Skeletal muscle cell abnormalities in acute hypophosphatemia during total parenteral nutrition.

Muscle tissue H2O, Na, K, Mg, Cl and total P were studied in 23 patients with acute hypophosphatemia during P-deficient total parenteral nutrition. Increased muscle extracellular water and low intracellular K and Mg with high intracellular Na were found. These abnormalities were detected either in previously underfed patients with low muscle P or in well-nourished, acutely ill subjects with muscle P near to normal. These findings show that acute depletion of extracellular inorganic P is associated with changes of muscle cell composition independently of muscle cell P content.