Post polio syndrome (PPS) affects people who have had the poliomyelitis virus, or polio, any time from 10 to 40 years before. Of the 300,000 polio survivors in the US, one-quarter to one-half will have symptoms of PPS. If the initial bout with polio was severe, there is a greater chance of developing post polio syndrome, and also a greater chance that the symptoms will be severe if they occur.
Individual nerve terminals in the motor units die, causing deterioration. Muscles that were already weakened by the first bout with the polio virus become even weaker. Post polio syndrome is not a recurrence of polio.
People with post polio syndrome can have fatigue, muscle and joint pain, and muscular atrophy. Atrophy means a wasting or decrease in the size of muscles. People with PPS have progressive muscle weakness. Sometimes the muscles in the spine atrophy and the symptoms mimic amyotrophic lateral sclerosis, or ALS, also known as Lou Gehrig's disease.
Some people also have intolerance to cold, and trouble with swallowing, breathing, and sleeping.
The cause of PPS is not entirely known; however, the syndrome of weakness decades following poliomyelitis is likely due to degeneration (slow loss) of motor nerve cells (those living in the spinal cord that innervate the muscles), in turn caused by normal aging in combination with the already decreased number of motor nerve cells lost during the bout of poliomyelitis.
The best way to prevent PPS is for all children to receive the polio vaccine to make sure that they never get polio in the first place. People who have had polio may benefit from a healthy lifestyle; however, there is no reliable way to prevent PPS in a person who has survived polio.
Post polio syndrome is difficult to diagnose because it progresses very slowly and is stable for long periods. It is hard to determine which muscle and nerve deficits are old and which are new. A neurological exam and lab tests can exclude other problems.
To find out what is going on in the body, healthcare professionals may use: magnetic resonance imaging (MRI) muscle biopsyanalysis of cerebrospinal fluid, obtained with a spinal tapmeasurements of muscle forceelectrophysiological studies, which examine the body's response to electrical stimulation. These would include electromyography and nerve conduction velocity studies.
The long term effects differ from person to person. Muscles become progressively weaker over time. The severity of the muscle weakness varies. As people develop more symptoms, they may have depression, anxiety, or lowered self-esteem. Support groups, medication, or counseling may help. Physical therapy can help people learn how to exercise properly and conserve energy.
Post polio syndrome is not contagious, so there are no risks to others.
The medication pyridostigmine can make some people feel less tired. Several medications are being studied that may improve strength or help motor neurons to grow. The role of exercise is much debated. Some healthcare professionals have thought that exercise can worsen the condition and that rest will preserve energy. Others have believed that exercise, in moderation, can help.
The current recommendation is to test people with PPS to find their tolerance. Tolerance is the level at which people begin to get tired or uncomfortable. People are then taught to exercise within their tolerance limits learning to pace themselves so they do not become fatigued.
Exercising muscles least affected by the PPS may be most helpful. Cardiovascular endurance exercise is thought to be more beneficial than strengthening exercises.
All medications can have side effects.
The course of post polio syndrome is unpredictable. However, a healthy lifestyle and exercise within tolerance can increase the individual's quality of life.
Regular visits to the healthcare professional are needed to monitor muscle weakness and fatigue over time.
Post-Polio Syndrome Fact Sheet, National Institute of Neurological Disorders and Stroke, 2000. [hyperLink url="http://www.ninds.nih.gov/patients/disorder/ppolio/ppolio.htm" linkTitle="www.ninds.nih.gov/patients/disorder/ppolio/ppolio.htm"]www.ninds.nih.gov/patients/disorder/ppolio/ppolio.htm[/hyperLink]
Polio Vaccines, CDC Health Topics, 1999.
An Approach to the Patient with Suspected Post Polio Syndrome, W Anderson, Easter Seal Society of Washington, 1995.
Taber's Cyclopedic Medical Dictionary, Thomas and Craven, eds., 1997.