MUSCLES
The Diagnosis andManagement Dystrophy
of
Childhood Muscular
"Clinicians Must Provide the Best Care and Fred A. Ziter, M.D., Kent G.
Allsop, R.P.T.,
Ph.D.
~HE
PURPOSE of this report is to outline views on the management of childhood or Duchenne muscular dystrophy (DMD). Still unknown, of course, is the fundamental defect in this disorder, and countless drugs have been unsuccessful in altering its course.’ Most reviews stress clinical nuances and latest research but provide little help to the practitioner.2,3 Our discussion deals with practical &dquo;state of the art&dquo; information for the physician who takes care of such cases without the assistance of a specialized clinic. For unless the physician provides the best management and support available, his patient and the family will feel hopeless and helpless, and may even become indifferent to life itself. our
Clinical
Description
.
Now that polio has been conquered, DMD is both the most frequent and the most disabling of the childhood neuromuscular disorders. DMD tends to have the
clinical course: 1) onset of sympbetween three and five years of age, 2)
following toms
From the Departments of Pediatrics and Neurology, Division of Pediatric Neurology, College of Medicine and Department of Physical Therapy, College of Health, University of Utah, Salt Lake City, Ut. 84132. This work was supported in by a grant from the Muscular Dystrophy Association of America, Inc.
part
Support Possible"
muscle weakness, wasting and involving first the pelvic and then the pectoral girdle, sparing the cranial nerve muscles, 3) calf muscle hypertrophy in most cases, 4) loss of independent ambulation by age 9 to 11 years, 5) slowly progressive generalized weakness and scoliosis during the teen years, and 6) respiratory failure before the third decade. In the early stages, the pelvic girdle weakness produces the characteristic lordotic stance and waddling gait, and the &dquo;climbing up&dquo; maneuver when the patient rises from a lying position (Gower’s sign). The hypertrophic relatively strong calf muscles coupled with a posteriorly displaced center of body gravity lead to the typical toewalking. These compensatory displacements of station and gait assist in maintaining the upright posture in the face of weak4 ness of some of the pelvic girdle muscles Similar muscle involvement about the shoulder girdle gives rise to palpable wasting of pectoralls major, lower trapezius, latissimus dorsi, serratus, and biceps.’ Isolated muscle testing will reveal these weaknesses, though these may be difficult to demonstrate in young children. This pattern of early selective muscle weakness leads to contractures in the form of plantar flexion with inversion of the foot,
progressive
contractures
540
Downloaded from cpj.sagepub.com at SIMON FRASER LIBRARY on May 31, 2015
and flexion of knees and hips. These contractures become apparent within three years after onset of the weakness, add significantly to the functional disability and, as will be described later, are preventable by
physical therapy. Loss of independent ambulation age 9
11I years. This
occurs
by
be precipitated by such events as intercurrent illness causing bed confinement, ill-advised to
can
surgery, or psychologic stresses-especially fear of falling. Although the tempo of muscle degeneration seems to decrease after puberty, the contractures and scoliosis progress. Weakness of respiratory . and trunk muscles begin to pose the greatest threat: restrictive lung disease leading to pneumonia and death. DMD affects other organs in addition to the voluntary muscles. Dystrophic cardiomyopathy is frequent, easily diagnosed and an important contributor to death.6 The clinical signs include tachycardia, various arrythmias, and congestive heart failure. The electrocardiogram shows tall right precordial R waves and deep limb and lateral precordial Q waves. This pattern is quite distinctive and related specifically to DMD.6 Curiously, a low IQ is common in these patients and has been the subject of several reports.7as The intellectual defect presents early in life, is nonprogressive and is not proportional to the severity of the myopathy ; it tends to limit academic achievement and narrows even further the activities available to the dependent dystrophic. Passivity and lack of motivation often results, and further curtails the patients’ efforts
tine
phosphokinase (CPK) (25 to 50 times normal), electromyographic (EMG) evidences of small motor unit potentials without fibrillations, and muscle biopsy findings of marked variation in muscle fiber size, necrosis, fibrosis, and fatty infiltration. The disturbances with cerebral or spinal cord lesions sometimes give rise to similar complaints. However, these are combined variously with spasticity, hyperactive reflexes, sensory defects, bowel and bladder disturb-
Dystrophic cardiomyopathy is frequent, easily diagnosed and an important contributor to death. The clinical signs include tachycardia, various arrythmias, and congestive heart failure.
sufficiently distinctive to warrant diagnosis of DMD. Final confirmation emerges from laboratory studies
and asymmetric findings, none of which is seen with DMD. The clinical picture of DMD may be mimicked also by other neuromuscular syndromes such as spinal muscular atrophy, dermatomyositis and rarer congenital myopathies. Since the prognosis and genetic and therapeutic implications vary with each of these disorders, precise identification is mandatory. The problem in differential diagnosis arises most often when DMD emerges as an apparently spontaneous mutation (lacking the characteristic inheritance pattern). Table 1 outlines the prominent clinical and laboratory findings traditionally found useful in resolving this important differential. The most characteristic and diagnostically helpful laboratory abnormality in DMD is marked elevation of the serum CPK level. Failure to find enzyme elevation of the magnitude of at least 25 to 50 times normal in a suspected case pretty well rules out DMD, though this enzyme level tends to fall towards normal when the disease reaches end-stage. Rarely, a patient with fulminating inflammatory muscle disease may show similar CPK elevations but the clinical picture of acute illness with fever, muscle tenderness and weakness, elevated sedimentation rate, and biopsy signs of muscle inflammation provide sufficient clues for that
which show marked elevation of
diagnosis.
toward
self-improvement.
