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post-polio syndrome

 
Dictionary: post-po·li·o syndrome   (pōst-pō'lē-ō')
 
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n.

A condition affecting poliomyelitis patients several decades after the initial attack, characterized by fatigue, muscular deterioration, pain in the joints, and respiratory problems.


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Neurological Disorder:

Post-polio syndrome

 
Home > Library > Health > Neurological Encyclopedia

Definition

Post-polio syndrome is a slowly progressing weakness that affects polio survivors decades after their initial bout with the disease.

Description

In order to understand post-polio syndrome, it's important to understand polio infection in general. Although people of any age can become infected with poliovirus, it tends to infect young children in particular. About 1% of all people who become infected with poliovirus will actually become ill. Initial symptoms include fever, nausea, and vomiting, followed by several symptom-free days. Some individuals then recover completely. Others go on to develop new symptoms, including severe head, back, and neck pain. These symptoms signal that the virus is invading the nervous system, causing inflammation, injury, and destruction of motor nerves (the nerves that are necessary for muscle movement). As motor nerves are destroyed, the muscles cannot receive messages from the brain. Without input from the brain, muscle tone becomes weak and floppy, and paralysis sets in. Over time, the muscle becomes atrophic (shrunken in size). Paralysis is usually asymmetric; that is, it affects only one side of the body. The paralyzed limbs retain their ability to feel. When the muscles of respiration are affected, the patient may need to be put on a mechanical ventilator.

It only takes a few days for the weakness and/or paralysis to progress to its maximum level of severity. Recovery continues for about six months, during which time the remaining unaffected motor nerves begin sprouting new branches to the muscles, in an attempt to compensate for the nerves that were completely destroyed. During this phase, the patient will regain some degree of functioning. After six months have passed, whatever disability remains will usually be permanent.

Post-polio syndrome occurs some decades after the original infection with polio. Initially, the subtly gradual progressive muscle weakness is barely noticed by the patient, but over time the decrement becomes increasingly obvious. In general, the more severe the original polio infection, the more severe the disability from post-polio syndrome.

Demographics

Only 1% of all people infected with poliovirus actually develop full-fledged polio. About 25-50% of polio survivors will eventually be affected with post-polio syndrome.

Causes and symptoms

Attempts to completely delineate the process by which post-polio syndrome develops have not been totally successful. A number of working theories have been developed.

  • The newer nerve sprouts that grew in order to compensate for lost motor units overtax the rest of the nerve, and over time the nerve begins to fail.
  • Injured nerves that regained function end up failing after years of overuse attempting to compensate for lost motor units.
  • Remaining particles of the poliovirus may precipitate a chemical response in the immune system that accidentally destroys the body's own nerves.
  • Spinal cord changes in polio survivors may adversely affect nerves over time.

Symptoms of post-polio syndrome include severe fatigue; decreased energy; gradually progressive muscle weakness and muscle atrophy; involuntary muscle twitching (fasciculation); muscle, joint and back pain; difficulty breathing and swallowing; and problems with sleep. The most severe muscle problems seem to occur in those muscles that were already affected by the initial bout of polio, although muscles that were not originally affected may also develop some new degree of weakness.

Diagnosis

Diagnosis should be suspected in any polio survivor experiencing new muscle weakness.

Four criteria are required to diagnose post-polio syndrome in a patient with gradually increasing muscle weakness:

  • known history of poliovirus infection with residual muscle weakness
  • history of recovery of some degree of muscle function, with a period of stability lasting at least 15 years
  • at least one limb demonstrating residual muscle atrophy, weakness, lack of normal reflex, and continued normal sensation
  • normal function of sphincter muscles (the muscles around the anus and the lower part of the esophagus)

Treatment team

The treatment team will depend in part on the specific symptoms encountered. In general, once diagnosed, the patient will benefit from work with a physical therapist, occupational therapist, and speech and language therapist. Specialists in arthritis, orthopedics, rehabilitation, and pulmonology may also be helpful.

Treatment

There is no cure for post-polio syndrome. Efforts are primarily directed at retaining mobility and improving patient comfort. Anti-inflammatory medications can help relieve muscle and joint pain by decreasing inflammation. Braces, wheelchairs, or motorized scooters may help very compromised patients retain some independence and mobility. Respiratory and sleep problems may interact with each other to create considerable distress. They may be relieved by the use of supplemental oxygen and/or breathing devices to help keep the airway open while sleeping.

