Also known as: Infantile Paralysis; Polio


Poliomyelitis is caused by an infection with the poliomyelitis virus, which is an enterovirus. Polio can appear at any age; but used to be more common in young children, hence the name infantile paralysis. It occurred in widespread epidemics particularly after the Second World War, but these have largely disappeared with the advent on effective immunization in the late 1950’s. Occasional new cases do, however, appear even in developed countries.


Medical text last updated June 2009 by Dr J M Shneerson, Consultant Physician, Director of the Respiratory Support and Sleep Centre, Papworth Hospital, Cambridge, UK.

What are the symptoms?

The majority of infections are characterised by a mild fever often with vomiting or diarrhoea. Weakness or complete paralysis of any of the skeletal muscles appears in a minority of subjects, but this may develop rapidly. After a few days or weeks the weakness begins to improve and may continue to do so for one to two years.

Post-polio syndrome
It has recently been recognised that after an interval of at least 35 years after the acute infection, a condition known as the post-polio syndrome may develop. This is due to dying back of the peripheral nerve fibres which were damaged, but regenerated after the acute illness. This causes weakness, pain and fatigue in muscles which were previously affected. Post-polio syndrome occurs in around 50 per cent of those who have had polio, but in 80 per cent of these it is either static or only slowly progressive. Specialist advice about how to adapt the lifestyle to minimise the risk of the progression of this syndrome is often effective. Respiratory support, usually with a non-invasive ventilator system used at night, may be needed if the respiratory (breathing) muscles are affected. Post-polio syndrome should be distinguished from similar symptoms which may be due to degenerative changes in the joints or soft tissues, peripheral nerve entrapment, or aging.

How is it treated?

The current recommendation for patients with poliomyelitis is to avoid excessive use of affected muscles. Individuals should pace any physical activity, taking regular breaks. Not exerting to the point of pain or fatigue is very important. Adaptations around the home such as lowering shelves or sitting when washing dishes can be used to reduce the effect of day-to-day activities on the muscles.

In the most severely affected patients, all the limb and trunk muscles as well as the breathing and swallowing muscles may be affected and treatment with mechanical respiratory support is required to maintain life. The most common long-term effect is weakness of one or more limbs.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
Not applicable.

Prenatal diagnosis
Not applicable.

Is there support?

The British Polio Fellowship

Helpline: 0800 018 0586
Email: info@britishpolio.org.uk
Website: britishpolio.org.uk

The Fellowship is a Registered Charity in England and Wales No. 1108335. It provides information, welfare and support to people in the UK living with the effects of Polio and Post Polio Syndrome (PPS). The Fellowship has groups and branches across the UK.

Group details last updated September 2014.

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