Differences Between COPD, Bronchitis, and Pneumonia

Photo Credit: Juliet Percival/Ikon Images.

The terms pneumonia, bronchitis, and COPD exacerbation are often used interchangeably. However, there are key differences that warrant explanation. Albeit, most of the time, these three conditions are treated very similarly and the terminology is less relevant. That said, it’s still important to understand the what is meant when clinicians use the words ‘pneumonia,’ versus ‘bronchitis’ versus ‘COPD exacerbation.’

COPD Exacerbation

A COPD exacerbation is simply an acute worsening of the symptoms of COPD, such as wheezing, shortness of breath, mucus production, and/or cough. Depending on the kind of COPD a patient has (emphysema or chronic bronchitis), these symptoms may be slightly different. Patients with chronic bronchitis generally have more mucus production and cough, whereas patients with emphysema have more shortness of breath, although either type of COPD can cause any number of these symptoms. A COPD exacerbation may be cause by an infection (virus, bacteria, or other kinds of pneumonia), but it may also be caused by non-infectious causes like fumes, irritants, or smoke. The treatment for an acute COPD exacerbation is often steroids, inhalers, and antibiotics (because bacterial infections often develop during an acute COPD exacerbation).

A Note About Lung Anatomy

Before we get into what it means to have bronchitis versus pneumonia, it's first necessary to explain that the lung is composed of many air tubes.

The biggest air tube is the windpipe (or trachea). The trachea branches into the right and left lung via the right and left bronchus. The bronchi then branch into even smaller airtubes called bronchioles. Finally, the bronchioles end in tiny air sacs called alveoli. Bronchitis involves an infection or inflammation of the bronchioles, whereas pneumonia involves pooling of infection in the alveoli.


There are two kinds of bronchitis: acute bronchitis and chronic bronchitis. Chronic bronchitis is one of the types of COPD. Patients with chronic bronchitis are treated with inhalers and the typical COPD medications, not antibiotics. However, when mucus production increases, the bronchioles (air tubes) become inflamed and airflow obstruction occurs, causing an acute worsening of symptoms (a COPD exacerbation). It is then that bronchitis becomes acute and antibiotics are initiated. Acute bronchitis is an infection or inflammation of the bronchioles but does NOT necessarily mean that pneumonia is present. Chest x-rays are usually normal. The term simply means that the air tubes are inflamed, or possibly infected with a virus, bacteria, or other kind of organism (the most common cause of acute bronchitis is a virus). Acute bronchitis is usually treated with oral steroids and often with antibiotics (even when pneumonia isn’t present).


Pneumonia may be caused by viruses, bacteria, or other organisms. The word pneumonia means that an infection has occurred deep in the lungs (beyond just the air tubes, or bronchioles). The air sacs pool with inflammation or pus caused by bacteria, and this is often seen on a chest x-ray.

Patients who have pneumonia often have acute COPD exacerbations including acute bronchitis. Pneumonia is often caused by bacteria, so antibiotics are typically given to patients. However, it is important to know that viruses can also cause pneumonia, and sometimes pneumonia that is caused by a virus can be complicated by bacterial pneumonia, too.

The Bottom Line

COPD exacerbations, bronchitis, and pneumonia are treated very similarly but have distinctions.The differences lie mainly in regards to the area of the lung that is affected. In all cases, steroids and inhalers are given, and antibiotics are very commonly prescribed.


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