The Post-Polio Task Force
Questions & Answers
What is post-polio syndrome (PPS)?
What are the most common symptoms of PPS?
How many people have PPS?
How does PPS affect quality of life?
How does PPS cause these symptoms?
How is PPS diagnosed?
Is there a cure for PPS?
How to manage new weakness?
How to manage fatigue?
How to manage pain?
How are other PPS symptoms managed?
Is PPS associated with emotional problems?
Are there any promising new treatments for PPS?
Other sources of information about polio-related topics is Post-Polio Health International's Handbook on the Late Effects of Poliomyelitis for Physicians and Survivors and past issues of Post-Polio Health.
Post-polio syndrome is a condition that affects polio survivors years after their recovery from their initial bout with polio. An interval of 30 to 40 years usually elapses before the first PPS symptoms occur, but intervals as short as 8 years and as long as 71 years have been documented.
Fatigue, new weakness and pain are the most common symptoms of PPS, but many other symptoms can also occur, including:
Fatigue, which occurs in 60% to 90% of people with PPS, may be the most common symptom, and is probably most responsible for disability associated with the syndrome. Some people experience PPS-related fatigue as general fatigue, which often is described as a flu-like exhaustion that worsens as the day progresses. This type of fatigue can also increase during physical activity, and may cause difficulty with concentration and memory. Others experience muscle fatigue, a form of muscle weakness that increases with exercise and improves with rest. In addition, many individuals experience symptoms of both general fatigue and muscle fatigue.
New weakness usually occurs in muscles that were affected during the original polio infection; however, this weakness also can occur in muscles that were not affected by the original polio infection, or at least did not seem to be affected at the time.
People with PPS may experience pain in their muscles and/or joints. Muscle pain is usually felt as an aching or sore feeling that occurs after light physical activity, and it frequently improves with rest. Joint pain can be chronic (lasting for a long time) or intermittent (occurring off and on for short periods of time), and it may intensify during physical activity.
Less common PPS symptoms may include:
- new muscle atrophy (loss of muscle bulk)
- respiratory insufficiency (breathing difficulties)
- dysarthria (speech disturbances)
- dysphagia (difficulty swallowing)
- muscle cramps
- cold intolerance
- fasciculations (muscle twitches)
- joint deformities
It is estimated that there are currently 640,000 survivors of polio in the United States. Studies suggest that 20% to 40% of those who have recovered from the initial polio infection go on to develop PPS; thus, there may be as many as 128,000 to 256,000 individuals with PPS in the United States.
NOTE: This data is from a 1987 survey by National Center for Health Statistics.
PPS is not typically a life-threatening condition, but it may cause significant discomfort and disability. The most common disability caused by PPS is deterioration of mobility. People with PPS may also experience difficulties performing daily activities such as cooking, cleaning, shopping and driving. Assistive devices such as canes, crutches, walkers, wheelchairs or electric scooters may be necessary for some people. If symptoms are extremely severe, these individuals may be required to change occupations or stop working altogether.
The exact mechanism by which PPS causes fatigue, pain and new weakness is not completely understood, but it is thought to be related to the gradual loss of individual nerve cells that make contact with muscle fibers, and subsequent loss of nerve transmission to these fibers. During the original polio infection, the poliovirus attacks motor neurons (nerve cells responsible for muscle movement), causing injury or death of those nerve cells. If this process occurs on a large enough scale, it can result in loss of muscle function, including weakness or paralysis. However, the body often employs strategies to compensate for lost functions - in this case, surviving nerve cells sprout extra branches, called axonal sprouts, that are able to attach to muscle fibers that have lost their original nerve supply. After this process of nerve reattachment, or reinnervation, the muscle fibers are able to work again, sometimes as well as before. Some researchers have suggested that PPS develops because these extra axonal sprouts cannot "hold" forever, but instead get weaker over time due to "overexertion" - in other words, they cannot sustain this additional activity indefinitely, because they were not designed to do so. Eventually, the sprouts degenerate, and the muscle fiber again loses its ability to contract.
It may be difficult to obtain a proper diagnosis of PPS, in part because there are no definitive tests for this condition. Some doctors dismiss PPS symptoms as being caused by psychological conditions such as depression. In addition, common PPS symptoms such as fatigue, pain and new weakness may also be caused by many other diseases. As a result, the diagnosis of PPS is one of exclusion, meaning that a doctor can only diagnose PPS by eliminating other potential causes of the patient's symptoms. In general, a doctor may suspect PPS in a polio survivor if:
- The individual is suffering from new muscle weakness, generalized or muscular fatigue, or pain involving the muscles and/or joints.
