Management of hyponatraemia in older people: old threats and new opportunities.

Hyponatraemia is the commonest electrolyte abnormality seen in clinical practice, and is especially prevalent in frail, older people. However, the serious implications of hyponatraemia in this age group are seldom recognized by clinicians. Hyponatraemia is associated with osteoporosis, impaired balance, falls, hip fractures and cognitive dysfunction. Even mild, apparently asymptomatic hyponatraemia is associated with prolonged stays in hospital, institutionalization and increased risk of death. Emerging evidence of the potential benefits of improved treatment of hyponatraemia is slowly generating renewed clinical interest in this area. The development of specific vasopressin-2 receptor antagonists (vaptans) has the potential to revolutionize the management of hyponatraemia, in particular for the syndrome of inappropriate antidiuretic hormone. However, challenges remain for the attending physician. Diagnosing the cause or causes of hyponatraemia in older people is difficult, and incorrect diagnosis can lead to treatment that worsens the electrolyte imbalance. Established treatments are often poorly tolerated and patient outcomes remain poor, and the role of vaptans in the treatment of older people is unclear. This review summarizes the existing evidence base and highlights areas of controversy. It includes practical guidance for overcoming some common pitfalls in the management of the elderly patient with hyponatraemia.