Calcium Homeostasis After Thyroid Surgery

Pia Lindblom

Calcium Homeostasis After Thyroid Surgery

Pia Lindblom

Surgery (Lund)

Research output: Thesis › Doctoral Thesis (compilation)

Abstract

Calcium homeostasis after thyroid surgery was studied during the immediate postoperative period and after one year. One day after hemithyroidectomy ionised calcium decreased whereas basal PTH did not change. EDTA stimulated maximal and total PTH secretion and set-point decreased on postoperative day 1 and normalised on day 7. One year after hemithyroidectomy (n=10) total calcium and 1.25(OH)2D3 decreased. EDTA and calcium infusion tests showed that maximal and total PTH secretion were unaltered. However, ionised calcium at maximal PTH secretion was reduced, the set-point slightly decreased and the ionised calcium/PTH relation curve left shifted. One year after hemithyroidectomy (n=45) ionised calcium decreased from 1.25±0.05 to 1.22±0.04 mmol/L (p=0.001) despite an unaltered PTH level (2.8±1.0 vs. 3.1±1.5 pmol/L, p=0.50). The marker of bone resorption 1CTP decreased. A reduction in ionised calcium was seen only in groups with reduced FT4. An independent association was found between reduced ionised calcium and altered TSH and FT4 levels. The peripheral effects of PTH were studied by using a six hour hPTH-(1-34) infusion protocol. Induced changes in serum levels of ionised calcium and 1.25(OH)2D3 and in urinary excretion of phosphate and n-cAMP, were not altered by a slight reduction in thyroid hormones at 3 months after hemithyroidectomy. Intraoperative PTH, measured immediately after total or near-total thyroidectomy, showed an independent association with postoperatively reduced serum calcium levels. Intraoperative PTH was lower among patients who developed biochemical hypocalcemia (p<0.001). Low intraoperative PTH identified the patients who required calcium intravenously within 24 hours postoperatively and predicted biochemical hypocalcemia with a sensitivity and specificity of 90 % and 75 %, respectively.

In summary, reduced PTH secretion is the main determinant of transient hypocalcemia after thyroid surgery. Low intraoperative PTH is a feasible predictor of postoperative hypocalcemia. Even minor thyroid surgery, i.e. hemithyroidectomy has sustained effects on calcium homeostasis due to the influence of reduced thyroid hormones on bone remodelling.

Original language	English
Qualification	Doctor
Awarding Institution	Surgery (Lund)
Supervisors/Advisors	[unknown], [unknown], Supervisor, External person
Award date	2002 Apr 11
Publisher	Department of Surgery and Gastroenterology, Lund University Hospital, SE-221 85 Lund, Sweden
ISBN (Print)	91-628-5166-7
Publication status	Published - 2002

Bibliographical note

Defence details

Date: 2002-04-11
Time: 10:15
Place: Lecture room 1, Central building, Lund University Hospital

External reviewer(s)

Name: Smeds, Staffan
Title: Professor
Affiliation: Linköping, Sweden

---

Article: I. STIMULATED PTH SECRETION TRANSIENTLY REDUCED AFTER THYROID SURGERY. Pia Lindblom, Johan Westerdahl, Anders Bergenfelz.Submitted.

Article: II. HEMITHYROIDECTOMY: LONG-TERM EFFECTS ON PARATHYROID FUNCTION - PRELIMINARY REPORT.Pia Lindblom, Johan Westerdahl, Anders Bergenfelz.World Journal of Surgery 2001;25:1155-1159.

Article: III. DECREASED LEVELS OF IONISED CALCIUM ONE YEAR AFTER HEMITHYROIDECTOMY: IMPORTANCE OF REDUCED THYROID HORMONES.Pia Lindblom, Stig Valdemarsson, Birger Lindergård, Johan Westerdahl, Anders Bergenfelz.Hormone Research 2001;55:81-87.

Article: IV. THE PERIPHERAL EFFECTS OF PTH ARE NOT ALTERED AFTER THYROID SURGERY IN EUTHYROID PATIENTS.Pia Lindblom, Anders Isaksson, Johan Westerdahl, Anders Bergenfelz.Hormone Research 2001;56:105-109.

