neuro

1212 THE JOURNAL OF BONE AND JOINT SURGERY

Diagnosis of Progressive Muscular Dystrophy

BY PAUL J. VIGNOS, JR., M.D.*, CLEVELAND, OHIO

An Instructional Course Lecture, The American Academy of Orthopaedic Surgeons

The muscular dystrophies are a group of hereditary disorders characterized by

progressive weakness and wasting of muscle. They are defined as primary myopathies

because the basic involvement is in the muscle fiber itself and rso reliable convinicinsg

evidence implicates the central nervous system as the cause of muscle weakness. The

etiology of muscular dystrophy is unknown, and no form of pharmacologic treatnssenst

is considered effective in any of the various forms of the disease.

However, experience in managing patients with muscular dystrophy for

thirteens years has indicated that it is possible to help these patients amid their

families to lead a more normal life arid attains maximum function corssistenst with the

severity of the disease. Ambulation, imsdepersdently arid in braces during the later

stages of the disease, can be prolonged in the childhood Duchenne type of dystrophy.

Joint conitractures occur early in the disease, especially ins Ducheninse dystrophy 1�

They may be minimized by early institutions of prophylactic passive stretchinsg of

joints. An important responsibility of the physician is the counseling of the patienst

arid the family regarding the activities of daily living, schooling, arid physical cx-

ercise programs. The physicians’s ability to give proper counseling anid supportive

management depends on early and accurate diagnosis. In a group of diseases with

unknowns causes, correct diagnosis is essential in order to make a prognosis, on

which realistic planning and counseling depend. With the increase ins knowledge of

the biochemical abnormalities in muscular dystrophy, it is possible that specific

pharmacologic treatment may be available in the foreseeable future. It seems likely

that no single, common biochemical abnormality will be found for all dystrophies �.

Therefore, the ability to place the patient in the proper diagnostic category will be

basic to the use of any new drug. If the biochemical abnormality in the various types

of dystrophy varies, the specific treatment will vary.

The diagnosis of muscular dystrophy may be difficult, particularly in the early

stages, and it is a frequent finding that the patient has consulted a number of

physicians before the correct diagnosis is made. The patient often �vill have beers

treated for a number of unrelated conditions, such as foot problems or slow de-

velopment.

The proper approach to diagnosis in patients with muscle weakness is the

systematic performance of a profile of tests and procedures done in proper sequensce.

The commonly occurring types of muscular dystrophy are relatively limited, but

the diseases with which they may be confused are numerous. The physicians often

fails to follow the proper sequence of steps in diagnosis or fails to perform all of the

necessary procedures to arrive at the correct diagnosis.

The early diagnosis and subsequent management of patients with muscular

dystrophy can be aided considerably by the routine performance of the following

profile of simple clinical and laboratory tests which have been found to be most use-

* Associate Professor of Medicine, Western Reserve University School of Medicine, and

Muscle Clinsic, University Hospitals, Cleveland, Ohio.

P. J. vIGNOS: 1)1AGNOSIS OF PROGRESSIVE MUSCULAR n)YsTR0PHY 1213

ful: (1) niansual muscle test, (2) determination of the seruns emizynses aldolase,

cneatinie phosphokinsase, or both, (3) electromyography, amid (4) muscle biopsy.

The muscle biopsy should be the last test performed because the selections of ann ap-

l)rupriate muscle for biopsy ofters depends on the results of the other tests. Fre�

(luenitly, only one or niore of these tests is performed, but it is essential that the

entire battery of tests be used amid that all the implications of the test results are

appreciated. At the same time, two additional procedures should be carried out:

(5) determinations of the twenty-four hour urimsary creatinse excretions amid (6) clas-

sificati(Ins of the patient’s quantitative funictionsal locomotor capacity. The measure-

merst (If urinary creatinse excretions adds little to diagmiosis, but is invaluable for

serial (luanstitative assessment of disease progression. Classification of the patient’s

(irranstitative fumsctionsal loconsotor capacity is essential for follow-up amid is of as-

sistansce irs diagnosis, since it relates the patient’s ability to perforns a specified

PhYsical activity to age.

