Introduction
An inflammation of the lung tissue, which is mostly due to the colonization with pathogens, is called pneumonia. In many cases, this is accompanied by a characteristic “typical” picture of accompanying signs of disease (symptoms) such as fever, chills, a slimy (productive) cough and accelerated breathing (tachypnea). In some forms of pneumonia, some or all of these typical signs are absent. Then the specialist speaks of an atypical pneumonia, which is also called “cold pneumonia” (due to lack of fever), or “dry pneumonia” (due to less pronounced, but above all non-mucusy (unproductive) cough).
Overview
Usually, other germs are responsible for an atypical, cold, dry pneumonia than for a typical pneumonia. However, the absence of the above-mentioned symptoms does not mean that atypical pneumonia is less dangerous than typical pneumonia. On the contrary, their absence often leads to a trivialization on the part of the patient and a delayed visit to the doctor. Thus, dry pneumonia can often progress far before it is detected and treated. Whereas in the past, the vast majority of pneumonia was caused by pneumococcus (Streptococcus pneumoniae) and took a typical course, today, due to the use of antibiotics, vaccinations, etc., the total number of pneumoniae infections is lower, but a considerable proportion of 20-40% is of an atypical, dry nature.
Causes of dry pneumonia
The spectrum of pathogens that can cause dry pneumonia (atypical pneumonia) is wide. In addition to various viruses and fungi (Pneumocystis jirovecii), parasitically living (intracellular) bacteria (Coxiella burnetii, Legionella pneumoniae, Mycoplasma, Rickettsia as well as Chlamydophila pneumoniae) in the host cells are the main causes of atypical pneumonia. In contrast to a typical pneumonia, not only an area of the lung (one or more lobes, therefore the typical pneumonia is also called lobar pneumonia), but the entire lung tissue is affected.
In most cases, the pathogens attack endogenous cells near the connective tissue basic structure of the lung (septa). Since the main inflammatory process does not take place in the alveoli, but “between the cells” (in the interstitium), atypical pneumonia is also called interstitial pneumonia. Among the classical representatives causing dry pneumonia are
- Mycoplasmas: cell-converting bacteria whose only host is humans.
Therefore, they can only be transmitted from person to person. Outbreaks occur more frequently in the autumn and winter months.
- Chlamydia: Bacteria “living” in human cells, which therefore cannot be detected in the patient’s blood. There are two strains of Chlamydia pathogens that cause respiratory diseases, one of which is transmitted from birds to humans.
- Legionella: These bacteria are mainly found in stagnant waters as well as air conditioning systems and nebulizers, etc. They are blown into the air we breathe and inhaled by humans, so that they enter the lungs.
- Viruses: Viruses are also among the causes of atypical pneumonia and, unlike bacteria, are usually treated purely symptomatically and only in rare serious cases with an antiviral agent.
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