Diagnosis Patients with DMD present
no
diagnostic
after the symptoms and signs have become well established. Even at five years of age, a boy with walking difficulty who has lumbar lordosis, waddling gait (especially when running), enlarged calves, and &dquo;Gower’s
problem
sign&dquo;
is
the tentative
serum crea-
ances,
541
Downloaded from cpj.sagepub.com at SIMON FRASER LIBRARY on May 31, 2015
Downloaded from cpj.sagepub.com at SIMON FRASER LIBRARY on May 31, 2015
Downloaded from cpj.sagepub.com at SIMON FRASER LIBRARY on May 31, 2015
TABLE 1. Clinical and
to
Laboratory Differences Among the
Occasionally, the pediatrician will be asked evaluate a clinically normal male infant
toddler whose mother has male relatives with DMD. In this situation, testing for the serum CPK level can be very useful, since patients in the preclinical phase do have markedly elevated serum CPK levels, often as early as the neonatal period.
or
Management Family Orientation and
Genetic
Counseling
The initial informational phase should include a general description of the signs, symptoms, and protracted course of DMD with the parents. Positive aspects of the anticipated disability should be emphasizede.g., although when the child reaches the teen years he may be confined to a wheelchair, nevertheless he will be able to attend public schools and participate in most social activities. Those aspects which deal with symptoms, their cause, and treatment should be openly discussed. It is best that the child not be present during the discussion dealing with genetic counseling, anticipated disability, and ultimate prognosis. Ample time must be allowed to assess parental attitude, anxiety, and uncertainty about their son’s disease. Family acceptance of the diagnosis may be time consuming but is crucial since denial may lead to medical &dquo;shopping,&dquo; enhance the child’s disability, and incite family discord.
Common Neuromnscular Disorders
of Childhood
Since DMD is inherited as an X-linked trait, the abnormal gene is carried by phenotypically normal females but is expressed fully only in males. Roughly 40 per cent of cases seen do not have a family history of dystrophy, and are looked upon as new mutations. About 70 to 80 per cent of females who carry the abnormal gene have an elevated serum CPK (2 to 10 times normal).~ Hence, this test should be done on all females in the family. Other modes of carrier detection such as the finding of mild muscle weakness, calf hypertrophy, abnormal EMG, or changes on muscle biopsy are less helpful compared with the serum CPK. No method of prenatal diagnosis is currently available. Gravid females who are known carriers can be offered abortion if the fetus is found to be male. Recognition of the carrier state has improved with the use of CPK, but 20’ to 30 per cent of known carriers will have normal enzyme levels. This complicates genetic counseling since we cannot assure a female at risk that she is not a carrier, even when all available tests are normal. Goals of Treatment
The tempo of the muscle degeneration be reversed or even temporarily retarded by any known pharmacologic or physical agent.’ Confronted with the gloomy outlook of a downhill course spanning nearly cannot
544
Downloaded from cpj.sagepub.com at SIMON FRASER LIBRARY on May 31, 2015
decades, the parents and patient often go through an emotional upheaval. Denial, guilt, depression, indifference, or hostility two
be expressions of their hopelessness and frustration. The clinician, faced with this situation, can propose a positive approach based on the following: 1) some of the complications which magnify the functional disability of DMD are predictable and preventable ; 2) an active program of physical therapy and the timely application of braces can prolong ambulation and more closely approximate the normal independence of later childhood; and 3) if a specific treatment ever becomes available, those in optimal physical condition are most apt to bene-fit. The remainder of this paper focuses on two main thrusts of supportive care: 1) preventing disability which leads to premature loss of ambulation, and 2) prolonging independent ambulation through the use of braces. can
.
,
Preventable
Disability
Patients with DMD can typically remain without assistance until the age of about ten years. Negative factors such as contractures, disuse atrophy, obesity, medical complications, and various emotional stresses can curtail this ambulatory period significantly. They not only magnify the disability, but may hasten the basic degenerative process. Prevention of these complications maintains the muscle strength needed for ambulation, and facilitates the transition to braced ambulation when that becomes
ambulatory
necessary. Contractures
Flexion contractures of the hips, knees, and ankles from early, selective muscle involvement will often exaggerate the weakness. These can be prevented 10 by passive and active range of motion exercises, performed on the child by parents for ten minutes twice each day. These exercises should be supervised by periodic visits with a physical therapist; they should be initiated early to prevent contractures rather than delayed until after they begin. Active exercise is desirable, although
overexertion may lead to falling and must be avoided. Ambulation sufficient to satisfy the child’s home, school, and recreational needs can substitute adequately for routine
programmed exercises. The degree of medical supervision required in the home physical therapy program is variable. Clinic visits with the physician and physical therapist every three months are usually sufficient to control contractures.
The most characteristic and
diagnostically helpful laboratory abnormality in DMD is marked elevation of the serum CPK level. Contractures in the upper extremities follow the muscle wasting more closely and produce less functional incapacity. We encourage exercises consisting of shoulder abduction, elbow extension, forearm supination, and wrist extension. Proper prevention of contractures can prolong ambulation, avoid the need for tendon lengthening procedures, and facilitate the transition to long leg braces when these become necessary.
