Endocrine Abstracts

Graves’ disease is one of the reversible causes of pulmonary hypertension (PAH). The association was first reported in 1980. Studies have suggested an elevated pulmonary artery systolic pressure in about 36% of patients with Graves’ disease by Doppler echocardiography. We report a case of Graves disease associated with pulmonary hypertension in a young female.

Case report: A 41 year old female presented with history of worsening breathless and palpitations. She had atrial fibrillation with fast ventricular rate and a large right side pleural effusion. Her Thyroid functions showed FT4 of >100 (10.8–25.5 pmol/l), FT3 40.2 (3.1–6.3 pmol/l) and TSH <0.03 (0.27–4.20 mU/l). She had positive thyroid peroxidise antibodies (TPO) 450 (0–109 IU/ml) and positive TSH receptor antibodies (TRAB) 17.4 (0–1.5 U/l). She was treated with carbimazole, proparanolol and prednisolone. She was readmitted a month later with thyrotoxic storm, heart failure, right side pleural effusion and pulmonary odema. CT thorax showed an enlarged main pulmonary artery and an Echocardiogram showed estimated pulmonary artery pressure high at 43–48 mmHg. She received radioiodine and remains on low dose of carbimazole. Her recent thyroid functions are FT4 of 17.9, FT3 6.4 and TSH 0.15. Her Echocardiogram 4 months after the treatment showed an estimated pulmonary pressure of 25 mmHg.

Discussion: Pulmonary arterial hypertension (PAH) is defined as a mean pulmonary artery pressure (mPAP) of >25 mmHg at rest or >30 mmHg after exercise. In hyperthyroidism, increase in cardiac output and an elevated peripheral vascular resistance (PVR) result in elevation of pulmonary artery systolic pressure. TRAb also has a link with PAH suggesting an autoimmune etiology. Echocardiography may underestimate pulmonary artery systolic pressure in patients with severe pulmonary hypertension. In summary, hyperthyroidism is a cause of reversible pulmonary hypertension. Most of the patients have mild and asymptomatic pulmonary hypertension but exacerbation of PAH occurs in a fraction of these patients and may be the only manifestation. The prognosis in such cases depends solely on early detection and successful treatment of hyperthyroidism.