Article: V. LOW PTH LEVELS AFTER THYROID SURGERY: A FEASIBLE PREDICTOR OF HYPOCALCEMIA.Pia Lindblom, Johan Westerdahl, Anders Bergenfelz.Surgery: In press.

Subject classification (UKÄ)

Surgery

Free keywords

PTH-peripheral effects
hPTH-(1-34) infusion
EDTA infusion
Set-point
Vitamin D3
PTH
Calcium
Thyroid surgery
Postoperative hypocalcemia
Bone density.
Surgery
orthopaedics
traumatology
Kirurgi
ortopedi
traumatologi
Reduced thyroid hormones

Cite this

@phdthesis{a612c064d2ad49a899e6273df3e70556,

title = "Calcium Homeostasis After Thyroid Surgery",

abstract = "Calcium homeostasis after thyroid surgery was studied during the immediate postoperative period and after one year. One day after hemithyroidectomy ionised calcium decreased whereas basal PTH did not change. EDTA stimulated maximal and total PTH secretion and set-point decreased on postoperative day 1 and normalised on day 7. One year after hemithyroidectomy (n=10) total calcium and 1.25(OH)2D3 decreased. EDTA and calcium infusion tests showed that maximal and total PTH secretion were unaltered. However, ionised calcium at maximal PTH secretion was reduced, the set-point slightly decreased and the ionised calcium/PTH relation curve left shifted. One year after hemithyroidectomy (n=45) ionised calcium decreased from 1.25±0.05 to 1.22±0.04 mmol/L (p=0.001) despite an unaltered PTH level (2.8±1.0 vs. 3.1±1.5 pmol/L, p=0.50). The marker of bone resorption 1CTP decreased. A reduction in ionised calcium was seen only in groups with reduced FT4. An independent association was found between reduced ionised calcium and altered TSH and FT4 levels. The peripheral effects of PTH were studied by using a six hour hPTH-(1-34) infusion protocol. Induced changes in serum levels of ionised calcium and 1.25(OH)2D3 and in urinary excretion of phosphate and n-cAMP, were not altered by a slight reduction in thyroid hormones at 3 months after hemithyroidectomy. Intraoperative PTH, measured immediately after total or near-total thyroidectomy, showed an independent association with postoperatively reduced serum calcium levels. Intraoperative PTH was lower among patients who developed biochemical hypocalcemia (p<0.001). Low intraoperative PTH identified the patients who required calcium intravenously within 24 hours postoperatively and predicted biochemical hypocalcemia with a sensitivity and specificity of 90 \% and 75 \%, respectively. In summary, reduced PTH secretion is the main determinant of transient hypocalcemia after thyroid surgery. Low intraoperative PTH is a feasible predictor of postoperative hypocalcemia. Even minor thyroid surgery, i.e. hemithyroidectomy has sustained effects on calcium homeostasis due to the influence of reduced thyroid hormones on bone remodelling.",

keywords = "PTH-peripheral effects, hPTH-(1-34) infusion, EDTA infusion, Set-point, Vitamin D3, PTH, Calcium, Thyroid surgery, Postoperative hypocalcemia, Bone density., Surgery, orthopaedics, traumatology, Kirurgi, ortopedi, traumatologi, Reduced thyroid hormones",

