Physical Therapy Intervention in Post Polio Syndrome

Original Editor - Osama Faisal Top Contributors - Ananya Bunglae Sudindar, Kim Jackson, Nupur Smit Shah, Osama Faisal, Amanda Ager, Lauren Lopez, Admin and Peter Thwaites

What is Polio?

Poliomyelitis, also commonly known as polio, is a disease that mainly affects children below the age of 5. It is a highly infectious disease and spreads from person-person through the feacal-oral route or contaminated food and water. It is caused by the group C enterovirus known as Poliovirus (PV). PV mainly grows in the GI tract and can multiply and further spread to other parts of the body including nervous tissue. Upon spreading to the Central Nervous System, the virus targets motor neurons which results in its classical clinical presentation. The main symptoms of Poliomyelitis include:

• Fever
• General discomfort
• Severe limb pain
• Flaccid paralysis
• Myalgia
• Fatigue
• Nausea

Polio is not a new disease and was in fact first reported in England, by Michael Underwood, in 1789. He described cases of children who displayed weakness and paralysis of their lower extremities. Epidemics of poliomyelitis were first observed in Scandinavia, Western Europe, and the United States towards the end of the 19^th century and steadily grew in frequency and magnitude until the late 1950s and 1960s when the poliovirus vaccine was introduced. A vaccine first developed by Jonas E. Salk, using killed or inactivated poliovirus (IPV), was made available by injection in 1955. The introduction of the trivalent Sabin oral vaccine (OPV) in 1962 was the beginning of the plan to eradicate Polio, the vaccine was affordable and easy to administer providing a cheap and readily administered vaccine . Currently, cases due to wild poliovirus have decreased by over 99% since 1988, from an estimated 350,000 cases in more than 125 endemic countries to just two endemic countries (as of October 2023).

Post Polio Syndrome

Post-polio syndrome (PPS) is a condition that affects individuals who have previously had an initial poliovirus infection. PPS typically emerges after a period of at least 15 years of stability following the initial infection. The syndrome is characterized by the onset of new weaknesses, central and peripheral fatigue, musculoskeletal pain, and atrophy of previously unaffected muscles. The prevalence of PPS among people previously infected with poliovirus varies, with reported rates ranging from 20% to 75%. This condition can significantly impact various aspects of individuals' lives, including bodily functions, mobility, and physical strength, thereby affecting their ability to maintain an independent life.

Despite extensive research, the exact cause of PPS remains elusive. It is thought to develop from persistent stress on damaged motor units in individuals with poliomyelitis. One prevailing hypothesis suggests an imbalance between chronic denervation and reinnervation mechanisms crucial for maintaining muscle function. Another theory, rooted in muscle biopsy findings, proposes the reactivation of latent viruses in motor neurons as a potential contributor to PPS.

PPS can occur after 40 years of stable health following poliovirus infection and is the most prevalent progressive motor neuron disease in the USA. It is estimated that about 15–20 million people are living with polio worldwide and about 20%–80% of them will develop PPS.

Clinical Features

PPS presents a complex array of symptoms affecting both motor and non-motor functions, with fatigue and its associated factors playing a central role in the syndrome.

Fatigue:

Generalized fatigue is one of the most distressing sequelae of PPS. Its causes are multifactorial and can include muscle unit pathology, weight gain, respiratory compromise, polypharmacy, and poor sleep. Identification of key "fatigue-factors" is essential for effective management.

Motor symptoms:

• New onset muscle weakness
• Decreased endurance
• Muscle atrophy
• Myalgia
• Fasciculations
• Ambulatory difficulties.

Non-motor symptoms

• Frank sensory deficits
• Paraesthesias
• Cognitive deficits, including word finding difficulties, poor concentration, limited attention, memory impairment, and mood disturbances.
• Motor disability leading to reduced engagement in social activities and increased risk of social isolation.

