Hypernatremia and rhabdomyolysis.

We studied 18 consecutive in-hospital patients with hypernatremia, as well as developed an animal model to simulate hypernatremic dehydration to determine the occurrence of rhabdomyolysis associated with hypernatremia. Mean serum creatine kinase (CPK) levels for the patient group at peak rhabdomyolysis were 3279 +/- 887 IU/L. There was a significant linear correlation between serum sodium and corrected sodium versus CPK (R = 0.585 and 0.713, respectively). In the animal study, mean serum sodium and CPK values were significantly different (p less than 0.0010 and p less than 0.010, respectively). Pre- and post-hypernatremia values of all other electrolytes measured were unchanged. We conclude that hypernatremia has a direct cause and effect relationship with rhabdomyolysis.