author = "Pia Lindblom",

note = "Defence details Date: 2002-04-11 Time: 10:15 Place: Lecture room 1, Central building, Lund University Hospital External reviewer(s) Name: Smeds, Staffan Title: Professor Affiliation: Link{\"o}ping, Sweden --- Article: I. STIMULATED PTH SECRETION TRANSIENTLY REDUCED AFTER THYROID SURGERY. Pia Lindblom, Johan Westerdahl, Anders Bergenfelz.Submitted. Article: II. HEMITHYROIDECTOMY: LONG-TERM EFFECTS ON PARATHYROID FUNCTION - PRELIMINARY REPORT.Pia Lindblom, Johan Westerdahl, Anders Bergenfelz.World Journal of Surgery 2001;25:1155-1159. Article: III. DECREASED LEVELS OF IONISED CALCIUM ONE YEAR AFTER HEMITHYROIDECTOMY: IMPORTANCE OF REDUCED THYROID HORMONES.Pia Lindblom, Stig Valdemarsson, Birger Linderg{\aa}rd, Johan Westerdahl, Anders Bergenfelz.Hormone Research 2001;55:81-87. Article: IV. THE PERIPHERAL EFFECTS OF PTH ARE NOT ALTERED AFTER THYROID SURGERY IN EUTHYROID PATIENTS.Pia Lindblom, Anders Isaksson, Johan Westerdahl, Anders Bergenfelz.Hormone Research 2001;56:105-109. Article: V. LOW PTH LEVELS AFTER THYROID SURGERY: A FEASIBLE PREDICTOR OF HYPOCALCEMIA.Pia Lindblom, Johan Westerdahl, Anders Bergenfelz.Surgery: In press.",

year = "2002",

language = "English",

isbn = "91-628-5166-7",

publisher = "Department of Surgery and Gastroenterology, Lund University Hospital, SE-221 85 Lund, Sweden",

type = "Doctoral Thesis (compilation)",

school = "Surgery (Lund)",

}

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T1 - Calcium Homeostasis After Thyroid Surgery

AU - Lindblom, Pia

N1 - Defence details Date: 2002-04-11 Time: 10:15 Place: Lecture room 1, Central building, Lund University Hospital External reviewer(s) Name: Smeds, Staffan Title: Professor Affiliation: Linköping, Sweden --- Article: I. STIMULATED PTH SECRETION TRANSIENTLY REDUCED AFTER THYROID SURGERY. Pia Lindblom, Johan Westerdahl, Anders Bergenfelz.Submitted. Article: II. HEMITHYROIDECTOMY: LONG-TERM EFFECTS ON PARATHYROID FUNCTION - PRELIMINARY REPORT.Pia Lindblom, Johan Westerdahl, Anders Bergenfelz.World Journal of Surgery 2001;25:1155-1159. Article: III. DECREASED LEVELS OF IONISED CALCIUM ONE YEAR AFTER HEMITHYROIDECTOMY: IMPORTANCE OF REDUCED THYROID HORMONES.Pia Lindblom, Stig Valdemarsson, Birger Lindergård, Johan Westerdahl, Anders Bergenfelz.Hormone Research 2001;55:81-87. Article: IV. THE PERIPHERAL EFFECTS OF PTH ARE NOT ALTERED AFTER THYROID SURGERY IN EUTHYROID PATIENTS.Pia Lindblom, Anders Isaksson, Johan Westerdahl, Anders Bergenfelz.Hormone Research 2001;56:105-109. Article: V. LOW PTH LEVELS AFTER THYROID SURGERY: A FEASIBLE PREDICTOR OF HYPOCALCEMIA.Pia Lindblom, Johan Westerdahl, Anders Bergenfelz.Surgery: In press.

