Pneumonia: causes, symptoms and treatment

Pneumonia refers to inflammation of the lungs, specifically the tiny air sacs (alveoli) at the ends of the branches of your airways. It develops as the result of a chest infection caused by bacteria; although, less commonly, it can occur after a viral chest infection. 

It happens more often during the colder months of the year when infections such as the flu and common cold are more prevalent. 

In certain cases, pneumonia can be fatal — pneumonia is a common cause of death in the elderly in the UK. 

Who is most at risk of pneumonia?

Individuals at greater risk of pneumonia include the elderly and those with a weakened immune system (eg those with HIV, undergoing chemotherapy or taking long-term steroids), a poor cough reflex and/or swallowing difficulties. 

Aspiration pneumonia, in particular, presents a high risk of serious illness or death. This occurs when a foreign object, usually food or liquid, goes into your lungs. 

Your risk of pneumonia is also higher if you have a pre-existing lung disease (eg cystic fibrosis, chronic obstructive pulmonary disease (COPD)), are a smoker and/or have had a recent influenza infection or other upper respiratory tract infection. 

Exposure to high amounts of air pollution can make you more vulnerable to developing pneumonia too. 

Pneumonia symptoms and diagnosis

Common symptoms of pneumonia include a cough, fever, fatigue and breathlessness. In some cases, you may also experience chest pain and sweat excessively. 

In older people, pneumonia can also cause confusion and low blood pressure. 

Based on your symptoms, if your GP suspects that you have pneumonia, they will recommend that you have a chest X-ray and blood tests. 

They may also check how much oxygen is in your blood via a small device that clips onto your finger (a pulse oximeter). This is because pneumonia can make it harder to breathe, which can reduce how much oxygen passes into your blood.

Treating pneumonia

Pneumonia is treated with a course of antibiotics. Antibiotics usually need to be taken for five to 14 days, but depending on the type of bacteria causing your symptoms, you may need a longer course of antibiotics. 

A sample of your phlegm will be collected for analysis in a lab so that the microorganism (eg bacteria, virus or fungus) causing your pneumonia can be identified and more targeted treatment can be prescribed. Whilst waiting for your test results, your doctor may prescribe broad-spectrum antibiotics. 

If the bacteria Pseudomonas aeruginosa is identified as the cause of your pneumonia, you will need stronger antibiotics, and these may need to be administered directly into your bloodstream (ie intravenously) in a hospital setting.

In more severe cases of pneumonia, you may also need to be given oxygen and intravenous fluids in hospital. 

Outcomes after pneumonia

Most individuals recover from pneumonia in two to four weeks; however, it usually takes around six weeks for the changes that occur in your lungs as a result of pneumonia to resolve. 

If you are diagnosed with pneumonia, you will, therefore, need another chest X-ray around six weeks after you start treatment to check the health of your lungs. 

In most cases, pneumonia does not cause any significant, permanent damage to the lungs. However, in very severe cases, permanent lung damage may occur, which may reduce how well your lungs work. 

Reducing your risk of pneumonia

If your health means that you will be at continued risk of developing pneumonia, your doctor may recommend that you have the pneumococcal vaccine. This is given either as a one-off vaccine or a five-yearly vaccine, depending on whether you have certain underlying health conditions.

You can further reduce your risk of pneumonia by exercising regularly, quitting smoking and keeping up with your annual flu vaccination. 

You should also try to avoid highly polluted areas whenever possible — this includes both indoor and outdoor spaces. Indoors, faulty air-conditioning units increase the risk of infection with the bacteria Legionella pneumophila, which can cause pneumonia.