- The individual has experienced at least 10 years of good health (i.e., muscle functions have not deteriorated) since recovering from polio.
If these criteria are met, a doctor must still make sure that the symptoms are not caused by other medical conditions, including pulmonary (lung), cardiac (heart), hematologic (blood) or endocrine (hormonal) diseases, cancer, or some chronic infections. In addition, musculoskeletal diseases such as fibromyalgia, rheumatoid arthritis and osteoarthritis may also be confused with PPS. Fibromyalgia, a common musculoskeletal disorder that can cause generalized pain and tenderness as well as fatigue, is frequently seen in polio survivors, and may sometimes co-exist with PPS. In addition, many neurologic diseases - including amyotrophic lateral sclerosis (Lou Gehrig's disease), multiple sclerosis and Parkinson's disease - may cause PPS-like symptoms. However, even if an individual is found to have another condition that causes PPS-like symptoms, this does not rule out the possibility that he or she may also have PPS.
There is currently no cure for PPS. However, several drugs are being studied in the hopes that they will provide relief from some of its symptoms (see below). In addition, people with PPS have a wide range of non-drug options for symptom management. Depending on the individual, a typical strategy may involve physical therapy with careful use of exercise; occupational therapy, including instruction on lifestyle changes, such as avoiding over-exertion; use of assistive devices such as canes or walkers; appropriate weight loss if needed; and use of over-the-counter or prescription pain medications. Often, these management strategies are developed in consultation with the individual's primary care physician, along with a team of other health care professionals that may include a physiatrist (a doctor specializing in rehabilitative medicine), a neurologist, a rheumatologist or orthopedist, a physical therapist, an occupational therapist, a speech therapist, an orthotist (a person who creates othopedic devices), a social worker and a dietitian.
Strengthening, stretching and aerobic exercises may be useful for the management of new weakness, as is appropriate weight loss. However, not everyone benefits from the same types of exercise, and some individuals should avoid exercise altogether. In general, people with PPS should avoid exercise that causes joint pain, and should not exercise to the point of muscle pain or fatigue. It is important to avoid muscle overuse because this may result in increased weakness. If muscle overuse does occur, rest or supportive devices such as braces may be beneficial. Assistive devices - such as canes, crutches, manual wheelchairs, electric wheelchairs and motorized scooters - can be helpful for severe muscle weakness.
One way to manage PPS-related fatigue is through the use of energy conservation techniques. For example, daily activities that are not considered "critical," such as making a bed, can be discontinued. Or, household items and supplies can be relocated to make them more accessible. Some people may consider certain lifestyle changes, such as working only part-time or taking a job that is less physically demanding. In addition, it helps to learn to pace daily activities, which means taking regular breaks during long periods of physical activity. Regular rest periods or daytime naps, especially in the early afternoon, can be beneficial for managing fatigue. (People with PPS who work should also consider this type of rest schedule.) Finally, it is important to get a good night's sleep; doctors can provide advice on how to improve the quantity and quality of sleep. (It should be noted that breathing disorders such as sleep apnea may interfere with sleep and contribute to fatigue.)
There are different types of pain associated with PPS, and management strategies must be tailored accordingly. Some types of pain may be of muscular origin - such as muscle cramps or fibromyalgia - while others may result from joint and soft tissue problems that are secondary to PPS, including osteoarthritis, tendinitis, ligament strains and joint deformities. One way that people with PPS can manage pain is to modify the use of their extremities - for example, by periodically resting a leg that is causing discomfort. Certain "physiotherapeutic" techniques, including the application of ice or superficial heat, as well as the use of ultrasound and a method called transcutaneous electrical nerve stimulation or TENS, may be beneficial for pain management. Strengthening exercises, supportive devices such as braces and assistive devices can also help to relieve pain. Acetaminophen (e.g., Tylenol) and nonsteroidal anti-inflammatory drugs (such as ibuprofen [e.g., Advil], naproxen sodium [e.g., Naprelan, Aleve] and etodolac [Lodine]) are effective pain relievers that can be obtained over-the-counter or by prescription. In rare cases, steroid injections or surgery may be required to relieve a patient's pain.
An estimated 13 percent of people with PPS develop new breathing difficulties, most commonly caused by weakness of the respiratory muscles. Other factors may be pulmonary (lung) disease; spinal deformities such as scoliosis or kyphosis; obesity; smoking and/or sleep-associated breathing disorders (e.g., sleep apnea, a common problems in polio survivors). Many polio survivors who used a ventilator during their original polio infection may need to return to the use of a ventilator. Management of breathing and sleep problems can be achieved largely through the use of nocturnal (nighttime) ventilation. A small percentage of people with PPS suffer from dysphagia, or difficulty swallowing (often caused by weakness of the muscles of the pharynx or larynx). A videofluoroscopic evaluation may be needed. Swallowing problems can be managed with a variety of techniques, including eating smaller and more frequent meals during the day, avoiding eating when fatigued, and turning the head to one side or tucking down the chin while swallowing.
