Post-polio syndrome: renaissance of poliomyelitis?

Abstract

Poliomyelitis is an acute and infectious viral disease, transmitted primarily through oral-fecal contact or directly, person to person. Approximately 90% of the individuals infected by the polio virus do not present symptoms; however, the affected individuals can show a variety of symptoms if the virus reaches the bloodstream. In up to 2% of cases, the virus reaches the central nervous system  preferably infecting and destroying the motor neurons, resulting in muscular weakness and acute flaccid paralysis. Despite the expressive reduction in the number of cases, many people live with the consequences of the acute illness, thus representing a burden to the public healthcare systems. Many of these people present new manifestations as signs and symptoms that are called post-polio syndrome. It can be defined and characterized by new neuromuscular symptoms, which occur at least 15 years after a period of clinical and functional stability in patients with previous history of symptomatic poliomyelitis. The signs and symptoms characterizing the post-polio syndrome include new muscular weakness, muscular fatigue and atrophy, pain in joints and muscles, sleep disorders, intolerance to cold, respiratory and swallowing difficulties, and recent weight gain. Therefore, the aim of this review is to present the physiological changes caused by the new manifestation of symptoms in individuals with poliomyelitis