Wheezing

Overall, the most common causes are

Wheezing may occur in other disorders that affect the small airways, including heart failure Heart Failure (HF) Heart failure is a disorder in which the heart is unable to keep up with the demands of the body, leading to reduced blood flow, back-up (congestion) of blood in the veins and lungs, and/or... read more , a severe allergic reaction (anaphylaxis Anaphylactic Reactions Anaphylactic reactions are sudden, widespread, potentially severe and life-threatening allergic reactions. Anaphylactic reactions often begin with a feeling of uneasiness, followed by tingling... read more ), and inhalation of a toxic substance Gas and Chemical Exposure Symptoms depend on which gas or chemical is inhaled and how deeply and for how long it was inhaled. Symptoms may include irritation of the eyes or nose, cough, blood in the sputum, and shortness... read more . Wheezing caused by heart failure is called cardiac asthma.

Sometimes, otherwise healthy people wheeze during a bout of acute bronchitis Acute Bronchitis Acute bronchitis is inflammation of the windpipe (trachea) and the airways that branch off the trachea (bronchi) caused by infection. Acute bronchitis is usually caused by a viral upper respiratory... read more . In children, wheezing may be caused by bronchiolitis Bronchiolitis Bronchiolitis is a viral infection that affects the lower respiratory tract of infants and young children under 24 months of age. Bronchiolitis usually is caused by viruses. Symptoms include... read more (infection of the lower respiratory tract) or inhalation (aspiration) of a foreign object (see table Some Causes and Features of Wheezing Some Causes and Features of Wheezing ).

In people with wheezing, the following symptoms are of particular concern:

People with warning signs or shortness of breath should go to the hospital emergency department immediately, by ambulance if necessary. People who have wheezing that comes and goes and are not short of breath can usually wait a day or two.

Doctors first ask questions about the person's symptoms and medical history and then do a physical examination. What doctors find during the history and physical examination often suggests a cause and the tests that may need to be done (see table Some Causes and Features of Wheezing Some Causes and Features of Wheezing ).

Doctors determine whether the wheezing is occurring for the first time or has occurred before. If the person has had wheezing before, they determine whether current symptoms are different in nature or severity.

Important clues to a diagnosis are

Other symptoms that can provide clues to the diagnosis include shortness of breath Shortness of Breath Shortness of breath—what doctors call dyspnea—is the unpleasant sensation of having difficulty breathing. People experience and describe shortness of breath differently depending on the cause... read more , fever, cough Cough in Adults Cough is a sudden, forceful expulsion of air from the lungs. It is one of the most common reasons people see a doctor. The function of a cough is to clear material from the airways and to protect... read more , and sputum production. Doctors ask about the person's history of smoking and exposure to secondhand smoke.

During the physical examination, doctors check the person's temperature and heart and breathing rates. Doctors look for signs of respiratory distress and examine the lungs, particularly how well air moves in and out and whether wheezing seems to affect all of the lungs or only part. A doctor is usually able to detect wheezing by listening with a stethoscope as the person breathes. Loud wheezing can be heard easily, sometimes even without a stethoscope. To hear mild wheezing, doctors may need to listen with a stethoscope while the person exhales forcefully. A persistent wheeze that occurs in one location in smokers may be due to lung cancer. Doctors also examine the heart, nose and throat, limbs, hands, feet, and skin.

Tests are done to assess severity, determine diagnosis, and identify complications. They usually include the following:

If wheezing has occurred for the first time, a chest x-ray may help in the diagnosis. In people with persistent, repeated, or undiagnosed episodes of wheezing, pulmonary function tests Pulmonary Function Testing (PFT) Pulmonary function tests measure the lungs' capacity to hold air, to move air in and out, and to absorb oxygen. Pulmonary function tests are better at detecting the general type and severity... read more may be needed to help measure the extent of airway narrowing and to assess the benefits of treatment. If asthma seems possible but is not confirmed by pulmonary function tests, people may be asked to exercise or be given a drug that triggers wheezing in people with asthma. If airway obstruction occurs, asthma can be confirmed.

If doctors suspect a tumor or a foreign object lodged in an airway, they can insert a flexible viewing tube (bronchoscope Bronchoscopy Bronchoscopy is a direct visual examination of the voice box (larynx) and airways through a viewing tube (a bronchoscope). A bronchoscope has a camera at the end that allows a doctor to look... read more ) into the airway to identify the problem and, if it is an object, remove it.