Chronic dyspnea has a wide range of causes. The aim of the authors was to evaluate a diagnostic approach applied to patients with unexplained chronic (> 30 days) dyspnea, or when multiple causes were present. Methods: An algorithm for the work-up was applied: 1) complete history and physical examination; 2) bronchoprovocation test (BPT) and serial measurements of echocardiography; 3) cardiopulmonary exercise testing (CPET) and doppler echocardiography; 4) special tests: FRCT, V/Q scan, DCO, lung volumes, MIP, and others, as indicated. Results: Ninety patients were included, mean age of 51 ± 16 yr. Hyperventilation symptoms were present in 48, but associated with BHR or asthma in 19. Obstructive defect was present in 24 (asthma, 11; COPD, 8). Reduced FVC with normal FEV1/FVC was found in 10; explanations were asthma in 4, heart disease in 4. BPT was performed in 71 and was verified to be normal in 20; PEF variation was evaluated in 71, and was abnormal in 28, isolated in 16, and in 7 with asthma as final diagnosis. Echocardiography was performed in 44, and showed diastolic dysfunction in 11 out of 16 patients with final diagnosis of heart disease. CPET showed cardiovascular limitation in 19, hyperventilation in 19, and ventilatory defect in 12. CPET was decisive in 33 (38%), specially for heart diseases and to exclude causes suspected by clinical data. Respiratory disease was the explanation for dyspnea in 51 (59%): asthma (31), BHR (8), COPD (8), interstitial lung disease (4); other causes found were: heart disease (16), primary hyperventilation syndrome (8), obesity (5), neuromuscular disease (6), psychogenic dyspnea (2), and others (7). Multiple causes were found in 13 patients. Eight patients had non-recognizable etiology. Conclusion: An algorithm approach to chronic dyspnea resulted in diagnosis of 91% of the cases; spirometry, tests for BHR including PEF measurements, echocardiography, and CPET are essential for the investigation.

Keywords: Chronic dyspnea. Exercise test. Spirometry. Respiratory function tests. Bronchoprovocation tests. Peak expiratory flow. Echocardiography. Chest X-ray. Heart failure, congestive.