A useful first step in the differential diagnosis of muscle weakness is to categorize

the iatiemit’s muscle weakness as caused by either a primary myopathic disease or

a nseuropathic disease. The patient with mseurogensic motor disease has muscle weak-

ness because of involvement of the censtral nervous system or the peripheral nerves.

Neuropathy, poliomyelitis, and hereditary disease, such as peromieal muscular

atrophy, are included in the second category.

The specific patterning of muscle involvement ins the various forms of dystrophy

is j)erhaj)s the first guide in differential diagnosis. Testing of the strength of all

principal skeletal muscles by a complete manual muscle test is basic to the differens-

tUitiOn of nseuropathic disease from nsyopathic muscle weakmsess. The first indication

of a mieurogenic cause of muscle weakness is often the pattern of muscle involvement.

Irequenitly rieuropathic disease tends to show distal weakness in contrast to

proximal involvement characteristic of the various types of muscular dystrophy.

How’ever, there are exceptions to this rule, such as the amyotonia comigensita group

of diseases amid some cases of spinal atrophy amid poliomyelitis, which may have

proximal weakness. One must be cautious about categorizing diseases too rigidly by

proxinial or distal imivolvensent. The presence of fa.sciculations is a helpful signs that

suggests disease of the nervous system, since they are rare in myopathy. Testinig of

the superficial or stretch reflexes nsay be helpful. Only reduction or absence of deep

tendons reflexes is seems ins myopathy ; the reflexes are never increased as they are ins

neurogensic weakness with imivolvememst of the corticospirsal tracts.

The determination of the serum enzymes is helpful in distinguishing primary

niyopathy from mseurogensic muscle atrophy. The most reliable serum enzyme de-

terminations in the differential diagnosis of muscle disorders, are the serum aldolase

amid seruns creatimie kinase; transamimsases are also valuable but slightly less reliable.

Elevation of the concentration of these serum enzymes above normal probably mdi-

cates a primary myopathy with escape of the enzyme from the muscle fiber as a re-

suit. of active muscle degeneration, increase in muscle membrane permeability, or

both phenomena. Ins our experience, serum aldolase arid serum creatimse kinsase are riot

elevated in nieurogenic muscular atrophy. An elevated serum enzyme conicenitrationi

in a patient suspected of having neurogensic muscle weakness suggests an incorrect

diagnosis. Unfortunately, the serum enzymes will not always distinguish between

the myopathic amid nseurogensic types of muscle weakness because there is msot a cons-

sisterstly abnormal serum enzyme content in all types of myopathy. The enzymes

are always abnormally elevated irs only one type of muscular dystrophy, the severe

Duchennse variety. The serum aldola.se concerstration is elevated ins all boys with

early Duchenmie muscular dystrophy. The degree of elevation decreases ins this

dystrophy as the disease progresses, arid the amount of muscle mass available for

VOL. 49-A, NO. 6, SEPTEMBER 1967

1214 A.A.O.S. INSTRUCTIONAL COURSE LECTURE

releasing enszyme insto the seruns is diminished. However, the serunsi aldolase renssainss

abnormal except ins end-stage disease. The other commons forms of muscular

dystrophy ins the United States are the facioscapulohumeral arsd limb-girdle types.

The serum aldolase is elevated initially ins approximately SO per cent of patients with

linib-girdle dystrophy but ins only 20 per cent of those with facioscapulolsuniseral

dystrophy. The only other conimons form of primary myopathy is polymyositis. Its

our experience, the serum aldolase was elevated initially ins approximately uric-third

amid ultimately ins one-half of the patients with polymyositis � (Fig. 1).

Duchenne Limb-Girdle F. S. H. Polymyositis

8-

.7-

S.

.::.. S

6-

5- ..�:

Aldolase4 5 �:.

Units #{149}: i3. #{149}:: S

2- � S S

#{149}:#{149} .:. SS S

5555 .#{149}:... : #{149}:#{149}.a% #{149} � � . #{149}.#{149}�.m#{149}s. j �U., : ::#{149}#{149}

55555 .55.5

0� - ___ - ___ - S _FIG. 1

Serum aldolase concentrations in early progressive muscular dystrophy.

