Evaluation of the Role of Serum Phosphorus and Serum Magnesium in the Early Detection of Post Thyroidectomy Hypocalcaemia

ABSTRACT

Background: Hypocalcemia remains a common complication after thyroid surgery, particularly total thyroidectomy. By further evaluation of the relationship between phosphorus, magnesium and calcium, faster discharge of the patient may be achieved, and prophylactic medical treatment will be spared to the more serious complications.

Objective: The aim of this study was to evaluate the accuracy of hyperphosphatemia and hypomagnesemia for early prediction of post thyroidectomy hypoparathyroidism, in an attempt at earlier discharge from hospital.

Methods: Sixty patients were evaluated and admitted to HNESU for total or completion thyroidectomy. Serum calcium, phosphorus, and magnesium levels were measured pre-operatively and at 12, 24 hours, 1 and 6 months post-operatively.

Results: The mean age was 44+/-2 years old. Twelve patients (20%) developed hypocalcaemia post-operatively, and 6 of them (10%) experienced permanent hypocalcaemia. Among the permanent hypocalcaemic patients 5 had low calcium and magnesium 24 hours post-operatively and only 1 of them had low calcium and normal magnesium. None of them had elevated phosphorus 24 hours post-operatively.

Conclusion: Transit hypocalemia is quite significant in patients post-total Thyroidectomy. Serum phosphorus and magnesium have no role in predicting early (24 hours) post-thyroidectomy hypocalcaemia; however serum magnesium has a very effective role in the early prediction of transient versus permanent hypocalcaemia following total thyroidectomy operation. This can substitute the measurement of PTH which in turn can be cost effective since the P and Mg tests are cheap and widely available compared to PTH test.

KEYWORDS: Thyroid-Posphorus-Magnesium-Hypocalcemia-Parathormone.

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