Pneumonia is an inflammatory disease of the respiratory organ – the lungs. This disease, which is scientifically called pneumonia, is mostly caused by pathogens of various kinds – bacteria, viruses, fungi and other harmful organisms. In some cases, poisoning of the lung tissue by inhalation of toxic substances or gases can also cause inflammation.
Immunological processes also play a role, i.e. processes in which the immune system is directed against the body’s own cells. However, infections as cause are more relevant in principle. Pneumonia is the most common infectious disease in the world.
In Germany alone, 300,000 people a year are affected by this disease. In the meantime, good therapeutic approaches have been developed and the mortality rate for pneumonia is no longer high. However, this only applies to immunocompetent individuals, i.e. people with an intact immune system.
If the immune system is weakened, pneumonia can greatly worsen the patient’s general condition and even lead to death. The signs of pneumonia are strongly related to the cause of the disease. Depending on the pathogen, the course of the disease can vary.
The place where the pneumonia was formed also plays a role. A distinction is made between outpatient (outside the hospital) acquired pneumonia (CAP: community-acquired pneumonia) and nosocomial (during hospitalization) infection (HAP: hospital-acquired pneumonia). In principle, it can be said that a HAP has a worse prognosis than a CAP, because patients who develop pneumonia in addition to their actual suffering are usually immunocompromised (immunosuppressed).
Signs (symptoms) of pneumonia
Bacterial pneumonia, such as that caused by the bacterium Streptococcus pneumoniae, has a relatively rapid course. It is also called lobar pneumonia (lobus = lobe) because the inflammation is limited to one or more lobes of the lung. As soon as the mass of the pathogens has overwhelmed the patient’s immune system, there is increased blood flow to the lung tissue and a build-up of defense and blood cells as well as substances of the coagulation system.
These form an alveolar exudate, a liquid secretion in the pulmonary alveoli that catalyzes the inflammation. Within a few hours, a severe feeling of illness settles over the patient. The temperature rises up to 40°C and there is also chills.
The cough associated with the pneumonia is dry at the beginning. This changes after 2-3 days – yellow to red-brown sputum is produced. The inflammation continues to take its toll by affecting breathing and the heart.
Breathing difficulties occur even when the body is completely at rest (dyspnea at rest) and the speed of breathing increases to compensate for the reduced oxygen intake (tachypnea). This compensation is followed by the cardiovascular system – the heart beats faster in order to improve blood flow to the lungs (tachycardia). Due to the overall poor condition of the sick person, it is possible that the consciousness is affected.
It is observed that patients with severe pneumonia are confused and increasingly sleepy. The lung is surrounded by a kind of envelope, the pleura. It is attached to the lung on one side and to the thorax on the other.
If the pneumonia spreads and there is corresponding involvement of the pleura (pleuritis), the affected persons feel pain when breathing in addition to the general symptoms. While lobar pneumonia is localized, interstitial pneumonia is an unlimited infection. The interstitium is the tissue of the lung.
Interstitial pneumonia is mainly caused by viruses, but some bacteria can also be the cause of this disease. In contrast to lobar pneumonia, however, the inflammation is not in the alveoli, i.e. the lumen of the lung, but in the tissue, the interstitium. The defence cells absorb the pathogens and then wallow into the tissue, where the inflammatory processes take place.
Because the lung function itself is not restricted at the beginning, interstitial pneumonia is rather insidious. There is an infection without fever or only a slight increase in temperature (fever is always a sign of a bacterial infection! ), slight cough without sputum, but nevertheless increasing problems with breathing.Depending on the pathogen, general symptoms of an infection may occur: Feeling of illness, headache and aching limbs, pain in the neck and chest.
Both types of pneumonia described last are usually acquired on an outpatient basis. With HAP, i.e. a hospital infection, the clinical picture can be more complicated. As already mentioned, immunocompromised patients are more likely to be affected by hospital-acquired pneumonia.
This means that in addition to the serious underlying disease, there is another serious inflammation, which may not even be recognized as such. Often affected patients are already so limited in their condition that they need to be ventilated. Since they are not conscious, they cannot report any complaints.
The responsibility now lies with the medical and nursing staff. Newly occurring fever and changes in the blood count, such as in the inflammation parameters, can provide information about pneumonia. The oxygen content in the arterial blood should also be monitored to detect any loss of lung function.
Various factors can increase the risk of developing pneumonia. In many cases, secondary pneumonia develops. This means that the inflammation must be seen as the result of another underlying disease.
