A set of criteria for diagnosing post-polio syndrome has been developed by the Post-Polio Task Force, a group of researchers, clinicians and polio survivors. The onset of new muscular weakness after many years of stable functioning is perhaps the most characteristic symptom. Yet many of the symptoms of post-polio syndrome are so general that ruling out all possible causes is often impractical. For instance, new weakness may result simply from the lack of use of the muscles. Muscle weakness from disuse can mimic post-polio syndrome and complicate it. Regardless of the underlying cause, once the weakness begins it may initiate a cascade of other complaints that makes the original symptom impossible to identify.

MOST COMMON new health problems reported by post-polio patients in several clinical studies are fatigue, muscle pain, joint pain and weakness. Functional problems include walking and stair climbing.

As with many other chronic conditions, the essence of good medical care is to relieve symptoms, improve muscular function and enhance the patient's sense of well-being. This management strategy is frequently referred to as bracing and pacing. Effective intervention can be as simple as prescribing a cane or a wheelchair or as complicated as putting someone in an iron lung or providing some other form of assisted ventilation. For both physical and psychological reasons, patients are 8 encouraged to remain as active as possible. The new lifestyle, however, should incorporate regular rest breaks. An exercise program is desirable for virtually all patients. For some, this may be nothing more strenuous than gentle stretching or various types of yoga. For others, it may be considerably more vigorous and even include aerobic workouts.

With certain types of exercise in carefully monitored settings, some patients have been able to regain and maintain muscle strength. Although there are no magic bullets, medications can occasionally be helpful: for example, low doses of a tricyclic antidepressant may relieve muscle pain in some patients, and pyridostigmine may reduce fatigue and improve muscle strength.

As a general rule, the progression of symptoms is fairly slow and the overall prognosis is good, unless there are severe breathing or swallowing difficulties. Yet when reserves of strength and stamina are low, a minor change in the stability of the motor neurons can result in a disproportionately large loss of muscular function, which often is psychologically devastating.