This information is for people who have pneumonia, their family and carers, and for others who wish to know more about pneumonia. It covers the causes of pneumonia, its symptoms, treatment and prevention.
What is pneumonia?
Pneumonia is an inflammation of one or both lungs, which is usually caused by an infection. This inflammation causes the tiny air sacs (called the alveoli) within the lungs to become filled with fluid, making it harder for the lungs to function properly. To fight the infection, the body sends white blood cells to the lungs, but although this helps kill the germs it can also make it harder for the lungs to pass oxygen into the bloodstream.
What causes pneumonia?
Many different kinds of bacteria, viruses and, occasionally, fungi can cause pneumonia. The most common cause is a bacterium called Streptococcus pneumoniae, but in individual cases of pneumonia the cause is often not known. Some of these bacteria can live in the nose or throat without causing problems, and in most cases it is not known why they then suddenly make people ill. Others can be spread from person to person, but this is less common.
In winter the number of cases of pneumonia rises. This is because of person-to-person spread, and also because other infections common in the winter, such as influenza (flu), increase the risk of developing pneumonia.
Symptoms of pneumonia
Someone with pneumonia will feel unwell and experience symptoms that can be similar to flu or a chest infection.
When pneumonia is caused by the Streptococcus pneumoniae bacterium the onset can be very sudden and the condition can get worse very quickly. It can also be far milder, with symptoms developing gradually over days.
Almost all people with pneumonia will have a raised temperature – which can sometimes be very high and associated with sweats and shivering – along with a cough that brings up sputum (phlegm).
Rapid breathing suggests that the pneumonia is likely to be severe, and confusion is a serious sign.
A sharp pain in the side of the chest, which becomes worse when taking a deep breath, usually means that pleurisy has developed. This occurs when the thin outer covering of the lung becomes infected and inflamed by the pneumonia.
If you are experiencing the symptoms described here, seek medical advice as soon as possible.
Who is most at risk?
Anyone of any age can get pneumonia and approximately one person in 125 get the disease every year, but there are two groups of people for whom pneumonia is more of a threat.
First, there are those who are at extra risk of developing pneumonia – such as people with a weakened immune system.
Second, there are those who are not at extra risk of actually developing pneumonia, but if they do develop it the consequences for them may be worse – such as those with heart disease or other major medical problems.
Both these groups need to pay extra care to reduce their chances of developing pneumonia and its complications. People in these high risk groups include:
- babies and infants;
- older people;
- people with long-term heart, lung and kidney diseases, and those with diabetes;
- people with cancer, especially those receiving chemotherapy or who have leukaemia or lymphoma;
- people who smoke, and those who drink alcohol to excess; and
- people receiving drugs that suppress the immune system, and those with HIV/AIDS.
In addition to these groups, people who are in hospital for other problems sometimes develop pneumonia while they are there. This does not mean that the hospital is unhygienic, but that their resistance to the germs that can cause pneumonia has been weakened by their other medical problems.
Being a non-smoker is very important in reducing the risk of pneumonia. Smokers have an increased risk of developing pneumonia as well as other chest infections – and so do children whose parents smoke.
The viral infections that are common in winter can increase the risk of pneumonia, so it’s important for people to practise good hygiene and to use a tissue when they cough or sneeze and dispose of it immediately.
There are two types of vaccine available, but they only protect against cases caused by the most common form of pneumonia, the Streptococcus pneumoniae bacterium. The pneumococcal conjugate vaccine (PCV) is included in the British immunisation schedule for infants, with the first dose given at two months old, and is now licensed to protect against invasive disease caused by Streptococcus pneumoniae in adults aged 50 years and older. The second type of vaccine, pneumococcal polysaccharide vaccine (PPV), is available for anyone aged 65 and over or those over the age of two who fall into a high risk category. Most adults will only need to have it once.
Since simple flu can be complicated by going on to develop pneumonia, it is also a good idea for those at risk to have the influenza vaccine. This has to be given each winter.
Diagnosis and treatment
A doctor can often diagnose pneumonia based on the symptoms described in this leaflet and an examination of the chest, but definite confirmation of pneumonia needs a chest X-ray.
Antibiotics are the main treatment, along with rest and plenty of fluids to drink. Most people can manage at home with treatment from their GP, especially if they are otherwise fit and well and have support from family and friends. However, one in four people will be ill enough to need hospital admission, where both antibiotics and fluids may be given by drip into a vein and oxygen can be provided. Occasionally, extra help is needed with breathing and the person will be transferred to the Intensive Therapy Unit where they may be sedated and put on a breathing machine.
People who have been admitted to hospital with other medical problems but who then develop pneumonia are at special risk of becoming very ill and may require different, more powerful antibiotics.
In the days before antibiotics, pneumonia was often fatal. Nowadays, the vast majority of people make an uncomplicated recovery to good health. However, some people with severe pneumonia do still die despite the best available care.
Milder pneumonia will usually mean just a few days to a week of being unwell, followed by a steady return to normal activity. Severe pneumonia, which needs hospital admission, may mean it takes weeks or months to feel fully fit again, but longer term complications are very unusual.
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Last medically reviewed: November 2011
Due for review: November 2013
For references call 020 7688 5555
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