The lungs, an organ of the respiratory system, expand to inhale air through the mouth and nose. The air travels through the trachea into the bronchi that branch into smaller airways known as bronchioles. The bronchioles lead to alveoli—tiny air sacs surrounded by capillaries—that function to exchange oxygen with the blood. Diseases of the lungs can inhibit the flow of air and trigger the coughing mechanism—a reflex that occurs upon stimulation of nerves in the airways. A wheezing cough describes the sound of a cough when the airways are inflamed.
Asthma
Asthma, a chronic lung disease, affects 22 million people in the United States—6 million of them children—according to the National Heart, Lung and Blood Institute. Asthma causes the lining of the airways to swell and the muscles around the airways to tighten. This results in narrowing of the airways, which restricts the flow of air. Asthma also triggers an increase in mucus production.
Although the exact cause of asthma remains unknown, several factors contribute to the onset of the disease, including genetic factors, environmental triggers and previous respiratory infections. Asthma produces symptoms that range from mild to severe. The most common symptoms include wheezing that occurs while breathing and coughing, a chronic cough, chest tightness, and shortness of breath.
Chronic Bronchitis
Bronchitis describes inflammation and irritation of the bronchial tubes—or airways. Irritation of the bronchial tubes causes mucus production to increase, which impedes the flow of air into and out of the lungs. Chronic bronchitis defines a condition that lasts for longer than three months, according to the American Academy of Family Physicians.
The most common cause of chronic bronchitis is smoking tobacco products, but exposure to chemical fumes, dust and other substances can also lead to this disease. The symptoms of chronic bronchitis include difficulty breathing and wheezing with a chronic cough.
Bronchiectasis
Bronchiectasis describes a condition characterized by the destruction and widening of the airways. Congenital bronchiectasis means the condition is present at birth. Acquired bronchiectasis occurs as a result of other medical conditions or damage to the airways. Children who inhale a foreign object can develop bronchictasis. Medical conditions such as pneumonia, whooping cough or measles can cause bronchiactasis. Approximately half of all cases of bronchiectasis occur as a result of cystic fibrosis—a genetic lung disease, according to MedlinePlus.
The widened airways of bronchiectasis cause the airways to become flabby and scarred, which decreases the ability to clear mucus. As excess mucus builds up, dust, pollen and germs can accumulate, increasing the risk for infection. Symptoms include shortness of breath, wheezing and a daily cough lasting months to years that produces large amounts of mucus, according to the National Heart, Lung and Blood Institute.
