muscular system from want of proper use and exercise; malnutrition from
a diet deficient in amount or defective in kind, or in childhood from
too rapid growth; the chronic wasting diseases; the state of
convalescence from acute maladies; and, finally, degenerative diseases
of the muscles themselves,--all favor the development of myalgia. Among
the acute diseases which by their derangement of nutritive processes
especially render those who have suffered from them liable to this
painful affection of the muscles during convalescence, is acute
articular rheumatism or rheumatic fever. It is this fact, taken
together with the use of a misnomer, that has given rise to the view
that the muscles share with the serous and fibrous structures in the
lesions of that disease, and that myalgia is rheumatism of the muscles.
There is, however, over and above these defects in nutrition, an
especial predisposition or idiosyncrasy, the nature of which is
unknown, which renders certain individuals far more liable to suffer
myalgic pain than others. This predisposition is encountered in those
who have an inherited or acquired gouty habit and in those who are free
from gout with perhaps equal frequency. It is not associated with a
special liability to true rheumatism.
(_B_) Exciting Causes.--Myalgia is a local affection, and depends for
its causation upon a derangement of the balance between the nutrition
of the affected muscles and the work they have been called upon to do.
Hence the most common exciting cause is (_a_) overwork pure and simple,
especially overwork which brings into excessive and prolonged exercise
unaccustomed muscles. Next in frequency is (_b_) exposure to cold, and
especially to damp cold, when overheated or overfatigued. Finally
(_c_), inevitable and incessant contractions, such as are physiological
and are performed without consciousness or sensation in a healthy state
of the {531} muscles, will, in muscles that are defectively nourished
or have undergone fatty, granular, or fibroid degeneration, cause more
or less distinct myalgia.
As examples of myalgia due to the first of this group of causes (_a_) I
may cite the pain in the adductors of the thighs after a hard ride when
out of practice; the epigastric pain in children suffering from measles
or other acute affection attended with persistent cough; and the pain
of spasm, in particular that which follows tonic spasm, such as occurs
from reflex causes in the calves of the legs at night and in bathers.
Many of the pains of childhood, which are classed in common parlance
together under the name of growing pains, are myalgic in their nature.
Examples of the second form (_b_) may be instanced in the pains of wry
neck or lumbago, such as often occur in those who, being very tired,
but otherwise healthy, fall asleep in a draught of air, or in those
who, coming home at evening in cold weather, find a leaking pipe in the
cellar, and stooping over to stop it, or in some other emergency of
every-day life, bring into excessive use unaccustomed muscles in an
atmosphere that is at once cold and damp.
Examples of the third group (_c_) are common enough in the flying or
fixed muscular pains and soreness that occur in wasting chronic
diseases and in the convalescence from acute maladies when prolonged
muscular effort is too early undertaken. Certain forms of præcordial
pain that occur in degenerative lesions of the muscular substance of
the heart are without doubt myalgic in character, and will, when the
clinical data of such conditions come to be more fully understood, be
recognized as having more or less diagnostic value.
SYMPTOMATOLOGY.--The chief symptom, the one symptom that is common to
all the cases, is pain. It is sometimes, especially in acute cases,
constant; more frequently it is very slight or wholly absent when the
patient is at rest, with the affected muscles in full extension, but it
is invariably present or aggravated when the muscles are called into
action. It is experienced throughout the muscular mass, but is most
intense at or near the point of tendinous insertion. Its character is
usually stabbing or stitch-like, but prolonged; sometimes it is acutely
dragging or tearing; in others it is like the soreness felt on moving a
contused or inflamed part. It is frequently in acute cases, almost
always in chronic cases, accompanied by a sensation of stiffness in the
affected muscles. The pain is essentially the same in all cases,
variations in its character and severity being determined by the
opportunities afforded the muscle for physiological rest. It is in
accordance with this statement that the most obstinate, and the most
severe form of myalgia is that which occurs in the intercostal muscles
and their fibrous aponeuroses--pleurodynia. Here the affected muscles
are constantly concerned in the movements of respiration, and have no
time for physiological rest except in the intervals of those movements.
Scarcely less stubborn and severe are the myalgias of the great
muscular masses, of which the principal function is to maintain by
their nicely-balanced and ever-varying contractions the erect position
of the head and trunk. Less painful and of shorter duration are the
myalgias of the limbs--less painful because prolonged intervals of
absolute rest may be voluntarily secured; of shorter duration, because
it is by rest that the balance of the nutrition is most speedily
restored.
