Post-polio syndrome (PPS, or post-poliomyelitis syndrome) is a condition that affects approximately 25–50% of people who have previously contracted poliomyelitis—a viral infection of the nervous system—after recovery from the initial paralytic attack. Typically the symptoms appear 15-30 years after the original infection, at an age of 35 to 60. Symptoms include acute or increased muscular weakness, pain in the muscles, and fatigue.
The precise mechanism that causes PPS is unknown. It shares many features with the post-viral chronic fatigue syndrome, but unlike that disorder it tends to be progressive, and as such can cause a tangible loss of muscle strength. Treatment is primarily limited to adequate rest, conservation of available energy, and supportive measures, such as leg braces and energy-saving devices such as powered wheelchairs, analgesia (pain relief) and sleep aids.
Signs and symptoms
After a period of prolonged stability individuals who had been infected and recovered from polio begin to experience new signs and symptoms, characterised by muscular atrophy (decreased muscle mass), weakness, pain and fatigue in limbs that were originally affected or in limbs that didn't seem to have been affected at the time of the initial polio illness. PPS is a very slowly progressing condition marked by periods of stability followed by new declines in the ability to carry out usual daily activities. Most patients become aware of their decreased capacity to carry out daily routines due to significant changes in mobility, decreasing upper limb function and lung capability. Fatigue is often the most disabling symptom; even slight exertion often produces disabling fatigue and can also intensify other symptoms. Problems breathing or swallowing, sleep-related breathing disorders, such as sleep apnea and decreased tolerance for cold temperatures are other notable symptoms.
Increased activity during intervening healthy years between the original infection and onset of PPS can amplify the symptoms. Thus, contracting poliomyelitis at a young age can result in particularly disabling PPS symptoms."