PY - 2002

Y1 - 2002

N2 - Calcium homeostasis after thyroid surgery was studied during the immediate postoperative period and after one year. One day after hemithyroidectomy ionised calcium decreased whereas basal PTH did not change. EDTA stimulated maximal and total PTH secretion and set-point decreased on postoperative day 1 and normalised on day 7. One year after hemithyroidectomy (n=10) total calcium and 1.25(OH)2D3 decreased. EDTA and calcium infusion tests showed that maximal and total PTH secretion were unaltered. However, ionised calcium at maximal PTH secretion was reduced, the set-point slightly decreased and the ionised calcium/PTH relation curve left shifted. One year after hemithyroidectomy (n=45) ionised calcium decreased from 1.25±0.05 to 1.22±0.04 mmol/L (p=0.001) despite an unaltered PTH level (2.8±1.0 vs. 3.1±1.5 pmol/L, p=0.50). The marker of bone resorption 1CTP decreased. A reduction in ionised calcium was seen only in groups with reduced FT4. An independent association was found between reduced ionised calcium and altered TSH and FT4 levels. The peripheral effects of PTH were studied by using a six hour hPTH-(1-34) infusion protocol. Induced changes in serum levels of ionised calcium and 1.25(OH)2D3 and in urinary excretion of phosphate and n-cAMP, were not altered by a slight reduction in thyroid hormones at 3 months after hemithyroidectomy. Intraoperative PTH, measured immediately after total or near-total thyroidectomy, showed an independent association with postoperatively reduced serum calcium levels. Intraoperative PTH was lower among patients who developed biochemical hypocalcemia (p<0.001). Low intraoperative PTH identified the patients who required calcium intravenously within 24 hours postoperatively and predicted biochemical hypocalcemia with a sensitivity and specificity of 90 % and 75 %, respectively. In summary, reduced PTH secretion is the main determinant of transient hypocalcemia after thyroid surgery. Low intraoperative PTH is a feasible predictor of postoperative hypocalcemia. Even minor thyroid surgery, i.e. hemithyroidectomy has sustained effects on calcium homeostasis due to the influence of reduced thyroid hormones on bone remodelling.

AB - Calcium homeostasis after thyroid surgery was studied during the immediate postoperative period and after one year. One day after hemithyroidectomy ionised calcium decreased whereas basal PTH did not change. EDTA stimulated maximal and total PTH secretion and set-point decreased on postoperative day 1 and normalised on day 7. One year after hemithyroidectomy (n=10) total calcium and 1.25(OH)2D3 decreased. EDTA and calcium infusion tests showed that maximal and total PTH secretion were unaltered. However, ionised calcium at maximal PTH secretion was reduced, the set-point slightly decreased and the ionised calcium/PTH relation curve left shifted. One year after hemithyroidectomy (n=45) ionised calcium decreased from 1.25±0.05 to 1.22±0.04 mmol/L (p=0.001) despite an unaltered PTH level (2.8±1.0 vs. 3.1±1.5 pmol/L, p=0.50). The marker of bone resorption 1CTP decreased. A reduction in ionised calcium was seen only in groups with reduced FT4. An independent association was found between reduced ionised calcium and altered TSH and FT4 levels. The peripheral effects of PTH were studied by using a six hour hPTH-(1-34) infusion protocol. Induced changes in serum levels of ionised calcium and 1.25(OH)2D3 and in urinary excretion of phosphate and n-cAMP, were not altered by a slight reduction in thyroid hormones at 3 months after hemithyroidectomy. Intraoperative PTH, measured immediately after total or near-total thyroidectomy, showed an independent association with postoperatively reduced serum calcium levels. Intraoperative PTH was lower among patients who developed biochemical hypocalcemia (p<0.001). Low intraoperative PTH identified the patients who required calcium intravenously within 24 hours postoperatively and predicted biochemical hypocalcemia with a sensitivity and specificity of 90 % and 75 %, respectively. In summary, reduced PTH secretion is the main determinant of transient hypocalcemia after thyroid surgery. Low intraoperative PTH is a feasible predictor of postoperative hypocalcemia. Even minor thyroid surgery, i.e. hemithyroidectomy has sustained effects on calcium homeostasis due to the influence of reduced thyroid hormones on bone remodelling.

KW - PTH-peripheral effects

KW - hPTH-(1-34) infusion

KW - EDTA infusion

KW - Set-point

KW - Vitamin D3

KW - PTH

KW - Calcium

KW - Thyroid surgery

KW - Postoperative hypocalcemia

KW - Bone density.

KW - Surgery

KW - orthopaedics

KW - traumatology

KW - Kirurgi

KW - ortopedi

KW - traumatologi

KW - Reduced thyroid hormones

M3 - Doctoral Thesis (compilation)

SN - 91-628-5166-7

PB - Department of Surgery and Gastroenterology, Lund University Hospital, SE-221 85 Lund, Sweden

ER -

Calcium Homeostasis After Thyroid Surgery

Abstract

Bibliographical note

Subject classification (UKÄ)

Free keywords

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Cite this