Clinical decision making in the management of the late sequelae of poliomyelitis.

This article describes a physiologic approach to clinical decision making in the management of the late sequelae of poliomyelitis. To provide a basis for understanding this approach, the clinical features of poliomyelitis are first described. Although research has contributed to our understanding of the late sequelae of poliomyelitis, reports of controlled treatment-outcome studies are scant.

Poliomyelitis

During the early 1950s, the peak years of the most recent North American poliomyelitis epidemic, over 56,000 people a year were affected. [1,2] As a result of highly successful vaccination programs, however, fewer than 12 persons per year have been reported to have developed poliomyelitis since the mid-1970s. [3]

Many individuals who developed poliomyelitis during this epidemic experienced an initial or minor illness within 7 days of infection that consisted of a sore throat, headache, and fever. [4,5] Some individuals also experienced meningeal irritation and nuchal stiffness. [6] Most of these individuals recovered completely, and some were never even aware they were infected by a poliovirus. [7,8] If the virus accessed the central nervous system via the circulation, major illness with its concomitant neuromuscular signs and symptoms became apparent within 14 days. [5] Strict bed rest was enforced in the acute stages until the febrile illness subsided. [9] The neuromuscular signs and symptoms of the disease included muscle weakness, pain, and stiffness. [10] Breathing and swallowing difficulties and choking were less common. [11,12]

Mortality from poliomyelitis was less than 5% in patients without bulbar involvement and was reported to be as high as 10% in adults with bulbar involvement. [10] Respiratory insufficiency, the leading cause of death secondary to respiratory muscle paralysis or bulbar involvement, or both, necessitated ventilatory support in the form of a tank ventilator, chest ventilator, or rocking bed. [12] Some patients learned to breathe glossopharyngeally for up to several hours while off ventilatory support. [11] If the muscles involved in swallowing were affected, the patient was at high risk of aspiration and death from pneumonia. Inability to maintain a patent airway necessitated that a patient have a tracheostomy. For some individuals, permanent tracheostomies were needed.

Of those individuals who developed paralytic poliomyelitis, 50% recovered with no residual paralysis and the remaining 50% had residua ranging from mild to severe impairment. [13] Most patients achieved peak recovery within 6 to 12 months; however, some patients reqiured 2 to 3 years to achieve peak recovery. [14] Common deformities that were often surgically corrected included equinus deformities, genu valgum, genu recurvatum, limb-length discrepancy, and spinal deformities (eg, scoliosis, kyphosis, and compensatory lumbar hperextension). [15,16] Despite the disruption of a major illness with residual neuromusclar and musculoskeletal deficits, individuals who had poliomyelitis generally led normal lives. They completed their education, entered the work force, had families, and enjoyed most of the same recreational activities as those enjoyed by people with no history of poliomyelitis. [17,18]

Late Sequelae of

Poliomyelitis

Symptoms

Since the late 1970s, a growing number of people who have had poliomyelitis have reported problems that occur 30 to 40 years after they developed the disease. [19-42] These individuals typically report having had a prolonged period of stable functioning. Problems that are now being reported years after the onset of the disease include increased fatigue, weakness, and pain. In addition, some individuals are reporting breathing difficulty, decreased physical endurance, problems with swallowing, choking, increased sensitivity to cold, and psychological problems. Appendix 1 summarizes late-onset complaints that have been reported by people who have had poliomyelitis.

Although the proportion of individuals who may be at risk of developing the late sequelae of poliomyelitis cannot be accurately predicted, estimates range from 20% to 80%. [30,43,44] It appears that, as the number of individuals who are over 30 years post-onset increases, the estimate of those who exhibit new problems correspondingly increases. Risk factors for exhibiting the late sequelae include being hospitalized, contracting poliomyelitis after the age of 10 years, requiring mechanical ventilation, and having paralysis involving all four limbs during the acute phase of the disease. [45] Individuals who reported rapid functional recovery after extensive initial involvement also appear to be at risk of developing late sequelae. [46]

