Polio's Late Effects


        With the extermination of the polio virus in the United States, polio became an all-but-forgotten disease. For the most part, those of us who had it learned to cope with whatever residual disabilities the disease had caused. We married, had children, progressed in our careers, and lived essentially ordinary lives. We gave the disease that had so disrupted our childhoods little thought. Whatever damage it had done occurred decades ago, and we thought it would not affect us again. We were wrong.  Dead wrong. Almost as if its ghost had risen to avenge its death, polio slipped back into the news in the early 1980's with reports that many polio survivors were now experiencing new and unexpected symptoms.

        Actually, there had been periodic evidence of late polio effects dating back to the 1800's, and it is reported that Elliot Roosevelt believed his father was experiencing these late effects toward the end of his life (Speier, Owen, Knapp, and Canine, 1990). Still, it was thought that these were isolated, atypical cases.

        In the late 1970's, however, a polio survivor wrote to the Rehabilitation Gazette, a newsletter for individuals with disabilities, reporting increased muscle weakness. Many other polio survivors responded, describing similar symptoms, and the magnitude of the problem started to become apparent. The national media soon pounced on this phenomenon and began running features on "the crippler's return."

        Symptoms most typically reported by those experiencing these late effects are (1) excessive fatigue and reduced endurance; (2) new joint and muscle pain; (3) progressive muscle weakness, not only in muscles previously affected, but also in muscles apparently unaffected by acute polio; (4) new or increased breathing difficulties, in some cases requiring the use of ventilatory devices; and (5) cold intolerance that contributes to muscle weakness and is accompanied by burning pain (Jones, Speier, Canine, and Owen, 1989).  The severity of the symptoms is quite variable, and in some cases individuals may require additional bracing, or may find that they now need canes or a wheelchair. Lifestyle changes may also become necessary (Owen, 1990).

        These post-polio symptoms have been given a variety of names including post-poliomyelitis progressive muscular atrophy (PPMA), late effects of acute poliomyelitis, and most commonly, post-polio syndrome.  The Post-Polio Research Task Force prefers the term Post-Polio Sequelae, but because post-polio problems tend to be vague and ill-defined, perhaps Dr. David Bodian's suggestion of "things that happen to people who once had polio" is the most appropriate title (Owen and Speier, 1986).

        Since no one had predicted that these "things" would happen to polio survivors, physicians typically did not attribute the symptoms to the late effects of polio. Thus, as was the case for many of those whose stories appear in this book (Polio's Legacy: An Oral History), polio survivors often experienced frustration and depression due to misdiagnosis (Frick and Bruno, 1986).

        Typically the new symptoms begin 30 or more years after the acute polio infection.  Though the symptoms may be acutely precipitated by illness or injury, usually their onset is gradual.  Therefore, it is often difficult for individuals to pinpoint exactly when they started to experience new polio-related problems.

        Estimates of the prevalence of post-polio sequelae vary greatly.  Richard Owen (1990) reported that surveys provide estimates ranging between 20 and 80%. Though not consistently found in all studies, it appears that those who contracted polio after age ten are more likely to develop post-polio symptoms (Speier, Owen, Knapp, and Canine, 1987). Additionally, those most impaired at the time of their acute illness and who then experienced the most recovery of function may also be at a greater risk (Headley, 1995).

        The cause of post-polio syndrome is another of polio's many enigmas. Though some writers have speculated that it may be due to persistent or recurrent infection with the polio virus (Shariff, Phil, Hentges, and Ciardi, 1991), most researchers report no evidence of recurrent infection (Owen, 1990; Yarnell, Wice, & Maynard, 1994).  Neither is there evidence that these new symptoms are related to multiple sclerosis or amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease) as some have speculated  Rather, it is probable that new, polio-related symptoms have multiple causes including muscle imbalances (i.e. extra stress placed on stronger muscles to compensate for weaker ones), overuse/abuse of weakened muscles (weakened muscles already functioning near capacity may be more susceptible to injury), and deconditioning/undertraining (deconditioning of already weakened muscles may result in reduced strength and stamina sufficient to make walking and other basic functions more difficult).

        Premature aging of nerve tissue may be another possible cause (Owen, 1990).  People normally experience a very gradual decline in nerve cells and in muscle strength after age 50.  However, since those who had polio have already lost some nerve cells, they may experience these declines earlier in life. Additionally, new medical conditions that are a typical part of the aging process for all individuals, may be exacerbated by polio's late effects. As Frederick Maynard noted, "(This) perspective suggests people with a history of polio residual weakness are especially vulnerable to losses in functional capacity as they age because of an increasing statistical probability that they will develop non-polio related medical problems and experience an exaggerated impact on function from them" (Yarnell, Weiss, & Maynard, 1994, p.9).

