The 9 types of Pneumonia (causes, symptoms and treatment)

Any condition that puts the health of the lungs at risk is extremely serious. In this organ an essential activity is carried out for the correct functioning of the body, and it is none other than the exchange of gases.

In other words, it is where oxygen (O2) is collected, an element necessary for cells to obtain energy for their functions; and carbon dioxide (CO2) is released, a residual element of this process of obtaining energy and which is toxic to cells, so it must be expelled from the body. So any abnormality that affects this exchange is detrimental to the health of the person.

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Pneumonia: inflammation of the lung

There are quite a few diseases that affect the lungs, one of the most common being pneumonia. Its importance is such that this condition is among the most frequent causes of death in the world.

Several criteria are used to differentiate different types of pneumonia, but they all share that they are inflammations due to an immune response to an infectious agent in the alveoli (gas exchange zone) and tissues surrounding.

Common symptoms of pneumonia are cough with sputum formation, breathing difficulties, chest pain, fever, and chills. The level of severity depends on the infectious agent.

The use of criteria to identify pneumonia is a necessary method to know which of them the patient is suffering and thus follow the appropriate treatment for their improvement. Pneumonia is a group of diseases, each caused by a different microorganism. There are many ways to separate the different types of pneumonia, here we will expose several of these criteria, but they are not the only ones available for this task.

Types of pneumonia according to the causative agent

The classic classification separates pneumonia by the pathogen that causes it, but at the clinical level it is not very useful, because at the beginning of a treatment samples have not yet been analyzed to determine the infectious agent that the patient. However, for a general study of the disease it is ideal.

1. Gram positive bacteria

There is a criterion to separate bacteria which is the use of gram stain, that according to how the cell is stained, gram positive and gram negative bacteria are differentiated. In the case of positive ones in this stain, there are two well-known cases.

Pneumococcal pneumonia is a type of pneumonia caused by the bacteria Streptococcus pneumoniae, commonly known as pneumococci. It is the most frequent case, since there are almost 80 different types of pneumococci, and each one needs its own antibody, that is, being infected by one of these does not immunize you from the rest. It is normally generated after a viral infection that weakens the respiratory tract, facilitating its entry into the lungs.

The other case is staphylococcal pneumonia, an infection caused by the bacteria Staphylococcus aureus. Rs rare in cases outside of hospitals, however within them it is more common to become infected, since it usually affects children and the elderly, or people with previous pathologies. The appearance of pus with this bacterium is very typical.

2. Gram negative bacteria

Having seen the first group, now touch the gram negatives. Unlike the first, these tend to be much more aggressive and, therefore, they are a more serious type of pneumonia. Some example bacteria are Klebsiella, Legionella or Pseudomonas and they are infections more typical of acquiring in hospitals. They have a great capacity to damage tissue relatively quickly, for this reason they are very serious conditions, with the possibility of being lethal.

For example, the bacterium Hemophylus influenzae, especially its type B strain, causes serious infections in meninges or lungs in children under six years of age, but thanks to its vaccine it does not cause big problems today in day.

3. Atypical pneumonias

This group includes the types of pneumonia caused by bacteria that are not included in the above, in addition to generating pneumonia much milder than those already mentioned above, which would be typical. Mainly here are the microorganisms of the genus Mycoplasma and Chlamydia. A good example of these is pneumonia caused by Mycoplasma pneumoniae, which is the most common cause in people 5 to 35 years of age.

4. Viral pneumonia

Inflammations in the lungs can also be caused by the entry of viruses, such as the flu or herpes. The main problem with this is that they are not treated with drugs, and antivirals are only used in severe cases.

5. Fungal pneumonias

This type of pneumonia is normally very mild and even the infected person does not realize they have it. Caused by fungal infection in the respiratory tract, mainly by these three: Histoplasma capsulatum, Coccidioides immitis and Blastomyces dermatitidis.

Pneumonia according to the fungal area

Not all infections affect the same area of ​​the respiratory system or in the same way. Therefore, there is also another criterion to separate pneumonia.