Although the late sequelae of poliomyelitis affecting the peripheral musculature cannot be considered life-threatening, they can seriously compromise the person's ability to maintain employment, manage a household and family, and maintain independence in self-care. [20,45] Late-onset complications involving respiratory and swallowing dysfunction, however, can predispose an individual to respiratory compromise and a life-threatening situation. The diversity of the late sequelae of poliomyelitis, the apparent increase in the number of people who are reporting new problems, and the inability to accurately predict who is at risk are factors that have led some investigators to describe these late-onset complications as a significant public health care concern. [31,47]

There have been several reports of psychological problems and depression in individuals who have had a history of poliomyelitis. [18,48-50] These problems have been attributed to late-onset loss of function and to the perception that late-onset deterioration may go undetected and therefore untreated by health care practitioners because of the lack of awareness of the disorder. [49] Furthermore, recounting their histories has been reported to be traumatic for many individuals who have recovered from poliomyelitis, because this was a period of psychological and physical isolation from their parents and family. [27] Many individuals have been reported to fear dependency on others and the possibility of needing walking aids and mobility devices. [18,27,49] This fear may explain the reluctance of some people to seek medical attention or to follow such recommendations as a reduction in activity or the use of assistive aids and devices. [51]

The late sequelae of poliomyelitis have relatively recently been identified as a unique clinical entity warranting the attention of the health care community. [20] The delay in recognition of the late sequelae of poliomyelitis as a clinical entity may reflect that the disease has been well-controlled since the epidemic. As a result, poliomyelitis and its late sequelae may have been less salient to health care professionals in recent decades. The health care community, however, has been sensitized to the late-onset complications of poliomyelitis as a result of two significant meetings this past decade between health care workers and people who have had poliomyelitis. [30,31] These meetings have provided some of the impetus for health care practitioners and researchers to direct their attention to the late sequelae of poliomyelitis.

Proposed Mechanisms

Several mechanisms have been proposed to explain the late sequelae of poliomyelitis. There is no support for the notion that the poliovirus has been reactivated. [33] Other more plausible possibilities include pathophysiologic changes within those muscles in which the anterior horn cells were damaged by the poliovirus. [40] These muscular changes could reflect overwork of muscles, terminal axonal degeneration, and impaired impulse transmission. [25,41,52-54] For the purposes of this article, overwork of muscle is defined as a condition in which physiological demand exceed capacity, [51,55-57] resulting in an inability to perform daily activities.

The late sequelae of poliomyelitis may reflect chronic physical compensations, involving affected and apparently unaffected limbs, that result from imbalances in the muscle strength of the trunk and limbs, limb-length discrepancy, curvature of the spine, "hip hiking" or circumduction, foot drop, the lack of orthoses or improperly fitting orthoses, or the use of inappropriate walking aids and mobility devices. [51,58] Muscles that were not considered to have been affected at the onset of the disease have been reported to manifest the late sequelae of poliomyelitis in some individuals [29,59]; therefore, any muscle potentially can exhibit the late-onset complications.

Physical debility secondary to poliomyelitis may contribute to increased energy cost at submaximal work rates, such as those associated with activities of daily living, and reduced movement economy compared with the nondisabled individual. [36,60] Reduced movement economy may contribute to increased fatigue--a common complaint of those individuals experiencing the late sequelae. A vicious cycle can be perpetuated in which fatigue, weakness, pain, and loss of function restrict physical activity, which in turn leads to further muscle and cardiorespiratory deconditioning and further reduction in function and activity.

Age-related decreases in the number of motor units in people who have had poliomyelitis have also been implicated in the late sequelae of the disease. These decreases may lead to a greater loss of function in these individuals than in their nondisabled counterparts. [4,61] The normal rate of decline in motor units with age has been estimated at 2% per decade after the age of 20 years and 5% per decade after the age of 60 years. [62] When this normal rate of decline occurs in a person who has had poliomyelitis and who therefore has a smaller motor unit pool, greater functional decline likely results than in the nondisabled individual.

Altered immunologic responses have been suggested to have some role in the etiology of the late sequelae of poliomyelitis. [63,64] Ginsberg et al [64] reported that individuals who have had poliomyelitis have altered immune status compared with individuals who do not have a history of poliomyelitis and individuals with multiple sclerosis. The relationship between immunologic status and the late progression of poliomyelitis warrants further clarification.

