E-Poster Presentation ESA-SRB-ANZBMS 2021

Dilated cardiomyopathy associated with thyroid storm due to Graves’ disease (#370)

Kay Hau Choy 1 , Sarah Chalak 2 , Rena Cao 3 , Marwan Obaid 2 4 , Tang Wong 2 4 5 , Jeff Flack 2 4 5
  1. Department of Endocrinology and Diabetes, Barwon Health, Geelong, VIC, Australia
  2. Diabetes Centre, Bankstown-Lidcombe Hospital, Bankstown, NSW, Australia
  3. Department of Aged Care, Bankstown-Lidcombe Hospital, Bankstown, NSW, Australia
  4. Faculty of Medicine, University of New South Wales, Randwick, NSW, Australia
  5. School of Medicine, Western Sydney University, Campbelltown, NSW, Australia

Background: Dilated cardiomyopathy (DCM) is an uncommon manifestation of hyperthyroidism. We describe a case of DCM associated with Graves’ disease.

Case: A 60-year-old man presented with acute dyspnoea and palpitations. Pertinent examination findings included mild disorientation, temperature of 37.9oC, hand tremors, a large goitre, thyroid bruit and lid lag. Heart rate was irregularly irregular at 240 beats/minute, indicative of atrial fibrillation, with blood pressure of 120/90mmHg and signs of mild congestive cardiac failure. Biochemistry revealed freeT4 of >100pmol/L(range:12-22), freeT3 of 42.7pmol/L(range:3.0-7.8) and undetectable thyroid-stimulating hormone (TSH). Of note, pathology undertaken two years ago following an emergency department presentation with fatigue demonstrated severe hyperthyroidism, but this result was inadvertently missed, and he had not sought any medical care until this presentation. He was diagnosed with thyroid storm complicated by heart failure. Propylthiouracil 200mg 6-hourly and intravenous hydrocortisone 100mg 6-hourly were initiated. Oral metoprolol and intravenous esmolol were administered for rate control but unfortunately led to cardiogenic shock. Cardioversion resulted in sinus rhythm and a transient blood pressure improvement. Inotropes were subsequently commenced. Echocardiogram revealed left ventricular (LV) systolic dysfunction with septal wall hypokinesis, left atrial enlargement and increased LV filling pressure, consistent with DCM. He was weaned off inotropes after 48 hours. TSH-receptor antibodies returned positive, confirming Graves’ disease. Ten days later, improved thyroid function (freeT4 19.1pmol/L, freeT3 6.5pmol/L) coincided with normalisation of LV systolic function. He was discharged home following a 7-week admission. He achieved euthyroidism 3 months later with carbimazole, with no cardiomyopathy recurrence on continued follow-up and was referred for a thyroidectomy.

Conclusion: In contrast to cardiomyopathy of other origins, hyperthyroidism-associated DCM is usually reversible with appropriate treatment. Clinicians should be vigilant of the risk of precipitating cardiac decompensation in patients with hyperthyroidism-induced cardiomyopathy with beta blockers, which are commonly used for rate control and symptomatic relief.