Atrophy
of Disuse
Prolonged inactivity is detrimental to the child with DMD. Many patients after they have been confined to bed because of illness, injury, or surgery, are not able to resume walking. Hence, when necessary bed rest is going to last longer than a few days, physical therapy must be started in order to maintain muscle strength and range of motion. Early postoperative ambulation is vital after elective procedures, and lightweight walking casts must be employed early in the treatment of fractures of the lower extremities.&dquo; The parents should be instructed to notify the physician if the child becomes even temporarily bedridden. Even one or two hours of continuous inactivity, aside from sleep, should be discouraged. Sedentary activities such as watching television can be better spent standing or interrupted by ambulation. 545
Downloaded from cpj.sagepub.com at SIMON FRASER LIBRARY on May 31, 2015
A daily goal of at least three hours ambulation is realistic and probably adequate to maintain strength and minimize contractures when disability is moderate. The child who regresses to less ambulation than that will likely lose unassisted walking within months. A wheelchair should be avoided unless necessary prolonged standing or walking is
unduly fatiguing
or
In busy school slow gait can proceed to his destina-
risky.
corridors, the child with leave class early, tion unimpeded.
to
a
frequently request information on activity permitted. Activity as tolerated should be allowed such that fatigue after an average night’s rest is absent.5 Parents
amount
of
Obesity
&dquo;
Inactivity, boredom, and overfeeding by family and friends are among the factors predisposing to obesity in DMD. Obesity hampers all treatments and is a major contributor to premature loss of ambulation. This hazard must be explained to the patient and family during the initial visits, since prevention of obesity is far easier than weight reduction. Sometimes the diet of the entire family has to be changed in order to manage the patient effectively. Medical Complications The medical complications seen in patients with DMD stem, for the most part, from the muscle degeneration and weakness. Falling during the late ambulatory period may fracture the thinned bones of the extremities, and the resulting bed confinement may lead to permanent loss of ambulation. Recognition of this danger has prompted early postoperative use of lightweight walking casts with moderate success.10 The ambulatory dystrophic tolerates the usual childhood illnesses reasonably well unless bed confinement is necessary. Routine immunizations should be given and no unusual precautionary measures, such as influenza vaccinations, are necessary. The risk of life-threatening pneumonia increases as weakness progresses. In the ad-
vanced dystrophic, the key abnormality is restricted pulmonary function with reduced vital capacity. Scoliosis, elevated dystrophie diaphragms, atelectasis and pulmonary fibrosis are contributing factors. An upper, respiratory infection in a patient with advanced weakness may lead to bronchial involvement with dyspnea, cough, and cyanosis. Aggressive respiratory care in a hospital with close monitoring, postural drainage and intermittent positive pressure breathing may be lifesaving. The chronic use of prophylactic antibiotics or of permanent assisted ventilation should be avoided. The cardiac manifestations in DMD deserve emphasis, since these may be frequent and life threatening even in the ambulatory dystrophic. A number of arrhythmias have been described. The most significant problem, congestive heart failure, may be a preterminal event in advanced cases or may develop in the ambulatory patient. In the latter situation, treatment with digoxin and diuretics may induce remission of cardiac symptoms lasting for years. It has been assumed that restricted physical activity imposed by the muscle weakness has a’ saving effect on compromised cardiac function. The risks from anesthesia grow as weakness progresses. The respiratory depressant effect of barbiturates, the cardiotoxic properties of halothane, and the paralytic effect of standard succinylcholine doses are to be avoided. The risks of anesthesia are not to be regarded lightly when elective procedures are being considered, and careful monitoring of cardiac and respiratory function and avoidance of potassium overload and gastric dilatation are crucial. Emotional Factors
Some patients with DMD show high intellectual capacity and strong motivation, and achieve excellent emotional and physical adjustment to their disease. More, however, show passivity, restricted interests, and relative withdrawal. As explanation, mild to moderate intellectual impairment is common in these patients and imposes educational and emotional handicaps. Heavy reliance on
546
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others for their physical needs gives rise to intrafamily strains. Finally, complex emotional adjustments have to be made whin a child realizes he has a disease which is poorly understood, which will continually erode the quality of his existence and in the end, perhaps as a relief, will induce premature death. Unless these emotional factors are recognized and the secondary problems prevented, the patient will display little motivation, accept setbacks dispassionately, and resist efforts toward improvement. In this setting, any treatment program is likely to fail and further compound the emotional
problems. effective approach tional problems is preventive, The
most
to
the
for adjustment to and continued use of braces against the relative ease of wheelchair
existence.ll In our clinic, we individualize each case in assisting each family with this difficult decision. The second point is that not all patients with DMD can master braced ambulation for reasons either attitudinal or physical. The cooperative, motivated patient with feelings of self-sufficiency has a better chance of success with braces than the passive, Active exercise is desirable, although overexertion may lead to falling and must be avoided.
emo-
the with a realfamily Cooperative parents istic understanding of the disease and the aims of treatment can inspire the patient and sustain his interest and motivation. On the other hand, when parents are apathetic and indecisive, treatment will likely fail to achieve the goals desired. A skilled social worker can be invaluable in lending emotional support, reinforcing goals, and helping resolve conflicts within the family. Occasional psychiatric consultations may be
through
unit.
required. Adherence to the above program helps prevent the complications which lead to premature loss of ambulation but will not specifically retard the muscle degeneration. Inevitably, the gait becomes increasingly precarious and the daily ambulation time becomes less. At this point, one should consider the use of long leg braces. to
Braced Ambulation
dull child. Needless to say, continuous reinforcement is required from parents, physician, and physical therapist. The third consideration is that some
dependent,
patients can never adapt to braces because they lack sufficient trunk strength. The following prerequisites are necessary for successful bracing: absence of contractures, an accurate brace prescription, and application properly timed. Freedom from plantar and hip flexion contractures is essential since the long leg braces require posterior displacement of the dystrophic’s center of gravity4-an adjustment which is impossible if lower limb conpresent. In the latter situation, release of tendons may be needed surgical to brace just prior application.10,12 Experience has shown that surgical release of lower limb contractures in the ambulatory dystrophic is detrimental to gait stability unless followed by bracing. Violation of this tractures are
principle produces
Three important points should be considered when bracing a patient with DMD. The first is philosophical. Are the rewards of successful bracing worth the efforts required? In reply, many patients achieve a relatively stable gait for at least three years after application of long leg braces. In view of the shortened life span of the dystrophic, this short postponement of the wheelchair may be significant. At the same time, one must weight the effort required
a
but wheelchair-bound our
tion
cosmetically improved patient. With most of
patients, however, the faithful use of momaneuvers performed regularly from the
has obviated the need for such surgery. The braces employed are long leg, steel double uprights with a knee spring lock, knee strap, and adjustable ankle stop.~3 Their length should be adjusted to fit 2 cm below the ischial tuberosities and allow the patient to &dquo;sit&dquo; on the upper straps. Such braces essentially &dquo;bypass&dquo; the lower exoutset
547
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sufficient trunk maintain balance and forward to strength of the Since motion pelvis. swing of the shoulders and upper extremities is also necessary, crutches and walkers are not
tremities but do
require
References 1. 2.
3.
employed. Premature use of braces impedes ambulation. On the other hand, delay until the patient has ceased walking will make it difficult to recover the lost function. The best guideline for proper timing of brace application is to brace those patients whose daily ambulation time has diminished to less than one hour and who require external support while walking.
4.
5. 6.
7.
’
The physical therapist plays a crucial role supporting, motivating, and training such a patient during the transition to stable braced ambulation. Success will give several additional years of independent walking, greater self-sufficiency, and substantial postponement of the restrictions imposed
wheelchair. The treatment outlined relies on supportive measures which yield results which are not dramatic. Specialized clinics are most suitable for delivery but primary practitioners must be prepared to offer their services whenever the need arises.
by
8.
9.
10.
11.
a
Nature-in
Argument for Antenated Testing An
a
A. T.: Therapy in muscular dystrophy. Med. Ann. D.C. 23: 15, 1954. Rowland, L. P.: Progressive muscular dystrophy. In Merritt, H. H., A Textbook of Neurology, Philadelphia, Lea and Febiger,1973. Walton, J. N.: Disorders of Voluntary Muscle, 2nd ed. Boston, Little, Brown & Co., 1969. Siegel, I. M.: Pathomechanics of stance in Duchenne muscular dystrophy. Arch. Phys. Med. 53: 403, 1972. Zundel, W. S., and Tyler, F. H.: The muscular dystrophies. N. Engl. J. Med. 273: 537, 1965. Perloff, J. K.: Cardiomyopathy associated with heredofamilial neuromyopathic diseases. Mod. Conc. Cardiov. Dis. 40: 23, 1971. Prosser, E. J., Murphy, E. G., and Thompson, M. W.: Intelligence and the gene for Duchenne muscular dystrophy. Arch. Dis. Child. 44: 221, 1969. Dubowitz, V., and Crome, L.: The central nervous system in Duchenne muscular dystrophy. Brain 92: 805, 1969. Milhorat, A. T., and Goldstone, L.: The carrier state in muscular dystrophy of the Duchenne type. JAMA 194: 131, 1965. Vignos, P. J., Jr.: Rehabilitation in progressive muscular dystrophy. In Licht, S., Rehabilitation and Medicine, New Haven, Conn., E. Licht, 1968. Taft, L. T.: The care and management of the child with muscular dystrophy. Develop. Med. Child. Neurol. 15: Gucker, T.: Orthopedic management of progressive muscular dystrophy. J. Am. Phys. Ther. Assoc. 44: 243, 1964. Spencer, G. E., and Vignos, P. J.: Bracing for ambulation in childhood progressive muscular dystrophy. J. Bone Joint Surg. (Am.) 44: 234,
Milhorat,
510, 1973.
12.
13.
1962.
cathartic vein-
gets rid of many blighted ova and many malformed and karyotypically abnormal fetuses. One exis the confirmed evidence to 60 per cent of spontaneously aborted fetuses have an abnormal karyotype, whereas only 0.5 per cent of living newborns have similar abnormalities. The difference is striking and indicates. that the great majority of fetuses with chromosomal aberrations are spontaneously eliminated. Those few who reach the end of gestation do so because Natiire-
ample
that 25
.
perhaps by
an
eliminate them. eral
oversi~ht-fails to Physicians in gen-
vow to do their best to corNature’s errors. There is little reason, why we should not correct this error of Nature. Perhaps, in the future, moral, religious, and political illogicalities will no longer shackle our medical actions and unscientific considerations will no longer hamper a truly humane approach to this problem.―~f~M.s- Zellweger, loutrt CiEy, in Developmental Medicine and Child i’~eurolo~~l, October 1975.
rect
548
Downloaded from cpj.sagepub.com at SIMON FRASER LIBRARY on May 31, 2015
The Diagnosis andManagement Dystrophy
of
Childhood Muscular
"Clinicians Must Provide the Best Care and Fred A. Ziter, M.D., Kent G.
Allsop, R.P.T.,
Ph.D.
~HE
PURPOSE of this report is to outline views on the management of childhood or Duchenne muscular dystrophy (DMD). Still unknown, of course, is the fundamental defect in this disorder, and countless drugs have been unsuccessful in altering its course.’ Most reviews stress clinical nuances and latest research but provide little help to the practitioner.2,3 Our discussion deals with practical &dquo;state of the art&dquo; information for the physician who takes care of such cases without the assistance of a specialized clinic. For unless the physician provides the best management and support available, his patient and the family will feel hopeless and helpless, and may even become indifferent to life itself. our
Clinical
Description
.
Now that polio has been conquered, DMD is both the most frequent and the most disabling of the childhood neuromuscular disorders. DMD tends to have the
clinical course: 1) onset of sympbetween three and five years of age, 2)
following toms
From the Departments of Pediatrics and Neurology, Division of Pediatric Neurology, College of Medicine and Department of Physical Therapy, College of Health, University of Utah, Salt Lake City, Ut. 84132. This work was supported in by a grant from the Muscular Dystrophy Association of America, Inc.
part
Support Possible"
muscle weakness, wasting and involving first the pelvic and then the pectoral girdle, sparing the cranial nerve muscles, 3) calf muscle hypertrophy in most cases, 4) loss of independent ambulation by age 9 to 11 years, 5) slowly progressive generalized weakness and scoliosis during the teen years, and 6) respiratory failure before the third decade. In the early stages, the pelvic girdle weakness produces the characteristic lordotic stance and waddling gait, and the &dquo;climbing up&dquo; maneuver when the patient rises from a lying position (Gower’s sign). The hypertrophic relatively strong calf muscles coupled with a posteriorly displaced center of body gravity lead to the typical toewalking. These compensatory displacements of station and gait assist in maintaining the upright posture in the face of weak4 ness of some of the pelvic girdle muscles Similar muscle involvement about the shoulder girdle gives rise to palpable wasting of pectoralls major, lower trapezius, latissimus dorsi, serratus, and biceps.’ Isolated muscle testing will reveal these weaknesses, though these may be difficult to demonstrate in young children. This pattern of early selective muscle weakness leads to contractures in the form of plantar flexion with inversion of the foot,
progressive
contractures
540
Downloaded from cpj.sagepub.com at SIMON FRASER LIBRARY on May 31, 2015
and flexion of knees and hips. These contractures become apparent within three years after onset of the weakness, add significantly to the functional disability and, as will be described later, are preventable by
physical therapy. Loss of independent ambulation age 9
11I years. This
occurs
by
be precipitated by such events as intercurrent illness causing bed confinement, ill-advised to
can
surgery, or psychologic stresses-especially fear of falling. Although the tempo of muscle degeneration seems to decrease after puberty, the contractures and scoliosis progress. Weakness of respiratory . and trunk muscles begin to pose the greatest threat: restrictive lung disease leading to pneumonia and death. DMD affects other organs in addition to the voluntary muscles. Dystrophic cardiomyopathy is frequent, easily diagnosed and an important contributor to death.6 The clinical signs include tachycardia, various arrythmias, and congestive heart failure. The electrocardiogram shows tall right precordial R waves and deep limb and lateral precordial Q waves. This pattern is quite distinctive and related specifically to DMD.6 Curiously, a low IQ is common in these patients and has been the subject of several reports.7as The intellectual defect presents early in life, is nonprogressive and is not proportional to the severity of the myopathy ; it tends to limit academic achievement and narrows even further the activities available to the dependent dystrophic. Passivity and lack of motivation often results, and further curtails the patients’ efforts
tine
phosphokinase (CPK) (25 to 50 times normal), electromyographic (EMG) evidences of small motor unit potentials without fibrillations, and muscle biopsy findings of marked variation in muscle fiber size, necrosis, fibrosis, and fatty infiltration. The disturbances with cerebral or spinal cord lesions sometimes give rise to similar complaints. However, these are combined variously with spasticity, hyperactive reflexes, sensory defects, bowel and bladder disturb-
Dystrophic cardiomyopathy is frequent, easily diagnosed and an important contributor to death. The clinical signs include tachycardia, various arrythmias, and congestive heart failure.
sufficiently distinctive to warrant diagnosis of DMD. Final confirmation emerges from laboratory studies
and asymmetric findings, none of which is seen with DMD. The clinical picture of DMD may be mimicked also by other neuromuscular syndromes such as spinal muscular atrophy, dermatomyositis and rarer congenital myopathies. Since the prognosis and genetic and therapeutic implications vary with each of these disorders, precise identification is mandatory. The problem in differential diagnosis arises most often when DMD emerges as an apparently spontaneous mutation (lacking the characteristic inheritance pattern). Table 1 outlines the prominent clinical and laboratory findings traditionally found useful in resolving this important differential. The most characteristic and diagnostically helpful laboratory abnormality in DMD is marked elevation of the serum CPK level. Failure to find enzyme elevation of the magnitude of at least 25 to 50 times normal in a suspected case pretty well rules out DMD, though this enzyme level tends to fall towards normal when the disease reaches end-stage. Rarely, a patient with fulminating inflammatory muscle disease may show similar CPK elevations but the clinical picture of acute illness with fever, muscle tenderness and weakness, elevated sedimentation rate, and biopsy signs of muscle inflammation provide sufficient clues for that
which show marked elevation of
diagnosis.
toward
self-improvement.
