Burton Andrew G, Hopper Kate
IDEXX Laboratories, North Grafton, MA.
Department of Veterinary Surgical and Radiological Sciences, University of California, Davis, CA.
J Vet Emerg Crit Care (San Antonio). 2019 Sep;29(5):461-471. doi: 10.1111/vec.12881. Epub 2019 Aug 26.
To review the pathophysiology, diagnostic approach, and treatment recommendations for hyponatremia in dogs and cats.
Hyponatremia almost always results from an increase in total body water (TBW), and not from loss of sodium. Abnormalities in antidiuretic hormone (ADH) are commonly part of the etiology of hyponatremia.
Diagnosis of hyponatremia focuses on the cause of the increase of TBW. Assessment of the patient's volume status and measurement of urine sodium concentration are important factors. Measurement or calculated estimation of plasma osmolality can also guide the assessment of hyponatremia.
Too rapid correction of serum sodium can precipitate osmotic demyelination syndrome. As a general rule, serum sodium concentration should be raised ≤10 mmol/L over 24 hours, but rapid increases in serum sodium are indicated if neurologic abnormalities are evident. Serum sodium can be increased using hypertonic saline, with dosing based on the patient's calculated sodium deficit. Treatment of the underlying cause of water ingestion or retention is also required to fully resolve hyponatremia.
Mortality rates are significantly higher in dogs and cats with hyponatremia compared to those with normal serum sodium concentrations, even in patients with mild hypontremia (<5 mmol/L below the lower value of the reference interval). Hyponatremia is also associated with increased risk of death if present during specific disease states in dogs.
综述犬猫低钠血症的病理生理学、诊断方法及治疗建议。
低钠血症几乎总是由总体液量（TBW）增加所致，而非钠丢失引起。抗利尿激素（ADH）异常通常是低钠血症病因的一部分。
低钠血症的诊断重点在于TBW增加的原因。评估患者的容量状态及测量尿钠浓度是重要因素。测量或计算血浆渗透压也可指导低钠血症的评估。
血清钠纠正过快可引发渗透性脱髓鞘综合征。一般而言，血清钠浓度应在24小时内升高≤10 mmol/L，但如果有明显的神经异常，则表明血清钠需快速升高。可使用高渗盐水提高血清钠水平，给药剂量基于患者计算出的钠缺失量。还需要治疗水摄入或潴留的根本原因，以完全纠正低钠血症。
与血清钠浓度正常的犬猫相比，低钠血症犬猫的死亡率显著更高，即使是轻度低钠血症（低于参考区间下限5 mmol/L）的患者也是如此。在犬的特定疾病状态下出现低钠血症时，死亡风险也会增加。
