Pneumonia is swelling (inflammation) of the tissue in one or both lungs.

It's
usually caused by a bacterial 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.
Symptoms of pneumonia
The symptoms of pneumonia can develop suddenly over 24 to 48 hours, or they
may come on more slowly over several days.
Common symptoms of pneumonia include:
a cough which may be dry, or produce thick yellow, green, brown or
blood-stained mucus (phlegm)
difficulty breathing your breathing may be rapid and shallow, and you
may feel breathless, even when resting
rapid heartbeat
fever
feeling generally unwell
sweating and shivering
loss of appetite
chest pain which gets worse when breathing or coughing
Less common symptoms include:
coughing up blood (haemoptysis)
headaches
fatigue
nausea or vomiting
wheezing
joint and muscle pain
feeling confused and disorientated, particularly in elderly people
When to see your GP
See your GP if you feel unwell and you have typical symptoms of pneumonia.
Seek urgent medical attention if you're experiencing severe symptoms, such
as rapid breathing, chest pain or confusion.
Who's affected?
In the UK, pneumonia affects around 8 in 1,000 adults each year. It's more
widespread in autumn and winter.
Pneumonia can affect people of any age, but it's more common and can be
more serious in certain groups of people, such as the very young or the
elderly.

People in these groups are more likely to need hospital treatment if they develop
pneumonia.
What causes pneumonia?
Pneumonia is usually the result of a pneumococcal infection, caused by bacteria
called Streptococcus pneumoniae.
Many different types of bacteria, including Haemophilus influenzae and
Staphylococcus aureus, can also cause pneumonia, as well as viruses and, more
rarely, fungi.
As well as bacterial pneumonia, other types include:
viral pneumonia most commonly caused by the respiratory syncytial
virus (RSV) and sometimes influenza type A or B; viruses are a common
cause of pneumonia in young children
aspiration pneumonia caused by breathing in vomit, a foreign object,
such as a peanut, or a harmful substance, such as smoke or a chemical
fungal pneumonia rare in the UK and more likely to affect people with
a weakened immune system
hospital-acquired pneumonia pneumonia that develops in hospital
while being treated for another condition or having an operation; people
in intensive care on breathing machines are particularly at risk of
developing ventilator-associated pneumonia
Risk groups
The following groups have an increased risk of developing pneumonia:
babies and very young children
elderly people
people who smoke
people with other health conditions, such as asthma, cystic fibrosis, or a
heart, kidney or liver condition
people with a weakened immune system for example, as a result of a
recent illness, such as flu, having HIV or AIDS, havingchemotherapy, or
taking medication following an organ transplant
Diagnosing pneumonia
Your GP may be able to diagnose pneumonia by asking about your symptoms
and examining your chest. Further tests may be needed in some cases.
Pneumonia can be difficult to diagnose because it shares many symptoms with
other conditions, such as the common cold, bronchitisand asthma.
To help make a diagnosis, your GP may ask you:
whether you feel breathless or you're breathing faster than usual

 how long you've had your cough, and whether you're coughing up mucus
and what colour it is
if the pain in your chest is worse when you breathe in or out
Your GP may also take your temperature and listen to your chest and back with
a stethoscope to check for any crackling or rattling sounds.
They may also listen to your chest by tapping it. Lungs filled with fluid produce
a different sound from normal healthy lungs.
If you have mild pneumonia, you probably won't need to have a chestX-ray or
any other tests.
You may need a chest X-ray or other tests, such as a sputum (mucus) test
or blood tests, if your symptoms haven't improved within 48 hours of starting
treatment.
Treating pneumonia
Mild pneumonia can usually be treated at home by:
getting plenty of rest
taking antibiotics
drinking plenty of fluids
If you don't have any other health problems, you should respond well to
treatment and soon recover, although your cough may last for some time.
As pneumonia isn't usually passed from one person to another, it's safe to be
around others, including family members.
However, people with a weakened immune system should avoid close contact
with a person with pneumonia until they start to get better.
For at-risk groups, pneumonia can be severe and may need to be treated in
hospital.
This is because it can lead to serious complications, which in some cases can be
fatal, depending on a person's health and age.
Read more about treating pneumonia.
Complications of pneumonia
Complications of pneumonia are more common in young children, the
elderly and those with pre-existing health conditions, such as diabetes.
Possible complications of pneumonia include:
pleurisy where the thin linings between your lungs and ribcage (pleura)
become inflamed, which can lead to respiratory failure
a lung abscess a rare complication that's mostly seen in people with a
serious pre-existing illness or a history of severe alcohol misuse
blood poisoning (septicaemia) also a rare but serious complication
You'll be admitted to hospital for treatment if you develop one of these
complications.

Preventing pneumonia
Although most cases of pneumonia are bacterial and aren't passed on from one
person to another, ensuring good standards of hygiene will help prevent germs
spreading.
For example, you should:
cover your mouth and nose with a handkerchief or tissue when you cough
or sneeze
throw away used tissues immediately germs can live for several hours
after they leave your nose or mouth
wash your hands regularly to avoid transferring germs to other people or
objects
A healthy lifestyle can also help prevent pneumonia. For example, you should
avoid smoking as it damages your lungs and increases the chance of infection.
Find out how to stop smoking.
Excessive and prolonged alcohol misuse also weakens your lungs' natural
defences against infections, making you more vulnerable to pneumonia.
People at high risk of pneumonia should be offered the pneumococcal
vaccine and flu vaccine.