In 99% of cases, polio is a mild condition which produces very few symptoms. In fact, some people will not notice any symptoms at all. A mild case of polio usually causes flu-like symptoms, which may include:
- sore throat,
- fever,
- nausea,
- vomiting,
- diarrhoea, and
- constipation.
These symptoms can appear three to 21 days after someone has become infected with the virus.
Paralytic polio
The paralytic form of polio is extremely rare with less than 1% of people contracting the condition. The first symptom of this form of polio is a fever. Between five and seven days after the fever, other symptoms will develop, including:
- headache,
- back and neck stiffness,
- constipation, and
- increased sensitivity to touch.
As the name suggests, paralytic polio can also cause paralysis of your muscles because the condition damages the nerve cells in your body. This means that your muscles are no longer able to function normally. Someone with paralytic polio may find that their limbs appear loose and floppy.
Paralytic polio can also affect your:
- breathing,
- ability to see,
- ability to hear,
- ability to smell,
- ability to taste and swallow,
- muscles in the face,
- heart, and
- intestines.
It is usually the breathing muscles (lungs and diaphragm) which are predominantly affected. If these breathing muscles become paralysed, the body is unable to get enough oxygen, and a ventilator (artificial breathing machine) is normally required. See 'treatment' section for more information about this. This form of polio is a potentially fatal condition.
The extent of the paralysis will depend on how many nerve cells have been affected. If the cells have only been damaged, recovery from the paralysis is more likely. However, if the cells have been completely destroyed, the paralysis is likely to be permanent.
Post-polio syndrome
The symptoms of post-polio syndrome tend to appear between 10 and 40 years after the initial illness. Most people with post-polio syndrome find that their symptoms develop gradually.
Common symptoms of post-polio syndrome include:
- new muscle weakness and muscle pain,
- fatigue and exhaustion,
- joint pain,
- difficulty swallowing,
- difficulty breathing,
- decreased tolerance of cold temperatures,
- difficulty concentrating,
- memory problems,
- depression, and
- sleep apnoea (where you have irregular breathing at night, and are sleepy during the day).