Differential Diagnosis

The differential diagnosis of the late sequelae of poliomyelitis is one of exclusion and necessitates that other factors that may contribute to the manifestations of these late sequelae be excluded. [43,65] The diagnosis is based principally on the history and physical examination. Three requirements for a diagnosis are a confirmed history of poliomyelitis, a stable period of functioning for at least a decade after the initial onset of the disease, and the onset of one or more of the late sequelae of poliomyelitis. [13,30]

The role of electromyography (EMG) in the differential diagnosis of the late sequelae of poliomyelitis is controversial; however, EMG result can be useful in ruling out other diagnoses such as amyotrophic lateral sclerosis or Guillain-Barre syndrome. [43] Some investigators [40,52,61,66-68] have proposed EMG criteria as a basis for diagnosis or for establishing the presence of progressive muscular atrophy. Although diagnostic EMG criteria have not been widely accepted, Feldman [69] and Feldman and Soskolne [70] have reported the use of EMG results as a basis for prescribing nonfatiguing strengthening exercises as well as for diagnosis. On the basis of muscle biopsy evidence, however, Cashman and colleagues [25] concluded that EMG lacked sensitivity in distinguishing between ongoing denervation in the muscles of individuals with stable poliomyelitis and those with new problems. Thus, these investigators concluded that EMG may have a limited role in diagnosis of the late sequelae of poliomyelitis. Nerve conduction studies have been reported to be useful in ruling out conditions such as mononeuropathies and carpal tunnel syndrome in some individuals. [71]

The term used to denote the late-onset complications of poliomyelitis has not been standardized in the literature. The terms "late effects," "late sequelae," and "post-polio syndrome" are frequently used interchangeably. The term "syndrome," however, is a misnomer in that a syndrome, by definition, refers to a combination of symptoms that occur together and constitute a unique clinical entity. [72] This definition is not consistent with the late effects of poliomyelitis in that the symptoms may occur singly or in any combination. The terms "late sequelae" and "late effects," however, are technically correct when used to denote the late-onset complications of poliomyelitis.

Assessment

Although the focus of this article is on clinical decision making in the management of the late sequelae of poliomyelitis, the approach described can also be applied to patients who have had poliomyelitis and are being examined for some other problem and for those who are undergoing a baseline assessment but who are not reporting any new problems. [28] An appropriate assessment may help avert adverse consequences of routine medical and surgical procedures that individuals with a history of poliomyelitis are reported to tolerate less well than their nondisabled counterparts. [45,49]

The assessment of patients who exhibit the late sequelae of poliomyelitis includes a detailed history and the fundamental components of the physical examinations of the neuromuscular, musculoskeletal, and cardiorespiratory systems. Such a comprehensive assessment is necessary if treatment is to be directed at the underlying causes of the late sequelae rather than at their effects. [73] This article focuses on selected aspects of the history and physical examination that warrant particular attention in the assessment of this patient population. Specifically, elements of the history, the physical examination of the musculokeletal and cardiorespiratory systems, and the assessment of fatigue and functional status are described.

History

Although details of the acute illness may be difficult to determine from the patient interview because the patient may have been too young or the caregivers may be deceased, the chronology and details of recent changes may be recalled more readily. Information that is useful in establishing a baseline of the patient's functional status includes the patient's age at onset of the acute illness and the number of years post-onset, the presentation and course of the acute illness, the course of recovery and functional status at peak recovery, and the various occupational and recreational activities the patient could engage in at peak recovery. Comparing the patient's present physical and functional status with that at his or her peak level of stable functioning provides a means of gauging the type and rate of functional decline. Details of changes in orthoses, walking aids, and mobility devices can further document corresponding changes in the patient's functional status. Medications may mimic or affect the late sequelae of poliomyelitis; therefore, a patient's medications must be noted along with their potential side effects. A detailed comprehensive history of recent changes in the patient's physical and functional status will identify the critical foci of the physical examination.