{532} There is usually some degree of tenderness over the whole extent
of the myalgic area, becoming more marked in the regions of tendinous
insertion, to which it is, however, in many cases restricted. It is
elicited upon moderately firm pressure, and is not associated with
cutaneous hyperæsthesia.
Spasm is absent in the acute cases, except when the muscles are brought
into use. Its occurrence has much to do with the intensity of the
suffering then caused: in chronic cases a condition of tonic spasm or
spastic rigidity, with more or less persistent painfulness, comes on,
and finally in very chronic cases such tissue-changes take place as
result in great impairment or absolute loss of contractile power, with
or without atrophy.
Objective signs are absent, except that it is evident that the patient
assumes by preference an attitude of repose, and that he keeps the
involved structures as much at rest as possible. Pyrexia does not
occur; the appetite and digestion are not impaired; acid sweats are not
present; the urine shows no constant or characteristic alteration;
there is no tendency to endo- or pericardial inflammation. If
constitutional disturbance be present, it is trifling and due to
prolonged local suffering and want of sleep. In by far the greater
number of instances the patient remains in his usual health except the
local malady.
Myalgia may affect the voluntary, and perhaps also the involuntary,
muscles of any part of the body. Those most frequently involved are
those subjected to continuous and excessive work, and at the same time
liable to exposure to cold and damp. Single muscles or groups may be
affected. The most common and important varieties are--
(1) Cephalodynia, manifested as a superficial headache, increased by
movement of the scalp and attended by tenderness on pressure.
(2) Torticollis; wry neck, stiff neck--a very common form, involving
the muscles of the neck, especially the sterno-cleido-mastoid. The
affection is usually limited to one side, toward which the occiput is
more or less firmly rotated and flexed. Great pain is experienced in
attempting to turn the head in the opposite direction. The position is
extremely constrained and awkward; the head cannot be moved in any
direction without moving the whole body, and every effort at motion is
accompanied by pain which calls forth involuntary grimaces.
(3) Omodynia, Scapulodynia, Dorsodynia--forms in which the muscles of
the shoulders and upper part of the back are affected. They are very
common, especially among laboring men.
(4) Pleurodynia, Myalgia of the Chest-walls.--The intercostals,
pectorals, and serratus magnus may be involved. The pain is frequently
referred to the region of the interdigitations of the serratus magnus
with the external oblique. It is very often seated in the
infra-axillary region, and is much more common on the left side. It is
usually very severe, and is increased by all movements that bring the
affected muscles into play. The focus of pain is sometimes a very
limited spot, which is exquisitely tender upon pressure. Sometimes the
pain alters its position from time to time. It is increased by deep
inspiratory efforts and such acts as sneezing and coughing. Extreme
flexion of the trunk from side to side also aggravates the pain.
Pleurodynia sometimes comes on in consequence of severe and protracted
cough, as in patients suffering with phthisis. It is then apt to affect
both sides.
{533} This form of myalgia simulates pleurisy, from which it is to be
distinguished only by careful physical examination.
(5) Myalgia of the abdominal walls usually affects the recti muscles,
and often assumes the guise of an acute, agonizing pain in the
epigastric or pubic regions--occasionally so severe as to be mistaken
for peritonitis. It is sometimes due to cough, especially in measles,
but is more commonly met with in overworked and underfed tailors and
cobblers as a result of the excessive action of the recti muscles in
maintaining the bent posture assumed by such craftsmen at their toil.
(6) Lumbago, myalgia lumbalis.--The great muscular mass occupying the
lumbar region is peculiarly prone to attacks of myalgia. Lumbago is
very common in the middle and later periods of life. The attack is
usually sudden and severe. Both sides are, as a rule, affected, but not
to the same extent. There is constant pain across the loins, dull and
aching, rarely absent altogether, always sharply aggravated by such
movements as bring the affected muscles into play, and then becoming
stabbing in character and almost unbearable in intensity. The spine is
held stiffly, and the body is often bent slightly forward. Efforts to
stand erect, to rise from the sitting posture, or to recover from the
stooping position, such as is assumed in lacing one's shoes and the
like, greatly aggravate the pain. In the more severe cases the patient
cannot stir in his bed. There is usually tenderness upon pressure, and
palpation often discovers a distinct sense of abnormal tension and
resistance in the muscles.
(7) The aching, dragging pain in the back of the neck common in
poorly-nourished, nervous women and in other cases of neurasthenia, the
so-called pain of nervous exhaustion, is myalgia. It is felt chiefly
during fatigue, is present in the erect posture, and is almost always
relieved when the patient lies down. It is referred sometimes to the
base of the skull, sometimes to the whole of the back of the neck, but
more commonly to the spinal region just above the level of the upper
borders of the scapula, and constitutes a harassing symptom of the
cases in which it occurs. In this connection it must be pointed out
that many of the pains of that obscure condition to which the term
spinal irritation has been vaguely applied are myalgic.