Diagnosis Patients with DMD present
no
diagnostic
after the symptoms and signs have become well established. Even at five years of age, a boy with walking difficulty who has lumbar lordosis, waddling gait (especially when running), enlarged calves, and &dquo;Gower’s
problem
sign&dquo;
is
the tentative
serum crea-
ances,
541
Downloaded from cpj.sagepub.com at SIMON FRASER LIBRARY on May 31, 2015
Downloaded from cpj.sagepub.com at SIMON FRASER LIBRARY on May 31, 2015
Downloaded from cpj.sagepub.com at SIMON FRASER LIBRARY on May 31, 2015
TABLE 1. Clinical and
to
Laboratory Differences Among the
Occasionally, the pediatrician will be asked evaluate a clinically normal male infant
toddler whose mother has male relatives with DMD. In this situation, testing for the serum CPK level can be very useful, since patients in the preclinical phase do have markedly elevated serum CPK levels, often as early as the neonatal period.
or
Management Family Orientation and
Genetic
Counseling
The initial informational phase should include a general description of the signs, symptoms, and protracted course of DMD with the parents. Positive aspects of the anticipated disability should be emphasizede.g., although when the child reaches the teen years he may be confined to a wheelchair, nevertheless he will be able to attend public schools and participate in most social activities. Those aspects which deal with symptoms, their cause, and treatment should be openly discussed. It is best that the child not be present during the discussion dealing with genetic counseling, anticipated disability, and ultimate prognosis. Ample time must be allowed to assess parental attitude, anxiety, and uncertainty about their son’s disease. Family acceptance of the diagnosis may be time consuming but is crucial since denial may lead to medical &dquo;shopping,&dquo; enhance the child’s disability, and incite family discord.
Common Neuromnscular Disorders
of Childhood
Since DMD is inherited as an X-linked trait, the abnormal gene is carried by phenotypically normal females but is expressed fully only in males. Roughly 40 per cent of cases seen do not have a family history of dystrophy, and are looked upon as new mutations. About 70 to 80 per cent of females who carry the abnormal gene have an elevated serum CPK (2 to 10 times normal).~ Hence, this test should be done on all females in the family. Other modes of carrier detection such as the finding of mild muscle weakness, calf hypertrophy, abnormal EMG, or changes on muscle biopsy are less helpful compared with the serum CPK. No method of prenatal diagnosis is currently available. Gravid females who are known carriers can be offered abortion if the fetus is found to be male. Recognition of the carrier state has improved with the use of CPK, but 20’ to 30 per cent of known carriers will have normal enzyme levels. This complicates genetic counseling since we cannot assure a female at risk that she is not a carrier, even when all available tests are normal. Goals of Treatment
The tempo of the muscle degeneration be reversed or even temporarily retarded by any known pharmacologic or physical agent.’ Confronted with the gloomy outlook of a downhill course spanning nearly cannot
544
Downloaded from cpj.sagepub.com at SIMON FRASER LIBRARY on May 31, 2015
decades, the parents and patient often go through an emotional upheaval. Denial, guilt, depression, indifference, or hostility two
be expressions of their hopelessness and frustration. The clinician, faced with this situation, can propose a positive approach based on the following: 1) some of the complications which magnify the functional disability of DMD are predictable and preventable ; 2) an active program of physical therapy and the timely application of braces can prolong ambulation and more closely approximate the normal independence of later childhood; and 3) if a specific treatment ever becomes available, those in optimal physical condition are most apt to bene-fit. The remainder of this paper focuses on two main thrusts of supportive care: 1) preventing disability which leads to premature loss of ambulation, and 2) prolonging independent ambulation through the use of braces. can
.
,
Preventable
Disability
Patients with DMD can typically remain without assistance until the age of about ten years. Negative factors such as contractures, disuse atrophy, obesity, medical complications, and various emotional stresses can curtail this ambulatory period significantly. They not only magnify the disability, but may hasten the basic degenerative process. Prevention of these complications maintains the muscle strength needed for ambulation, and facilitates the transition to braced ambulation when that becomes
ambulatory
necessary. Contractures
Flexion contractures of the hips, knees, and ankles from early, selective muscle involvement will often exaggerate the weakness. These can be prevented 10 by passive and active range of motion exercises, performed on the child by parents for ten minutes twice each day. These exercises should be supervised by periodic visits with a physical therapist; they should be initiated early to prevent contractures rather than delayed until after they begin. Active exercise is desirable, although
overexertion may lead to falling and must be avoided. Ambulation sufficient to satisfy the child’s home, school, and recreational needs can substitute adequately for routine
programmed exercises. The degree of medical supervision required in the home physical therapy program is variable. Clinic visits with the physician and physical therapist every three months are usually sufficient to control contractures.
The most characteristic and
diagnostically helpful laboratory abnormality in DMD is marked elevation of the serum CPK level. Contractures in the upper extremities follow the muscle wasting more closely and produce less functional incapacity. We encourage exercises consisting of shoulder abduction, elbow extension, forearm supination, and wrist extension. Proper prevention of contractures can prolong ambulation, avoid the need for tendon lengthening procedures, and facilitate the transition to long leg braces when these become necessary.