The risk factor “age” has to be distinguished from this: people of old age as well as small children fall ill faster than people of other age groups. Lung diseases: If a disease of the lung already exists, the risk of developing an inflammation is logically increased. The following belong to the classic diseases: COPD (Chronic Obstructive Lung Disease) – a disease that mostly affects smokers and restricts the lungs in various functions; cystic fibrosis (MS) – an autoimmune disease; bronchiectasis – a dilatation of the bronchi; emphysema – the final stage of many chronic lung diseases, in which the lungs lose their elasticity.
As a result of all these diseases, the lungs lose vitality and the cells are increasingly damaged. This makes it easier for pathogens in particular to settle.
- Lung diseases: If a disease of the lung already exists, the risk of developing an inflammation is logically increased.
The following belong to the classic diseases: COPD (Chronic Obstructive Lung Disease) – a disease that affects smokers to a large extent and restricts the lungs in various functions; cystic fibrosis (MS) – an autoimmune disease; bronchiectasis – a widening of the bronchi; emphysema
- -the terminal stage of many chronic lung diseases, in which the lungs lose their elasticity. Through all the above mentioned diseases the lung loses vitality and the cells are increasingly damaged. This makes it easier for pathogens in particular to settle.
Immunosuppression: If the immune system is limited, the body’s defence against any pathogens and harmful external influences is weakened.
The pathogens are not countered and they can attack the body unhindered. Since the lung is an optimal entry point – it is moist, warm and well supplied with blood – an infection is often found in immunocompromised patients. The immune system can be switched off by various diseases, but also by the treatment of other diseases.
Such treatments include chemotherapy for cancer – the chemotherapeutic agent is designed to kill cancer cells, inevitably killing healthy cells as well – or drug-based immunosuppression, as must be done after an organ transplant to reduce the risk of being rejected by the body. Diseases that limit the immune system include diabetes mellitus and alcoholism. Both are associated with an unhealthy lifestyle and poor general condition, which has a negative impact on the immune system.
However, both of these diseases represent influenceable conditions that can be kept within limits with proper therapy. Cancer and HIV infection cannot be influenced by the patient per se. In principle, an HIV infection can be prevented by sexual contraception and careful handling of blood, but once infected, there is no cure at the current state of knowledge.
With the right medication, the course of the disease can be slowed down and a worsening of the condition can be delayed for years. In the final stage, however, there is always AIDS – the Acquired Immune Deficiency Syndrome.The HI-viruses attack the defence cells of the immune system and destroy them. This opens the door to any kind of infection and a slight cold can turn into a severe pneumonia that is fatal.
- Immunosuppression: If the immune system is limited, the body’s defence against any pathogens and harmful external influences is weakened. The pathogens are not countered and they can attack the body unhindered. Since the lung is an optimal entry point – it is moist, warm and well supplied with blood – an infection is often found in immunocompromised patients.
The immune system can be switched off by various diseases, but also by the treatment of other diseases. Such treatments include chemotherapy for cancer – the chemotherapeutic agent is designed to kill cancer cells, inevitably killing healthy cells as well – or drug-based immunosuppression, as must be done after an organ transplant to reduce the risk of being rejected by the body. Diseases that limit the immune system include diabetes mellitus and alcoholism.
Both are associated with an unhealthy lifestyle and poor general condition, which has a negative impact on the immune system. However, both of these diseases represent influenceable conditions that can be kept within limits with proper therapy. Cancer and HIV infection cannot be influenced by the patient per se.
In principle, an HIV infection can be prevented by sexual contraception and careful handling of blood, but once infected, there is no cure at the current state of knowledge. With the right medication, the course of the disease can be slowed down and a worsening of the condition can be delayed for years. In the final stage, however, there is always AIDS – the Acquired Immune Deficiency Syndrome.
The HI-viruses attack the defence cells of the immune system and destroy them. This opens the door to all kinds of infections, and a mild cold can turn into a serious pneumonia that can be fatal.
- Other factors: Inhalation of various substances can cause lung tissue inflammation. These include gastric acid or food waste.
It is already known that tobacco smoking in general damages the lungs and can cause various chronic lung diseases. The risk of developing pneumonia also increases with the consumption of tobacco products. The conditions in which intensive care patients are hospitalized are also a risk for the lungs: both bedriddenness (shallow breathing throughout) and intubated ventilation (bypassing the body’s own defense system) can promote pneumonia.
All articles in this series: