Post-polio syndrome is a poorly understood condition that can affect people who have had polio in the past.
Polio is a viral infection that used to be common in the UK, but is now rare.
Most people who had polio would have fought off the infection without even realising they were infected.
Some people with polio would have had paralysis, muscle weakness and shrinking of the muscles. But usually, these problems would have either gone away over the following weeks or months, or remained the same for years afterwards.
Post-polio syndrome is where some of these symptoms return or get worse many years or decades after the original polio infection.
Post-polio syndrome can include a wide range of symptoms that develop gradually over time, including:
The condition can have a significant impact on everyday life, making it very difficult to get around and carry out certain tasks and activities.
The symptoms tend to get gradually worse over many years, but this happens very slowly and treatment may help slow it down further.
Post-polio syndrome is rarely life-threatening, although some people develop breathing and swallowing difficulties that can lead to serious problems, such as chest infections.
Post-polio syndrome only affects people who've had polio. It usually develops 15 to 40 years after the infection.
The condition has become more common in the UK in recent years, because of the high number of polio cases that occurred during the 1940s and 1950s, before routine vaccination was introduced.
It's estimated that there are around 120,000 people living in the UK who survived polio when they were younger. Some of these have, or will develop, post-polio syndrome.
It's not known exactly how many polio survivors are or will be affected by post-polio syndrome. Estimates vary from as low as 15% to as high as 80%.
The exact cause of post-polio syndrome is unclear. It's not known whether anything can be done to prevent it.
The leading theory is that it's the result of the gradual deterioration of nerve cells in the spinal cord (motor neurones) that were damaged by the polio virus. This would explain why the condition can take years to appear.
Post-polio syndrome isn't contagious. The theory that the polio virus may lie dormant in your body, causing post-polio syndrome when it becomes reactivated at a later stage, has been disproven.
It's not clear why only some people who've had polio develop post-polio syndrome. Those who had severe polio when they were younger may be more likely to develop the condition.
There's currently no cure for post-polio syndrome, but support and a range of treatments are available to help manage the symptoms and improve quality of life.
Some of the ways that symptoms of post-polio syndrome may be managed include:
Read more about treating post-polio syndrome.
The British Polio Fellowship is a leading charity for people affected by polio and post-polio syndrome. It provides a range of useful resources, information and services.
You can contact the telephone helpline on 0800 043 1935, or visit the British Polio Fellowship website.