Atrophy
of Disuse
Prolonged inactivity is detrimental to the child with DMD. Many patients after they have been confined to bed because of illness, injury, or surgery, are not able to resume walking. Hence, when necessary bed rest is going to last longer than a few days, physical therapy must be started in order to maintain muscle strength and range of motion. Early postoperative ambulation is vital after elective procedures, and lightweight walking casts must be employed early in the treatment of fractures of the lower extremities.&dquo; The parents should be instructed to notify the physician if the child becomes even temporarily bedridden. Even one or two hours of continuous inactivity, aside from sleep, should be discouraged. Sedentary activities such as watching television can be better spent standing or interrupted by ambulation. 545
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A daily goal of at least three hours ambulation is realistic and probably adequate to maintain strength and minimize contractures when disability is moderate. The child who regresses to less ambulation than that will likely lose unassisted walking within months. A wheelchair should be avoided unless necessary prolonged standing or walking is
unduly fatiguing
or
In busy school slow gait can proceed to his destina-
risky.
corridors, the child with leave class early, tion unimpeded.
to
a
frequently request information on activity permitted. Activity as tolerated should be allowed such that fatigue after an average night’s rest is absent.5 Parents
amount
of
Obesity
&dquo;
Inactivity, boredom, and overfeeding by family and friends are among the factors predisposing to obesity in DMD. Obesity hampers all treatments and is a major contributor to premature loss of ambulation. This hazard must be explained to the patient and family during the initial visits, since prevention of obesity is far easier than weight reduction. Sometimes the diet of the entire family has to be changed in order to manage the patient effectively. Medical Complications The medical complications seen in patients with DMD stem, for the most part, from the muscle degeneration and weakness. Falling during the late ambulatory period may fracture the thinned bones of the extremities, and the resulting bed confinement may lead to permanent loss of ambulation. Recognition of this danger has prompted early postoperative use of lightweight walking casts with moderate success.10 The ambulatory dystrophic tolerates the usual childhood illnesses reasonably well unless bed confinement is necessary. Routine immunizations should be given and no unusual precautionary measures, such as influenza vaccinations, are necessary. The risk of life-threatening pneumonia increases as weakness progresses. In the ad-
vanced dystrophic, the key abnormality is restricted pulmonary function with reduced vital capacity. Scoliosis, elevated dystrophie diaphragms, atelectasis and pulmonary fibrosis are contributing factors. An upper, respiratory infection in a patient with advanced weakness may lead to bronchial involvement with dyspnea, cough, and cyanosis. Aggressive respiratory care in a hospital with close monitoring, postural drainage and intermittent positive pressure breathing may be lifesaving. The chronic use of prophylactic antibiotics or of permanent assisted ventilation should be avoided. The cardiac manifestations in DMD deserve emphasis, since these may be frequent and life threatening even in the ambulatory dystrophic. A number of arrhythmias have been described. The most significant problem, congestive heart failure, may be a preterminal event in advanced cases or may develop in the ambulatory patient. In the latter situation, treatment with digoxin and diuretics may induce remission of cardiac symptoms lasting for years. It has been assumed that restricted physical activity imposed by the muscle weakness has a’ saving effect on compromised cardiac function. The risks from anesthesia grow as weakness progresses. The respiratory depressant effect of barbiturates, the cardiotoxic properties of halothane, and the paralytic effect of standard succinylcholine doses are to be avoided. The risks of anesthesia are not to be regarded lightly when elective procedures are being considered, and careful monitoring of cardiac and respiratory function and avoidance of potassium overload and gastric dilatation are crucial. Emotional Factors
Some patients with DMD show high intellectual capacity and strong motivation, and achieve excellent emotional and physical adjustment to their disease. More, however, show passivity, restricted interests, and relative withdrawal. As explanation, mild to moderate intellectual impairment is common in these patients and imposes educational and emotional handicaps. Heavy reliance on
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others for their physical needs gives rise to intrafamily strains. Finally, complex emotional adjustments have to be made whin a child realizes he has a disease which is poorly understood, which will continually erode the quality of his existence and in the end, perhaps as a relief, will induce premature death. Unless these emotional factors are recognized and the secondary problems prevented, the patient will display little motivation, accept setbacks dispassionately, and resist efforts toward improvement. In this setting, any treatment program is likely to fail and further compound the emotional
problems. effective approach tional problems is preventive, The
most
to
the
for adjustment to and continued use of braces against the relative ease of wheelchair
existence.ll In our clinic, we individualize each case in assisting each family with this difficult decision. The second point is that not all patients with DMD can master braced ambulation for reasons either attitudinal or physical. The cooperative, motivated patient with feelings of self-sufficiency has a better chance of success with braces than the passive, Active exercise is desirable, although overexertion may lead to falling and must be avoided.
emo-
the with a realfamily Cooperative parents istic understanding of the disease and the aims of treatment can inspire the patient and sustain his interest and motivation. On the other hand, when parents are apathetic and indecisive, treatment will likely fail to achieve the goals desired. A skilled social worker can be invaluable in lending emotional support, reinforcing goals, and helping resolve conflicts within the family. Occasional psychiatric consultations may be
through
unit.
