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Pneumonia is an infection of the deep parts of the lungs called the alveoli. This is where oxygen is transferred into the blood from the air, but during pneumonia the alveoli are invaded by bacteria or viruses which then causes the alveoli to fill up with fluid and white cells in an attempt by the body to kill the bugs. Alveoli filled with fluid and cells is called consolidation and shows up on the X ray, and is also why patients with pneumonia become breathless as there is less lung available to transfer oxygen into the blood. If the pneumonia spreads to affect the edge of the lung, then it can inflame the membrane that covers the lung called the pleura. This causes a lot of pain, especially on breathing in, and is called pleurisy. back to top
The commonest causes of pneumonia are:
If someone has a weakened immune system due to drug treatment for cancers or organ transplantation, then there are a large number of other bugs that can cause pneumonia, the most important of which are the fungi Aspergillus and Pneumocystis, or a virus called cytomegalovirus. In addition, there are a very large number of rare causes of pneumonia both in normal and immunocompromised patients. back to top
The main symptoms are cough, sputum production, fever, and feeling generally ill, sometimes with shortness of breath and chest pain on breathing in. Usually, the symptoms have only lasted for a few days or a week or two, but can be longer with the more unusual causes. Most patients with pneumonia have mild disease and so can be treated out of hospital, but in a minority it can be a very severe infection and require admission to hospital or even the intensive care unit. back to top
By identifying the combination of evidence of infection with new consolidation – consolidation is recognised either by seeing it on the chest X-ray or hearing abnormalities on listening to the lung. We try to find which bug is causing the pneumonia by sending sputum, blood or urine to the laboratory for special tests. back to top
Yes, with antibiotics to kill the bug and by giving the patient additional oxygen to boost the oxygen level in the blood. Most bacteria are killed readily by antibiotic treatments, although antibiotic resistance can be a problem on occasions. Some viruses and fungi are actually quite hard to kill with antibiotics, but these infections are rare unless someone has a weakened immune system. Pneumonia occasionally can lead to infection of the surface of the lung, called empyema, and this may need insertion of a tube to drain the infected fluid or even surgery. back to top
Pneumonia is an acute infection from which most patients will make a rapid recovery. Many patients do suffer from easily getting tired for a couple of months after having had pneumonia, but this gradually improves. Amazingly, even with severe pneumonia, the lung usually recovers and has no lasting damage, although occasionally there might be some scarring of the lung (rarely leading to bronchiectasis) or lung surface (the pleura).
At present, the recommendation is that the elderly (over 65 years) and people with chronic diseases affecting the chest, kidneys, liver or brain should be vaccinated against the pneumococcus with the Pneumovax vaccine as they have an increased risk of pneumonia. Smoking also increases the risk of developing pneumonia, and if someone has had one episode of pneumonia, they should stop smoking to help prevent another. Children in the UK are now automatically vaccinated as infants against infections with the pneumococcus with the Prevenar vaccine. back to top
At UCL, Dr Brown leads an internationally recognised research group into the pneumococcus aiming to identify why it can cause pneumonia, and to develop new vaccines or other treatments to prevent pneumonia. The research is mainly laboratory based and has been funded by the Medical Research Council, the Wellcome Trust and the British Lung Foundation as well as local charities.