Intra or postoperative PTH by chemiluminescence immunoassay predicts postoperative hypocalcemia in thyroidectomized children.

FREIRE ANALÍA; CHIESA ANA; ACHA O; BRASLAVSKY D; GRINSPON R; TROIANO MARINA; MORINI M; BALLERINI G; ROPELATO MG; GRUÑEIRO DE PAPENDIECK L

Coasta do Sauipe, Bahia, Brazil

Congreso; XXI Annual Meeting of the Latin American Society for Pediatric Endocrinology (SLEP); 2010

Latin American Society for Pediatric Endocrinology

Objective: To evaluate the effectiveness of intra and postoperative PTH determination to predict postoperative hypocalcemia in thyroidectomized patients. Methods: 20 patients undergoing total thyroidectomy were prospectively and longitudinally studied. PTH (ICMA, CVs <5.4%, functional sensitivity=8pg/mL) was measured pre, intra and post surgery (baseline, 5 and 60 minutes after glandular extraction). Signs or symptoms of hypocalcemia and total calcium (TCa) or ionized calcium (iCa) were monitored regularly for 48 hours postoperative. Hypocalcemia was defined as TCa <8 mg/ dL and/or iCa <0.8 nmol/L. ROC curves were used to identify the PTH level that provided the best prediction of postoperative hypocalcemia according to their sensitivity (S), specificity (Sp) diagnostic efficiency (DEf) and positive predicted value (PPV). Results:10/20 patients developed hypocalcemia, 40% in the first 6 hours, 40% at 24 hours and 20% at 48 hours post surgery. In 3/10 it was symptomatic. Intraoperative PTH<14 pg/mL predicted hypocalcemia with S: 80%, Sp:100%, DEf: 90%(95%CI, 72–100) and PPV:100%, while postoperative PTH<14 pg/mL showed S: 80%, Sp:90%, DEf: 82%(95%CI, 63–100) and PPV:80%. Relative Risk of developing hypocalcemia after thyroidectomy was 9 when PTH intra/postoperative <14 pg/mL.To evaluate the effectiveness of intra and postoperative PTH determination to predict postoperative hypocalcemia in thyroidectomized patients. Methods: 20 patients undergoing total thyroidectomy were prospectively and longitudinally studied. PTH (ICMA, CVs <5.4%, functional sensitivity=8pg/mL) was measured pre, intra and post surgery (baseline, 5 and 60 minutes after glandular extraction). Signs or symptoms of hypocalcemia and total calcium (TCa) or ionized calcium (iCa) were monitored regularly for 48 hours postoperative. Hypocalcemia was defined as TCa <8 mg/ dL and/or iCa <0.8 nmol/L. ROC curves were used to identify the PTH level that provided the best prediction of postoperative hypocalcemia according to their sensitivity (S), specificity (Sp) diagnostic efficiency (DEf) and positive predicted value (PPV). Results:10/20 patients developed hypocalcemia, 40% in the first 6 hours, 40% at 24 hours and 20% at 48 hours post surgery. In 3/10 it was symptomatic. Intraoperative PTH<14 pg/mL predicted hypocalcemia with S: 80%, Sp:100%, DEf: 90%(95%CI, 72–100) and PPV:100%, while postoperative PTH<14 pg/mL showed S: 80%, Sp:90%, DEf: 82%(95%CI, 63–100) and PPV:80%. Relative Risk of developing hypocalcemia after thyroidectomy was 9 when PTH intra/postoperative <14 pg/mL.Methods: 20 patients undergoing total thyroidectomy were prospectively and longitudinally studied. PTH (ICMA, CVs <5.4%, functional sensitivity=8pg/mL) was measured pre, intra and post surgery (baseline, 5 and 60 minutes after glandular extraction). Signs or symptoms of hypocalcemia and total calcium (TCa) or ionized calcium (iCa) were monitored regularly for 48 hours postoperative. Hypocalcemia was defined as TCa <8 mg/ dL and/or iCa <0.8 nmol/L. ROC curves were used to identify the PTH level that provided the best prediction of postoperative hypocalcemia according to their sensitivity (S), specificity (Sp) diagnostic efficiency (DEf) and positive predicted value (PPV). Results:10/20 patients developed hypocalcemia, 40% in the first 6 hours, 40% at 24 hours and 20% at 48 hours post surgery. In 3/10 it was symptomatic. Intraoperative PTH<14 pg/mL predicted hypocalcemia with S: 80%, Sp:100%, DEf: 90%(95%CI, 72–100) and PPV:100%, while postoperative PTH<14 pg/mL showed S: 80%, Sp:90%, DEf: 82%(95%CI, 63–100) and PPV:80%. Relative Risk of developing hypocalcemia after thyroidectomy was 9 when PTH intra/postoperative <14 pg/mL.Results:10/20 patients developed hypocalcemia, 40% in the first 6 hours, 40% at 24 hours and 20% at 48 hours post surgery. In 3/10 it was symptomatic. Intraoperative PTH<14 pg/mL predicted hypocalcemia with S: 80%, Sp:100%, DEf: 90%(95%CI, 72–100) and PPV:100%, while postoperative PTH<14 pg/mL showed S: 80%, Sp:90%, DEf: 82%(95%CI, 63–100) and PPV:80%. Relative Risk of developing hypocalcemia after thyroidectomy was 9 when PTH intra/postoperative <14 pg/mL. Conclusion: Intra and postoperative PTH accurately predicts postoperative hypocalcemia, identifying those thyroidectomized patients at risk and allowing immediate prophylactic treatment.Intra and postoperative PTH accurately predicts postoperative hypocalcemia, identifying those thyroidectomized patients at risk and allowing immediate prophylactic treatment.