported by 36 patients (21.8%). The mean concentration of PTH for normocalcaemia (80 cases), asymptomatic hypocalcaemia (49 cases) and symptomatic patients (36 cases) were 31.0 ng/L, 19.6 ng/L and 11.9 ng/L, respectively. The mean decline level for the three groups were 28.6%, 52.6% and 78.0%, respectively. PTH value and its decline level had a poor predicting value for symptomatic hypocalcaemia and high negative predicting value for asymptomatic patients. The serum calcium concentration more than 2.0 mmol/L, PTH level higher than 15 ng/L and PTH decline less than 50% had the good negative predicting value of 97.6%, 90.3% and 96.5%, respectively.


CONCLUSIONS
Postoperative PTH and its decline level were significantly correlated with postoperative serum calcium concentration but had a low accuracy for predicting symptomatic hypocalcaemia. The serum calcium concentration more than 2.0 mmol/L, PTH level higher than 15 ng/L and PTH decline less than 50% had the good predicting value for asymptomatic patients. Calcium should be routinely supplemented in the first 24 h after total thyroidectomy to reduce the rate of hypocalcemia and the severity of hypocalcemia symptoms.
An
Chang-ming
CM
Department of Head and Neck Surgery of Cancer Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100021, China.
Tang
Ping-zhang
PZ
Xu
Zhen-gang
ZG
Zhang
Bin
B
Zhang
Zong-min
ZM
Yan
Dan-gui
DG
Li
Zheng-jiang
ZJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002118:Calcium / Q000097:blood*; D002648:Child; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000097:blood / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000032:analysis*; D011184:Postoperative Period; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000601:surgery; D013965:Thyroidectomy / Q000009:adverse effects*; D055815:Young Adult
D010281:Parathyroid Hormone; D002118:Calcium