Parathyroid hormone: an early predictor of symptomatic hypocalcemia after total thyroidectomy.
OBJECTIVE
The purpose of this study was to evaluate if the measurement of peri-operative parathyroid hormone (PTH) is able to identify patients with increased risk of developing symptoms of hypocalcemia.


METHODS
Forty patients who underwent total thyroidectomy were studied prospectively. Ionized serum calcium and PTH were measured after induction of anesthesia, one hour (PTH1) and one day after surgery (PTH24). Patients were evaluated for symptoms of hypocalcemia and treated with calcium and vitamin D supplementation as necessary.


RESULTS
Symptomatic hypocalcemia developed in 16 patients. Symptomatic patients had significant lower PTH1 and greater drops in PTH levels. The selection of 12.1 ng/L as PTH1 level cutoff level divided patients with and without symptoms with 93.7% sensitivity and 91.6% specificity. The selection of 73.5% as the cutoff value for PTH decrease resulted in 91.6% sensitivity and 87.5% specificity.


CONCLUSIONS
PTH1 levels and the drop in PTH levels are reliable predictors of developing symptomatic hypocalcemia after total thyroidectomy.
Head and Neck Surgery, Universidade Federal de São Paulo (Unifesp), São Paulo, SP, Brazil. fabvanderlei@terra.com.br
Felipe Augusto Brasileiro
FA
Vanderlei
Jose Gilberto Henriques
JG
Vieira
Flavio Carneiro
FC
Hojaij
Onivaldo
O
Cervantes
Ilda Sizue
IS
Kunii
Monique Nakayama
MN
Ohe
Rodrigo Oliveira
RO
Santos
Marcio
M
Abrahão
D015415:Biomarkers / Q000097:blood; D002118:Calcium / Q000008:administration & dosage / Q000097:blood*; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010280:Parathyroid Glands; D010281:Parathyroid Hormone / Q000097:blood*; D011237:Predictive Value of Tests; D011300:Preoperative Care; D011446:Prospective Studies; D012306:Risk; D013965:Thyroidectomy / Q000009:adverse effects*; D014807:Vitamin D / Q000008:administration & dosage; D014815:Vitamins / Q000008:administration & dosage
D015415:Biomarkers; D010281:Parathyroid Hormone; D014815:Vitamins; D014807:Vitamin D; D002118:Calcium