Pneumonia or bacterial pneumopathy: symptoms, diagnosis and course
Pneumonia or bacterial pneumonitis is an acute bacterial infection of the lungs, most often caused by pneumococcus, but also by Mycoplasma pneumoniae and other bacteria. It occurs immediately or may complicate the course of a viral pneumonia, such as that caused by influenza.
A person suffering from bacterial pneumonia or pneumopathy will present a variety of symptoms: fever, cough, chest pain, shortness of breath, headache, malaise, etc. The diagnosis is confirmed by a chest X-ray. The disease is usually cured, but complications can occur.
What is pneumonia?
Pneumonia: a bacterial infection of the lungs
Pneumonia is an acute respiratory infection of the lung tissue caused by bacteria, also known as bacterial pneumonitis. Various bacteria may be involved.
Pneumococcus
Streptococcus pneumoniae or pneumococcus is the most common cause. Pneumococcus is not transmitted from person to person, so there are no epidemics. The bacterium usually affects only one of the two lungs.
Mycoplasma pneumoniae
After pneumococcus, Mycoplasma pneumoniae is the bacterial agent most frequently implicated in acute community-acquired pneumonia, accounting for 30-50% of these infections. These infections are most frequently seen in children and young adults under the age of 40, but can affect all age groups. They are rare in the under-4s and over-60s.
The bacterium Mycoplasma pneumoniae is transmitted from person to person by inhalation of respiratory particles, and can therefore be responsible for small epidemics, particularly in groups (families, classrooms, offices, etc.). The bacteria reach both lungs in the form of infiltrates.
Other bacteria, more rarely
Legionella pneumophila, Haemophilus influenzae, etc. are much more rarely implicated in bacterial penumiopathy.
How does pneumonia occur?
Generally, germs in the air enter the lungs through the respiratory tract when you breathe. But they can also come from the oral cavity or the ENT (ear, nose and throat) tract.
When these bacteria enter the alveoli, they cause inflammation. The alveoli then fill with pus and fluid, causing the symptoms of pneumonia.
Other causes of infectious pneumonia: viruses and fungi
Pneumonia can be caused by bacteria.
But there are also diffuse pneumonias, affecting both lungs, caused by viruses:
- influenza virus;
- respiratory syncytial virus, which causes respiratory infections in young children
- chickenpox or measles viruses;
- Covid-19 SARS-CoV-2 virus.
In these viral pneumopathies, there is diffuse involvement of both lungs. Treatment with antibiotics is useless and ineffective. However, in rare cases, bacterial pneumonia may occur after viral lung disease and complicate the course.
More rarely, a fungus may be involved in the onset of pneumopathy.
Factors favouring the onset of pneumonia
There are many factors that can contribute to the development of pneumonia.
Age
Pneumococcal pneumonia can occur at any stage of life, but is more common before the age of two and after the age of 65.
Mycoplasma pneumoniae pneumonia is most frequently seen in children and young adults under the age of 40, but can affect all age groups. It is rare in the under-4s and over-60s.
Pre-existing lung disease
All chronic lung diseases are associated with an increased risk of pneumonia:
- adult and childhood asthma;
- chronic obstructive pulmonary disease (COPD);
- smoking;
- cystic fibrosis, etc.
Acute viral pneumonia such as influenza can be complicated by bacterial pneumonia.
Hospitalisation
Any hospitalisation, particularly in intensive care, is likely to result in pneumonia, especially when respiratory assistance has been provided (intubation, being put on a respirator). In this case, it is a nosocomial infection.
Immune deficiency
Infection with HIV (human immunodeficiency virus), chemotherapy, long-term corticosteroid therapy or any treatment that reduces immune defences may be to blame.
Swallowing problems
The elderly often have difficulty swallowing. In the event of inhalation by false swallowing, the risk of pneumonia is high.
Symptoms of bacterial pneumonia
The symptoms of bacterial pneumonia vary depending on the bacteria involved and the condition of the person affected.
