[Characteristics and Clinical Course of Adults Hospitalized with Severe Hyponatremia Associated with Inappropriate...

Severe hyponatremia in hospitalized patients is associated with greater morbidity and mortality and its main cause is the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Little is described in our environment in relation to the etiology, clinical and laboratory characteristics, response to treatment and mortality of these patients.

To describe the etiology, symptoms, laboratory, response to treatment and mortality of adults hospitalized with severe hyponatremia due to SIADH.

Retrospective study of hospitalized patients with severe hyponatremia <125 mEq/L and urinary sodium ≥30 mEq/L, excluding patients with thiazide use.

89 patients were obtained, of which 31 used thiazides. The average age of the remaining 58 was 75.6 years. The average sodium was 116.8 mEq/L. Regarding etiology, 31.0% used drugs associated with SIADH, mainly SSRIs (20.7%); 22.4% had cancer; 12% stress conditions; 5.17% neurological pathology, and 10.3% acute respiratory pathology. The most frequent symptoms were impaired consciousness of varying degrees. There was no response to therapy in 15.5%; 58.6% had a partial response, and 25.9% a total response. The average plasma sodium at discharge was 133.5 mEq/L. There were no deceased patients.

The most frequent causes of SIADH were drugs, mainly SSRIs, and neoplasms. The use of hypertonic saline solution was associated with a better final response to treatment. Only 15.5% of patients were discharged with a sodium level <130 mEq/L.