STUDIES ON THE INTRACELLULAR WATER, SODIUM AND POTASSIUM IN THYROTOXIC MYOPATHY AND IN THYROTOXIC PERIODIC PARALYSIS

Abstract

Biochemical analysis of intracellular water, sodium, potassium and nitrogen in biopsied muscle was attempted in 24 thyrotoxic myopathy, in 10 thyrotoxic periodic paralysis and in 19 control subjects. Water and electrolytes studies were done by chloride assumption.1. Serum electrolytes in all groups remained in normal range except remarkable fall of potassium during paralytic attack of thyrotoxic periodic paralysis.2. In thyrotoxic myophathy, total and intracellular water in solid tissue basis decreased by 11.6% and 12.9% respectively, through no significant alteration was observed in thyrotoxic periodic paralysis during either paralytic or non-paralytic state.3. Intracellular sodium content and concentration in muscle specimen increased in thyrotoxicosis and in thyrotoxic periodic paralysis during non-paralytic state. Intracellular potassium, in reverse, decreased significantly in either thyro toxicosis or during paralytic attack of thyrotoxic periodic paralysis. However in non-paralytic state intracellular potassium concentration did not differ significantly from control subjects.4. Since decrease of total nitrogen in biopsied specimen (10.4%) limited by half of the decrease of intracellular potassium (20.8%), this potassium depletion was not the result by muscle destruction.5. Linear correlation between grip strength and intracellular potassium concentration of biopsied muscle was proved in thyrotoxic myopathy.