Shortness of breath, or dyspnea, is often an important sign of a serious medical problem. If you have dyspnea, your doctor must take all the time necessary to pin down the correct diagnosis, since making the right diagnosis is critical in choosing the best treatment. Fortunately, it is likely that your doctor will have a very clear idea of what is causing your dyspnea after talking to you about your medical history, and performing a careful physical examination. When he or she is finished with this initial evaluation, it often only takes one or two additional tests to confirm the diagnosis. Then, treatment can get started and you'll be on your way to breathing easier.
What Does Dyspnea Feel Like?Dyspnea is a feeling of breathlessness, of not getting enough air. It can be accompanied by chest tightness, feeling like you are suffocating, or a feeling of panic. Dyspnea most often occurs in discrete episodes, but it can become continuous or progressive. While some forms of dyspnea have an obvious cause you can identify yourself (such as strenuous exercise), unexplained dyspnea should always be evaluated by a doctor.
What Kinds of Medical Conditions Can Cause Dyspnea?
Lung and airway disorders
- Disorders involving the lungs themselves, including emphysema, lung cancer, pulmonary fibrosis, or sarcoidosis.
- Disorders of the airways including asthma and bronchitis.
- Infections involving the lungs or airways including bacterial pneumonia, histoplasmosis or tuberculosis.
- Disorders of the blood vessels in the lungs including pulmonary hypertension and pulmonary embolus.
- Other lung or chest conditions including restrictive lung disease or pneumothorax.
- Heart disorders
- Almost any cardiac disorder can produce shortness of breath (including coronary artery disease, heart valve disease, arrhythmias or pericardial disease), but dyspnea is most common in heart failure.
- Anxiety disorders ("panic" attacks)
- Deconditioning (being very "out of shape" due to illness or sedentary lifestyle).
- Other medical conditions including anemia (low red blood cell count), dysautonomia, and thyroid disorders.
What Are Some Important Clues To the Cause Of Dyspnea?Here are important clues your doctor should be looking for in trying to determine the cause of your dyspnea.
- Are you a current or past smoker? (suggests lung disease, heart disease)
- Do you have a sedentary lifestyle, elevated cholesterol, hypertension, diabetes, or other cardiac risk factors? (suggests heart disease)
- Do you have a history of exposure to toxins that can produce lung disease?
- Do you have a weakened immune system, or recent exposure to infectious agents? (suggests pneumonia or other infectious pulmonary disease)
- Have you had recent surgery, prolonged bed rest, or a long airplane trip? (suggests pulmonary embolus)
- Have you had a recent illness with a prolonged period of inactivity? (suggests deconditioning)
- Do you have symptoms of other medical conditions that can produce dyspnea (such as thyroid disease, or dysautonomia)?
- Does the pattern of your dyspnea suggest a particular cause?
- Is your dyspnea either persistent or steadily worsening? (This pattern is suggestive of pneumonia or other lung disease, or heart failure.)
- Does your dyspnea come and go, in fairly discrete episodes? (This pattern can be suggestive of asthma, emphysema, recurrent pulmonary embolus, or coronary artery disease.)
- Does your dyspnea occur chiefly when you lie down, or in the middle of the night? (This pattern is suggestive of heart failure.)
What Other Testing May Be Necessary?If your doctor suspects lung disease, it is likely that he or she will want a chest x-ray and pulmonary function tests to help confirm the diagnosis. If a pulmonary embolus is suspected, it is likely you will need a lung scan (an imaging test that looks for blockages in the arteries of the lung), D-dimer test (a blood test that looks for signs of a recent blood clot), and an ultrasound test of your legs (to look for a blood clot). If heart disease is thought to be the cause, your doctor is likely to begin with an echocardiogram to assess the function of your heart. Blood tests may be helpful if your dyspnea is thought to be related to anemia, thyroid disease, or infection.
The Bottom LineUnexplained or unexpected dyspnea can be caused by a number important and potentially dangerous medical conditions, so if you are experiencing this symptom you should be evaluated as soon as possible by a doctor. In most cases, after doing a thorough initial medical evaluation (medical history and physical examination), a careful doctor will have a pretty good idea as to what is causing the problem. Further testing can then be specifically directed toward confirming the suspected diagnosis.
Identifying the correct cause of shortness of breath is important enough that, if you believe your doctor has rushed through his/her evaluation of your dyspnea, or otherwise seems unable to pin down the likely cause, you should strongly consider seeing another physician.
Parshall MB, Schwartzstein RM, Adams L, et al. An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea. Am J Respir Crit Care Med 2012; 185:435. Abstract available here.