Endocrine Abstracts

Introduction: Profound thyrotoxicosis commonly presents with heat intolerance, sweating, weight loss, palpitations, tremor, goitre and eye signs in the case of Grave’s disease. Typically, thyroid storm is differentiated by marked volume depletion, congestive cardiac failure, cardiac arrhythmias, confusion, nausea and vomiting, often with extreme agitation. The wide-ranging and systemic manifestations associated with profound hyperthyroidism are mediated through the thyroid hormone receptor present in most tissues throughout the body.

Case Presentation: A 16 year old female presented to the emergency department with increasing shortness of breath over the last two months. She had a previous history of surgically-corrected patent ductus arteriosus, bilateral sensorineural hearing loss and depression and anxiety, with no previous history of endocrine disease. She was apyrexial, found to be tachycardic and tachypnoeic with an elevated jugular venous pressure, but no signs of thyrotoxicosis. Her biochemistry was notable for free T3 >50 pmol/l, free T4 >100 pmol/l, TSH <0.01 mU/l, thyroid-stimulating immunoglobulins 27.30 IU/l and a peak NT-proBNP of 29,258 ng/l. She was admitted for further investigation and treatment. Echocardiogram demonstrated biventricular failure with a left ventricular ejection fraction of 35% and severe tricuspid regurgitation associated with right ventricular failure. She was initially treated with carbimazole, propranolol and hydrocortisone. She deteriorated rapidly with increasing breathlessness and became unresponsive requiring prolonged intubation and intensive care unit stay. She was transferred to the specialist tertiary centre to consider mechanical bridging therapy and heart transplant but she recovered with milrinone infusion and was repatriated for continuation of management. She was extubated successfully after 3 weeks and subesquently completed ward-based rehabilitation. On discharge, her hyperthyroidism and decompensated heart failure status resolved, and her most recent echocardiogram observed a left ventricular ejection fraction of 45-49% with trivial-mild tricuspid regurgitation and a NT-proBNP of 179 ng/l. Her free T3 was 6.2 pmol/l, free T4 16.4 pmol/l and TSH <0.01 mU/l. She was discharged on carbimazole 15 mg once daily.

Conclusion: The key learning points from this case are that severe thyrotoxicosis can present with shortness of breath and no other typical hyperthyroidism symptoms, and patients can present with severe heart failure in the absence of Grave’s disease signs and symptoms. Importantly, the treatment of Grave’s thyrotoxicosis can resolve cardiac impairment, therefore we recommend assessing thyroid status, an inexpensive test, early in such cases to prevent Grave complications.