Musculokeletal Status

Unaffected muscles and joints may show signs of weakness and strain after having compensated for affected muscles and joints for many years. [36,74] In addition, muscles that were not considered to have been affected at the onset of the disease have been reported to manifest late-onset progressive muscle atrophy in some patients. [52] Thus, muscles and joints presumed to be unaffected by poliomyelitis at the onset of the disease warrant as thorough an assessment as affected muscles and joints.

Secondary to an imbalance of muscle strength and musculoskeletal deformity, individuals who have had poliomyelitis may have an abnormal gait that causes them to deviate from the midline from a negligible to an extreme degree. As the deviation from the midline increases, the energy cost of ambulation increases and movement economy decreases. [75] The use of walking aids can also increase energy expenditure during ambulation. [76] This may explain why patients with a history of poliomyelitis, with or without walking aids, exhibit a greater range of oxygen uptake over a range of walking speeds and grades than do nondisabled persons. [60] Detailed gait analysis will therefore help identify means of reducing excessive energy expenditure as well as associated mechanical stresses.

The musculoskeletal assessment should include investigation of other conditions that may coexist with the late sequelae of poliomyelitis including arthritis, bursitis, tendinitis, faciitis, old fractures, acute and chronic sprains and strains, joint instabilities, ligamentous strain, nerve root compression, and radicularlike pain, which has been reported to resemble the sensation experienced by patients at the onset of the disease. [71,74,77] These conditions can contribute to disuse and overwork of muscles and joints; to the vicious cycle of muscle weakness, pain, and deconditioning; and to further reduced activity and loss of function.

Cardiorespiratory Status

With respect to pulmonary function, forced expiratory capacities can be impaired in individuals with a history of poliomyelitis, [3,32,34] regardless of whether they report having had cardiorespiratory complications during the acute stage of their disease or now report shortness of breath. [78] These changes may reflect inspiratory and expiratory muscle weakness. [79] Expiratory muscle pressure, an index of expiratory muscle strength, has been reported to be more severely affected than inspiratory muscle pressure, or inspiratory muscle strength. [78] This finding supports the belief that some individuals who have had poliomyelitis are prone to weak, ineffectual coughing and risk of aspiration.

Although a person's cardiorespiratory status at rest may be unremarkable, cardiorespiratory limitations cannot be ruled out unless the individual's response to exercise has been assessed. Because individuals with neuromuscular and musculoskeletal deficits may be physically unable to perform a maximal exercise test, however, a submaximal exercise test--the gold standard for determining functional work performance--may be useful in assessing work performance. [60,80] Unaffected or less-involved limbs may need to be used to effect a range of acute exercise responses for the purpose of performing an exercise test. A profile of the patient's response to exercise can provide an index of endurance, or physical work capacity, and identify factors that limit exercise (eg, cardiopulmonary limitations, musculoskeletal limitations, pain, fatigue).

Fatigue

Fatigue is a primary symptom reported by patients with the late sequelae of poliomyelitis; therefore, its etiology, antecedent events, mitigating influences, and course warrant detailed investigation. Factors that may contribute to fatigue in this population include overworked muscles, excessive energy expenditure at submaximal work loads during performance of activities of daily living, deconditioning, and sleep disturbances; or some combination of these factors may be responsible. If the assessment can determine to what degree these various factors contribute to fatigue, then treatment can be specifically directed at these underlying causes.

Fatigue can be assessed using a visual analogue scale or a modified Borg scale. [81] Patients can rate their fatigue over time and in relation to various activities on the basis of numbers or descriptors, ranging from 0 (no fatigue) to 10 (maximally incapacitating fatigue). In addition, if the patient can identify exacerbating and mitigating factors, then guidelines for activity and rest can be established.

Functional Status

The means of assessing functional status and the patient's ability to perform activities of daily living can be based on his or her residual deficits. Some patients may be candidates for performing an exercise test in which functional work capacity or submaximal work performance is determined. [60,82-85] Other means of assessing functional status include evaluating the patient's ability to perform activities of daily living according to performance-based criteria or established functional assessment scales. [86-88] Questionnaires can also be used to assess functional status. Determining what activities a patient has spontaneously reduced over time may provide important and possibly neglected clues to changes in function. The usefulness of questionnaires in assessing function may be limited, however, because they are dependent on the patient's judgment and recall. The use of tables that provide the energy costs of common activities to estimate functional work capacity is not valid in individuals whose deformity or increased work of breathing correspondingly increases the energy cost of activity.

