Resumen:
We present the case of a 53-year-old woman who underwent total thyroidectomy as a multinodular goiter treatment, which after surgery presented hypocalcemia that did not reverse with combined therapy of calciotropic hormones and calcium supplementation. The symptomatology remission was reached only after the prescription of magnesium lactate tablets. It is known that hypocalcemia is the main complication of this surgery, however, little is known about hypomagnesemia and its role as a cause and consequence of the imbalance in calcium homeostasis in this kind of patients. The clinical and biochemical evolution of the patient is evaluated, as well as the pathophysiology of hypocalcemia due to magnesium deficiency that involves a large number of processes such as renal, intestinal and bone function.