        Related to the theory of premature aging, research reported by Jones, Speier, Canine, and Owen (1989) suggested that a major cause of the late effects of polio may be "failure of terminal axonal sprout function causing defective transmission at the neuromuscular junction" (p. 325).  While this explanation sounds quite complex, what these writers are saying is that some nerve cells (neurons) that survived the acute polio infection sprouted new axons that took over the control of muscle fibers that did not have surviving neurons. These "giant motor neurons must labor more than normal neurons just to maintain daily activities. After many years of continued overuse, these enlarged motor neurons eventually suffer from a kind of metabolic exhaustion that leads to an inability to regenerate new axon sprouts to replace degenerating ones" (Halstead, 1998, p. 39). In other words, the neurons simply burn themselves out and the muscles they controlled no longer function.

        It has also been recently speculated that some post-polio symptoms, particularly increasing fatigue, may be due to irregularities in the arousal center (reticular activating system) of the brain stem, which was affected in some polio survivors.  Weakened or damaged neurons in the brain stem may be particularly susceptible to underoxygenation when individuals who lack endurance over- exert themselves.  Since it has been shown that many polio survivors are type A personalities, prone to driving themselves to exhaustion (Speier, Owen, Jones, and Seizert, 1990), it may be that they are likely to push themselves to the point where this underoxygenation occurs. Additionally, since the reticular activating system of the brainstem is essential in the body's management of stress, some researchers believe "that, at least in some cases, extreme exhaustion and fatigue may be related to a reduced capacity of the reticular system to respond to what otherwise would appear as... typical daily stress."
(Yarnell, Wice, & Maynard, 1994, p.8)

        Since the causes of post-polio syndrome are not definitely known, it is not surprising that there currently is no "cure."  However, there are ways to ease the symptoms.  According to Lauro Halstead (1998), a combination of "bracing and pacing" is often the best form of treatment. In other words, polio survivors need to slow down and adjust their lifestyle to incorporate regular rest breaks. Additionally, some may need to start (or return to) the use of braces, a cane, or a wheelchair. These are very difficult adjustments for most polio survivors. Halstead noted that he has never met a polio survivor who did not deny or at least downplay the extent of her/his disability. Neither have I. This denial often prevents us from seeking needed diagnosis and treatment. Therefore, overcoming one's denial is the first, and perhaps most crucial step to learning to deal with polio's late effects.

        When medical help is sought, medications such as mestinon, which is used with myasthenia gravis patients, and symetral, most often used with Parkinson's patients, may be prescribed.  Both of these drugs may improve the functioning of damaged or weakened nerve cells (Speier, Owen, Jones, and Seizert, 1990), and medications such as elavil that are often prescribed to combat depression can be helpful in the treatment of polio-related chronic fatigue.  Prednisone, a steroid often used to treat multiple sclerosis, is also being used with some post-polio patients, and The National Institute of Neurological Disorders and Strokes is experimenting with the use of nerve growth factor, "a protein that spurs the proliferation of nerve axons" (Elmer-Dewitt, 1994, p. 55).

        Additionally, a carefully prescribed aerobic exercise program that alternates activity and rest may help many who are experiencing post-polio symptoms.  This sort of exercise program has "been shown to increase conditioning, muscle endurance, and oxygen intake without further damaging weakened muscles" (Owen, 1990, p. 2).  It has been found that exercising three times per week gives optimal results (Speier, Owen, Jones, and Seizert, 1990).

        In conclusion, there seem to be no definitive answers regarding the causes and  treatment of polio's late effects. However, new information is continually being learned. Therefore, it is important for polio survivors to keep abreast of any and all pertinent developments. Perhaps the best recommendation, however, would be for all polio survivors to get a thorough evaluation at a facility with experience diagnosing and treating the late effects of polio. They may not have all the answers, but at least such a facility will be able to provide the best possible advice for those of us dealing with polio's latest, and hopefully last, challenge.

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Information on this page is from Chapter 1 of my book, Polio's Legacy: An Oral History  (Sass, 1996) which is available fromUniversity Press of America. This page was posted by Edmund Sass, Ed. D. and was last updated February 19, 2001. You may e-mail him at esass@csbsju.edu.