Many case exist in latent form, but in manifest case it is more frequently seen in women.
The estimated prevalence of the disorder is 5-10 case per 100,000 population. In the acute attack the neurological dysfunction can involve any portion of the nervous system. It is believed that an imbalance in the autonomic innervation of the gut leads to abdominal pain which is commonly associated with the attack. If peripheral neuropathy, such as pain in the back and legs or parathesias occurs it is almost always preceded by abdominal pain. Complete flaccid paralysis can develop over a few days.