The effects of body pneumonia
Pneumonia is an infection that affects lung alveoli. These are small sacks covered with blood vessels in which the gas exchange is performed, that is, carbon dioxide (CO2) is expelled and oxygen from the outside is captured. That is why the consequences of body pneumonia are so important.
It is estimated that there are 2 to 10 cases per 1000 inhabitants per year, of which between 20 and 35 % require hospital admission. In patients without other diseases, mortality is in 1 %, but can reach 40 % in admitted patients, especially in intensive care units (ICU). Depending on the patient’s situation, it can become serious.
To know how pneumonia can affect the body, in this article we will explain the process through which your body passes from that you are infected until you suffer from the disease.
Effects of body pneumonia
- Pneumonia is the consequence of two conditions that occur simultaneously:
- Arrival and proliferation of microorganisms in the alveoli.
- Inflammatory response of the guest, which will condition the clinical manifestations and the severity of the disease.
How do microorganisms get to the lungs?
Pneumonia is caused by bacteria, viruses, fungi and parasites, being bacteria and viruses the most frequent pathogens. Currently, a greater number of viruses are increasingly identified as causal pneumonia agents. Two types of pneumonia can be given:
- Pneumonia caused by the same virus: primary pneumonia. An example would be pneumonia caused by SARS-COV-2 (COVID-19)
- Bacterial pneumonia secondary to a viral infection of the respiratory tract. For example, the flu is often complicated by bacterial pneumonia.
The respiratory tract are constantly exposed to microorganisms. The lung can colonize bacteria, viruses and other microorganisms through the following mechanisms:
Aspiration of microorganisms present in the throat
Our respiratory and digestive system are intimately related through pharynx. The pharynx joins the nose and mouth to the larynx (respiratory system) and the esophagus (digestive system). The food we eat after passing through the pharynx should only enter the esophagus, since in the larynx only air can enter. To do this, there is a structure called epiglotis that closes the larynx preventing that between the food and directing it towards the esophagus.
All people have in the nasal and oral bacteria cavity and, sometimes, viruses, which do not cause us normally. However, larynx, trachea, bronchi and lungs must be sterile, that is, they should not contain any microorganism, because otherwise they would cause an infection. Therefore, as we have explained before, in the larynx only enters air.
During the dream, the throat musculature and the epiglottis relaxes, therefore, there may be microaspirations. We call this way to the passage of small contents of the pharynx, such as saliva, food, etc., To the larynx. These microaspirations can contain microorganisms that, after passing through the larynx, pass to the lung. This mechanism occurs in the vast majority of people who develop pneumonia, and even in healthy people without any disease.
On the other hand, there are people who have a diminished level of consciousness and do not have good control of epiglottis. This causes them to have massive aspirations of food, drinks or saliva towards larynx, producing the colonization of their lungs.
Inhaled route
People regularly inhale small amounts of air microorganisms, and they can reach the airways.
These microorganisms can come from an infected person who coughs or sneezes without protection, infecting those around him.
Hematogenous route
This mechanism usually happens in people who have the affected immune system, or also known as immunosuppressed. That is, your body has no defense mechanism to fight infections.
These people can present, for example, bacteria circulating through the blood. These bacteria can pass to the respiratory tract, affecting the lungs. In conclusion, the hematogenous route is based on the passage of blood microorganisms to the lungs. Luckily, this route is very uncommon.
From an infection in pleura or mediastinum
The lung is surrounded by layers called pleura. These layers can be infected and, by contiguity, the infection passes into the lung. In addition, among the lungs we find different structures that make up the mediastinum, such as the heart. Sometimes, the mediastinum can suffer infections and they can pass to the lung affecting it.
Hospital pneumonia
In the hospital, people admitted by other diseases can contract pneumonia. The most frequent infection mechanism of this type of pneumonia is associated with the fan, that is, it occurs in intubated and respirator patients.
Intubation is based on the passage of a direct tube from the outside to larynx preventing epiglottis from preserving the airway without microorganisms. Pathogens from abroad have an easier way to enter the lungs and infect them.
Therefore, intubation has to be performed in special situations, when the patient’s life is in danger, since, by other means it fails to breathe properly.
Defense mechanism
If these microorganisms enter the lungs they are easily eliminated by the defense mechanisms of our body, which include:
The reflection of cough, which helps expel mucus and strange substances. The cilia of the cells that cover the pulmonary airways, which prevent microorganisms from invading the lungs. These cilia are like small mobile filaments that push mucus and strange substances up to be expelled when coughing.
Lung cells produce substances that attack microorganisms by destroying them.
In the lungs there are some cells of the organism defense system that are naturally there, protecting the alveoli. They are called alveolar macrophages, and their function is to eat microorganisms and kill them.
When these defense mechanisms fail or inhale a lot of microorganisms or microorganism is very powerful, body pneumonia occurs.
How does our body respond?
If primary defense mechanisms have not been able to expel the microorganism, our body produces an inflammatory response. This inflammatory response is caused by the release of substances by alveolar macrophages:
- Substances that produce fever. This is because, at a higher temperature, microorganisms can be inactivated and more easily destroyed.
- Substances that attract other defense cells, such as neutrophils. In turn, neutrophils produce purulent secretions that can cover the alveoli preventing the gas exchange and causing a sensation of drowning because we do not reach oxygen to the blood to the blood.
To be able to understand it better, we put the following simile: the macrophages are the soldiers in the first line of battle, but if they see that they are losing the fight, they call the reinforcements to help them overcome the enemy. These reinforcements would be the rest of the defense cells.
However, reinforcements attracted by macrophages can trigger harmful clinical manifestations for the person. Therefore, for our body to stop producing this defense response, the patient has to be treated correctly to eliminate the microorganism.
conclusion
In summary, it has to be clear that the clinical manifestations of pneumonia are not caused by the pathogen but by the inflammatory response of the person. Therefore, people with a stronger immune system will have more symptoms than an immunosuppressed person.
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