Urinary phosphate excretion after total thyro-parathyroidectomy in thyroid carcinoma

It is well established that deficiency of parathyroid hormone causes an increase of the tubular reabsorption of inorganic phosphate. Earlier evaluations, however, are based on animal experiments or in clinical studies where the degree of a postoperative hypoparathyroidism is not clearly defined. Eight patients with thyroid cancer have been operated on with a total thyroparathyroidectomy, biopsy of all identified parathyroids and autotransplantation of these glands. During a postoperative period of 3-5 days there is an arrest of the paraghyroid function before the glands have a new vascular supply. The levels in the serum and urine of calcium, phosphate, sodium, potassium, magnesium, chloride and creatinine were recorded. The excretion of phosphate diminished to unmeasurable values, indicating a complete tubular reabsorption of phosphate. After 5-6 days, when the autografted parathyroids began to function, phosphate reappeared in the urine together with a slow increase in S-Ca. No substitution with calcium or vitamin D was given in the postoperative period.