CENTRAL PONTINE MYELINOLYSIS AND PONTINE LESIONS AFTER RAPID CORRECTION OF HYPONATREMIA - A PROSPECTIVE MAGNETIC-RESONANCE-IMAGING STUDY

The rate at which profound hyponatremia should be corrected is the focus of a recent clinical debate. We prospectively studied neurological outcomes with serial magnetic resonanace imaging in 13 hyponatremic subjects with serum sodium concentrations of less than 115 mmol/L (mean initial serum sodium concentration, 103.7; range, 93–113 mmol/L). All subjects were corrected to mildly hyponatremic levels at 24 hours and ultimately underwent an increase in serum sodium concentration of 25 mmol/L without development of hypernatremia. Magnetic resonance imaging revealed the development of pontine lesions in 3 patients. The correction rate of hyponatremia over the first 24 hours was significantly faster in patients with pontine lesions (mean ± SD, 1.25 ± 0.4 mmol/(L ± hr) versus 0.74 ± 0.3 mmol/(L ± hr); ±<0.05). Initial sodium concentration was also significantly lower in the pontine lesion group (97.3 ± 6.7 vs 105.6 ± 5.2 mmol/L,p ± <0.05). We conclude that the correction rate of hyponatremia plays a significant role in the pathogenesis of pontine lesions in individuals with profound hyponatremia who undergo large increases in sodium concentration as a result of severe initial hyponatremia. Copyright © 1990 American Neurological Association