Post-polio syndrome (PPS) is a condition that affects polio survivors many years after recovery from an initial attack of the poliomyelitis virus. PPS is characterized by a further weakening of muscles that were previously affected by the polio infection.
The most common symptoms include slowly progressive muscle weakness, fatigue (both general and muscular), and a decrease in muscle size (muscular atrophy). Pain from joint deterioration and increasing skeletal deformities such as scoliosis are common.
Some individuals experience only minor symptoms, while others develop more visible muscle weakness and atrophy.
PPS is rarely life-threatening but the symptoms can interfere significantly with the individual's capacity to function independently.
While polio is contagious, PPS is not transmissible. Only a polio survivor can develop PPS.
Presently, no prevention has been found that can stop deterioration or reverse the deficits caused by the syndrome.
A number of controlled studies have demonstrated that nonfatiguing exercises may improve muscle strength and reduce tiredness.
Doctors recommend that polio survivors follow standard healthy lifestyle practices: consuming a well-balanced diet, exercising judiciously (preferably under the supervision of an experienced health professional), and visiting a doctor regularly.
There has been much debate about whether to encourage or discourage exercise for polio survivors or individuals who already have PPS.
A commonsense approach, in which people use individual tolerance as their limit, is currently recommended.
Preliminary studies indicate that intravenous immunoglobulin therapy may reduce pain, increase quality of life, and improve strength modestly.
PPS is a very slowly progressing condition marked by long periods of stability.
The severity of PPS depends on the degree of the residual weakness and disability an individual has after the original polio attack.
People who had only minimal symptoms from the original attack and subsequently develop PPS will most likely experience only mild PPS symptoms.
People originally hit hard by the polio virus, who were left with severe residual weakness, may develop a more severe case of PPS with a greater loss of muscle function, difficulty in swallowing, and more periods of fatigue.
Scientists are working on a variety of investigations that may one day help individuals with PPS.
Some basic researchers are studying the behavior of motor neurons many years after a polio attack.
Others are looking at the mechanisms of fatigue and are trying to discover the roles played by the brain, spinal cord, peripheral nerves, neuromuscular junction (the site where a nerve cell meets the muscle cell it helps activate), and muscles.
Determining if there is an immunological link in PPS is also an area of intense interest.
Researchers who discovered inflammation around motor neurons or muscles are trying to find out what causes this immunological response.