Typically, when pneumonia is caused by pneumococcus bacteria, symptoms appear suddenly and the patient presents with:
- a high fever (39-40°C) with chills from the outset
- a dry cough
- shortness of breath
- chest pain, which may occur on one side only when coughing or breathing;
- general malaise.
You should therefore consult your GP as soon as possible, especially if you are elderly or have a chronic illness (COPD, cystic fibrosis, asthma, etc.), in the following cases:
- you have a fever and a cough that coughs up;
- yellow, green, rust-coloured or blood-tinged;
- you have a high fever with digestive problems, muscle pain or abdominal pain;
- you have recently experienced chest pain that worsens when you breathe deeply;
- you have difficulty breathing
- you feel confused;
- you have a cold, bronchitis or other viral illness (flu, etc.) that is getting worse instead of better.
But when the Mycoplasma pneumoniae bacterium is involved, the symptoms appear gradually and are often less characteristic:
- low-grade fever
- moderate cough
- little chest discomfort.
Other symptoms may be present: headaches, joint and muscle pains, malaise.
Diagnosis of pneumonia
To diagnose pneumonia, the doctor will ask the patient how they feel and about their medical history.
He will examine the patient and listen to the lungs, looking for abnormal noises called "rales" in one lung in the case of pneumococcal pneumonia, or more often in both lungs in the case of Mycoplasma pnaemoniae pneumonia.
Additional tests may be ordered, such as a blood test to look for signs of bacterial infection.
Finally, the diagnosis of pneumonia is confirmed by a chest X-ray, which shows the presence of:
- an infectious focus localized to one lung in the case of pneumococcal pneumopathy;
- or, on the contrary, a uni or bilateral diffuse pulmonary infiltrate in the case of Mycoplasma pneumoniae pneumopathy.
The course of bacterial pneumonia
Recovery from bacterial pneumonia
With antibiotic treatment, the fever falls rapidly, the cough becomes hacking, and the pneumonia progresses towards recovery. Any abnormalities visible on X-ray take longer to disappear.
Complications of pneumococcal pneumonia
Pneumococcal pneumonia can be complicated by:
- septicaemia: the germ responsible spreads in the blood. It can then colonise other organs (e.g. the meninges);
- a lung abscess (a cavity in the lung filled with pus);
- pleurisy: fluid appears between the two layers of the pleura. This fluid may become purulent;
- decompensation of a chronic illness (diabetes, heart failure, COPD, asthma, etc.).
If any of these complications occur, the patient must be admitted to hospital.
Complications of Mycoplasma pneumoniae pneumonia
Manifestations other than pulmonary
Mycoplasma pneumoniae pneumonia may be accompanied by extra-respiratory symptoms:
- a rash on the skin and mucous membranes, erythema nodosum;
- rheumatological manifestations, with joint pain ;
- neurological symptoms (meningitis, inflammation of the nerves, etc.);
- haemolytic anaemia, purpura due to a drop in the number of blood platelets;
- inflammation of the lining of the heart (pericarditis).
Respiratory complications
Pneumopathy worsens or, in the case of pre-existing respiratory disease (COPD, asthma), becomes unstable.
An initial asthma attack may occur during the course of pneumopathy.
An effusion of fluid between the layers of the pleura is sometimes observed.
For whom is pneumonia more serious?
The seriousness of bacterial pneumonia varies according to the germ responsible, the person's general condition and the severity of the illness.
Complications are more common in people over 65 and in those with chronic illnesses:
- heart failure or the after-effects of a stroke;
- chronic kidney disease
- liver disease (cirrhosis, hepatic steatosis, for example);
- chronic obstructive pulmonary disease (COPD);
- immunodepression (HIV, cancer, etc.);
- sickle-cell anaemia.
In addition, having already had pneumonia, being hospitalised within the year or living in an institution (e.g. a retirement home) can all contribute to the development of complications following pneumonia.