Endocrine Abstracts

Background: Takotsubo cardiomyopathy (TC) is characterised by acute, transient left ventricular apical ballooning precipitated by emotional or physiologically stressful stimuli and has been previously associated with Graves’ disease based on few clinical reports. More recently, the association with exogenous thyrotoxicosis and radioiodine-induced thyroiditis has also been described. Iatrogenic hyperthyroidism on patients under levothyroxine replacement therapy for hypothyroidism had never been reported as a cause of TC. The authors describe two female patients with TC associated with levothyroxine over-replacement.

Case description: A 74- and 48-year-old female patient, medicated with levothyroxine (2.27 and 1.85 μg/kg respectively) for autoimmune thyroiditis was both admitted on our emergency room with precordial pain. The first had an ECG with ST-segment elevation in the anterior precordial leads, and the latter had sinus tachycardia with deep T-wave inversion and QT interval prolongation. Further investigation revealed a mild elevation of cardiac biomarker levels, severe apical hypokinesis but no significant coronary lesions on catheterisation. The suppressed TSH levels were only demonstrated on the cardiac intensive care unit: 0.21 and 0.07 mIU/l (0.35–5.50) respectively. Both patients showed improvement of the apical hypokinesis on the discharge echocardiogram and normalisation of cardiac biomarker levels. Levothyroxine dose was reduced.

Commentary: This case report emphasizes the importance of correct dose adjustment on patients under levothyroxine replacement therapy and stresses that TSH should be determined in patients presenting with acute coronary syndrome and typical finding of TC.