Clinical Decision Making

in Management

Clinical decision making in the management of the patient with the late sequelae of poliomyelitis constitutes a particular challenge, because injudicious treatment may exacerbate the patient's symptoms, leading to further deterioration and loss of function. [74,89] A reasonable objective of intervention, therefore, is to aim for the maximal benefit-to-risk ratio, that is, the greatest degree of function with the least potential short- or long-term risk. On the basis of the current literature, the potential for risk in this patient population is twofold. The risk of further loss of function may be exacerbated by aggressive treatment and by the inappropriate use of rest and reduced activity. [90-92] Thus, the clinician needs to determine the balance between activity or exercise and rest for each patient, prescribe the optimal components of treatment for that patient if treatment is indicated, and plan for periodic follow-up and review of the patient's status. [28]

Possible outcomes of the assessment include no intervention; prescription of a balance between activity and rest, a reduction in activity, or an increase in activity, interventions to improve postural alignment, prescription of orthoses, and weight control; prescription of walking aids and mobility aids; respiratory care; recommendations for lifestyle modification; or some combination of these outcomes (Appendix 2).

No Intervention

An outcome of no intervention can be based on evidence that the patient is achieving an optimal level of function, given the patient's specific deficits and the demands of daily activities, and that the contribution of this level of function to future deterioration is considered to be minimal based on the assessment. [93] Although no intervention may be indicated, patient education and periodic follow-up are justifiable preventive measures.

Balance Between Activity

and Rest

The current literature supports the belief that muscles affected by poliomyelitis have diminished phyisologic reserves to accommodate to work. [57] A balance between activity and rest, therefore, has been advocated as a means of providing restorative rests for muscles during an activity or over the course of a day and of reducing biomechanical stress on muscles and joints. [51,89,93-95] Excessive fatigue and exhaustion have been reported to be potentially detrimental for the patient with the late sequelae of poliomyelitis and should be avoided. [43,59] A balance between activity and rest is believed to minimize fatigue and prolong the patient's ability to endure physical activity throughout the course of the day.

The prescription of rest may be particularly important for the individual who has negligible physiologic capacity to meet the demands placed on muscles, either affected or unaffected by the poliovirus, even during low-intensity activities of daily living. [74,93] The decision to recommend predominantly rest, however, must be justified, given the negative consequences of inactivity [90-92] and the fact that these negative consequences may be accentuated in the patient with the late sequelae of polioymelitis. [29,51,59]

Several published reports [51,74,89,93-95] have advocated activity pacing and energy conservation. By reducing the patient's amount of activity, the patient potentially can conserve his or her energy for other types of activities. Judicious use of wheelchairs (manual and electric), scooters, and walking aids may conserve energy for activities other than ambulation and propelling a wheelchair that are associated with a high-energy demand. Research is needed to determine the specific components of the prescription of activity-rest regimens that will maximize the benefit-to-risk ratio of this intervention for a given patient.

Decreased Activity Versus

Increased Activity

The role of exercise in the management of the late sequelae of poliomyelitis has been controversial. This controversy, in part, reflects the concern that injudicious exercise may lead to further functional deterioration. [74,89] The rationale for the prescription of strengthening or aerobic exercise, therefore, must be unequivocally established to ensure that such interventions will be maximally beneficial and minimally detrimental to short- or long-term function.

