Inflammation and narrowing of the airways causes wheezing; the result of a chain reaction of sorts as bronchioles and alveoli become inflamed and swollen, causing airway constriction, limiting the flow of air into the lungs. Wheezing often occurs in conjunction with other symptoms such as increased sputum production, shortness of breath, reduced oxygen or increased carbon dioxide levels. Wheezing can appear suddenly, or be an ongoing symptom of a chronic disease. Symptoms of wheezing include chest tightness, shortness of breath, fever when associated with an infection, a dry hacking or wet congested cough, increased sputum or mucus production, a low oxygen level and an increased respiratory and heart rate.
Asthma
The major telltale symptom of asthma is wheezing, which worsens if not treated. Normally air mixed with oxygen comes into the lungs and passes through the bronchioles, then into the alveoli, allowing the uptake of oxygen, and the release of carbon dioxide. Asthma impairs this process. As allergens bombard the bronchioles and alveoli, inflammation and swelling occurs, blocking the flow of air into the lungs. As a result, the lungs produce mucous; this further blocks the airway, causing wheezing, chest tightness and shortness of breath. According to the Mayo Clinic, if not treated, an acute asthma attack can be life-threatening.
Chronic Bronchitis
Chronic bronchitis is an ongoing, progressive disease of the lower respiratory tract, and a component of chronic obstructive pulmonary disease. Symptoms include a persistent loose, congested wet cough with the production of large amounts of sputum or mucus. According to the National Heart, Lung and Blood Institute, chronic bronchitis can be a disabling disease, particularly when coupled with emphysema. Severe wheezing occurs when chronic inflammation is further irritated by a viral or bacterial respiratory infection.
Emphysema
Emphysema, a component of chronic obstructive pulmonary disease, affects the lower respiratory tract, and is often associated with cigarette smoking, exposure to second-hand smoke, and environmental pollutants. According to the Centers for Disease Control and Prevention, emphysema can also be the result of genetics and the absence of alpha-1 antitrypsin, a protein that protects the lungs.
Airway Obstruction
Airway obstruction is also a cause of wheezing due to a blockage, either by an object, or by a physiological response to an allergen or event. Airway obstruction is the result of choking, altered consciousness, gasping, panic, a sudden and severe allergic reaction, to shell fish, for example, and a multitude of other causes. An airway obstruction causes impaired breathing as the airway continues to narrow until the blockage is either removed, such as a food item, or treatment relieves the allergic reaction.
