February 14, 2017

What is pneumonia?
Pneumonia is an inflammation of the tissue of the lungs. Lungs are formed of tubes called bronchi, which divide themselves into smaller tubes called bronchioles. Bronchioles will eventually end with small bags called alveoli. These alveoli contain immune cells like epithelial cells, alveolar macrophages whose function is to clear our lungs of dust that we ingest (cigarette smoke, polluted air…) and pathogens. However, it happens that our lungs have to clear too many impurities and after being “over-assaulted”, they will fail to fulfil their duty (because the alveoli are full of fluids). Therefore, inflammation and then pneumonia will take place. The symptoms of pneumonia are characterized by cough, breath impairments as well as fever (1).

What is the epidemiology?

This pathology affects mainly children under the age of 5. According to the World Health Organization, the number of casualties of pneumonia among children accounts for nearly 1 million. This means that 15% of deaths among children under 5 are related to pneumonia. A recent report from the National Health Service states that every year 1 to 1000 adults are also infected.

What causes pneumonia?

Basically, pneumonia is an infection. Several germs can be responsible for triggering this pathology. However, it is more likely to be of a bacterial than a viral origin. We call that community-acquired pneumonia in which Streptococcus pneumoniae accounts for more than half of the infections (2). Others pathogens involved are Hemophilus influenzae, Staphylococcus aureus, rhinoviruses or Klebsiella pneumoniae. Parasites as well as fungi also can lead to pneumonia. Of course, some people are more prone to be infected than others: this is the case of babies, older people who have a weak immune system, immune compromised patients and smokers (1).

What treatments are offered?
According to the severity of the case, treatment is more or less heavy. Antibiotics are sufficient for moderate pneumonia with no needs for the patient to be hospitalized. However, severe cases can lead to complications and hospitalization is strongly required (1). Patients fail to breathe normally (a ventilator is needed to help them), and for the acute cases, it ends with septicaemia (blood full of pathogens) which usually means amputation or death. This occurs when patients were weakened by others pathologies, as pneumonia often behaves as an opportunistic disease.

Nonetheless, in 2010, a new vaccine was introduced and is able to protect children against a significant number of strains (3). This has considerably reduced the number of pneumonia-related complications and hospitalizations.

To conclude, pneumonia is a pathology which can have a wide range of causes. However, it can be prevented, but as soon as the disease progresses; it may be too late to stop it.


2. Sharma et al, May 2007, "Radiological imaging in pneumonia: recent innovations". Current Opinion in Pulmonary Medicine