[Hyponatremia and hypernatremia in the elderly]

The study aimed at evaluating an incidence of hypo- and hypernatremia in the elderly and the results of therapy. Hyponatremia. The studies involved 18 patients aged 69.8 +/- 5.9 years with hyponatremia of 126.8 +/- 2.7 mmol/L. The main causes of hyponatremia were: diuretics, diarrhoea, and vomiting. Sodium deficit was calculated prior to the treatment in all patients. An analysis of hyponatremia incidence indicates that hyponatremia was diagnosed in 1.39% of patients over 60 years, hospitalized within 1989-1990. Sodium deficit in this group was 495.5 +/- 167.7 mmol. Sodium chloride solution was given intravenously to 12 patients, according to the "free correction" principle (a mean increase in serum sodium level was 0.17 +/- 0.07 mmol/L per hour). Mortality in such treated patients was 33%. Sodium chloride was not given to 6 out of examined patients. In 12 patients (66.6%) hyponatremia developed prior to hospitalization, in 6 patients (33.3%) during hospitalization. Mortality rate was 16.6% and 50%, respectively. This confirms higher mortality rate of the rapidly developing hyponatremia in the hospitalized elderly patients. In some cases hyponatremia may constitute iatrogenic complication, especially in the elderly given diuretics in an uncontrollable way. Own experience suggests that elderly patients with a risk of hyponatremia require close monitoring and early compensation of the electrolyte disorders. Hypernatremia. The studies involved 20 patients aged 71.4 +/- 7.7 years with hypernatremia of 155.6 +/- 8.4 mmol/L. A total water deficit (DH20) was calculated in this group. An analysis of hypernatremia incidence showed that this state was diagnosed in 1.55% of patients treated at the Department of Arterial Blood Hypertension within 1989-1990. Total water deficit was 3.9 +/- 1.9 L. A 5% glucose was given intravenously to 15 patients whereas oral fluid therapy was carried out in 5 patients. A mean corrected DH2O in the first day was 46.0 +/- 21.0%. Mortality rate in this group was 65%. It is worth mentioning that 37% of patients with chronic hypernatremia which developed prior to hospitalization died while in case of the acute hypernatremia developed in the hospital mortality rate was 83%. A significant effect on the results of therapy plays an early correction of hypernatremia. Mortality rate in case of DH2o supplementation below 30% during the first 24 hours is about 66%., if DH2o supplementation is 31-60%, a mortality rate is 63%, and in DH2o supplementation over 60% mortality rate is 100%. The obtained results suggest that hypernatremia in the elderly is related to the high mortality rate (65%). An early decrease of water deficit increases mortality rate in patients with hypernatremia.