It is agreed generally that the two most reliable seruns erszynsse determinsationss

ins the diagnosis of skeletal muscle disease are the serum aldolase arid the seruns

creatimie kinase. The seruns aldolase is a reliable determinations ins the clinical

laboratory arid has the advamitage of having beers tested thoroughly arid evaluated.

The creatinie kimiase enzyme assay has beers advocated as preferable to the seruns

aldoiase reactioni because of greater specificity amid sensitivity. The creatinse kiniase

reactions is nsore specific for niuscle disease than the aldolase assav because of the

greater concentration of creatimse kimiase in skeletal nsuscle with lesser amounts ins

cardiac muscle or cerebral cortex 2 Aldoiase is founsd ins high conscenitratiors in skeletal

muscle, hut it is found also in other nions-muscular tissues, such as the liver arsd 1)100(1

cells. The seruns creatinse kimiase assay is believed to be nsore sensitive ins the diagnsusis

of Iii�’(I1)iIth\’ because there is a greater absolute amid relative increase over 1sornisal ins

the serum (‘onscentration of this enzyme for a given patient as (onispared with the

seruns aldolase concenst.rations. Simultarseous deternsiniat ions ()f seruns aldolase arid

creatirse kinase have l)een made on 210 patiersts with muscle disease. The results

i1i(li(’�ited clearly that the greater sensitivity of the (‘reatirse kiniase deterniinsat ions

gives it a clear-cut advarstage ins the detections of carriers of Duchieninie nssuscular

dystrophy. An elevation of creatinie kinsase ins a mother is reliable evidence of a

prol)able carrier of dystrophy. However, failure to find an elevated creatimse kinsase

THE JOURNAL OF BONE ANI) JOINT SIIIGE1(Y

P. J. VIGNOS: DIAGNOSIS OF PROGRESSIVE MUSCULAR DYSTROPHY 1215

(hoes riot rule out the possibility that she is a carrier, for only two-thirds of probable

or known carriers have abnormal elevations of creatine kimsase �. The serum creatinie

kinsase is preferred also for its greater specificity ins multiple-system diseases with

inivolvemenit (If the liver or other organs. Glycolytic emszynies, such as aldolase arid

transaminiases, are found ins highs concentration ins liver, but onsly minsinsuni creatimse

kinsase tt(tiVit�’ is preserst �. Because of increased sensitivity, determination of the

serum creatinse kimiase appears to be advantageous ins detecting abnormal elevations

(If seruns enzymes ins patients with minsimum active destructions of muscle. Examples

(If sli(’h i)atienits are those with far advanced muscular dystrophy arsd a few l)atienits

with facioscapulohumeral dystrophy ins whom the muscle mass is so reduced arid the

ansounit of enizvnse leaking into the blood is so small that only the more sensitive

(Feat i ne ki nsase determiniat ions will reveal an abmiormalit v. Relatively few cli mucal

situata)nis arise ins the differential diagnosis of muscle disease ins which the creatinie

kinase has a definite advantage over the serum aldolase. The advantages ins spec�-

ficity Uhid sensitivity of the serum creatinse kimsase must be weighed against the greater

lability of this enzyme that requires blood specimens to reach the laboratory for

freezinig ns(Ire quickly. The creatinse kinsase determination, being technically more

(lifficUlt, is also subject to more pitfalls in the laboratory than the relatively straight-

f( )rward pr(I(’edure for serum aldolase.

The electromyogram is a second useful tool ins distinguishing whether nsyopathy

or haver niotor mseurors disease is responsible for muscle weakrsess. Ins myopathies, the

individual nu)tor unit l)otenltial (lecreases ins size during voluntary contractions amid

the niumber and rate of unit firings increase relatively, whereas lower motor neurons

(lisenise nitty produce changes ins t he opposite direct ions. Spontaneous electrical

activity ins the form of fibrihlations may provide an additional helpful diagniostic clue

pointing to a mseurogemsic process. It should be stressed that although electromyog-

raphv may help to differentiate the two general types of disease, it will nsot differen-

title 5I)ecific disease entities withini the over-all categories of myopathic or nseuro-

pnithic (li5e�s5e.

