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The Late Effects of Polio: An Overview


POLIOMYELITIS (infantile paralysis) has been eradicated from nearly every country in the world since the approval for use of the Salk (1955) and Sabin (1962) vaccines. According to the World Health Organization (WHO), no more than 1,500 cases of acute poliomyelitis were reported in 2001. The number of countries in which poliomyelitis is endemic dropped from 20 in 2001 to 10 at the beginning of 2002. The WHO target date for declaring the world polio-free is 2005.

WHO estimates there are 20 million people worldwide with some degree of disability caused by poliomyelitis. A 1996 National Center for Health Statistics survey reported a preliminary estimate of one million survivors in the United States. About 450,000 of them reported paralysis resulting in some form of impairment.

For years most of these polio survivors lived active lives, their memory of polio long forgotten, their health status stable. By the late '70s, polio survivors were noting new problems of fatigue, pain, and additional weakness. By the mid-'80s, health professionals and policymakers recognized these new problems as being real and not "only in the patients' minds." Studies on this phenomenon called "post-polio syndrome" have been – and are still being – conducted in research institutions and medical centers.

The survivors of poliomyelitis may experience symptoms that include:

These general symptoms are experienced in varying degrees, and their progression can be insidious. They should not be dismissed simply as signs of aging alone. Current research indicates that the length of time one has lived with the residuals of polio is as much of a risk factor as chronological age. It also appears that individuals who experienced the most severe original paralysis with the greatest functional recovery are having more problems now than others with less severe original involvement.

The diagnosis of post-polio syndrome is one of exclusion.

A definitive test is not yet available. Some of the confusion and doubt among polio survivors, health professionals, and family members is due to the lack of common understanding of terminology. It is helpful to think of post-polio problems in the following categories, remembering that the groupings are not distinct but parts of a continuum.

The largest and most inclusive category is called Late Effects of Polio or Polio Sequelae and is defined as specific new health problems which result from polio-caused chronic impairments, e.g., degenerative arthritis of overused joints, carpal tunnel syndrome and other repetitive motion problems, tendinitis, bursitis, failing joint fusions, overstressed joints due to compensatory body mechanics.

Post-Polio Syndrome, a sub-category of the late effects of polio, is defined as a neurologic disorder characterized by increased weakness and/or abnormal muscle fatiguability. The cluster of symptoms includes new weakness, intense fatigue, and pain in muscles and joints resulting in decreased endurance and diminished function. Most clinicians use the following criteria to diagnose post-polio syndrome.

To distinguish new, slowly progressive muscle weakness that is neurologic in origin from musculoskeletal and/or wear and tear problems, researchers coined the phrase Progressive Post-Polio Muscular Atrophy (PPMA), defined as progressive new weakness and atrophy in muscles with clinical or subclinical signs of chronic partial denervation/reinnervation compatible with previous acute poliomyelitis. The term is used less often today, giving way to post-polio syndrome.

Polio survivors may experience one or more of the problems described above and should not become unnecessarily concerned about the label for their symptoms.

Polio survivors may experience the same health difficulties as the general population, some with symptoms mimicking post-polio syndrome, some magnified due to neurologic damage from former acute polio.

The current consensus of opinion explaining post-polio symptoms focuses on the nerve cells and their corresponding muscle fibers. When the poliovirus destroyed or injured motor neurons, muscle fibers were orphaned and paralysis resulted. Polio survivors who regained movement did so because nerve cells recovered to a certain extent. Further recovery is attributed to the ability of non-affected neighboring nerve cells to "sprout" and reconnect to the orphaned muscles. Survivors living for years with this restructured neuromuscular system are now experiencing the consequences - overworked surviving nerve cells and overworked muscles and joints, compounded by the effects of growing older. While the search for a viral cause continues, there is no conclusive evidence to support the concept that post-polio syndrome is a reinfection of the poliovirus.

As the first step in management ...

Polio survivors should undergo a complete, general medical evaluation by a primary care physician and a specialized neuromuscular evaluation by a knowledgeable and experienced polio specialist to establish a baseline from which to judge future changes and to develop an appropriate treatment plan.

Polio survivors should first and foremost take care of their health by seeking periodic, basic medical attention. Be nutrition-wise, avoid or reverse excessive weight gain, and stop smoking or over-indulging in alcohol.

Polio survivors should listen to their bodies. Avoid activities that cause pain - pain is a warning signal. Avoid unrestrained use of pain killers, especially narcotics. Do not overuse muscles but do continue activity that does not worsen the symptoms. In particular, do not over-exercise or continue to exercise through pain. Avoid activity that causes fatigue lasting more than ten minutes.

Polio survivors experiencing symptoms should pace themselves in their daily activities, resting when tired. Stop for a 15- to 30-minute rest when needed, perhaps several times a day. Management may include the increased use of assistive devices. A change of equipment or new bracing may be recommended.

Polio survivors should educate themselves, their families, and if need be, their health professionals. Post-Polio Health International, through its conferences and publications, provides accurate and updated information. Polio survivors may benefit from the support and knowledge of other polio survivors.

For a basic overview of polio's late effects ...

"Information about the late effects of polio ... for polio survivors, for families and friends, for health professionals," is available online as well as in printed form with three easily detachable sections.