Woodward Michael, Gonski Peter, Grossmann Mathis, Obeid John, Scholes Ron, Topliss Duncan J
Aged Care Services, Austin Health, Melbourne, Victoria, Australia.
Department of Medicine, The University of Melbourne, Austin Health, Melbourne, Victoria, Australia.
Intern Med J. 2018 Jan;48 Suppl 1:5-12. doi: 10.1111/imj.13682.
Hyponatraemia (serum sodium concentration below 135 mmol/L) is the most common electrolyte disturbance and occurs commonly in older people. The causes can be complex to diagnose and treat and many published guidelines do not focus on the issues in an older patient group. Here, we are principally concerned with diagnosis and management of euvolaemic and hypervolaemic hyponatraemia in hospitalised patients over 70 years old. We also aim to increase awareness of hyponatraemia in residential aged care facilities and the community. Hyponatraemia can have many causes; in older people, chronic hyponatraemia can often be the result of medications used to treat chronic disease, particularly thiazide or thiazide-like drugs (such as indapamide) or drugs acting on the central nervous system. Where a reversible trigger (such as drug-induced hyponatraemia) can be identified, hyponatraemia may be treated relatively simply. Chronic hyponatraemia due to an irreversible cause will require ongoing treatment. Fluid restriction can be an effective therapy in dilutional hyponatraemia, although poor compliance and the burdensome nature of the restrictions are important considerations. Tolvaptan is an oral vasopressin receptor antagonist that can increase serum sodium concentrations by increasing electrolyte-free water excretion. Tolvaptan use is supported by clinical trial evidence in patients with hypervolaemic or euvolaemic hyponatraemia below 125 mmol/L. Clinical trial evidence also supports its use after a trial of fluid restriction in patients with symptomatic hyponatraemia above 125 mmol/L. The use of tolvaptan is affected by regulatory restriction of chronic therapy due to safety concern and the non-subsidised cost of treatment.
低钠血症（血清钠浓度低于135mmol/L）是最常见的电解质紊乱，常见于老年人。其病因诊断和治疗可能很复杂，许多已发表的指南并未关注老年患者群体的相关问题。在此，我们主要关注70岁以上住院患者等渗性和高渗性低钠血症的诊断和管理。我们还旨在提高老年护理机构和社区对低钠血症的认识。低钠血症可能有多种原因；在老年人中，慢性低钠血症通常是用于治疗慢性病的药物所致，特别是噻嗪类或类噻嗪类药物（如吲达帕胺）或作用于中枢神经系统的药物。如果能确定可逆性诱因（如药物性低钠血症），低钠血症的治疗可能相对简单。由不可逆原因导致的慢性低钠血症需要持续治疗。限液在稀释性低钠血症中可能是一种有效的治疗方法，尽管依从性差和限液的负担性质是重要的考虑因素。托伐普坦是一种口服血管加压素受体拮抗剂，可通过增加无电解质的水排泄来提高血清钠浓度。在血清钠浓度低于125mmol/L的高渗性或等渗性低钠血症患者中，临床试验证据支持使用托伐普坦。临床试验证据也支持在血清钠浓度高于125mmol/L的有症状低钠血症患者进行限液试验后使用托伐普坦。由于安全问题以及治疗费用无补贴，托伐普坦的使用受到慢性治疗监管限制的影响。