Recovery and rehabilitation

The physical therapist should design a thoughtful exercise program to maintain and increase flexibility, although it is important not to overtax already weakened muscles and nerves. Occupational therapy can help the individual learn methods to compensate for muscle weakness, and still retain independence in the activities of daily living. Speech and language therapists can be helpful for swallowing problems.

Clinical trials

A clinical trial through the National Institute of Neurological Disorders and Stroke is studying whether the drug modafinil might be helpful in treating the relentless fatigue of post-polio syndrome.

Prognosis

Because the increase in muscle weakness is so gradual, post-polio syndrome is generally thought to have a good prognosis, rarely causing significantly more severe impairment and disability. In a few rare cases, however, progressive weakening of the muscles of respiration can result in death.

Resources

BOOKS

Modlin, John F. "Poliovirus." In Principles and Practice of Infectious Diseases, edited by Gerald L. Mandell. London: Churchill Livingstone, Inc., 2000.

Nath, Avindra, and Joseph R. Berger. "Poliomyelitis." In Cecil Textbook of Medicine, edited by Lee Goldman. Philadelphia: W.B. Saunders Company, 2003.

Roos, Karen L. "Viral Infections." In Textbook of Clinical Neurology, edited by Christopher G. Goetz. Philadelphia: W.B. Saunders Company, 2003.

WEBSITES

National Institute of Neurological Disorders and Stroke (NINDS). Post-polio Syndrome Fact Sheet. Bethesda, MD: NINDS, 2003.

ORGANIZATIONS

National Institute of Neurological Disorders and Stroke (NINDS). 9000 Rockville Pike, Bethesda, Maryland 20892. 800-411-1222. prpl@mail.cc.nih.gov. http://clinicaltrials.gov/ct/show/NCT00067496?order=1.


Rosalyn Carson-DeWitt, MD


 
Medical Dictionary: post-po·li·o syndrome
Top
Home > Library > Health > Medical Dictionary
(pōst-pō'lē-ō')
n.

A condition occurring most often in individuals who contracted severe cases of polio before age 10 and characterized by fatigue, exhaustion, muscle weakness, painful joints, and occasionally difficult breathing.

 
Wikipedia: Post-polio syndrome
Top
Home > Library > Miscellaneous > Wikipedia
Post-polio syndrome
Classification and external resources
Arthur C. Clarke developed post-polio syndrome in 1984 after initially contracting polio in 1962.[1]
ICD-10 B91.
ICD-9 138
eMedicine pmr/110 
MeSH D016262

Post-polio syndrome (PPS, or post-poliomyelitis syndrome) is a condition that affects approximately 25–50% of people who have previously contracted poliomyelitis—a viral infection of the nervous system—after recovery from the initial paralytic attack. Typically the symptoms appear 15-30 years after the original infection, at an age of 35 to 60. Symptoms include acute or increased muscular weakness, pain in the muscles, and fatigue.

The precise mechanism that causes PPS is unknown. It shares many features with the post-viral chronic fatigue syndrome, but unlike that disorder it tends to be progressive, and as such can cause a tangible loss of muscle strength.[2] Treatment is primarily limited to adequate rest, conservation of available energy, and supportive measures, such as leg braces and energy-saving devices such as powered wheelchairs, analgesia (pain relief) and sleep aids.

Contents

Signs and symptoms

After a period of prolonged stability individuals who had been infected and recovered from polio begin to experience new signs and symptoms, characterised by muscular atrophy (decreased muscle mass), weakness, pain and fatigue in limbs that were originally affected or in limbs that didn't seem to have been affected at the time of the initial polio illness.[3] PPS is a very slowly progressing condition marked by periods of stability followed by new declines in the ability to carry out usual daily activities.[4] Most patients become aware of their decreased capacity to carry out daily routines due to significant changes in mobility, decreasing upper limb function and lung capability. Fatigue is often the most disabling symptom; even slight exertion often produces disabling fatigue and can also intensify other symptoms.[5] Problems breathing or swallowing, sleep-related breathing disorders, such as sleep apnea and decreased tolerance for cold temperatures are other notable symptoms.[3]

