Post-polio syndrome (PPS) can cause a wide range of symptoms that can significantly affect everyday life.
These tend to develop gradually and get worse very slowly over time.
Fatigue (tiredness) is the most common symptom of post-polio syndrome. It can take many forms, including:
Organising your activities so that you don't over-exert yourself and taking regular rests can help reduce your fatigue.
Increasing muscle weakness is another common symptom of post-polio syndrome. It can be easy to confuse muscle weakness with muscle fatigue, but they are different.
Muscle weakness is where you're increasingly unable to use affected muscles, whether you feel tired or not. Weakness can occur in muscles that were previously affected by a polio infection, as well as in muscles that weren't previously affected.
There may also be associated shrinking of affected muscles, known as atrophy.
Muscle and joint pain are also common in post-polio syndrome. Muscle pain is usually felt as a deep ache in the muscles or muscle cramps and spasms.
The pain is often worse after you've used the affected muscles. It can be particularly troublesome during the evening after a day's activities.
Joint pain is similar to arthritis and consists of soreness, stiffness and a reduced range of movement.
As well as the common symptoms of post-polio syndrome, a number of associated symptoms can also develop from the combination of fatigue, muscle weakness, and muscle and joint pain.
Because of common symptoms such as tiredness and muscle weakness, most people with post-polio syndrome become less physically active than they used to be.
This can often lead to weight gain and, in some cases, obesity. This in turn can make any fatigue, muscle weakness and pain worse.
As well as weight gain, the combination of fatigue, weakness and pain can also make walking difficult, leading to increasing mobility problems.
Many people with post-polio syndrome will need a walking aid, such as crutches or a stick at some stage, and some people may eventually need to use a wheelchair.
Some people with post-polio syndrome find breathing can be difficult because the muscles used for breathing become weaker.
This can cause problems such as shortness of breath, interrupted breathing while you sleep (sleep apnoea), and an increased risk of chest infections.
If you have post-polio syndrome, it's important to get medical advice as soon as possible if you experience symptoms of a possible chest infection, such as coughing up discoloured phlegm or blood, chest pain and wheezing.
Sleep apnoea may affect people with post-polio syndrome. The walls of the throat relax and narrow during sleep, interrupting normal breathing.
This can cause problems such as feeling very sleepy during the day, headaches and increased fatigue.
Weakness in the muscles you use for chewing and swallowing may lead to swallowing problems (dysphagia), such as coughing or choking when you eat or drink.
If you have post-polio syndrome, it's important to get medical advice if you have difficulty swallowing.
You may experience changes in your voice and speech, such as hoarseness, low volume or a nasal-sounding voice, particularly after you've been speaking for a while or when you're tired.
Swallowing problems are usually mild and progress very slowly. A speech and language therapist may be able to help.
Some people with post-polio syndrome find they become very sensitive to cold temperatures or a sudden drop in temperature. This may be as a result of poor blood supply.
Because of this intolerance to cold, people with post-polio syndrome may need to wear extra layers of clothing to try to stay comfortable.