Clinical Spectrum of Hyponatremia in Patients with Stroke

Introduction Hyponatremia is a common electrolyte imbalance, which is readily observed in patients with ischemic as well as hemorrhagic stroke. It is mostly hypoosmolal and may be due to syndrome of inappropriate anti-diuretic hormone (SIADH) or cerebral salt wasting syndrome (CSWS). The aim of this study was to evaluate the clinical spectrum of hyponatremia in patients of both hemorrhagic and ischemic strokes. Methods In this prospective observational study, all patients admitted with stroke were screened for serum sodium levels right after hospital admission. Patients with serum sodium levels <135 mEq/L were included. Their demographic characteristics, type of stroke, etiology of hyponatremia, and site of hemorrhage/vascular territory ischemia was included. Results Hyponatremia was diagnosed in 34.2% of patients. Their mean serum sodium level was 130.4 ± 3.5 (mEq/L). Ischemic stroke was more common in the hyponatremia group (67.7%), and SIADH was a more common cause of hyponatremia (71.1%). In hyponatremic patients with hemorrhagic stroke, right putamen hemorrhage was seen in 50% of patients with SIADH, and right thalamus was seen in 73.3% patients with CSWS. In hyponatremic patients with ischemic stroke, left middle cerebral artery ischemia was seen in 47% patients with SIADH and right middle cerebral artery ischemia was seen in 55% patients with CSWS. Conclusion In patients with hyponatremia secondary to stroke, ischemic stroke is a common entity. SIADH remains a more frequently witnessed underlying pathology in hyponatremic stroke patients.