Hypomagnesemia associated with hypocalcemia after total thyroidectomy: an observational study.
BACKGROUND
Serum magnesium is frequently low in patients with hypocalcemia after total thyroidectomy. The aim of the present study was to analyze the variations in serum magnesium and calcium concentrations after total thyroidectomy, and the relationship between both ions.


METHODS
We conducted an observational study of 142 patients who had undergone total thyroidectomy, measuring serum calcium and magnesium levels preoperatively and on the day following surgery. The incidence of postoperative hypocalcemia was compared with that of postoperative hypomagnesemia.


RESULTS
A total of 142, total thyroidectomies were performed: 54 patients (38%) presented with hypocalcemia on the first postoperative day. A marked decrease in blood magnesium in the group of patients with hypocalcemia was observed when compared to those with normal calcemia on the first postoperative day (mean variation respectively, 0.125 ± 0.065 mmol/L versus 0.035 ± 0.020 mmol/L; P = 0.0002).


CONCLUSIONS
Hypomagnesemia is significantly associated with early hypocalcemia following thyroidectomy.
Head and Neck Surgery Department, University of São Paulo Medical School (LIM 28).
Renata Regina da Graça Lorencetti
RR
Mahmoud
Head and Neck Surgery Department, University of São Paulo Medical School (LIM 28).
Vergilius José Furtado de Araujo
VJ
Neto
Head and Neck Surgery Department, University of São Paulo Medical School (LIM 28).
Wellington
W
Alves
Head and Neck Surgery Department, University of São Paulo Medical School (LIM 28), Instituto do Câncer do Estado de São Paulo (ICESP), São Paulo, Brazil.
Chin Shien
CS
Lin
Head and Neck Surgery Department, University of São Paulo Medical School (LIM 28), Instituto do Câncer do Estado de São Paulo (ICESP), São Paulo, Brazil.
Ana Kober Nogueira
AK
Leite
Head and Neck Surgery Department, University of São Paulo Medical School (LIM 28), Instituto do Câncer do Estado de São Paulo (ICESP), São Paulo, Brazil.
Leandro Luongo
LL
Matos
Head and Neck Surgery Department, University of São Paulo Medical School (LIM 28).
Vergilius José Furtado de Araujo
VJ
Filho
Head and Neck Surgery Department, University of São Paulo Medical School (LIM 28).
Claudio Roberto
CR
Cernea
D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000097:blood*; D008274:Magnesium / Q000097:blood*; D008297:Male; D008875:Middle Aged; D013965:Thyroidectomy / Q000009:adverse effects*
D008274:Magnesium
hypocalcemia; magnesium; parathyroid; thyroidectomy