A third important test is the muscle biopsy, which gives two kinds of irsfornsa-

tans. 1”irst, it usually determines svhether the disease is nieurogeniic insvolving the

lO’IVCl’ niotor neuron, as evidenced b�’ a histological picture (If atrophy of groups of

muscle fibrils caused by motor unit involvement, or whether the disease is myopathic

sh(Iwing the tyj)ictLl changes of muscle degeneration characterize(l l)y necrosis of

flillscle fibers amid central migratu)ni (If sarcolemmel nuclei. Second, muscle biopsy

makes it j)ossihle to gains an inspressiomi of the severity (If (lamage to the muscle

tissue.

The j)r’imary nisyopat hies are characteri zed usually by nsuscle weakness wi t 1s nit

pains (Table I). The muscle bioj)sy (Iloes riot distinguish reliably between the ins-(livi(lUntl types of mv(Ii)athv. Only a few of the rare forms of myopathy have spe(ific

hi st ( )l( Igi (‘nil finidi rigs. These i uclude sarcoid myopathy, nemalimie my(Ipathy �, central

(ore disease �, 501(1 51. niyojjathy that hints giant abniornnal niitochonidria � Sarcoid

nsivopathv is the onsly disease in this group that cans be distinguished reliably by the

stani(lar(l heniatux�’hini arid eosini stairs. For a histological diagmsosis (If the other

diseases sj)e(’ial stairss, 511(15 as the Gonsori trichronse stairs, arid specialized handling

using fr’esh frozen tissue are required or the electrons microscope must he used.

Biopsy i�’ill riot differentiate the three commons types (If muscular dystrophy. Onsly

(Ic(’asiomsallv will the muscle biopsy he sufficienstly chara(teristic to differentiate

� )lvflsvoSit i5 unequivocally from muscular dystrophy.

An important Prere(lnnisite for’ the selections of the I)r�l)er muscle for biopsy is a

(‘nsrefnnhl\’ perfornse(1 manual niuscie test. All too frequently the muscle for l)iopsy is

(hOseli without prior fornial nius(’le testing. \Iuscles often are selected for biopsy



TABLE I

PRIMARY MYOPATHY: MUSCLE WEAKNESS WITHOUT PAIN

Proximal Distal

Frequent

Muscular dystrophy Myotonsic dystrophy *

DucheisneLimb-girdleFacioscapulohumeral

PolynsyositiS �

Steroid myopathy �

Rare

Thyrotoxic myopathy � Distal muscular dystrophy

Sarcoid myopathy �

Ophthalmoplegic muscular dystrophyNemaline myopathy tCentral core disease tMyopathy with giant abnormal mitocho ndria t

* Extramu.scular symptoms and signs.

t Underlining indicates specific histological findings.

because of surgical accessibility or tradition. When these criteria are used the biopsy

results oftens are miegative. The choice of the proper muscle for biopsy depenids on the

acuteness and type of muscle disease under considerations. If the disease is of recent

onset and, therefore, classed as acute, as ins some patienits with polymyositis, it is

advantageous to select the weakest accessible muscle of suitable size ins order to

obtains a positive biopsy specimens. Ins chroisic disease, such as muscular dystrophy,

a very weak muscle should riot be chosen. Such a weak muscle often shows onily

end-stage muscle disease with replacement of muscle fibers by fat amid connective

tissue. A muscle of approximately 50 per cerst strength or fair grade is more likely to

give a positive biopsy with good histopathological definition irs chronic disease. The

importance of selecting the proper muscle for diagnosis was demonsstrated in a series

of patients with polymyositis by correlation of the positive pathological diagniosis

with the strength of the muscle biopsied �. Irs this series whens muscles with sigmiificanit

weakness were selected, the muscle biopsies were positive twice as often. Thus, when

the muscles biopsied were little involved, as shown by a grade of fair plus or better,

positive results were obtained in only one-third of the biopsies ; whereas, whens weak

muscles were chosen with a grade of fair or less, positive results were obtained ins two-

thirds of the biopsies.

