Q. I had polio as a child and have recently been experiencing pain and noticeable weak¬ness in my legs. I have diffi¬culty walking any distance and tire easily. Could this have anything to do with my polio?
A. Many of the people who had polio years ago, are now experiencing new problems and disabilities associated with the disease. These include progressive weakness and/or muscle atrophy, poor endurance for normal daily tasks, unexplained joint or muscle pain, reduced flexibility and mobility, breathing and sleep difficulties and poor tolerance of cold. Some individuals have had to return to using braces, canes or crutches. People whose polio affected the muscles they use for breathing may now need oxygen or respirators. Many suffer unexplained pain in the areas originally affected by polio. The cause of these problems –
which physicians call post-polio syndrome – are not fully understood.
Post-polio syndrome was brought to national attention in 1981 at a conference in Chicago, I1. At the time, the major theories about the cause of post-polio syndrome included premature aging of polio-involved muscles, failure of the stronger muscles which compensate for those weakened by polio, and the possibility of recurrent infection with the polio virus. Some speakers pointed out a high incidence of allergies or immune disorders. Others discussed the possibility of damage to post-polio muscles from chronic overuse of the weakened muscles.
There is a strong probability that post-polio syndrome is due to the malfunction of the large field motor nerve cells which compensate for those weakened or destroyed by polio. Paralytic polio is a viral disease of the central nervous system that causes
inflammation and damage to nerve cells and tissue in the lower brain and spinal cord. Some of the affected nerve cells die, while others recover. The recovering cells sprout branches to connect with muscles whose nerve cells had died. Some of these cells now supply up to five to 10 times their original number of muscle fibers. Due to the complexity of its structure, this system of cells is suscep¬tible to fatigue and blocking of nerve messages to individual muscle fibers. When one of these nerves fail, a person may loose a considerable amount of muscle function.
In 1981, the staff of Sister Kenny Institute started work to help determine the incidence rate and possible causes of post-polio syndrome and what treatments would be most beneficial. Many interacting factors had to be considered. It had been suggested that overuse and aging of weakened muscles damaged the stronger muscles which compensated for those affected by polio. Exercise was con¬sidered by many to be a cause of post-polio degeneration. Rushing through daily activities, running and sustained lifting or carrying were often reported as activities which lead to increased weakness.
Early research indicated that individuals with post-polio could strengthen quadricep muscles by careful weight lifting. Yet, few of the early patients coming into the Sister Kenny Institute clinic were involved in an active cardiopulmonary conditioning program. Overuse of unconditioned muscles is compounded in post-polio people because their central nervous systems don’t adequately monitor fatigue – they don’t know when their muscles have been over used. Other medical problems such as excess weight muscle and joint injuries degenerative arthritis and new neurologic diseases can all add to the loss of muscle strength in a person who had polio years ago.
In the June 9, 1989, issue of the Journal of the American Medical Association, Sister Kenny institute staff mem¬bers published an article about the research we have conducted on adapted cardiopul¬monary conditioning for people with post-polio syn¬drome. The study showed that it is possible to carry out a safe and effective exercise program that provides cardiac conditioning and increases endurance in individuals with post-polio syndrome.
Currently, we are conducting a study involving the use of Mestinon, a drug used to treat myasthenia gravis, a disease in which a defect in nerve-to-muscle conduction results in marked muscle fatigue. Graphic records of muscle contractions following re¬peated electrical stimulation (electromyography) in some persons with post-polio syn¬drome are very similar to those in persons with myasthenia gravis.
Although there is no cure for post-polio syndrome, there are ways to ease the symptoms. Your physician should care-fully assess your medical his¬tory and new symptoms, general health and your level of waking ability, hand mo¬bility, flexibility and muscle strength. Measuring lung function and cardiovascular fitness is also important. A prescribed exercise program, adequate rest and use of adap¬tive equipment or aids such as canes, braces, or a wheel-chair, may help decrease your symptoms.
Special thanks to Richard Owen M.D., medial director of Sister Kenny Institute for his assistance in producing this column.
For more information on post-polio syndrome and Sister Kenny Institute’s Post-Polio Clinic or to submit questions on medial or rehabilitative issues for future columns write: medial Issues and Disability, Sister Kenny Institute, Dept. 16601, 800 E. 28th St., Min¬neapolis, MN 55407-3799.
