The Syndrome of Inappropriate Antidiuresis

Hyponatremia, the most common electrolyte abnormality, is frequently caused by the syndrome of inappropriate antidiuresis (SIAD), where excessive secretion of antidiuretic hormone leads to water retention and hypotonic hyponatremia. This clinical review outlines the pathophysiology, diagnostic criteria, and management strategies for SIAD, emphasizing its prevalence in older adults and association with conditions like cancer, pulmonary diseases, and CNS disorders. Diagnostic challenges include distinguishing SIAD from other forms of hyponatremia, with urine osmolality and sodium levels playing key roles. Treatment varies by severity: emergency management with hypertonic saline for severe symptoms, and fluid restriction, sodium chloride, urea, or tolvaptan for chronic cases. The article also highlights emerging therapies like empagliflozin and underscores the risks of overcorrection, including osmotic demyelination.

Hyponatremia, the most common electrolyte abnormality, is frequently caused by the syndrome of inappropriate antidiuresis (SIAD), where excessive secretion of antidiuretic hormone leads to water retention and hypotonic hyponatremia. This clinical review outlines the pathophysiology, diagnostic criteria, and management strategies for SIAD, emphasizing its prevalence in older adults and association with conditions like cancer, pulmonary diseases, and CNS disorders. Diagnostic challenges include distinguishing SIAD from other forms of hyponatremia, with urine osmolality and sodium levels playing key roles. Treatment varies by severity: emergency management with hypertonic saline for severe symptoms, and fluid restriction, sodium chloride, urea, or tolvaptan for chronic cases. The article also highlights emerging therapies like empagliflozin and underscores the risks of overcorrection, including osmotic demyelination.