Some Causes of Subacute* Dyspnea
Cause | Suggestive Findings | Diagnostic Approach† |
|---|---|---|
Pulmonary causes | ||
COPD exacerbation | Cough, productive or nonproductive Poor air movement Accessory muscle use or pursed lip breathing | Clinical evaluation Sometimes chest x-ray and arterial blood gas measurement |
Fever, productive cough, dyspnea, sometimes pleuritic chest pain Focal lung findings, including crackles, decreased breath sounds, and egophony | Chest x-ray Sometimes blood and sputum cultures WBC count | |
Cardiac causes | ||
Substernal chest pressure with or without radiation to the arm or jaw, often provoked by physical exertion, particularly in patients with risk factors for CAD | ECG Cardiac stress testing Cardiac catheterization | |
Crackles, S3 gallop, and signs of central or peripheral volume overload (eg, elevated neck veins, peripheral edema) Dyspnea while lying flat (orthopnea) or appearing 1–2 hours after falling asleep (paroxysmal nocturnal dyspnea) | Chest x-ray BNP measurement Echocardiography | |
Muffled heart sounds or enlarged cardiac silhouette in patients with risk factors for pericardial effusion (eg, cancer, pericarditis, SLE) Possibly pulsus paradoxus Orthopnea | Echocardiography | |
Other causes | ||
Elevated respiratory rate | Basic metabolic panel ABG measurement | |
Tachycardia, warm skin, lid lag, tremor | TSH and free T4 measurement | |
* Subacute dyspnea occurs within hours or days. | ||
† Most patients should have pulse oximetry and, unless symptoms are clearly a mild exacerbation of a known chronic disease, chest x-ray. | ||
ABG = arterial blood gas; CAD = coronary artery disease; COPD = chronic obstructive pulmonary disease; SLE = systemic lupus erythematosus; S3 = third heart sound; T4 = thyroxine; TSH = thyroid stimulating hormone; WBC = white blood cell. | ||