Flaccid paralysis is a condition in which extreme muscle weakness or paralysis is coupled with an inability to contract the muscles. Loss of muscle tone and muscular atrophy are also symptoms. Acute flaccid paralysis (AFP) can be caused by a wide range of disorders, infections, and agents.
Some causes of AFP include antagonists, spine damage or disease (such as a tumor), demyelinating diseases like multiple sclerosis (hyperlink?), myasthenia gravis, botulism, tick/snake bites, and various viruses.