Causes of Pneumonia

Causes and development of pneumonia

Pneumonia can have various causes.
It can be caused by bacteria. Pathogens such as:

  • Pneumococci
  • Staphylococci
  • but also rarer ones such as legionella
  • or chlamydia / mycoplasma

to carry.

In some cases, pneumonia can also develop as part of hospital infections.

Read more about the topic: Hospital germs

Viruses can also cause pneumonia.

The most common are:

  • RS virus (a virus of the airways)
  • Paramyxoviruses
  • but also herpes viruses.

Infections with fungi (e.g. Candida, Aspergillus) occur almost exclusively in people with a weakened immune system (immunocompromised people) in front.

Typical pneumonia (pneumonia) is mostly caused by bacteria.
Most of the inflammation is in the alveoli (Alveoli), and the thin branches of the bronchi (Bronchioles).
If only one lobe of the lung is affected, it is called lobar pneumonia (lobus = Rag), which is mostly caused by pneumococci.

Read more on the topic: Superinfection

Atypical pneumonia is often caused by mycoplasma and legionella, which are bacteria, but also by viruses and fungi.

In this form, the inflammatory deposits are more likely to be found in the interstitium (intermediate tissue).

In people infected with HIV, there is a general weakness in the immune system. The T-lymphocytes, our body's defense cells, are destroyed and the defense against bacteria, viruses and fungi is made more difficult.
Fungal infestation of the lungs can be observed almost exclusively in people with weakened immune systems. These mushrooms cannot harm a healthy adult.

In the case of aspiration pneumonia (stomach contents / gastric juice gets into the lungs), the cause of the inflammation is not the pathogen, but the acidic gastric juice.
Elderly and debilitated people, the chronically ill, but also alcoholics and children are particularly at risk of developing pneumonia.

Anatomy of air ducts

Figure bronchiole: Plastic representation of the end branch with vascular network
  1. Bronchiole
    (cartilage-free smaller
    Bronchus) -
  2. Branch of the pulmonary artery -
    Pulmonary artery
  3. End bronchiole -
    Respiratory bronchiolus
  4. Alveolar duct -
    Alveolar duct
  5. Alveolar septum -
    Interalveolar septum
  6. Elastic fiber basket
    of the alveoli -
    Fibrae elasticae
  7. Pulmonary capillary network -
    Rete capillare
  8. Branch of a pulmonary vein -
    Pulmonary vein

You can find an overview of all Dr-Gumpert images at: medical illustrations

Causes of Smoking

Smoke can be one of many factors causing pneumonia.

When smoking, more and more particles are deposited over the years, which come directly from the cigarette and which are contained in the smoke. These particles reach the innermost part of the lungs, the alveoli.
The cilia, which are actually responsible for moving dirt and dust from the lungs back towards the mouth, gradually stick together and can no longer do their job.

Instead of the cilia, more goblet cells are formed, which produce mucus. In the end, so much mucus is produced that it can no longer be removed. It also makes it easier for smoking pollutants to get into the lungs. The lining of the lungs often becomes inflamed and this changes the tissue. The bronchial walls noticeably thicken and this means that less air gets into the lungs. The gas exchange takes place only inadequately. The changes in the lungs make them even more susceptible to bacteria, viruses and fungi, which, due to the lack of cilia, can penetrate directly into the lungs with hardly any resistance.
These pathogens cause pneumonia in many patients.

Hypothermia as a cause of pneumonia

Hypothermia (Hypothermia) occurs when the body temperature drops below the normal 36.5 to 37 degrees.

For many people, hypothermia is caused by an accident on the water and when outside temperatures are low or in the mountains, often in winter. Even drunk and especially homeless people who cannot stay in a heated room are often victims of the Hypothermia. The hypothermia lowers the immune system. That means it can no longer work as well.
The immune system is usually there to ensure that our body is largely protected from invading bacteria, fungi and viruses. The more pronounced it is, the less often we get sick or a disease occurs visibly. Sometimes the body fights silently with the pathogens. If people are hypothermic, the effectiveness of the immune system drops drastically. The main cause of the lung infection (pneumonia) are bacteria. But viruses and fungi can also trigger them. Now these pathogens can penetrate the body much more easily and have to reckon with much less resistance.
This is how you can get pneumonia after hypothermia.

Causes in children / babies

Young children and babies in particular are very susceptible to pneumonia (pneumonia). Again, this is often due to the not yet so pronounced immune system. In addition, it is often overused in childhood when illnesses spread in kindergartens or elementary schools.
Pathogens can penetrate the small bodies all too easily and cause pneumonia.

In children and babies, however, there are different pathogens than in adults that cause pneumonia. The bacteria of the Staphylococcus aureus, Haemophilus influenzae type b and the Pneumococci. The former occur practically everywhere in nature and also live on warm-blooded organisms on the skin and mucous membranes and in the upper respiratory tract. They are also found in food and water.

If the immune system is not yet developed or weakened, these bacteria take over and can invade the body. The bacterium of Haemophilus influenzae type B usually occurs in the first 5 years of life and can cause very severe respiratory diseases. But there is a vaccination against it. The pneumococci are also very dangerous bacteria that can cause serious diseases, especially in the respiratory tract, but also meningitis and otitis media. They are mostly passed on through droplet infection. This is also a certain risk once the children attend kindergarten. But there is also a vaccination against these bacteria.

In addition, foreign body aspiration can lead to a local inflammatory reaction caused by pathogens on the foreign body.
The cause of swallowing lies in the insufficiently developed act of swallowing.

Read more on the topic: Vaccinations against pneumonia