required. Adherence to the above program helps prevent the complications which lead to premature loss of ambulation but will not specifically retard the muscle degeneration. Inevitably, the gait becomes increasingly precarious and the daily ambulation time becomes less. At this point, one should consider the use of long leg braces. to
Braced Ambulation
dull child. Needless to say, continuous reinforcement is required from parents, physician, and physical therapist. The third consideration is that some
dependent,
patients can never adapt to braces because they lack sufficient trunk strength. The following prerequisites are necessary for successful bracing: absence of contractures, an accurate brace prescription, and application properly timed. Freedom from plantar and hip flexion contractures is essential since the long leg braces require posterior displacement of the dystrophic’s center of gravity4-an adjustment which is impossible if lower limb conpresent. In the latter situation, release of tendons may be needed surgical to brace just prior application.10,12 Experience has shown that surgical release of lower limb contractures in the ambulatory dystrophic is detrimental to gait stability unless followed by bracing. Violation of this tractures are
principle produces
Three important points should be considered when bracing a patient with DMD. The first is philosophical. Are the rewards of successful bracing worth the efforts required? In reply, many patients achieve a relatively stable gait for at least three years after application of long leg braces. In view of the shortened life span of the dystrophic, this short postponement of the wheelchair may be significant. At the same time, one must weight the effort required
a
but wheelchair-bound our
tion
cosmetically improved patient. With most of
patients, however, the faithful use of momaneuvers performed regularly from the
has obviated the need for such surgery. The braces employed are long leg, steel double uprights with a knee spring lock, knee strap, and adjustable ankle stop.~3 Their length should be adjusted to fit 2 cm below the ischial tuberosities and allow the patient to &dquo;sit&dquo; on the upper straps. Such braces essentially &dquo;bypass&dquo; the lower exoutset
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sufficient trunk maintain balance and forward to strength of the Since motion pelvis. swing of the shoulders and upper extremities is also necessary, crutches and walkers are not
tremities but do
require
References 1. 2.
3.
employed. Premature use of braces impedes ambulation. On the other hand, delay until the patient has ceased walking will make it difficult to recover the lost function. The best guideline for proper timing of brace application is to brace those patients whose daily ambulation time has diminished to less than one hour and who require external support while walking.
4.
5. 6.
7.
’
The physical therapist plays a crucial role supporting, motivating, and training such a patient during the transition to stable braced ambulation. Success will give several additional years of independent walking, greater self-sufficiency, and substantial postponement of the restrictions imposed
wheelchair. The treatment outlined relies on supportive measures which yield results which are not dramatic. Specialized clinics are most suitable for delivery but primary practitioners must be prepared to offer their services whenever the need arises.
by
8.
9.
10.
11.
a
Nature-in
Argument for Antenated Testing An
a
A. T.: Therapy in muscular dystrophy. Med. Ann. D.C. 23: 15, 1954. Rowland, L. P.: Progressive muscular dystrophy. In Merritt, H. H., A Textbook of Neurology, Philadelphia, Lea and Febiger,1973. Walton, J. N.: Disorders of Voluntary Muscle, 2nd ed. Boston, Little, Brown & Co., 1969. Siegel, I. M.: Pathomechanics of stance in Duchenne muscular dystrophy. Arch. Phys. Med. 53: 403, 1972. Zundel, W. S., and Tyler, F. H.: The muscular dystrophies. N. Engl. J. Med. 273: 537, 1965. Perloff, J. K.: Cardiomyopathy associated with heredofamilial neuromyopathic diseases. Mod. Conc. Cardiov. Dis. 40: 23, 1971. Prosser, E. J., Murphy, E. G., and Thompson, M. W.: Intelligence and the gene for Duchenne muscular dystrophy. Arch. Dis. Child. 44: 221, 1969. Dubowitz, V., and Crome, L.: The central nervous system in Duchenne muscular dystrophy. Brain 92: 805, 1969. Milhorat, A. T., and Goldstone, L.: The carrier state in muscular dystrophy of the Duchenne type. JAMA 194: 131, 1965. Vignos, P. J., Jr.: Rehabilitation in progressive muscular dystrophy. In Licht, S., Rehabilitation and Medicine, New Haven, Conn., E. Licht, 1968. Taft, L. T.: The care and management of the child with muscular dystrophy. Develop. Med. Child. Neurol. 15: Gucker, T.: Orthopedic management of progressive muscular dystrophy. J. Am. Phys. Ther. Assoc. 44: 243, 1964. Spencer, G. E., and Vignos, P. J.: Bracing for ambulation in childhood progressive muscular dystrophy. J. Bone Joint Surg. (Am.) 44: 234,
Milhorat,
510, 1973.
12.
13.
1962.
cathartic vein-
gets rid of many blighted ova and many malformed and karyotypically abnormal fetuses. One exis the confirmed evidence to 60 per cent of spontaneously aborted fetuses have an abnormal karyotype, whereas only 0.5 per cent of living newborns have similar abnormalities. The difference is striking and indicates. that the great majority of fetuses with chromosomal aberrations are spontaneously eliminated. Those few who reach the end of gestation do so because Natiire-
ample
that 25
.
perhaps by
an
eliminate them. eral
oversi~ht-fails to Physicians in gen-
vow to do their best to corNature’s errors. There is little reason, why we should not correct this error of Nature. Perhaps, in the future, moral, religious, and political illogicalities will no longer shackle our medical actions and unscientific considerations will no longer hamper a truly humane approach to this problem.―~f~M.s- Zellweger, loutrt CiEy, in Developmental Medicine and Child i’~eurolo~~l, October 1975.
rect
548
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