Myalgia manifests itself furthermore in the limbs, in the diaphragm,
and occasionally in the muscles of the eyeballs.
The COURSE of the attack is in the simpler forms acute and transient;
it frequently, however, becomes chronic, and not uncommonly presents
the characters of the chronic form from the beginning. Again, it
sometimes attacks in succession several muscles or groups of muscles,
and in by far the greater number of individuals it shows a tendency to
recur from time to time.
DURATION.--The duration of acute attacks is usually brief, lasting from
a few hours to several days; that of the chronic form is indefinite,
tending to last years, sometimes, under unfavorable circumstances, a
lifetime, with varying periods of exacerbation and remission, which
are, after the disease is fully established, much influenced by the
phases of the weather.
The TERMINATION of acute myalgia is commonly in full recovery, but the
tendency to subsequent attacks is to be borne in mind, and guarded
{534} against by the exercise of wholesome precautions in the matter of
hygiene. Neglected cases of chronic myalgia not rarely terminate in
permanent alterations of the muscular structure, with loss of
contractile power and rigidity, with or without atrophy.
COMPLICATIONS.--In the acute forms there are no complications, properly
so called. In the more severe cases of the chronic form there is danger
of nutritive changes in the tissues entering into the formation of
joints, and loss of function from want of use.
SEQUELS.--There are no sequels other than those just pointed out.
PATHOLOGY AND MORBID ANATOMY.--As indicated by the various names by
which myalgia has been known, the principal theories advanced to
account for the morbid manifestations are three in number: (1) that the
malady is a rheumatism of the muscles; (2) a form of neuralgia; (3) an
inflammation.
(1) Muscular Rheumatism.--That this affection should be popularly
associated with rheumatism is not surprising when the character of the
pain is regarded, its aggravation on movement, and the temporary or
permanent crippling which it occasions; especially when we call to mind
the exceedingly vague and indefinite ideas which prevail in regard to
rheumatism. But that it should be looked upon, far and wide, among
physicians as a form of rheumatism, and described as such in the
systematic works--that it should be regarded as due to the same causes
as rheumatism and treated from that point of view--is certainly as
remarkable as it is misleading.
Let us look at the facts. Nothing is easier: the two affections are
under our daily observation side by side; in this climate and among
working people few maladies are more common.
On the one hand we behold a constitutional disease with widespread
manifestations--a special joint inflammation, which tends neither to
the deposit of urate of soda nor to suppuration; a peculiar acid
secretion from the skin; highly acid urine; a notable tendency to
inflammatory heart complications; marked pyrexia. We observe also a
marked disposition to recurrence and to the hereditary transmission of
the diathesis.
The phenomena of rheumatism may be ill defined; that is to say, the
attack may be subacute, but the features are the same; or they may
linger and assume the chronic form, in which fever is replaced by a
peculiar alteration in the fluids of the body, showing itself in a dull
anæmic complexion and a greasy skin; but in all cases the seat of the
disease-signs is in the joints; it is articular.
On the other hand, myalgia is not a general malady nor the expression
of one. It is scarcely a disease at all. It is purely local. A muscle
or a group of muscles, overworked, cry out, and this cry is interpreted
by the sensation of pain. It is to be borne in mind that the overwork
may be absolute, or merely relative to the healthfulness of the muscle
at the time. In either case there is a derangement between the balance
of work and nutrition in the muscle. The secretions are not altered;
there is no sweating; the urine presents no abnormal conditions.
Endo- and pericarditis never occur as complications; fever is absent.
The attack is often light, and quickly passes away. If it become
chronic, further nutritive changes take place. The muscle becomes
rigid, and often atrophies. According to Froriep and Virchow, as {535}
quoted by Jaccoud[2] and Niemeyer,[3] the fasciculi are beset here and
there with thickened connective tissue. Vogel observed in several
chronic cases the neurilemma of the nerves supplying the part to be
thickened, hardened, and adherent.
[Footnote 2: _Traité de Pathologie interne_, Paris, 1871.]
[Footnote 3: _Lehrbuch der Speciellen Pathologie und Therapie_, Berlin,
1871.]
In all cases the affection limits itself to the muscles. The joints
remain free. When they undergo changes it is after a long time and as a
result of want of use or of reflex disturbances of nutrition through
the nervous system. Nothing is known of hereditary predisposition to
myalgia. In the manifest tendency to recur in the same individual it
and rheumatism are alike. In all essential points their clinical
resemblance is of the most superficial kind. It is clear, then, that
the processes which give rise to the phenomena of rheumatism do not
directly affect the muscular system.
