THE NATURE OF MYXEDEMA: ALTERATIONS IN THE SERUM ELECTROLYTE CONCENTRATIONS AND RADIOSODIUM SPACE AND IN THE EXCHANGEABLE SODIUM AND POTASSIUM CONTENTS

Abstract

Radioactive isotopes of Na and K were used to determine the radiosodium space and the exchangeable Na and K contents in 13 subjects with myxedema. The serum Na concentration was below 135 meq/l in 4 of 8 subjects prior to therapy; these same 4 subjects had values for the radiosodium space above 300 ml/kg. Four patients in whom serial determinations of the radiosodium space were made during thyroid therapy showed a progressive decrease in the values obtained. In general, the changes in exchangeable Na content paralleled those of the radiosodium space. The exchangeable K determinations obtained after initiation of thyroid therapy were slightly lower than the initial ones.