Chronic bronchitis and emphysema are two of the more common types of chronic obstructive pulmonary diseases (COPD). These are conditions that affect normal air flow and gas exchange through the airways and lungs. It mainly occurs in long-term and heavy smokers but due to individual susceptibility, not every smoker is affected. Both conditions often overlap in patients and may co-exist to varying degrees. One condition, however, will be predominant and there are important differences, both in the pathogenesis and clinical presentation, that should be noted.
Emphysema is an abnormal dilatation of the air spaces with destruction of alveolar walls (lung air sacs). It is at these walls that the main exchange of gas between the air and the blood stream occurs. The terminal and respiratory bronchioles are often involved as well. Air flow restriction is primarily due to the loss of lung elasticity although airway narrowing may also be present.
Chronic bronchitis is the persistent inflammation of the bronchi and bronchioles with a cough and sputum lasting for at least 3 months in two consecutive years. The most notable feature of chronic bronchitis is the excessive mucus production in the airways that obstruct the flow of air, which is also compounded by smooth muscle hypertrophy and swelling of the walls of the bronchi and bronchioles.
Difference between Chronic Bronchitis and Emphysema Symptoms
There are a number of differences in the clinical presentation, demographic and results of investigations but this may vary. The prominent physical presentation that may indicate a difference between the two conditions are discussed below.
Blue Bloater vs Pink Puffer
The “blue bloater” versus “pink puffer” phenotypes are used to describe the typical presentation of chronic bronchitis and emphysema respectively. This is related to the oxygen and carbon dioxide levels in the blood (oxygenation), difficulty breathing (dyspnea) and complications like cyanosis, polycythemia and edema.
“Blue bloaters” in chronic bronchitis describes the poorly oxygenated lung where hypercapnia (excess carbon dioxide in the blood) leads to cyanosis (bluish discoloration especially of the lips and limbs) and edema (swelling), initially of the periphery and then generalized often associated with acidosis and right heart failure. Read more on chronic bronchitis symptoms.
The “pink puffer” emphysema patient is initialy well oxygenated but strains to breathe due to collapse of the airways during expiration. This leads to the pursed lips with prolonged exhalation and polycythemia (too many red blood cells) causes redness of the skin. Read more on emphysema symptoms.
However, in the poorly oxygenated emphysema patient, this typical pink puffer appearance may not be present. It is also important to remember that both chronic bronchitis and emphysema may co-exist thereby altering the presentation from that which is expected of the typical blue bloater and pink puffer phenotypes.
Cough, Mucus and Breathlessness
Due to the disruption in airflow and oxygenation, breathlessness (dyspnea) is present in both chronic bronchitis and emphysema. This is mild in chronic bronchitis and is more prominent in the late stages of the disease. Breathlessness in emphysema is present from the early stage and is very severe compared to chronic bronchitis.
Cough is present from the early stages of chronic bronchitis and the sputum is profuse, often increasing as the disease progresses. With emphysema, mucus production is minimal and cough becomes evident in the late stages. Acute infections may further exacerbate mucus production in both types of COPD although it is more common in chronic bronchitis.