Hyponatremia and takotsubo syndrome: a review of pathogenetic and clinical implications

Hyponatremia is a common electrolyte abnormality with important prognostic and therapeutic implications. It might exert detrimental effects on various organ systems including the central nervous system (CNS), bone, and heart along with its potential association with poor quality of life. These adverse effects might be largely mediated through a variety of mechanisms including osmotic stress, dysfunctional transmembrane exchangers, and enhanced oxidative stress. Interestingly, hyponatremia might also have an important association with takotsubo syndrome (TTS) that has been universally considered as a reversible form of cardiomyopathy usually emerging in response to various stressors. In this context, severe hyponatremia was previously reported to serve as a direct trigger of TTS evolution largely through its potential impact on CNS and heart. However, pathogenetic and clinical implications of hyponatremia still need to be thoroughly evaluated in patients with TTS. This paper aims to analyze the clinical features of published cases with TTS primarily triggered by hyponatremia and also aims to discuss the association between hyponatremia and TTS from a broader perspective.