What Is Wheezing?

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Wheezing is a common but frightening symptom that often prompts people to see their doctor. It is defined as a high-pitched whistling sound that occurs with breathing.

Overview

Wheezing can occur both with breathing in (inspiratory wheezing) and with breathing out (expiratory wheezing), though it is more common with breathing out. While many people—and physicians as well—think of asthma when they hear wheezing, it's important to note that "all that wheezes is not asthma."

In addition to other causes of wheezing, sometimes people have more than one condition which leads to wheezing. That's a long-winded way of saying that anyone who has wheezing should have a very careful evaluation of their symptoms.

Auscultation

Before talking about wheezing, it's important to know whether the sounds you hear in your lung are truly wheezing. Why? Because there are other sounds that can be mistaken for wheezing and making an accurate assessment can be critical in finding the causes.

Physicians use the term auscultation to describe the process of listening to the lungs for the presence or absence of "normal" lung sounds as well as any sounds that are not ordinarily heard.

Wheezing vs. Stridor

Stridor is a symptom that is often mistaken for wheezing. This is important because there are a few causes of stridor which are serious medical emergencies.

Stridor has a sound that is usually monophonic—only one note rather than a variety of musical notes.

It tends to be higher in pitch than the sounds due to wheezing and occurs predominately during inspiration. Stridor is usually loudest over the anterior neck, whereas wheezing can be loudest in different regions depending on which airways are most affected.

Unlike stridor, wheezing is often a medium pitched sound which is loudest during expiration.

It has a fairly continuous musical sound including more than one note.

Causes

The most common causes of wheezing are asthma and COPD. The sound of wheezing is created by a narrowing of the airways. This can be due to swelling or blockage anywhere from the throat down to the smallest airways. Some possible causes include:

  • Asthma—The most common cause of wheezing.
  • Anaphylaxis—This is a severe allergic reaction (often due to a bee sting or eating nuts or shellfish) that causes swelling in the throat and is a medical emergency.
  • Bronchitis—This can be both acute (lasting only a few days) or chronic (lasting weeks to months to years).
  • Bronchiolitis—This is an infection that involves the smallest airways (bronchioles) and is most common in children.
  • Inhaling (aspirating) a foreign body—Choking can sometimes cause wheezing if the object that is inhaled does not completely obstruct the airways. Often people recall choking, such as on a piece of steak or in the case of children, on other objects. But sometimes, especially when an object does not completely obstruct the airways (such as a piece of carrot), people may not remember a choking episode.
  • Pneumonia
  • COPD—Chronic obstructive pulmonary disease, such as emphysema, may cause wheezing.
  • Bronchiectasis—A widening of the airways often due to childhood infections or cystic fibrosis is sometimes difficult to diagnose and may at first be attributed to another cause of wheezing.
  • Epiglottitis—A medical emergency marked by symptoms such as fever, drooling, and sitting in an upright position in an attempt to breathe, epiglottitis is caused by an infection of the epiglottis, a small piece of cartilage attached to the end of the tongue.
  • Viral infections such as respiratory syncytial virus (RSV)—Many viral infections can cause wheezing, especially in children.
  • Lung cancer—The first symptom of lung cancer may be wheezing, making it important to identify the cause of wheezing even if the cause appears obvious.
  • Heart failure
  • Pulmonary embolism—Blood clots in the legs may break off and travel to the lungs (pulmonary emboli).
  • Acid reflux—It may not seem obvious, but acid reflux is a fairly common cause of wheezing.
  • Hypersensitivity pneumonitis—Chronic inflammation of the lungs caused by such things as moldy hay and bird droppings may have wheezing as the first symptom.
  • Medications (especially aspirin)
  • Vocal cord dysfunction—Caused by one or both of the vocal cords closing unintentionally during breathing. This is also known as “vocal cord asthma.”

Diagnosis

If you have been wheezing, it is important to see your doctor—even if you feel you know the cause or have experienced wheezing in the past. Even if you have been diagnosed with asthma, make sure to contact your doctor with any change in your symptoms.

Call your doctor (or 911) immediately if you are experiencing chest pains, lightheadedness, are finding it hard to catch your breath, or note a bluish tint to your lips and skin. Swelling of your face, neck, and lips could be a sign of a life-threatening allergic reaction.

Evaluation

The first thing your doctor will do (after making sure you are comfortable and stable) is take a thorough medical history and perform a physical exam. Some of the questions they may ask you include:

  • When did your symptoms begin?
  • Have you ever had symptoms like this before?
  • Is your wheezing worse at night or during the day?
  • Have you been stung by a bee or have you eaten foods that may cause serious allergic reactions, such as shellfish or nuts?
  • Do you have any other symptoms, such as a cough, shortness of breathchest painhives, swelling of your face or neck, or coughing up blood?
  • Do you have a personal or family history of asthma, eczema, lung diseases, or lung cancer?
  • Do you, or have you ever, smoked?
  • Have you choked while eating?

Testing

Tests to evaluate your wheezing and determine a cause will vary depending upon your history. In an emergency, emergency personal and technicians begin with "ABD." This stands for airway, breathing, then circulation. It is important to assess these before going on to try to determine what is actually causing the wheezing. Testing may include:

  • Oximetry to check the oxygen level in your blood
  • Chest x-ray
  • Spirometry
  • Blood tests, such as a white blood cell count to look for signs of infection
  • Pulmonary function tests
  • CT scan of your chest
  • Bronchoscopy if your doctor is concerned that you may have aspirated (breathed in) a foreign object or that you may have a tumor in or near your airways
  • Laryngoscopy to look at your larynx and vocal cords
  • Allergy testing if your doctor feels that you have allergies that are causing your airways to spasm

Treatment

Depending on how serious your symptoms are, your doctor will first do what is necessary to make you comfortable and control your symptoms. Since there are many possible causes of wheezing, further treatment will depend on the cause of your wheezing.

The first steps are to ensure you are getting adequate oxygen into your lungs and that the oxygen you breathe in makes it to all of the cells of your body. Oxygen therapy is commonly used. If an allergic reaction is the cause, injectable epinephrine is often given.

Other treatments will depend upon the underlying causes of the wheezing. For example, treatments for asthma will be used to alleviate narrowing of the airways due to asthma, whereas a procedure such as bronchoscopy may be recommended if it's thought that a foreign body in the airways could be causing your symptoms.

Sources:

Kasper, Dennis L., et al. Harrison's Principles of Internal Medicine. New York: McGraw Hill Education, 2015. Print.

Irwin, R. Evaluation of wheezing illnesses other than asthma in adults. UpToDate. 8/13/15.

Oo, S., and P. Le Souef. The wheezing child: an algorithm. Australian Family Physician. 2015. 44(6):360-4.

Sarkar, M., Madabhavi, I., Niranjan, N., and M. Dogra. Ascultation of the respiratory system. Annals of Thoracic Medicine. 2015. 10(3):158-68.

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