Strengthening exercise. Feldman [69] and Feldman and Soskolne [70] advocate the use of nonfatiguing strengthening exercises for muscles exhibiting the late sequelae of poliomyelitis based on EMG studies. Their protocol initially involves five repetitions of lifting a weight that is 50% of the weight the muscle can life without fatigue, which was not operationalized. The frequency of contractions is increased gradually to 30 repetitions (ie, three sets of 10 repetitions each). Although Feldman [69] reported that increases in muscle strength, as measured with a myometer, result from this regimen, the protocol is difficult to replicate. The EMG criteria for identifying the late sequelae of poliomyelitis are unclear, and defining the initial training weight is subjective. Whether such isolated muscle training contributes to further deterioration, given that weight training results in a highly specific training response and possible overwork of the muscle, [96,97] or whether this regimen enhances work performance remains to be established.

Einarsson and Grimby [98] have reported short-term increases in quadriceps femoris muscle strength, measured with a Cybex [R] II dynamometer, (*1) in patients who have had poliomyelitis; however, they cautioned against the widespread use of such strength training, as the long-term consequences are not known. This caveat is supported by the fact that muscles affected by poliomyelitis do not have the physiologic capacity to adapt to resistive strengthening exercise. [57]

Aerobic exercise. Several investigators [82-85] have examined the aerobic exercise respones of patients who have had poliomyelitis. Owen and Jones [84] and Jones et al [85] advocated aerobic exercise based on similar criteria recommended for the nondisabled person. These investigators studied the exercise responses of patients to cycle ergometry. Owen and Jones [84] described their exercise testing procedures, but provided no data. Jones et al [85] reported that, based on the results of a maximal exercise test and the use of a prescriptive target heart rate range, a 16-week aerobic training program produced a conventional aerobic training response in this patient population. Despite this apparently positive result, however, the diagnostic criteria for the late effects of the disease were not detailed and specific methodologic details were not reported. Finally, the potential long-term negative consequences of using training criteria developed for nondisabled persons in the management of patients with the late sequelae of poliomyelitis were not addressed.

Dean and Ross [60] have also proposed the use of aerobic exercise as a means of enhancing function. These investigators, however, argued that the indications for exercise programs in this patient population and the prescription of such programs are distinct from those for nondisabled individuals. The indications and rationale for aerobic exercise need to be firmly established. If aerobic exercise is indicated, the exercise regimen must be modified to minimize potential deleterious effects, for example, by avoiding exercising chronically overworked muscles and biomechanically strained joints and by prescribing the level of exercise based on subjective as well as objective criteria. Dean and Ross [60] proposed that a modified low-intensity aerobic exercise regimen can enhance endurance while minimizing overwork and the negative consequences of inactivity [99,100] in some patients with a history of poliomyelitis.

Although some patients may be deconditioned, the presence of unrelenting fatigue may preclude the prescription of a modified aerobic training program. In this case, a prescription of rest, despite the fact that deconditioning may be contributing to fatigue and weakness, may have greater justification. Muscle strength and conditioning will therefore be maintained at levels commensurate with daily activity tolerated by the patient within the limits of fatigue.

Low-intensity swimming and aquatic exercise may have a role in the management of the late effects of poliomyelitis. [51] Water exercise can provide both strengthening and aerobic exercise stimuli while minimizing overwork of muscle and biomechanical stress. The components of the swimming or aquatic exercise program are prescribed based on each patient's needs.

Postural Alignment, Orthoses,

and Weight Control

Residual deformity and paralysis can increase the energy cost of ambulation. [60,75,96,101,102] Excessive energy expenditure that is associated with abnormal gait may contribute to late-onset fatigue and can be minimized by using interventions designed to compensate for deformity and improve postural alignment. Some patients may benefit from the prescription of an orthosis or from the modification of an existing orthosis to ensure joint protection and improved movement economy and safety. Excess body mass can further contribute to excessive energy demands during transferring and ambulation [103] and to fatigue. Weight control, therefore, may help reduce the fatigue experienced by some patients. [51]

Stretching may have a role in maintaining the extensibility of muscle and connective tissue and joint range of motion in patients with the residua of poliomyelitis. [51] Stretching must be performed judiciously, however, in situations in which the patient may derive greater functional benefit and be safer with reduced joint range of motion. When the legs, for example, contribute minimally to normal gait, it is important that the legs can be easily swung through during crutch walking. In addition, stretching is obviously inappropriate for any joint that has been fused to improve function.

