Pneumonia is inflammation (swelling) of the tissue in one or both of your lungs. It is usually caused by an infection.
At the end of the breathing tubes in your lungs are clusters of tiny air sacs. If you have pneumonia, these tiny sacs become inflamed and fill up with fluid.
Terms such as bronchopneumonia, lobar pneumonia and double pneumonia are sometimes used, but refer to the same condition with the same causes and treatment.
Common symptoms of pneumonia include:
- a cough
- difficulty breathing
When to see your GP
If you experience any of the symptoms of pneumonia, see your GP.
You may need a chest X-ray or further tests to confirm the diagnosis.
If you are experiencing severe symptoms such as rapid breathing, chest pain or confusion, seek urgent medical attention.
Read more about how pneumonia is diagnosed.
What causes pneumonia?
The most common cause of pneumonia is a pneumococcal infection caused by bacteria called Streptococcus pneumoniae.
However, there are many different types of bacteria and viruses that can lead to pneumonia.
Good hygiene and a healthy lifestyle can help prevent pneumonia. Try to avoid smoking, as it damages your lungs and increases the chance of infection.
Read more information about the causes of pneumonia.
How is pneumonia treated?
Mild pneumonia can usually be treated at home with antibiotics, rest and fluids. People who are otherwise healthy will normally recover well.
For people with other health conditions, pneumonia can be severe and may need to be treated in hospital.
This is because pneumonia can lead to complications, some of which can be fatal, depending on the health and age of the patient. These include:
- respiratory failure (when the lungs cannot take in enough oxygen) due to the air sacs filling with water
- lung abscesses
- blood poisoning (septicaemia)
Who is affected?
In the UK, pneumonia affects around one in 100 adults each year. It is more common during autumn and winter.
Pneumonia can affect people of any age, although it is more common and can be more serious in groups such as:
- babies, young children and elderly people
- people who smoke
- people with other health conditions, such as a lung condition or weakened immune system
People in these groups are more likely to need treatment in hospital.