Over time, the damaged tracts fail to recover completely and the deficits become permanent. The signs and symptoms of M.S. can be quite varied depending upon the tracts affected. In fact, the disease can be fatal if physiologically important pathways, such as those supplying respiratory muscles, are involved. It is not uncommon for signs and symptoms to appear after an infection, vaccination or surgical procedure. Since both anterior and posterior nerve roots can be affected, both sensory and motor deficits can occur.
Deterioration usually begins low in the cord and affects the lower extremities first.
As the disease progresses, it moves bilaterally up the cord toward the cranial nerves and can impair respiratory movements requiring ventilation. Autonomic nerves are not exempt and can result in serious arhythmias of the heart when involved. However, in some cases death can result from respiratory impairment or emboli resulting from immobilization of lower extremities. Hyperactivity disorders are just as their name implies, areas of the brain of varying sizes within which neurons display bouts of hyperactivity resulting in seizures. Seizures, as well as their classification schemes, can be quite varied ranging from mild, transient loss of attention to the convulsions of Grand Mal epilepsy.