In this way we can distinguish with lobar pneumonia, which affects an entire lobe of the two that have the lungs; bronchopneumonia, which affects both the lungs themselves as well as the air transport routes (the bronchi); necrotizing pneumonias, that the affected areas of the respiratory system originate necrosis or tissue death; or interstitial pneumonia, inflammation that affects the connective tissue of the alveoli.

The criterion of the formation of necrosis is very useful to identify its cause, since they are normally anaerobic microorganisms, that is, they cannot live in an environment with oxygen.

Depending on the scope of acquisition

This is a more decisive classification for rapid clinical identification. and refers to whether the pneumonia has been obtained outside or inside a hospital. They are not the same microorganisms in these two environments, which makes it possible to rule out infectious agent just by knowing where the patient was infected.

The first type of pneumonia is called nosocomial or intrahospital, and are those that manifest at be admitted to a hospital for more than 48 hours and was not in incubation prior to entering the center. Here the infectious agents are more resistant, since a hospital has a higher level of hygiene than many other locations or people are weakened and therefore are admitted to a hospital.

For the rest, they are grouped into community-acquired or out-of-hospital pneumonia, and as its name indicates, it is when the infection has not originated within a health center.

Depending on the guest

As the last criterion that we will mention to differentiate pneumonia is according to the immunity of the patient. Like is logic, It is not the same for a person to have an operational immune system to the one that does not, and this serves to identify the infectious agent that causes it. This criterion differentiates between immunocompetent and immunosuppressed pneumonia.

Thinking that the defensive system stops many of these pathogens before they can act, so their partial or total absence is a risk factor. Opportunistic infections take advantage of this lack of defense, since they are microorganisms that do not cause diseases under normal conditions.

The case of the Coronavirus

Finally, we can present a case that can cause pneumonia that affects us all because of its global scope. I am not talking about other than SARS-CoV-2, the cause of COVID-19. Commonly called coronavirus, it is a virus from the Coronaviridae family, which infects its hosts in the respiratory tract.

The general cycle of a virus within its host is to infect cells, where it injects its genetic content and takes control of its mechanisms for the duplication and replication of that material. In addition, it also uses it for the manufacture of other protein components that form the virus (like the capsule, where the genetic content is stored). In other words, the virus dominates other cells to make copies of it and thus grow in number. Once a limit of units is reached, it activates the destruction of the cell for the release of viruses.

In the case of coronavirus, the pathogen invades cells of the respiratory tract, mainly of the alveoli, so the infection and destruction of cells in this tissue affects our breathing. Therefore, its main symptoms are fever (infection), cough and feeling short of breath (affects the area of ​​gas exchange). In more severe cases, pneumonia and acute respiratory syndrome, lung failure due to accumulation of blood (edema) in the organ, develop.

The general problem with viruses is that no medication is used for their treatment, since antivirals are restricted in use. Normally, the aim is to minimize symptoms and make use of devices that facilitate functions (for example, respirators). And the vaccine is a preventive element to avoid catching the disease. For this reason, in this case, what is sought as a quicker solution is an effective treatment that helps to minimize the damage of the virus and most importantly, take preventive measures to stop the expansion.

Bibliographic references:

• Dr. Percy Miranda Paz. "Pneumonia". 2004. https://www.saludarequipa.gob.pe/epidemiologia/ASIS/docs/Doc/Sala%20situacional%20Neumonias.pdf

• Carlos José Álvarez Martínez. "Pneumonia: Concept, classification and diagnosis". https://www.neumomadrid.org/wp-content/uploads/monogix_1._neumonias-concepto.pdf

• General Council of Pharmaceutical Colleges. ”Coronavirus COVID-19”. 2020. https://www.portalfarma.com/Profesionales/campanaspf/Asesoramiento-salud-publica/infeccion-coronavirus-2019-nCoV/Documents/Informe-tecnico-Coronavirus.pdf