What Causes Pneumonia?


Story at-a-glance

  • Pneumonia can actually be brought on by different types of germs, including viruses, bacteria, and fungi, that you inhale
  • Knowing the cause of pneumonia is extremely important, as it is crucial in determining the course of treatment for this illness

You should know that there is not just one primary cause of pneumonia. This illness can actually be brought on by different types of germs, including viruses, bacteria, and fungi, that you inhale. Knowing the cause of pneumonia is extremely important, as it is crucial in determining the course of treatment for this illness.

Primary Causes of Pneumonia

Bacterial pneumonia affects people of all age, and can either develop on its own or after a severe case of cold or flu.1

Viral pneumonia is brought on by respiratory viruses, and is prevalent in young children and seniors. This is usually not serious, and heals in a short span of time.

However, viral pneumonia caused by the flu virus can be severe or fatal, and is especially dangerous to pregnant women or people with heart or lung problems. Bacteria can also lead to complications with viral pneumonia.

Fungal pneumonia is caused by opportunistic fungi and may develop upon the inhalation of damaging spores, such as from the soil or birds’ droppings.2 Although it is relatively uncommon in most of the U.S, it may be acquired in places such as Mexico, South America, and Africa.3

Examples of infections that can lead to fungal pneumonia include histoplasmosis, cryptococcosis coccidiomycosis, aspergillosis, blastomycosis.4

Another potential cause of pneumonia is mycoplasma. These are the smallest free-living disease agents known today. They are neither bacteria nor virus, yet they have traits of both.

Mycoplasma usually leads to a mild form of this illness, which may become severe in some cases. It affects all age groups, but is most common in older children and young adults.

How Do These Organisms Infiltrate Your Body?

Most of the time, your body can effectively filter out these harmful organisms – your immune system, your ability to cough, and the cilia (small hair-like structures) in your nose all work together to keep these germs out of your lungs and body .

However, there are instances when the germs manage to infiltrate your body, and enter your lungs, leading to infections. Factors that may influence this include:

Having a weak immune system

When the fungi, bacteria strain, or virus is very strong

Being unable to cough, such as when you’re sedated or you’ve had a stroke – this causes germs to stay in your airway

These Settings Can Increase Your Risk for Pneumonia

When these damaging organisms reach your lungs, your immune system immediately goes into action, and sends many types of cells to attack the bacteria/fungi/virus. These cells cause your lungs’ alveoli or air sacs to become red and inflamed, filling up with fluid and pus. This is what leads to the common symptoms of pneumonia. So how do you catch these pneumonia-causing organisms? They can be acquired through different settings, such as:

Your community or environment. Also known as community-acquired pneumonia, this refers to pneumonia cases that come from sources other than hospitals or health care facilities.

Hospital-acquired pneumonia. This refers to pneumonia that develops during a hospital stay, and may be more serious, as the bacteria may be more resistant to antibiotics. Patients who use ventilators and other breathing machines are at a high risk of this type.

Healthcare acquired pneumonia. People who live in long-term care facilities (such as nursing homes) or treated in outpatient clinics and kidney dialysis centers, are at high risk of healthcare acquired pneumonia.

Another lesser known but possible cause of pneumonia is aspiration. This is what happens when you accidentally inhale food, saliva, or vomit into your lungs. Aspiration pneumonia is most common in people who have problems with their gag reflex, such as those with brain injury or excessively used drugs or alcohol.5


Pneumonia: Introduction

What Is Pneumonia?

Is Pneumonia Contagious?

Pneumonia Duration

Pneumonia Types

Pneumonia Causes

Pneumonia Symptoms

Pneumonia Treatment

Pneumonia In Children

Pneumonia In Elderly

Bronchitis vs Pneumonia

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Pneumonia Types

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Pneumonia Symptoms

[+]Sources and References [-]Sources and References

  • 1 Healthline, October 20, 2015
  • 2, 5 Mayo Clinic, March 14, 2015
  • 3 Medscape, Aug 1, 2014
  • 4 Medical News Today, June 10, 2015