The muscle biopsied in muscular dystrophy often has beems the gastrocniemius.

This is a relatively poor choice for biopsy, because the strength of the gastrocmsensius

is well preserved in early muscular dystrophy and the chance of obtainsimsg a definite

positive histological diagnosis is decreased. In additions, for physical and psychologic

reasonis, this muscle is a poor choice for biopsy. Psychologically, any future weakness

involving the leg used for biopsy may be attributed by the child to the surgical pro-

cedure. Furthermore, discomfort after the biopsy may cause muscle spasm, tens-

porarily impair walking, and increase contracture of the heel cord.

The rectus abdominis muscle, which is involved early, has givers umsifornily

positive histological results in progressive muscular dystrophy of the Duchemsne

variety. This muscle can be biopsied without apparent adverse psychological or

physical reaction.

Performance of three procedures-serum enzyme determination, electromyog-

raphy, arid muscle biopsy-usually will allow the patient with muscle weakness to be

placed irs one of the two major disease categories, neurogenic or myopathic. Ability

THE JOURNAL OF BONE AND JOINT SURGERY

P. J. VIGNOS: DIAGNOSIS OF PROGRESSIVE MUSCULAR DYSTROPHY 1217

to categorize the illness as one of these two types of disease greatly narrows the

diagnostic possibilities.

However, differential diagnosis of the specific type of muscular dystrophy may

he (lifficlilt. The classifications of the dystrophies is usually based on the clinical finn!-

inigs. The principal forms of muscular dystrophy-Duchennse, limb-girdle, amid

facioscapulohumeral-differ with respect to heredity, age of onset, arid speed of

progression. However, these features overlap so much that the usual clinsical find-

inigs are most helpful. In our experience, the patterns of the individual muscle weak-

msess has beers the most reliable basis for diagnosis. The impressions conveyed irs the

medical literature is that the patterns of weakness of the major types of dystrophy

are so distinctive that they are completely characteristic. However, a more critical

look at the evidence suggests that the diseases produce variations on a commons

thense of nsuscle weaknsess.

The weakness irs the primary myopathies usually is found ins the proximal

IiiUscles (Table I). The only commons myopathy with early weakness of distal muscles

is nsivotomiic dystrophy irs which there is weakness ins the anterior tibial arid peroneal

muscles (If the leg amid ins the distal nsuscles of the hand. Atrophy of the temporahis

5411(1 masseter muscles, producing a typical skull-like facies, also occurs. This dis-

tinictlv different patterning of muscle weakness generally suggests the diagrsosis.

\Iyotonia, inisibihit�’ to relax a muscle after contraction, is seers most frequently ins

the hands. Noni-nsuscular lesiomss-cataracts on slit-lamp examinations, testicular

atrophy, arid j)remature frontal baldnsess ins males-help to confirm the diagnosis.

Over a period of thirteens years serial evaluations have beers performed oni 121

l)atiensts with muscular dystrophy. The patient sample, classified essentially accord-big t(I the scheme of Walton, included severity-eight Duchemsmse, twenty-six limb-

gi rdle, arid ��evemsteers facioscapulohumeral dystrophies. Evaluations of these patients

inichinded a complete history amid physical examinations, serial follow-up clinical cx-

amisinsationis at three-month intervals, serial functional tests of physical performance,

seruns aldolase arid urinian’v creatimie determinations, electrodiagniostic studies,

muscle biopsy, arsd serial manual tests of muscle strength. Computer analysis (If the

data has demonstrated a characteristic patterns of muscle weakness conimons to

all dvstrophiies and a patterns of weakness peculiar to each of the three major types.

Idenstificationi of this patterning of the muscle involvement early ins the disease has

been an aid irs early accurate diagnosis.