Sleep disorders

• Restless leg syndrome (RLS)
• Sleep-related breathing disturbances
• Obstructive sleep apnea (OSA)
• Excessive daytime somnolence (EDS)
• Periodic limb movement in sleep (PLMS)

Note: Sleep disorders likely play a role in the pathogenesis of fatigue in PPS

Other associated symptoms

• Generalized fatigue
• Cold intolerance
• Dysarthria
• Dysphagia
• Respiratory compromise

Diagnosis

Diagnosis of PPS is currently based on March of Dimes criteria, a modified version of the Halstead criteria. It includes:

1. Prior paralytic poliomyelitis with evidence of motor neuron loss, as confirmed by history of the acute paralytic illness, signs of residual weakness and atrophy of muscles on neuromuscular examination, and signs of nerve damage on electromyography (EMG). Rarely, persons have subclinical paralytic polio, described as a loss of motor neurons during acute polio but with no obvious deficit. That prior polio now needs to be confirmed with an EMG. Also, a reported history of nonparalytic polio may be inaccurate.
2. A period of partial or complete functional recovery after acute paralytic poliomyelitis, followed by an interval (usually 15 years or more) of stable neuromuscular function.
3. Gradual onset of progressive and persistent new muscle weakness or abnormal muscle fatigability (decreased endurance), with or without generalized fatigue, muscle atrophy, or muscle and joint pain. Onset may at times follow trauma, surgery, or a period of inactivity, and can appear to be sudden. Less commonly, symptoms attributed to post-polio syndrome include new problems with breathing or swallowing.
4. Symptoms that are present for at least a year.
5. Exclusion of other neurologic, medical, and orthopeadic problems as causes of symptoms

Physical Therapy Management

Physical therapy management for post-polio syndrome (PPS) involves a multidisciplinary approach to address the various symptoms and challenges faced by individuals with PPS. It is essential to individualize the treatment approach based on the patient's specific needs, preferences, and response to interventions. Regular reassessment and collaboration with other healthcare professionals are crucial for optimal care.

Physical Therapy Management Considerations

• It is important to recognize the difficulty of sustaining high exercise intensities for prolonged periods, particularly in severely fatigued individuals. Training regimes must be highly individualized and exercise prescription can be based on certain individual markers such as Aerobic Threshold (AT) or Rate of Perceived Exertion (RPE).
• Efficiently evaluate muscle function which includes endurance and strength. Understanding that improvements in muscle function may be challenging in persons with PPS due possibility of hypertrophied muscle fibers.
• Training programmes must be tailored towards daily activities and functional independence. It should involve training muscle groups that may be disused or deconditioned and focusing on exercises that mimic daily tasks.
• Recognize the potential limitations of exercise modes that primarily focus on the lower extremities.
• Emphasize the importance of monitoring the actual training dose to ensure the prescribed intensities are achieved.

Physical Therapy Interventions

Exercise and Mobility

• Exercise programmes must be designed to improve strength, endurance, and flexibility through low-impact activities to reduce stress on the muscles and joints.
• Incorporate exercises that target weakened muscles with a focus on gradual progression to prevent excessive fatigue.
• Non-fatiguing strengthening exercises such as isokinetic and isometric exercises can be included in the programme.
• In addition to traditional exercises, aquatic therapy can also be beneficial due to its low-impact nature and the buoyancy of water providing support.The video below demonstrates a few exercises that can be performed as a part of aquatic therapy to improve lower limb strength and mobility:

Manual Therapy and Modalities

• Appropriate strategies can be developed to manage musculoskeletal pain associated with PPS which may include manual therapy or heat/cold therapy. It is vital to collaborate with other healthcare providers to explore pharmacological interventions for pain management when necessary.
• Therapeutic ultrasound therapy and myofascial mobilization (Graston® technique) have been utilized for releasing stiffness and restoring function to affected muscles and joints.

Orthotics and Assistive Devices

• Evaluate the need for properly fitted orthoses to improve biomechanical movement patterns and conserve energy during activities. It must be ensured that orthotic devices adequately support the patient's weakened muscles and contribute to overall functional improvement.
• Assess the need for mobility aids such as canes, crutches, walkers, or wheelchairs based on individual functional abilities and provide guidance on the selection and proper use of these assistive devices to enhance independence and reduce the risk of falls.

Energy Conservation Techniques

• Energy conservation techniques can be taught to patients to reduce fatigue. Emphasize the importance of pacing physical activities to avoid overexertion. Encourage patients to plan their daily activities with sufficient rest periods to conserve energy.
• Physiotherapists can guide patients on prioritizing tasks and utilizing assistive devices to reduce overall energy expenditure.

Prevention

At present there is no treatment that can prevent or reverse Post Polio Syndrome. The quality of life of people with PPS can be improved through symptomatic management. Symptomatic management includes lifestyle modification, physiotherapy, usage of assistive devices, and pharmacological means.