Shortness of Breath



    What Are the Specific Causes of Dyspnea?

    When Should I Seek a Physician Evaluation for Dyspnea?
    What Will a Physician Do to Evaluate Dyspnea?
    What Will a Physician Do to Treat Dyspnea?
    What Can I Do to Prevent Dyspnea?Introduction

“Shortness of breath” or “breathlessness” is a subjective term used widely to describe a person’s awareness of his or her own difficulty breathing, the unpleasant sensation of labored breathing, or respiratory discomfort.  Physicians call shortness of breath “dyspnea” (1).  There are many, many causes of dyspnea, and some are much more serious than others.  Dyspnea can be caused by diseases, infections, and injuries of the lungs, diseases of the heart, upper respiratory infections, injury, poor physical fitness, inhalation of a foreign object, anxiety, and metabolic abnormalities.  Dyspnea can be acute, meaning that it comes on relatively suddenly and disappears after treatment, or it can be chronic, meaning that it persists for a long time--perhaps for the rest of the patient’s life.  Acute dyspnea may be caused by an illness such as pneumonia or asthma, whereas patients with chronic bronchitis, emphysema, or “COPD” (chronic obstructive pulmonary disease) tend to have chronic dyspnea in spite of ongoing treatment.  There is also “acute-on-chronic” dyspnea, in which a patient with chronic lung disease has an acute deterioration; this often compels the patient to assume a “tripod” position to minimize the work of breathing (FIGURE 1, (FIGURE 1, reproduced by permission from UCSD "Catalog of Clinical Images" at with permission of Charlie Goldberg, MD). 

Dyspnea may occur with or without wheezing (as in asthma), primarily at night or only with exertion (typical with congestive heart failure), or without warning (as in pulmonary embolism, the passage of a blood clot from a deep vein in the body--typically the legs--into the circulation of the lungs).  Dyspnea may indicate life-threatening illness, psychologic difficulties, poisoning, or merely an ongoing nuisance to the patient (2). 

What Are the Specific Causes of Dyspnea?

The causes of acute dyspnea--that is, shortness of breath that comes on over minutes, include:


  • pneumothorax, or collapsed lung (FIGURE 2), which usually results from trauma to the chest, whether blunt (such as a fall or automobile accident that breaks ribs) or penetrating (such as a stab wound or a gunshot wound), but can also occur “spontaneously.”  Spontaneous pneumothorax is actually rather common, and usually results from the rupture of a “bleb,” or abnormal air-filled sac of lung tissue, most often in younger people (age 20-40) who are tall and thin.  Traumatic pneumothorax and associated injuries may be fatal, and treatment usually involves inserting a needle and tube into the chest.  Spontaneous pneumothorax may or may not require specific treatment and is hardly ever life-threatening; 


Shortness of Breath

  • pulmonary embolism, or a blood clot lodged in and blocking one of the arteries supplying blood flow to the lungs (FIGURE 3).  Such clots usually originate elsewhere in the body, especially in the legs.  Sudden onset of dyspnea in a person with a swollen leg and/or coughing up blood is very worrisome for pulmonary embolism, which can be life-threatening.  Patients with this combination of symptoms should go to the closest emergency department;
  • bronchospasm, or wheezing, which is usually due to a flare-up of asthma (3) or to the inhalation of a noxious gas such as chlorine (bleach) or hydrogen sulfide.  If there are multiple people from one area with acute dyspnea, poisoning or toxic inhalation may be more likely.  As the word implies, “bronchospasm” is the “spasm” (concentric closing down) of the bronchial tubes (the small breathing tubes deep in the lungs).  There are medicines that physicians prescribe to block and reverse the spasm, and it is important that patients receive these urgently to prevent potentially serious outcomes;
  • heart problems, including heart attack and congestive heart failure.  In up to one-third of patients experiencing a heart attack, chest pain is not a predominant symptom.  In those patients, dyspnea is very common and may provide the treating physician a clue that the heart muscle is in jeopardy.  Sudden onset of shortness of breath, particularly at rest, should always prompt a physician evaluation, usually in an emergency department.  Congestive heart failure usually comes on a bit less acutely, and results from diminished pumping efficiency in the heart so that body fluids that are ordinarily circulated in the bloodstream actually back up into the lungs.  Fluid in the spaces of the lungs where oxygen and carbon dioxide are supposed to be exchanged makes that exchange less efficient and patients will feel short of breath because of a relative or absolute lack of oxygen.  Initial treatment of congestive heart failure often includes medications that help remove that fluid from the lungs; and
  • anxiety and hyperventilation: a sense of shortness of breath, often accompanied by generalized concern and hyper-awareness with a sense of panic, is common in patients with anxiety.  Patients who hyperventilate will often feel a tingling sensation around the mouth and in the fingers and hands.  There may also be lightheadedness and chest pain.  Trying to calm a patient with apparent anxiety may be helpful, but encouraging the patient to breathe into a paper bag is not advised (4).

