Normally the lung tissue is soft and flexible, which means it is easy to breathe, but in someone with IPF the lung tissue becomes stiffened and damaged from scarring. The process of the scarring of the lungs is called fibrosis, and once it has occurred the tissue does not recover.
IPF is caused by repeated injury to the lungs, leading to scarring. Scars generally serve a good purpose on the skin – they heal injured areas – but in the lungs, scar tissue stops the lungs doing their job of taking oxygen from the air that we breathe in, and passing the oxygen that the air contains across into the blood. The amount of lung scarring usually increases and is generally irreversible.
The speed at which the condition progresses varies: some people with the condition stay stable for many years, and others worsen more quickly. Unfortunately, IPF is a terminal disease with an average life expectancy of about 3-5 years after an early diagnosis. However, within that average, there are a small group of people who get worse very quickly and appear to have a disease very resistant to treatment, and another group who have a much more gentle time course with a slow reduction in physical condition over many years. About 20% of IPF patients, or one in five, are alive five years after diagnosis. This makes estimating life expectancy for an individual quite difficult.
Most people develop their symptoms after the age of 60 and the disease is uncommon in people below the age of 50. Men are affected more commonly than women.
The most common symptoms are:
• breathlessness, especially when exercising, such as walking up hills or stairs
• a chronic dry or hacking cough
• discomfort in the chest, although rarely is this described as severe pain
• finger “clubbing”, which is a change in the shape of the fingernails
• fatigue and weakness
• loss of appetite
• rapid loss of weight.