Walking Aids and

Mobility Devices

The prescription of walking aids (eg, canes and crutches) and mobility devices (eg, wheelchairs and scooters) can be based on the patient's functional status and needs and the potential for progressive deterioration. Most people require sufficient functional ability to work for at least some portion of the week, fulfill family and social obligations, and participate in recreational activities. Some patients with the late sequelae of poliomyelitis may need to rely either intermittently or continuously on walking aids and mobility devices to be able to participate in these three fundamental aspects of daily life. The use of such aids and devices enables the patient to effectively rest and preserve energy for activities other than those required for ambulation. [51,58] Although rest and reduced activity can be justified physiologically for the patient with a history of poliomyelitis, these interventions can also contribute to further dysfunction. Prescription of walking aids and mobility devices, therefore, requires careful thought so that the benefit-to-risk ratio of these interventions is maximized.

Respiratory Care

Regardless of initial respiratory or bulbar involvement, patients may exhibit late-onset breathing and swallowing problems. [78] Assessment of respiratory and swallowing functions, therefore, is justified in all patients. [28] Minimally, recommendations for preventive respiratory care are indicated. It is also advisable that family members learn the Heimlich maneuver and that patients learn to self-administer this procedure. If there is evidence of respiratory muscle weakness, assessment of the contribution of muscle disuse or fatigue secondary to muscle overwork will help establish whether respiratory muscle strengthening or rest is indicated. [3,104]

Late-onset breathing complications may require the need for ventilatory support. [3,105] Some patients who are dependent on mechanical ventilation may require support for more hours during the day. In addition, some patients who have not previously required mechanical ventilation may require some degree of ventilatory assistance.

Sleep disturbance has been associated with the late-onset complications of poliomyelitis. Sleep apnea has been reported to be successfully managed in some patients with the use of continuous positive airway pressure during the night. [106,107]

Respiratory complications may manifest in patients who require routine medical and surgical procedures (eg, general anesthesia) for other problems. [59] Wherever possible, such consequences must be anticipated.

Lifestyle Modification

Recommendations for lifestyle modifications may be gleaned from the assessment of the underlying factors that contribute to the manifestation of the late sequelae for a given patient. Similar to determining the indications for walking aids and mobility devices, lifestyle modifications may be most effective if they enable the patient to remain in the work force to some degree, to fulfill family and social obligations, and to participate in some recreational activities. [18,27,49] Recommendations may include change in type of employment, change in the way the work is performed, ergonomic changes to the work place, change in the total number of hours or days worked, change in the distribution of work hours over the course of the day or week, change in the patient's housing or changes to the home environment, use of home help, change in vehicle or mode of transportation, and promotion of family and social support. Like other physically challenged populations, patients who have had poliomyelitis may benefit from instruction in stress management and assertiveness training to enable them to manage life events more effectively. [49] Most patients are likely to benefit from a lifestyle review, regardless of what other interventions may be indicated in their management.

Future Research

Research is needed to characterize the natural history of the late sequelae of poliomyelitis and their causes. A greater knowledge of the pathophysiology of these late sequelae will provide a basis for directing treatment at the underlying cause whenever possible.

Subjective assessment and treatment-outcome measures have particular application in the management of patients with the late sequelae of poliomyelitis in that the new problems they report primarily include subjective attributes such as fatigue, endurance, and pain. Further study into the refinement of scales to assess these attributes would enhance the overall management of these patients.

Studies to evaluate the role of exercise testing in the assessment and management of the patient with the late sequelae of poliomyelitis are needed. Controlled treatment-outcome studies are needed to establish the efficacy of the prescription of both activity and rest, orthotic fitting, and lifestyle modification in mitigating the late sequelae of poliomyelitis.

