Pneumonia Season is Here

What are the types of pneumonia and how can you tell them apart?

Photo Credit: David Sacks/Stone.

With the winter weather comes an unfortunate reality for may patients with lung disease (especially those with COPD): pneumonia season. Although pneumonia can occur at any time of the year, the winter months are the time when pneumonias and other respiratory infections run rampant.

What are the types of pneumonia and how can you tell them apart?

Pneumonia is a commonly used term to describe an infection within the lung.

Pneumonia is most commonly diagnosed by chest x-ray or by healthcare provider after listening to the lungs with a stethoscope. Though the diagnosis of ‘pneumonia’ is relatively easy to make, distinguishing between the many causes of pneumonia may be quite difficult.

There are 5 major types of pneumonia.

Bacterial pneumonias

Bacterial pneumonias come in two ‘flavors’. There are “typical pneumonias” which means that the bacteria that is responsible for the infection is one of the classic organisms:  staphylococcus, streptococcus, and many others. There are also “atypical pneumonias” which are caused by other kinds of bacteria: legionella, chlamydia, mycoplasma, and others. The most common (and easiest) way to tell which kind of bacteria is growing is to obtain a sputum sample and send it to the laboratory. The laboratory can then report back which bacteria is growing. Often times, however, patients may have a bacterial pneumonia, but the bacteria doesn’t grow in the lab.

Regardless, typical bacterial pneumonias appear on a chest x-ray, usually in one lung but may spread to both lungs. Atypical pneumonias have a slightly different appearance on chest x-ray, although it is nearly impossible to tell for sure which kind of pneumonia a patient has by looking at an x-ray.

Patients with typical pneumonias classically have greenish sputum, although many patients may not cough up enough mucus to know this. These pneumonias are treated with antibiotics. Different antibiotics may be used based on the type of bacteria that is causing the infection. Atypical pneumonias have a slightly different appearance on chest x-ray, although it is nearly impossible to tell for sure which kind of pneumonia a patient has by looking at an x-ray. Patients with typical pneumonias classically have greenish sputum, although many patients may not cough up enough mucus to know this. These pneumonias are treated with antibiotics. Different antibiotics may be used based on the type of bacteria that is causing the infection.

Viral pneumonias

Viral pneumonias are slightly different than bacterial pneumonias in their classic symptoms. Viruses can cause pneumonia that is seen on a chest x-ray, but the pattern is more spread out and less focal on the image. The symptoms are typically more of wheezing and a dry cough.

Viral pneumonias are usually diagnosed with a nasal or oral swab. Treatment is usually fluids and rest, and sometimes antiviral medications are used.

Aspiration pneumonias

Aspiration pneumonia occurs in patients who have swallowing dysfunction,  which often occurs in patients with advanced age, stroke, or muscular disorders. When we swallow, parts of the throat move to protect food and particles from ‘going down the wrong pipe’ (into the lungs). When this mechanism is disrupted, tiny food particles (with bacteria riding along on the particles) can land in the lung and flourish into a bacterial pneumonia. In addition, acid and bacteria that live in the GI tract may creep up the esophagus, into the throat, and get inhaled into the lungs, also causing pneumonia. Our swallowing mechanism protects this from happening (called ‘airway protection’) but when this becomes disrupted, even mildly, an aspiration pneumonia may develop. Unfortunately, many patients don’t realize that the mechanism is disrupted as it can happen without any symptoms at all. This is why patients who get frequent pneumonias that are otherwise unexplained, may have swallowing tests performed. Aspiration pneumonia is treated with antibiotics, however, healthcare providers may select different antibiotics for this class of pneumonia than they would for bacterial pneumonias.

Fungal pneumonias

Fungal pneumonias classically affect patients who have immune deficiencies, are on steroids, or perhaps have an underlying lung disease. Depending on the region of the country and the type of exposures patients have, many different fungi can cause pneumonia. These fungi live in the air, soil, and water.  Anti-fungal medications (called azoles) are used to treat fungal pneumonia either in pill or IV form.

Other pneumonias

There are several other miscellaneous forms of pneumonia. Tuberculosis, PCP and other organisms can cause pneumonia. These types of infections require specialized treatment and are often diagnosed after ruling out the classic types of infections listed above or when specific risk factors exist.

The Bottom Line

Although we often use the term ‘pneumonia’ to describe any kind of infection in the lung, its important to know that not all pneumonias may be treated the same, and not all pneumonias require antibiotics.

Check out these Top 20 Pneumonia Facts from the American Thoracic Society.

Find out more details on specific types of pneumonias.

Stay tuned for the next article in this series to learn the answer the question: What is the difference between pneumonia, bronchitis, and a COPD exacerbation?

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