Diagnostic Approach to Hyperthyroidism with Cardiovascular and Pulmonary Complications

Initial Assessment and Laboratory Testing

Assess thyroid function with comprehensive thyroid panel to determine the severity and control of hyperthyroidism, as recommended by the American Heart Association 1
Order CBC, comprehensive metabolic panel, and NT-proBNP to evaluate for anemia, electrolyte abnormalities, liver dysfunction, and cardiac strain, according to the European Society of Cardiology 1, 2

Obtain ECG to assess for arrhythmias, which are common in hyperthyroidism and can contribute to dyspnea, as noted by the European Society of Cardiology 2
Schedule echocardiography to evaluate for right ventricular systolic pressure, left and right ventricular function, and signs of heart failure, which can manifest with hyperthyroidism, as recommended by the American College of Cardiology 1, 2, 3, 4

Perform complete pulmonary function tests to evaluate for underlying lung disease or respiratory muscle weakness, which can occur with thyroid dysfunction, as suggested by the American Thoracic Society 1, 5
Consider chest imaging to rule out parenchymal lung disease, which may present with relatively normal lung function, according to the European Respiratory Society 1
Schedule six-minute walk test to objectively assess exercise capacity and dyspnea, as recommended by the American Thoracic Society 1, 5

Use validated scales to quantify dyspnea and fatigue, such as the Borg scale or Visual Analog Scale, and the numeric rating scale 0-10, respectively, as suggested by the American College of Chest Physicians 5, 6
Assess for signs of heart failure, including peripheral edema, jugular venous distension, and pulmonary rales, as recommended by the American Heart Association 4

If pulmonary hypertension is suspected, right heart catheterization should be considered after completing non-invasive workup, as recommended by the European Respiratory Society 1, 3
Evaluate for autoimmune comorbidities with ANA screening, as autoimmune thyroid disease often coexists with other autoimmune conditions, according to the American College of Rheumatology 1

Schedule follow-up within 2-4 weeks to review test results before making major treatment decisions, as recommended by the American Heart Association 1
Consider cardiology and/or pulmonology consultation based on initial test results, as suggested by the European Society of Cardiology and the European Respiratory Society 1, 3