The most difficult problem is diagnosis ins the patient with early disease. The

term early (lisease cars be defined by use of a standard functional classifications 8 ins

which patients are graded on a scale of 1 through 10. On this scale the higher the

number is, the more severe the irsvolvement. A patient ins Class 1 cars walk in-

dependently arid climb eight standard steps in less than twenty-five seconds with-

out the aid of a stair railing. If a raihinsg is required to negotiate stairs, he is placed

in Class 2. Patients with Duchennse or limb-girdle dystrophy are regarded as havinsg

early disease if they are in Class 1 or Class 2. Ins facioscapulohumeral dystrophy,

univ patients irs Class 1 are regarded as having early disease. This differentiation is

made because the two former categon’nes of dystrophy are more common ins small

children. Normal children five or six years of age often use a railing for assistance

while climbing stairs.

The data from the manual muscle tests of the patients with early disease were

analyzed to determine whether specific muscles were involved or spared at this early

phase of the disease. A muscle was defined as involved if it was graded fair (50 percemst strength) or below. This grade was selected as indicative of definite weakness

because it implied significant functional impairment and was the most reliably

reproducible grade in the standard nsuscle testing examinations. Muscles described



TABLE II

PATTERNS OF �iIUSCLE WEAKNESS AND SPARmNG mN EARLY MUSCULAR 1)YsYRon’HY �

Neck and UpInvolved

per Extremity tSpared

Trirnik anid Lower ExtremityInvolved Spared

Commons ins all Lower trapezius Neck extenisors Gastrocniemius

groups Middle trapezius Tibialis posterior

Toe flexorsCommon in Rhomboids Upper trapezius Gluteus maximus

Ducheninse arid Latissimu.s dorsi Biceps Hip adductorslimb-girdle Inward rotators Triceps

Unsique pattern.sl)uchersnse Anterior neck

fiexors (SCM)Anterior Ilanist rings

abdominsalsGluteus medius

Tensor fasciae lataeLimb-girdle Brachioradialis IliopsoasFacioscapulo- Upper pectoralis Lower pectoralis Tibialis anterior Back extenisors

humeral major major Iliopsoas

(iluteus me(liusTensor fasciae

latae

Quadriceps

* Early: functional classes 1 arid 2 in Duchensne and limb-girdle types; functional Class 1 ins

the facioscapulohumeral type. Involved: muscle grade fair or below ins 66 per cent of tests. Spared:

muscle grade fair plus or better ins 90 per cent of tests.

t Excluding wrist and hand muscles.

as involved were found ins 66 per cent or more of the examinsationis of patients

characterized as having early disease, whereas muscles, described as spared (graded

fair plus or above), were found ins 90 per cent or more of examinations ins this same

group of patients.

All types of early muscular dystrophy defined by these criteria mansifest a

pattern of muscle weakness that is proximal in distributions. This early proximalmuscle weakness in dystrophy has been reported in the past, but the impressions

oftemi conveyed is that the patterns of muscle weakness in differemst types of early

dystrophy are quite distinct. Computer analysis of manual muscle tests, however,

revealed that actually the three types of dystrophy have a commons patterns of

muscle iisvolvememst (Table II), nsamely early involvement of the lower part of the

trapezius amid the middle part of the trapezius muscles.

A commons patterns of sparing was also foumsd irs all types of dystrophy. The

muscles spared were the neck extensors arid certain muscles of the posterior com-

partmemst of the leg, specifically, the gastrocnemius, posterior tibial, arid toe flexors.

Therefore, ins a givers patient suspected of having muscular dystrophy, if the eons-

moms muscle pattern of involvement is not seems, or if the muscles usually spared are

involved, one should consider it a strong possibility that the patienst has some other

form of muscle disease.

The early unique patterns of muscle weakness ins Ducheninse dystrophy was ins-

volvememit of the anterior neck flexors (sterniocleidomastoids) amid ins the trunsk arid

lower extremity weakness of the anterior abdomimsals and of the gluteus medius ansd

tensor fasciae latae. The muscles of the shoulder that were involved early, but riot

exclusively, were the lower and middle parts of the trapezius, the rhomboids,

latissimus dorsi, arid inward rotators. An important finding was that rio sinsgle

muscle was spared in this type of dystrophy except the hamstrings.

Irs limb-girdle dystrophy, early unique involvement of the iliopsoas was founsd.