Conclusions

Clinical decision making in the management of the late sequelae of poliomyelitis is based on current knowledge of their proposed pathophysiology and on the scant number of published controlled treatment-outcome studies. Maximizing the benefit-to-risk ratio of treatment intervention for each patient is a justifiable goal in that injudicious treatment such as conventional muscle strengthening or excessive rest can be deleterious. Any individual who has had poliomyelitis can benefit from a thorough assessemtn to provide a baseline of functional status that would be useful in the event of late-onset problems. Even if these individuals are not exhibiting new problems, a history of poliomyelitis

Appendix 1. Signs and Symptoms Associated with the Late Sequelae of Poliomyelitis (a)

General
  Increased weakness
  Increased fatigue
  REduced endurance for routine activities
  Lifestyle changes
  Increased instability and falling
  Need for walking and mobility aids
  Weight gain
  Dependent edema
  Genitourinary problems
  Gastrointestinal complaints
  Sexual problems
  Anxiety and depression
  Change in tone of voice
  Swallowing problems
  Choking
  Poor memory and concentration
  Sensitivity to cold
Neuromuscular
  Increased pain
  Muscle atrophy
  Muscle pain
  Local muscle fatiguq
  Increased or new muscle weakness
  Muscle twitching
  Muscle cramps
  Anterior nerve root entrapment
  Peripheral neuropathy
Musculoskeletal
  Joint deformity
  Spinal deformity
  Osteoporosis
  Degenerative joint disease
  Tendinitis
  Ligament laxity, especially in the knees
  Chronic back pain
Cardiorespiratory
  Increased shortness of breath
  Increased respiratory infections
  Difficulty in speaking
  Sleep distrubance
  Snoring
  Sleep apnea
  Morning headaches
  Daytime somnolence
  Peripheral swelling
  Weak cough
  (a) Modified from Holman. [43]

may become significant when these individuals are subjected to medical and surgical procedures for other problems. In addition, a balance of rest and acitvity, orthotic fitting, and weight control are justifiable preventive measures for individuals who have had poliomyelitis but who have not experienced late-onset problems.

A history of each patients' initial episode of poliomyelitis along with an assessment of any late sequelae provide a basis for determining what interventions, if any, are indicated. Given the potential for further deterioration in function, interventions need to be directed toward promoting the greatest degree of function and functional independence with the least risk of short- or long-term functional deterioration.

Gait analysis can provide an estimate of energy demands and movement economy during locomotion and a basis for postural correction interventions including the prescription for optimal orthotic fitting. Prescription of low-intensity modified exercise programs may have a role in improving muscle strength and in enhancing movement economy or cardiorespiratory conditioning, or both. Such programs require justification. They may be justified for those individuals who are not overworking their muscles to complete their activities of daily living. For individuals who are overworking their muscles, rest and a balance of their daily activities with rest may have greater justification. If this strategy is not effective, lifestyle modification may be the single most important priority. Because fatigue and pain are commonly associated with the late sequelae of poliomyelitis and may indicate further functional deterioration, consideration must be given to prescribing treatment interventions on the basis of subjective as well as objective criteria. Frequent follow-up is essential, regardless of which interventions are prescribed, to ensure treatment outcome is optimal. Thoughtful, physiologic-based practice will help to maximize the benefit-to-risk ratio of treatment in this patient population.

Appendix 2. Possible Treatment Outcomes Determined by the Assessment for the Patient with the Late Sequelae of Poliomyelitis

  1. No intervention is indicated at the
   present time
  2. Prescription of a balance of activity and
   rest
  3. Prescription of a reduction in activity
  4. Prescription of an increase in activity
     Modified strengthening program
     Modified conditioning program
  5. Prescription of postural correction,
   orthoses, and weight control
  6. Prescription of walking aids and mobility
   devices
     Canes or crutches
     Wheelchairs (manual or electric) or
     scooters
  7. Respiratory care
     Avoidance of smoking
     Avoidance of colds and flue
     Supported cough maneuvers/airway
     clearance
     Teaching the Heimlich maneuver
  8. Recommendations for lifestyle
   modification
     Work or work-place modification
     Home modification
     Home assistance
     Change in transportation
     Support of family and friends
     Stress management and assertiveness
     training
  9. Some combination of items 1-8
  (*) Cybex, Div of Lumex Inc, 2100 Smithtown Ave,
Ronkonkoma, NY 11779.

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E Dean, PhD, PT, is Assistant Professor, School of Rehabilitation Medicine, University of British Columbia, 2211 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2B5.