Serum tonicity, extracellular volume and clinical manifestations in symptomatic dialysis-associated hyperglycemia...

The absence of osmotic diuresis modifies the effects of hyperglycemia on body fluids in patients with advanced renal failure. To determine the relationship between clinical manifestations and abnormalities in tonicity and extracellular volume in such patients, we analyzed 43 episodes of severe dialysis-associated hyperglycemia (serum glucose exceeding 600 mg/dL) treated only with insulin. The main manifestations were dyspnea in 22 cases (pulmonary edema in 19), nausea and vomiting in 15, coma in 13 and seizures in 3, while 5 patients had no symptoms. Treatment with insulin resulted in a decrease in serum glucose value from 913 +/- 197 mg/dL to 170 +/- 78 mg/dL, an increase in serum sodium level from 125 +/- 5 to 136 +/- 5 mmol/L, and a fall in calculated serum tonicity value from 300 +/- 13 to 282 +/- 11 mmol/kg (all at p < 0.001). The ratio of the change in serum sodium level over change in serum glucose concentration was -1.50 +/- 0.22 mmol/L per 100 mg/dL. The percent increase in extracellular volume secondary to hyperglycemia developing from the prior euglycemic state and calculated from changes in serum sodium and chloride concentrations, was 10.9% +/- 4.6% (1.5% +/- 0.6% per 100 mg/dL increase in serum glucose level). All clinical manifestations dissipated after correction of hyperglycemia in 42 patients. One woman developed during treatment a fatal myocardial infarction. Dialysis patients with severe hyperglycemia may develop symptoms as a result of hypertonicity and extracellular expansion. Insulin alone may be sufficient treatment for these symptoms. The changes in serum tonicity and electrolytes during treatment are consistent with theoretical predictions.