Early ins the disease there was also a commons pattern of muscle involvement, but


P. J. vIGNOS: 1)nAGNOSIS OF PROGRESSIVE MUSCULAR DYSTROPHY 1219

it was rsot. unique since it was also seems ins Duchemine dystrophy. This patterns ins-

(‘bided the lower arid middle parts of the trapezius, rhomboids, latissimus dorsi arid

iniw’ard rotators ins the shoulder girdle, amid the gluteus maximus arid hip adductors ins

the lower extrensities. The omily muscle uniquely spared by this form of dystrophy

��‘as the brachioradialis.

Facioscapulohunseral dystrophy is perhaps the best defined type of dystrophy

arid shows the most restricted earls’ patternsinsg of muscle insvolvemerst. In the early

stage (If thse disease, unique involvement was found ins the upper part of the l)ectoralis

major ins the neck arid shoulder areas ansd ins the anterior tibial ins the lower cx-

trensitv. The early inivolvensenit of the shoulder girdle was oftems asymmetrical.

Patients with early facioscapulohumeral disease had more muscles uniquely spared

than the l)atienit with either of the other two types of dystrophy. The upper cx-

treniitv sh(Iwed sparing of the lower part of the pectorahs major, the inswar(i rotators

arid deltoid. The nsuscles of the trunk ansd l)elvic girdle which were uniquely spared

included thie back cxtcnssors, iliopsoas, giuteus medius, tensor fasciae latae, amid

(lt1�1dm’i(el)5. These pattermss of nsusclc involvement amid sparing ins most insstarscesshnnld niake it. possible to diagnsose the type of dystrophy.

Evens when the patterns of peripheral muscle insvolvemenst is kniowni, there nsay

he diagnostic problems; but these nitty be solved by exansinsations of the facial

niusculature. The diagnosis (If facioscapulohumeral dystrophy is supported es-

l)eciahlV by the Iresemice of weakness of nsuscles of facial expression. Initially, weak-

rsess nsisi�- l)e asvnsmetri(’al. The niost striking early finsdimsg was the asymmetric ap-

pearansce of the mouth on attempted whistling because of weakness of the ohicularis(Iris. Later, the (Ihi(’ularis oculi nsight be insvolved with the result that when the eye-

lids were closed lightly, a rim of white sclera was visible. The patients with the

Duchenimie type (If disease also showed early insvolvensenst of the facial muscles, but

this tended to be nsuch more subtle arid svnsmetrical being manifest by inivolvensenit

(If the mssuscles around the mouth that caused a peculiar transverse sniile. Absence

of iniv(Ilvensenit of the muscles arounsd the eye helped to differentiate the Duchemsnse

fn Ifli t lie facioscapulohunieral type.

Ins hinish-girdle disease, the facial muscles were well preserved arid only rarely

was there slight symmetric insvolvensemit of the zygomaticus niuscie which raises’ the

corners of the mouth during sniilirsg.

The nsost difficult diagnostic problemis is muscular dystrophy is to distinguish

Duchennie dystrophy frons the limb-girdle form ins children. This diagnosis is

panti(’ularly difficult ins ynnnig boys since, ins both fornss, the dystrophy may occur

before the age of ten years amsd the serunsi emizynse levels may be elevated. The pat-

tern (If nisuscle inivolvensenit PreviouslY cles(’ribed was of primary aid ins distiniguishinig

these diseases. The height of the abnormal elevations of serum enszymes was helpful

also, for the seruns aidolase tended to be over twice as high ins Ducheninse dystrophy.

There was overlap but a high serum enszyme level favored the diagnosis of Duchemsnse

dystrophy.

A much fli(Irc subtle differential Point is the decreased intellectual level, seers

uniquely ins Ducheminse muscular dystrophy. The means intelligence quotient of a

gn(Iup of thirty-eight children with Ducheninse muscular dystrophy was eighty-

three which was strikingly different front that found ins a variety of control groups

ins(’ludinsg nsale siblinsgs, children w’ith diabetes, and children with mseurogensic muscle

disease. The average intelligence quotients ins the control groups varied between 107

arid 1 15, arid the difference was highly significant statistically “. This relative intel-

lectual retardation ins Ducheninse dystrophy was often associated with a PersonalitY

patterns mansifested by dependency, withdrawal froni the outside world, inscreased

1)assivity, arid lack of anshitioms arid sponstanseity. Children with limb-girdle dystrophy

Von� 49-A, NO. 6, SEPTEMBER n967


tended to have niore rsormal intelligence quotients and did riot fall into the stereo-

typed Duchenne childhood type of personality pattern.

