Pneumonia isn't just a danger to the elderly; Pneumonia is at its peak in January and can strike anyone, young or old, including superstars like George Michael. Lisa Salmon reports.
FIGHTING for his life in hospital, George Michael was not a stereotypical elderly and infirm pneumonia victim.
The star, who was seriously ill in December, in intensive care with the potentially fatal lung disease, is only 48 and reportedly had no other health issues.
But although pneumonia is a condition far more common in the elderly, and those who have other underlying health conditions, Dr Jeremy Brown, chairman of the British Thoracic Society''s advisory committee on lung infection, explains many younger people get the disease every year.
"You have an increasing risk of getting pneumonia the older you are," says Dr Brown.
"However, a significant number of young, fit people get it too."
George Michael described his battle with the illness, which led to him cancel the rest of his Symphonica tour, as the worst month of his life.
The singer, who is now recovering at home, had bacterial pneumonia caused by the streptococcus pneumoniae bacteria (also known as pneumococcus). Dr Keith Prowse, honorary medical director of the British Lung Foundation, explains: "Bacterial pneumonias are the more common ones. They affect young people, come round most years, and anybody can get them. Being fit helps you get over it, but doesn''t stop you getting it."
Older people also get bacterial pneumonia, but very often their condition stems from a complication with another illness.
The British Thoracic Society estimate that up to 65,000 people a year in the UK die from pneumonia, although it warns the figure is a rough estimate, as many victims also suffer from other serious illnesses.
WHAT ARE THE CAUSES? Bacteria and viruses cause most cases of pneumonia, explains Dr Brown, and the peak period for the illness is January to March. The Influenza virus (flu) causes around 15-20% of cases, but the most common culprit is the pneumococcus bacteria, which is responsible for 40-50% of pneumonias (including George Michael's). Pneumococcus lives at the back of the throat and is present in up to 10% of adults, and many children. Occasionally it gets from the back of the throat to the lung and causes pneumonia.
"Normal lung defences will usually get rid of bacteria," says Dr Brown. "But a viral infection, like a cold, can make the lung less able to do this.
"It happens all the time, but only a very small minority of people end up with pneumonia."
WHAT HAPPENS NEXT? The air sacs (alveoli) in the lungs fill with fluid or pus instead of air as a result of infection, impairing the supply of oxygen to the body's tissues.
Doctors can hear the fluid crackling around when they listen to an infected person''s chest, and it can be seen on X-rays.
In severe cases, death occurs because the body is starved of oxygen, infection can spread to the blood and cause septicaemia poisoning, or there may be kidney failure.
CAN YOU SPOT THE SYMPTOMS? Symptoms include a cough, fever, shortness of breath, chills and sweating, sometimes sharp chest pain, and possible confusion. "It can be difficult to tell the difference between the early stages of pneumonia and an ordinary cough," says Dr Brown, although he points out that a winter cough will normally cause a slight temperature, rather than a very high one.
Pneumonia can cause breathlessness, but an ordinary cough shouldn't, unless there's underlying lung disease.
"Also, chest pain indicates you've got inflammation of the lining of the lung and that means it could be pneumonia," says Dr Brown.
"Generally, you feel even more grotty than you would with a normal winter bug."
It can be hard to tell whether pneumonia is viral or bacterial, although there are some characteristic features, explains Dr Prowse.
But identifying the cause can help patients get the correct treatment.
He adds that some people with acute bacterial pneumonia will cough up green or yellow mucus: "That gives the game away and there's probably bacterial infection," he says. "Viral pneumonias tend to be a bit more dramatic, in that they often produce a higher swinging temperature."
WHO IS AT RISK? People are at more risk of pneumonia if they smoke, drink too much, have underlying lung conditions like chronic lung disease or asthma, renal and liver disease, a neurological disease such as a previous stroke, diabetes, or are HIV positive.
"If everyone stopped smoking tomorrow, it's estimated that the number of cases of pneumonia would drop by about half," underlines Dr Brown.
While old age is a risk factor, possibly because older people's immune defences are weaker, the illness is also fairly common in very young children, aged under two years, warns Dr Brown.
HOW IS IT TREATED? The treatment for pneumonia is antibiotics and oxygen, and sometimes antiviral drugs. But while drugs will usually tackle the cause of the illness, the physiological consequences of the infection can last much longer.
Such consequences include damage to the air passages in the lungs, which leaves people more prone to subsequent chest infections, as well as a lack of energy and depression. Up to 80% of people aren't hospitalised with pneumonia, because their illness isn't severe, says Dr Brown. They can be successfully treated at home with antibiotics. The illness can vary widely in its severity, and a fraction of pneumonia victims will end up in intensive care, like Michael did.
Dr Prowse stresses that the majority of people recover from pneumonia, although he warns: "The longer it takes before you get treatment, the longer it takes to get over it. And it can take some time - it knocks the stuffing out of you."
It can take up to six months to recover from a bad bout of pneumonia.
VACCINATION The Department of Health recommends that all people aged 65 and over, plus others including younger people who have a serious medical condition, and pregnant women, should receive both pneumococcal and flu vaccinations.
As well as preventing flu, the flu vaccine will protect against influenza pneumonia, and decreases the chance of getting pneumonia due to pneumococcus and other bacteria (because people are often infected with such bacteria when they have flu).
There are two vaccines against pneumococcus - one is now routinely used on children, and Dr Brown says it's very good against around 70% of pneumococcal strains.
As well as decreasing pneumonia in children, Dr Brown says vaccinating young people also reduces the chance of adults getting pneumonia, because they can catch the pneumococcus bacteria from youngsters.
* RECOVERING: George Michael, left, making a statement about his recovery from pneumonia to the media outside his home in Highgate, north London