Some Causes and Features of Shortness of Breath
Cause |
Common Features* |
Tests† |
Acute (develops within minutes or hours) |
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Anxiety disorder—hyperventilation |
Shortness of breath related to a specific situation, often accompanied by agitation and tingling or numbness in the fingers and/or around the mouth Normal results on the heart and lung examination |
A doctor's examination |
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Wheezing that starts spontaneously or after exposure to specific stimuli (such as pollen or another allergen, an upper respiratory infection, cold air, or exercise) Usually a history of asthma |
A doctor's examination Sometimes one or more of the following tests:
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A foreign object that has been inhaled |
A cough or high-pitched wheezing that starts suddenly in people (typically infants or young children) without any symptoms of an upper respiratory infection or other illness |
A chest x-ray or CT Sometimes bronchoscopy |
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A heart attack or acute myocardial ischemia (inadequate blood flow and oxygen supply to the heart) |
Deep chest pressure that may or may not radiate to the arm or jaw, particularly in people with risk factors for coronary artery disease |
Electrocardiography Blood tests to measure substances called cardiac markers, which are released into the blood when the heart is damaged Sometimes cardiac catheterization |
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Often swelling (edema) of the legs Shortness of breath that worsens while lying flat (orthopnea) or that appears 1–2 hours after falling asleep (paroxysmal nocturnal dyspnea) Sounds suggesting fluid in the lungs, heard through a stethoscope Frothy, pink sputum, sometimes with blood streaks |
A chest x-ray Sometimes a blood test to measure brain natriuretic peptide (BNP), a substance that is produced when the heart. is strained Sometimes echocardiography |
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Pneumothorax (a collapsed lung) |
Sharp chest pain and rapid breathing that start suddenly May follow an injury or occur spontaneously, especially in tall, thin people and in people with COPD |
A chest x-ray |
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Pulmonary embolism (sudden blockage of an artery in a lung, usually by a blood clot) |
Sudden appearance of sharp chest pain that usually worsens when inhaling A rapid heart rate and a rapid breathing rate Often risk factors for pulmonary embolism, such as cancer, immobility (as results from being bedbound), blood clots in the legs, pregnancy, use of birth control pills (oral contraceptives) or other drugs that contain estrogen, recent surgery or hospitalization, or a family history of the disorder |
Specialized lung imaging tests, such as CT angiography, ventilation/perfusion (V/Q) scanning, or pulmonary arteriography. |
Subacute (develops over hours or days) |
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Angina or coronary artery disease |
Deep chest pressure that may or may not radiate to the arm or jaw, often triggered by physical exertion Often in people with risk factors for coronary artery disease |
Electrocardiography Stress testing Sometimes cardiac catheterization |
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A chronic obstructive pulmonary disease (COPD) flare-up |
Often a cough that may or may not produce sputum (productive or nonproductive) Wheezing and breathing through pursed lips In people who already have COPD |
A doctor's examination Sometimes a chest x-ray |
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Fever, a feeling of illness, and a productive cough Sudden appearance of sharp chest pain when taking deep breaths Certain abnormal breath sounds, heard through a stethoscope |
A chest x-ray |
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Chronic (present for many weeks to years) |
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Shortness of breath during exertion, progressing to shortness of breath at rest Normal lung examination results and oxygen levels in the blood |
A complete blood cell count |
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Abnormal lung sounds called crackles, heard through a stethoscope |
High-resolution CT of the chest |
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Obstructive lung disease |
A history of extensive smoking, a barrel-shaped chest, and difficulty moving air in and out of the lungs Usually in people who already have COPD |
A chest x-ray Pulmonary function testing (after the episode of shortness of breath subsides) |
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Physical deconditioning |
Shortness of breath only during exertion In older people with a sedentary lifestyle |
A doctor's examination |
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Pleural effusion (fluid in the chest cavity) |
Sometimes a history of cancer, heart failure, rheumatoid arthritis, systemic lupus erythematosus (lupus), or acute pneumonia |
A chest x-ray Often CT of the chest |
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Gradually worsening shortness of breath and fatigability, sometimes with cough
Sometimes an abnormal heart examination Sometimes leg swelling |
Echocardiography Right heart catheterization |
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Restrictive lung disease |
Gradually worsening shortness of breath in people known to have been exposed to inhaled irritants at work (occupational exposure) or to have a disorder of the nervous system |
A chest x-ray Pulmonary function testing (after the episode of shortness of breath subsides) |
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Stable angina or coronary artery disease |
Deep chest pressure that may or may not radiate to the arm or jaw, often triggered by physical exertion Often in people with risk factors for coronary artery disease |
Electrocardiography Stress testing Sometimes cardiac catheterization |
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* Features include symptoms and results of the doctor's examination. Features mentioned are typical but not always present. |
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† Doctors almost always measure the oxygen level in the blood and, unless symptoms are clearly a mild flare-up of an already diagnosed chronic disorder, take a chest x-ray. |
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‡ Asthma can also be a subacute cause of dyspnea. |
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§ Heart failure can also be chronic cause of dyspnea. |
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COPD = chronic obstructive pulmonary disease; CT = computed tomography. |
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