Endocrine Abstracts

Background: Thyrotoxicosis can present as heart failure, especially in elderly patients. We report a case of thyrotoxicosis causing reversible right-sided heart failure.

Case: A 75-year-old Caucasian lady presented with a month’s history of shortness of breath, abdominal distension and ankle oedema. She complained of hot sweats with palpitations, On admission, she was thyrotoxic with evidence of severe right sided heartfailure.Her ECG showed fast atrial fibrillation without ischaemic changes and chest X-ray showed cardiomegaly with bilateral pleural effusions. Her renal function and albumin were normal. Free T3 and T4 were elevated (FT4-40.4, FT3-10.1) with suppressed TSH (<0.01.) Her TBII was 66 and TPO antibody 58.3. Autoantibody screen was negative. Thyroid ultrasound revealed no discrete nodules and uptake on technetium scan was normal. Echocardiography demonstrated a dilated and poorly functioning right ventricle, pulmonary hypertension (60 mmHg) with severe tricuspid regurgitation, but normal left ventricular function. CT pulmonary angiography and trans oesophageal echocardiography excluded significant pulmonary emboli and intracardiac shunt as the cause of pulmonary hypertension. Effective symptomatic and biochemical improvement was achieved with frusemide, metoprolol, carbimazole and warfarin. Repeat echocardiography 3 months after discharge showed only mild right ventricular dysfunction with pulmonary artery pressure of 40 mmHg. Following radioiodine treatment the patient remains euthyroid.

Discussion: We believe in this case right-sided heart failure was due to thyrotoxicosis from Graves’ disease. No other cause for pulmonary hypertension was found and achievement of a euthyroid state improved symptoms. The mechanism of development of pulmonary hypertension in hyperthyroidism is unclear. Hyperthyroidism should be considered as a cause of secondary pulmonary hypertension and otherwise unexplained right heart failure as it is treatable and cardiac dysfunction may be completely reversible.