[Post-polio syndrome. Part I. The "legacy" of forgotten disease, challenges for professionals and polio survivors].

The outcome of paralytic polio was believed to be a stable neurological state. Now, it is established that polio has an additional, slowly progressive phase, called post-polio syndrome (PPS) that develops 30-40 years after the acute poliomyelitis in 25-80% of paralytic and about 40% of nonparalytic polio survivors. The clinical symptoms are nonspecific and usually include muscle weakness, fatigue and muscle or joint pain. Some patients suffer from muscular atrophy, respiratory insufficiency, dysphagia, sleep disturbances or cold intolerance. The etiopathogenesis of PPS is unclear and many factors, such as dysfunction of the surviving motor units, aging, defects of neuromuscular transmission, persistence of viral infection and immunological mechanisms, are considered.