Takotsubo Syndrome Associated with Isolated Hyponatremia: Case Report

Background: Electrolyte disorders have been exceptionally associated with the development of takotsubo syndrome (TTS). Case Presentation: A 73-year-old healthy and active woman was admitted to the Emergency Department for acute dyspnea and chest pain. She had no medical history, except for arterial hypertension successfully controlled by lisinopril. Laboratory investigations revealed marked and isolated hyponatremia, consistent with a syndrome of inappropriate antidiuretic hormone (SIADH) secretion. The diagnosis of takotsubo syndrome (TTS) was based on the echocardiogram and coronary angiography findings. Conclusion: Lisinopril appeared to be the most likely triggering factor of SIADH and hyponatremia, possibly deepened by a recent and transient increase of water intake. The mechanism linking hyponatremia and TTS is not fully understood.