Title : A tricuspid regurgitation like no other: Right heart overload secondary to hyperthyroidism
Abstract:
Background: Hyperthyroidism is a rare and underrecognized cause of right heart overload and pulmonary hypertension (PH). Thyrotoxicosis may induce functional tricuspid regurgitation (TR) via volume overload and annular dilation, even in the absence of structural left heart or pulmonary disease.
Case Presentation: A 50-year-old male smoker, recently diagnosed with hyperthyroidism (TSH 0.005 mIU/L), under carbimazole treatment (11 tablets/day), presented with acute dyspnea and palpitations. ECG showed right ventricular hypertrophy. Echocardiography revealed a dilated right atrium (23 cm²), moderate tricuspid regurgitation (grade 2), a non-dilated right ventricle, an inferior vena cava (IVC) of 25 mm (non-collapsing), and an estimated pulmonary artery systolic pressure (PASP) of 50 mmHg. The left heart was structurally and functionally normal.
Thoracic CT angiography ruled out pulmonary embolism and showed normal pulmonary arteries and parenchyma, but confirmed a dilated right heart and venae cavae. The diagnosis of thyrotoxic right heart overload was retained. The patient was treated with diuretics (spironolactone, furosemide) and beta-blockers.
At one-month follow-up, clinical and echocardiographic parameters had markedly improved: PASP decreased to 38 mmHg, right atrial area reduced to 18 cm², and IVC returned to normal size. TR persisted at the same grade but without right-sided volume overload.
Conclusion: This case highlights the importance of considering endocrine causes such as hyperthyroidism in patients with unexplained pulmonary hypertension or right heart overload. Functional TR and PH secondary to thyrotoxicosis may be fully reversible with appropriate medical management. Early diagnosis can prevent unnecessary invasive investigations and progression to irreversible right heart dysfunction.