Increased activity during intervening healthy years between the original infection and onset of PPS can amplify the symptoms. Thus, contracting poliomyelitis at a young age can result in particularly disabling PPS symptoms.[6]

Causes

Numerous theories have been proposed to explain post-polio syndrome. Despite this, there are currently no absolutely defined causes of PPS. The most widely accepted theory of the mechanism behind the disorder is "neural fatigue". A motor unit is a nerve cell (or neuron) and the muscle fibers it activates. Poliovirus attacks specific neurons in the brainstem and the anterior horn cells of the spinal cord, generally resulting in the death of a substantial fraction of the motor neurons controlling skeletal muscles. In an effort to compensate for the loss of these neurons, surviving motor neurons sprout new nerve terminals to the orphaned muscle fibers. The result is some recovery of movement and the development of enlarged motor units.[4]

The neural fatigue theory proposes that the enlargement motor neuron fibres places added metabolic stress on the nerve cell body to nourish the additional fibers. After years of use, this stress may be more than the neuron can handle, leading to the gradual deterioration of the sprouted fibers and, eventually, the neuron itself. This causes muscle weakness and paralysis. Restoration of nerve function may occur in some fibers a second time, but eventually nerve terminals malfunction and permanent weakness occurs.[4] When these neurons no longer carry on sprouting, fatigue occurs due to the increasing metabolic demand of the nervous system.[7] The normal aging process also may play a role. With age, most people experience a decrease in the number of spinal motor neurons.Because polio survivors have already have lost a considerable number of motor neurons, further age-related loss of neurons may contribute substantially to new muscle weakness. The overuse and underuse of muscles also may contribute to muscle weakness.[8]

Another theory is that people who've recovered from polio lose remaining healthy neurons at a faster rate than normal. However, little evidence exists to support this idea.[9] Finally, it has been proposed that the initial polio infection causes an autoimmune reaction, in which the body's immune system attacks normal cells as if they were foreign substances. Again, compared to neural fatigue, the evidence supporting this theory is quite limited.[9]

Diagnosis

Diagnosis of post-polio syndrome can be difficult, since the symptoms are hard to separate from complications due to the original poliomyelitis infection, and from the normal infirmities of aging. There is no laboratory test for post-polio syndrome, nor are there any other specific diagnostic criteria. Three important criteria are recognized, including: previous diagnosis of polio, long interval after recovery and the gradual onset of weakness.[10]

In general, PPS is a diagnosis of exclusion whereby other possible causes of the symptoms are eliminated.[11] Neurological examination aided by other laboratory studies can help to determine what component of a neuromuscular deficit occurred with polio and what components are new and to exclude all other possible diagnoses. Objective assessment of muscle strength in PPS patients may not be easy. Changes in muscle strength are determined in specific muscle groups using various muscle scales which quantify strength, such as the Medical Research Council (MRC) scale. Magnetic resonance imaging (MRI), neuroimaging, and electrophysiological studies, muscle biopsies, or spinal fluid analysis may also be useful in establishing a PPS diagnosis.[11]

Management

The treatment for post-polio syndrome generally palliative and consists of rest, analgesia (pain relief) and utilisation of mechanisms to make life easier such as powered wheelchairs. There are no reversive therapies. Fatigue is usually the most disabling symptom; energy conservation can significantly reduce fatigue episodes. Such conservation can be achieved with lifestyle changes, reducing workload and daytime sleeping. Weight loss is also recommended if patients are obese. In some cases, the use of lower limb orthotics can reduce energy usage. Medications for fatigue, such as amantadine and pyridostigmine, have not been found to be effective in the management of PPS.[7] Muscle strength and endurance training are more important in managing the symptoms of PPS than the ability to perform long aerobic activity. Management should focus on treatments such as hydrotherapy and developing other routines that encourage strength but do not affect fatigue levels.[7]

PPS increases the stress on the musculoskeletal system due to increasing muscular atrophy. A recent study showed that in a review of 539 PPS patients, 80% reported pain in muscles and joints and 87% only had fatigue.[12] Joint instability can cause significant pain in individuals with PPS should be adequately treated with painkillers. Supervised activity programs, decreasing mechanical stress with braces and adaptive equipment is recommended.[5][7]