Many individuals have difficulties adjusting to new disabilities. For some people with PPS, reliving their childhood experiences with polio can be a traumatic and even terrifying experience. To make matters worse, many doctors know very little about PPS, and some believe that the condition is only in the patient's head. Lacking proper medical and psychological advice, people with PPS are often forced to depend on their own resources to help them cope with their condition. Fortunately, PPS is gaining increasing attention in the medical community, and there is a growing number of health care professionals who understand PPS and can provide appropriate medical and psychological help. In addition, there are PPS support groups, newsletters and educational networks that provide up-to-date information about PPS while offering individuals the knowledge that they are not alone in their struggle (www.post-polio.org)
Several drugs are being studied in the hopes that they may prove effective in relieving some of the symptoms of PPS:
Human growth hormone (Humatrope) has been found to increase the production of a hormone in the body - insulin-like growth factor I or IGF-1 - that stimulates nerve cells to sprout additional extensions (axons). This drug, which is already approved for other uses, was tested in 6 people with PPS, producing little or no improvement in the subjects' muscle strength, endurance or recovery after fatigue. However, the study investigators suggested that longer-term treatment with human growth hormone might help some individuals with PPS.
Bromocriptine mesylate (Parlodel), a drug that is used to treat conditions such as Parkinson's disease, was found to improve symptoms of fatigue in 3 out of a total of 5 persons with PPS. Researchers are hoping to conduct larger studies to confirm the benefits of this drug.
Recombinant human insulin-like growth factor I (rhIGF-1) was shown to enhance the recovery of of strength in people with PPS after they engaged in tiring exercises, but the drug did not alleviate excessive fatigue caused by the exercises. The study involved 22 people with PPS.
Pyridostigmine (Mestinon), a drug currently approved to treat muscle fatigue associated with the neuromuscular disorder myasthenia gravis, has shown some promise in the treatment of PPS. In one study of the drug involving 27 people with PPS, more than half of the subjects reported less fatigue after receiving pyridostigmine. A separate study involving 27 people with PPS found that patients taking pyridostigmine showed minimal improvements in strength (based on objective measures) and fatigue levels (based on the individual's own opinion).
The potential benefits of pyridostigmine are being investigated further in a clinical trial called the North American Postpoliomyelitis Pyridostigmine Study, or NAPPS. Preliminary results have been released and pyridostigmine was not found to provide significant benefits with respect to quality of life, fatigue or isometric muscle strength compared with placebo, although a trend was noted towards increased strength in very weak muscles. [For more detailed information, see Research Reports - NAPPS Preliminary Data] This trial of 126 people with PPS was designed to determine the effectiveness of pyridostigmine in relieving PPS symptoms using measures of fatigue, muscle strength and general health. NAPPS will also determine the incidence and severity of any side effects associated with pyridostigmine. Adverse effects were seen in approximately 50% of individuals in previous trials of pyridostigmine; these side effects included loose stools and intestinal cramps, blurred vision, increased urinary frequency, muscle cramps and fasciculations (muscle twitches).
This multicenter, randomized, double-blinded trial of pyridostigmine in post-polio syndrome (Neurology 1999;53:1225) concluded &34;no significant differences between pyridostigmine and placebo-treated PPS patients on measures of quality of life, isometric strength, fatigue and serum IGF-I."
Check off the items in the following list that apply to you. If you check off the first item on this list and any of the subsequent ones, see a doctor.
I have had polio in the past and now I have:
__ Unaccustomed fatigue (this may be "general fatigue"), a feeling of total exhaustion, or "muscle fatigue," a rapid tiring of the muscles that increases with exercise and improves with rest.
__ New muscle weakness (may include muscles originally affected by polio infection, as well as muscles seemingly unaffected at the time).
__ Pain in my muscles and/or joints.
__ Breathing or swallowing difficulties.
__ Increased sensitivity to cold temperatures.
__ A decline in my ability to perform basic daily activities, such as climbing up stairs or bathing.
__ Difficulty sleeping.
For further information on polio and PPS, contact Post-Polio Health International (PHI), an organization with a forty-year history of collecting, creating, and disseminating information on issues relating to polio and post-polio syndrome.
Although the Post-Polio Task Force disbanded in 1999 because the research was concluded, the information that was developed for this section of the PHI website remains relevant to this date.