Less acute causes (that is, onset over hours to days) of dyspnea include all of the above concerns, pluspneumonia and other lung infections (such as bronchitis), the dyspnea of which is often but not always accompanied by fever and cough.  Elderly patients may not have clear pneumonia symptoms, but may be listless and less responsive than usual, in addition to their dyspnea.

Chronic dyspnea, which patients notice over hours to days, to years, is typically due to:

  • lung disease, especially chronic bronchitis or emphysema, often called “COPD” by physicians (5).  Such long-term lung disease is usually due to exposure to toxins, such as tobacco smoke, asbestos, silicone, etc.  Some chronic diseases that affect multiple organs in the body, such as sarcoidosis, can also cause ongoing dyspnea.  The treatment of chronic dyspnea is usually supportive; if patients’ breathing difficulty becomes much worse than usual, a physician evaluation should be sought;
  • heart disease, usually from repeated damage from heart attacks or congestive heart failure;
  • anemia, which may arise from a wide variety of causes, but causes shortness of breath (particularly with physician exertion) because of diminished oxygen-carrying capacity of the red blood cells; or
  • poor physical condition, usually associated with obesity.

Special considerations in children under the age of 2 years with dyspnea include congenital abnormalities of the lungs and heart, croup, and aspiration of a foreign body into the lung.                  

When Should I Seek a Physician Evaluation for Dyspnea?

          Generally speaking, someone experiencing acute onset of dyspnea should be evaluated by a physician as soon as possible, regardless of the suspected cause. This ordinarily means going to the nearest emergency department.  If the patient has been prescribed medications or other treatments in the past, it is usually all right to try those, but doing so should not delay transport to the emergency department. 

          Patients with a history of chronic dyspnea that becomes worse over minutes to hours should go to the emergency department.

          Patients who have dyspnea with any of the following accompanying problems should also seek emergency evaluation:

  • chest pain or tightness
  • lightheadedness, passing out, or confusion
  • trauma to the chest
  • coughing up blood
  • swelling of one leg or known deep vein thrombosis (DVT) anywhere in the body
  • a history of pulmonary embolism or other abnormal blood clotting in the past
  • asthma symptoms not responding to usual therapy
  • a history of spontaneous pneumothorax in the past
  • suspected toxic inhalation or poisoning
  • chronic dyspnea that does not improve with usual care

Patients with dyspnea and any of the following symptoms (and none of those listed above) should plan to see a physician within the next 24-48 hours, but not necessarily in an emergency department, unless their symptoms worsen:

  • fever
  • cough with greenish or yellow phlegm
  • chest pain with coughing
  • swelling of both legs
  • new symptoms of dyspnea when lying down to sleep
  • chronic dyspnea with activity that now is starting to persist after rest

What Will a Physician Do to Evaluate Dyspnea?

Physicians first make certain that a life-saving intervention, such as assisted breathing or treatment for a heart attack or blood clot in the lung is not needed.  This is done by interviewing and examining the patient, and inquiring about other medical problems, any accompanying symptoms, and any prior treatment.  In addition to measuring vital signs (temperature, blood pressure, pulse rate, and breathing rate), the physician will usually check a “pulse oximetry” reading at the fingertip, which is a painless method of assessing how well oxygen is being delivered to the tissues of the body.

