HẠ NATRI MÁU TRONG HỒI SỨC: HỘI CHỨNG TIẾT HORMON CHỐNG BÀI NIỆU KHÔNG THÍCH HỢP VÀ HỘI CHỨNG MẤT MUỐI NÃO QUA HAI CA LÂM SÀNG.

Abstract

Background: Hyponatremia is a common electrolyte disorder in critically ill patients and is associated with an increased risk of neurological complications and mortality. Among patients with central nervous system disorders, syndrome of inappropriate antidiuretic hormone secretion (SIADH) and cerebral salt wasting syndrome (CSW) are two important causes of hyponatremia. However, distinguishing between these conditions remains challenging because of their overlapping clinical and laboratory features.

Case presentation: We report two cases of hypotonic hyponatremia managed in the intensive care unit. The first case involved a 94-year-old woman with acute cerebellar infarction who presented with hyponatremia, elevated urinary sodium excretion, increased urine osmolality, and persistent polyuria. Her serum sodium level improved following volume and hypertonic saline replacement, treatment with tetracosactide, and subsequent maintenance therapy with fludrocortisone, suggesting cerebral salt wasting syndrome. The second case involved an 84-year-old man with severe hyponatremia, low plasma osmolality, elevated urinary sodium concentration, increased fractional excretion of uric acid (FEUA), and no evidence of heart failure, hypothyroidism, or adrenal insufficiency. His condition improved after fluid restriction and treatment with tolvaptan, consistent with a diagnosis of SIADH.

Conclusions: SIADH and CSW are important causes of hyponatremia in patients with central nervous system disorders, yet they require fundamentally different therapeutic approaches. Assessment of volume status, urinary sodium excretion, urine output, FEUA, and response to treatment plays a crucial role in the differential diagnosis and selection of appropriate management strategies.