Because PPS can fatigue facial muscles, as well as cause dysphagia (difficulty swallowing), dysarthria (difficulty speaking) or aphonia (inability to produce speech), persons with PPS may become malnourished due to difficulty eating. Compensatory routines can help relieve these symptoms such as eating smaller portions at a time and sitting down whilst eating.[13] PPS with respiratory involvement requires special management such as breathing exercises, chest percussion with a stethoscope on regular occasions for observation of the disease and management of secretions. Failure to properly assess PPS with respiratory involvement can increase the risk of missing aspiration pneumonia (an infection of the lower respiratory tract) in an individual. Severe cases may require permanent ventilation or tracheostomy. Sleep apnoea may also occur. Other management strategies that may lead to improvement improvement include smoking cessation, treatment of other respiratory diseases and vaccination against respiratory infections such as influenza.[5]

Prognosis

In general, PPS is not life-threatening. The major exception are patients left with severe residual respiratory difficulties, who may experience new severe respiratory impairment. Studies have shown that, compared to control populations, PPS patients lack any elevation of antibodies against the poliovirus, and because no poliovirus is excreted in the feces, it is not considered a recurrence of the original polio. Further, there is no evidence that the poliovirus can cause a persistent infection in humans. PPS has been confused with amyotrophic lateral sclerosis (ALS), which progressively weakens muscles. PPS patients do not have an elevated risk of ALS.[7]

There have been no sufficient longitudinal studies on the prognosis of post-polio syndrome; however, speculations have been made by several physicians based on experience. Fatigue and mobility usually return to normal over a long period of time. The prognosis also differs depending upon different causes and factors affecting the individual.[6] An overall mortality rate of 25% exists due to possible respiratory paralysis of persons with post-polio syndrome; otherwise, post-polio syndrome is usually non-lethal.[14]

Epidemiology

Post-polio syndrome occurs in approximately 25–50% of people who survive a poliomyelitis infection.[15] On average, it occurs 30-35 years afterwards; however, delays of between 8-71 years have been recorded.[16][17] The disease occurs sooner in persons which more severe initial infection.[17] Other factors that increase the risk of postpolio syndrome include increasing length of time since acute poliovirus infection, presence of permanent residual impairment after recovery from the acute illness,[17][16] and female sex.[18]