A chest radiograph (x-ray) is commonly part of the evaluation, although it may not reveal the underlying problem.  A chest x-ray, for example, will show congestive heart failure or a pneumothorax, but may be relatively normal in patients with asthma, pulmonary embolism, and sometimes even in early pneumonia. Blood tests may be required; usually the blood is obtained by puncturing a vein, but occasionally physicians need a more thorough analysis of how well the blood is carrying oxygen, and they will obtain blood from an artery, usually in the wrist or the inside of the elbow.  Although more painful for the patient, this “arterial blood gas” (ABG) analysis provides much useful information to the physician treating a patient with dyspnea.

An electrocardiogram (ECG or EKG) is obtained if there is any suspicion that the heart is involved in the patient’s dyspnea.  More specialized tests, such as an echocardiogram or a “CAT” scan of the chest are occasionally needed.

What Will a Physician Do to Treat Dyspnea?

          The treatment of dyspnea is entirely dependent upon its underlying cause.  The common denominator is that if patients are unable to breathe adequately for themselves, physicians will place a tube into the throat and assist the breathing so that adequate oxygen flow can be restored.  Beyond that extreme and uncommon measure, specific treatments for the causes of dyspnea include (but are not limited to):

  • for pneumothorax, treatment may range from simple observation, to the surgical placement of a tube into the chest to help re-inflate the collapsed lung
  • for pulmonary embolism, medications that thin the blood
  • for bronchospasm, medications (some inhaled [called “bronchodilators”], some given by mouth or intravenously) that relieve the spasm 
  • For toxic inhalation, usually removal from the offending substance, observation, and support are adequate
  • For suspected or confirmed heart attack, specific treatments are provided with medicines and sometimes in the cardiac catheterization laboratory; for congestive heart failure, diuretics (drugs that help rid the body of excess fluids) and medications that help the heart beat more efficiently are given
  • For anxiety and hyperventilation, exclusion of more serious causes of acute dyspnea, and relaxation therapy, psychotherapy, and sometimes medicines
  • For pneumonia, bronchitis, and other infections, antibiotics are often prescribed; many such infections, however, can also be caused by viruses, for which antibiotic therapy is not helpful
  • For chronic lung and heart problems, there are many, many chronic treatments that are tailored to the individual patient’s needs
  • For anemia, transfusion may be needed acutely; there are also medicines that can help the body produce more red blood cells over time
  • For poor physical condition, there is no acute treatment, but institution of healthy habits and a safe weight-loss regimen can be very helpful over time; avoiding tobacco use is essential to good lung and cardiovascular health
  • Dyspnea is a common and troubling symptom at the end of life, and affects not only patient but also the attending family.  Patients in hospice care often experience significant and uncomfortable dyspnea as their condition deteriorates.  Dyspnea in terminally ill patients, however, may be treatable; anxiety, fluid in the lungs, or pneumonia may cause dyspnea that may be at least partially reversible with treatment that does not violate the hospice approach, including the use of supplemental oxygen.  A physician should be consulted about such issues; at the end of life, narcotics may be used to keep the patient comfortable.

What Can I Do to Prevent Dyspnea?

           Acute dyspnea may often be avoided by such simple practices as good hygiene, like hand washing, avoiding prolonged contact with others who are ill with contagious diseases, taking medications prescribed for respiratory or cardiac ailments, and by avoiding inhalation of toxic substances, including tobacco smoke. Sometimes relief from acute dyspnea can be achieved simply by moving into an open-air area, or sitting in front of an open window.  Maintaining at least a reasonable level of physical fitness and avoiding obesity with exercise and a prudent diet will decrease the effort of breathing all during a person’s lifetime.  Chronic dyspnea may also be avoided by not smoking tobacco, by taking prescribed medications including the use of prescribed oxygen, and by observing healthy habits.