Another difficulty in the differential diagnosis of muscular dystrophy is cx-

elusion of polymyositis. The presence of skin rashes amid other cutaneous niansifesta-

tions, including edema, appears in only one-third of the patients, arid muscle pains

or tenderness may appear in only one-half of the patients �. If these ancillary finid-

ings, laboratory abnormalities, or both features do not appear, difficulties in

diagnosis may be marked. The over-all patterns of muscle weakmsess may simulate

closely the various forms of muscular dystrophy, but there are certaims importaist

differential points. The back extensors were involved in 70 per cent of the cases ins

our series of patients with polymyositis, and the neck extenisors were also inivolved

in approximately one-third of the patients �. These muscles tended to be insvolved

only very late ins any form of dystrophy. Weakness of these muscles early ins the

course of disease should point toward the diagnosis of polymyositis. The patterns

of muscle weakness ins polymyositis also tended to vary from the standard pattern

seen irs the other types of dystrophy. Facial muscle weakness was almost nseven seers

irs polymyositis. Difficulty in swallowing was seers in approximately one-third of the

patients w’ith polymyositis, but was rsever seen in any of the dystrophies except

terminally. Finally, patients with polymyositis usually showed a definite clinsical

response to high dose corticosteroids if the drug was givems early in the disease amid ins

sufficiently high doses (fifty to sixty milligrams of prednisone equivalent).

References

1. ARcHIBALD, K. C., and VIGN0S, P. J., JR.: A Study of Contractures in Muscular Dystrophy.Arch. Phys. Med. and Rehab., 40 : 150-157, 1959.

2. CoLoraBo, J. P.; RICHTERICH, R.; and RossI, E.: Serum-Kreatin-Phosphokinase: Bestimmursgund diagnostische Bedeutung. Kim. Wochenschr., 40 : 37-44, 1962.

3. PEARCE, J. M. S.; PENNINGTON, R. J. T.; and WALTON, J. N.: Serum Enzyme Studies insMuscle Disease. III. Serum Creatine Kinase Activity in Relatives of Patients with the DuchensneType Muscular Dystrophy. J. Neurol., Neurosurg. and Psychiat., 27 : 181-185, 1964.

4. SHY, G. M., and MAGEE, K. R. : A New Congenital Non-Progressive Myopathy. Brains, 79:610-621, 1956.

5. SHY, G. M.; ENGEL, W. K.; SOMERS, J. E.; and WANKO, THEODOR: Nemaline Myopathy. ANew Congenital Myopathy. Brain, 86 : 793-810, 1963.

6. SHY, G. M., and GONATAS, N. K.: Human Myopathy with Giant Abnormal Mitochondria.Science, 145 : 493-496, 1964.

7. VIGNOS, P. J., JR., and LEFKOWITZ, M.: A Biochemical Study of Certaini Skeletal �s1u.scleConstituents in Human Progressive Muscular Dystrophy. J. Clin. Invest., 38 : 873-881, 1959.

8. VIGN0s, P. J., JR., and ARCHIBALD, K. C. : Maintenance of Ambulation in Childhood 1\IuscularDystrophy. J. Chron. Dis., 12 : 273-290, 1960.

9. VIGN05, P. J., JR. ; BOWLING, G. F. ; and WATKINS, M. P.: Polymyositis. Effect of Corti-costeroids on Final Result. Arch. mt. Med., 114: 263-277, 1964.

10. WALTON, J. N.: Muscular Dystrophy and Its Relation to the Other Myopathies. Res. Publ.Assn. Res. Nerve. Ment. Dis., 38 : 378-421, 1960.

1 1 . WORDEN, D. K., and VmN0S, P. J., Ja. : Intellectual Function in Childhood ProgressiveMuscular Dystrophy. Pediatrics, 29 : 968-977, 1962.


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