See also

References

  1. ^ "Arthur C. Clarke, Premier Science Fiction Writer, Dies at 90.". New York Times. 18 March 2008. http://www.nytimes.com/2008/03/18/books/18cnd-clarke.html?hp. Retrieved on 2008-03-19. 
  2. ^ Bruno RL, Creange SJ, Frick NM (September 1998). "Parallels between post-polio fatigue and chronic fatigue syndrome: a common pathophysiology?". Am. J. Med. 105 (3A): 66S–73S. doi:10.1016/S0002-9343(98)00161-2. PMID 9790485. 
  3. ^ a b "Post-polio syndrome: Symptoms - MayoClinic.com". http://www.mayoclinic.com/health/post-polio-syndrome/DS00494/DSECTION=symptoms. Retrieved on 2009-02-23. 
  4. ^ a b c "Post-Polio Syndrome Fact Sheet: National Institute of Neurological Disorders and Stroke (NINDS)". http://www.ninds.nih.gov/disorders/post_polio/detail_post_polio.htm. Retrieved on 2008-12-30. 
  5. ^ a b c Jubelt B, Agre JC (2000). "Characteristics and management of postpolio syndrome". JAMA 284 (4): 412–4. doi:10.1001/jama.284.4.412. PMID 10904484. 
  6. ^ a b Howard RS (June 2005). "Poliomyelitis and the postpolio syndrome". BMJ 330 (7503): 1314–8. doi:10.1136/bmj.330.7503.1314. PMID 15933355. PMC: 558211. http://bmj.com/cgi/pmidlookup?view=long&pmid=15933355. Retrieved on 2008-12-24. 
  7. ^ a b c d e Khan F (August 2004). "Rehabilitation for postpolio sequelae". Aust Fam Physician 33 (8): 621–4. PMID 15373379. http://www.racgp.org.au/afp/200408/14617. Retrieved on 2008-12-24. 
  8. ^ "Post-polio syndrome: Causes - MayoClinic.com". http://www.mayoclinic.com/health/post-polio-syndrome/DS00494/DSECTION=causes. Retrieved on 2009-02-23. 
  9. ^ a b Stolwijk-Swüste JM, Beelen A, Lankhorst GJ, Nollet F (August 2005). "The course of functional status and muscle strength in patients with late-onset sequelae of poliomyelitis: a systematic review". Arch Phys Med Rehabil 86 (8): 1693–701. doi:10.1016/j.apmr.2004.12.022. PMID 16084828. 
  10. ^ "Post-polio syndrome: Tests and diagnosis - MayoClinic.com". http://www.mayoclinic.com/health/post-polio-syndrome/DS00494/DSECTION=tests-and-diagnosis. Retrieved on 2009-02-23. 
  11. ^ a b Silver JK, Gawne AC (2003). Postpolio Syndrome. Philadelphia: Hanley & Belfus. ISBN 1560536063. 
  12. ^ Ehde DM, Jensen MP, Engel JM, Turner JA, Hoffman AJ, Cardenas DD (2003). "Chronic pain secondary to disability: a review". Clin J Pain 19 (1): 3–17. doi:10.1097/00002508-200301000-00002. PMID 12514452. http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0749-8047&volume=19&issue=1&spage=3. Retrieved on 2008-12-24. 
  13. ^ Silbergleit AK, Waring WP, Sullivan MJ, Maynard FM (March 1991). "Evaluation, treatment, and follow-up results of post polio patients with dysphagia". Otolaryngol Head Neck Surg 104 (3): 333–8. PMID 1902934. 
  14. ^ Lindsay, Kenneth W; Ian Bone, Robin Callander, J. van Gijn (1991). Neurology and Neurosurgery Illustrated. United States: Churchill Livingstone. pp. 489–490. ISBN 0-443-04345-0. 
  15. ^ Jubelt, B; J Drucket (1999). Poliomyelitis and the Post-Polio Syndrome in Motor Disorders. Philadelphia: Lippincott Williams and Wilkins. pp. 381. 
  16. ^ a b Jubelt B, Cashman NR (1987). "Neurological manifestations of the post-polio syndrome". Crit Rev Neurobiol 3 (3): 199–220. PMID 3315237. 
  17. ^ a b c Ramlow J, Alexander M, LaPorte R, Kaufmann C, Kuller L (October 1992). "Epidemiology of the post-polio syndrome". Am. J. Epidemiol. 136 (7): 769–86. PMID 1442743. http://aje.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=1442743. Retrieved on 2008-12-24. 
  18. ^ Atkinson W, Hamborsky J, McIntyre L, Wolfe S (eds.) (2007). "Poliomyelitis" (PDF). Epidemiology and Prevention of Vaccine-Preventable Diseases (The Pink Book) (10th ed.). Washington DC: Public Health Foundation. pp. 101–14. http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/polio-508.pdf. 

Further reading

  • Bruno, Richard L. (2002). The Polio Paradox. New York: Warner Books. ISBN 0446529079. 
  • Maynard, F.M., & Headley, J.H. (Eds.) (1999). Handbook on the Late Effects of Poliomyelitis for Physicians and Survivors. Saint Louis, MO: GINI (now Post-Polio Health International). Information on 90 post-polio topics; a compilation of the research and experience of over 40 experts.
  • March of Dimes Birth Defects Foundation. (1999). Identifying Best Practices in Diagnosis & Care. Warm Springs, GA: March of Dimes International Conference on Post-Polio Syndrome
  • Nollet F. "Perceived health and physical functioning in postpoliomyelitis syndrome". Vrije Universiteit Amsterdam, 2002.
  • Nollet, F. "Post-polio syndrome". Orphanet Ecyclopaedia, 2003
  • Silver, Julie K. (2001). Post-Polio Syndrome: A Guide for Polio Survivors and Their Families. New Haven: Yale University Press. (Dr. Silver is Medical Director, Spaulding-Framingham Outpatient Center; Assistant Professor, Department of Physical Medicine and Rehabilitation, Harvard Medical School.)

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Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved.  Read more
Neurological Disorder. Gale Encyclopedia of Neurological Disorders. Copyright © 2005 by The Gale Group, Inc. All rights reserved.  Read more
Medical Dictionary. The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company.  Read more
Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Post-polio syndrome".  Read more

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