The credit of having first formulated this opinion, previously only
vaguely recognized, is due to Roche and Cruveilhier,[4] but Valleix,
Garrod, Flint, and other writers, who describe myalgia under the head
of muscular rheumatism, coincide in this view. Even the statement that
the two diseases are constantly associated is not borne out by the
results of extended clinical inquiries. My own observation has not
confirmed it. Of 7 cases[5] taken at random to illustrate a point of
treatment, 1 had followed an attack of rheumatic fever; 1 occurred in
an individual who had many years before suffered from rheumatism; and 5
gave no history whatever of that disease: 1 followed tonsillitis.
DaCosta[6] details 2 cases of myalgia--1 in the loins (lumbago),
associated with bronchitis or following it, the other occurring during
an attack of rheumatic fever and having its seat in the muscles of the
neck. In the latter case the constitutional disease yielded to
treatment which had no effect upon the local malady. Even were the
association much more frequent than it is found to be, the fact would
by no means establish a common causation, seeing that myalgia follows
other diseases which impair the nutrition of the body. It is worthy of
note that the groups of muscles most frequently involved in cases which
happen during or after acute diseases are those which must work
perforce--those which maintain the equilibrium of the body or carry on
respiration, etc. Hence we see wry neck, lumbago, pleurodynia
associated with other diseases; affections of the muscles of the
extremities after overwork pure and simple.
[Footnote 4: _Dict. de Méd. et de Chir. prat._, article "Arthrite."]
[Footnote 5: _Philada. Med. Times_, Nov. 7, 1874.]
[Footnote 6: _Penna. Hospital Reports_, vol. i.]
(2) Neuralgia.--Many observers have regarded myalgia as a neuralgia,
having its seat in the muscles. Valleix[7] wrote as follows: "Muscular
rheumatism and neuralgia have, in the correspondence of their symptoms,
their course, their exacerbations, in the absence of appreciable
anatomical lesions, the greatest resemblance to each other. These
affections often pass the one into the other.... The pain, which is the
capital symptom of neuralgia, expresses itself, according to our
observation, in three ways: If it remain concentrated in the nerves,
characteristic isolated painful points are found; here is neuralgia
properly so called. If the pain is diffused among the muscles, muscular
action is principally painful; we have muscular rheumatism. Finally, if
it be spread out upon the skin, an excessive sensibility of the
cutaneous surface results, and there exists {536} a dermalgia. These
three forms of an affection which is the same may all be present at the
same time, or two and two--neuralgia and dermalgia, neuralgia and
rheumatism, rheumatism and dermalgia." No wonder he found nothing more
difficult than to trace with exactitude the picture of this malady.
[Footnote 7: _Loc. cit._]
Flint[8] also regards myalgia as closely allied to neuralgia, and
states that, "being one of the neuroses, it has no anatomical
characters." It is not difficult to trace the results of this teaching
in the widespread confusion prevalent in regard to some very common
painful affections, as, for example, that painful form of stitch known
as pleurodynia, and the still more distressing gastrodynia. Even those
observers who refuse to class these affections as rheumatic are too
often at a loss as to whether they are neuralgic or purely muscular.
Anstie[9] has concisely contrasted the most important characters of
neuralgia and myalgia in a way that strongly urges the clinical
differences between them, as follows:
NEURALGIA. | MYALGIA.
Follows the distribution of a | Attacks a limited patch or patches
recognizable nerve or nerves. | that can be identified with the
| tendon or aponeurosis of a muscle,
| which, on inquiry, will be found to
| have been hardly worked.
|
Goes along with an inherited or | As often as not occurs in persons
acquired nervous temperament, | with no special tendency.
which is obvious. |
|
Is much less aggravated, | Is inevitably and very severely
usually, by movement than | aggravated by every movement of the
myalgia is. | part.
|
Is at first accompanied by no | Distinguished from the first by
local tenderness. | localized tenderness on pressure
| as well as on movement.
|
Points douloureux, when | Tender points correspond to
established at a later stage, | tendinous origins and insertions of
correspond to the emergence of | muscles.
nerves. |
|
Pain not materially relieved by | Pain usually completely, and always
any change of posture. | considerably, relieved by full
| extension of the painful muscle or
| muscles.
[Footnote 8: _Practice of Medicine_.]
[Footnote 9: _Neuralgia and Diseases that Resemble it_.]
(3) Inflammation.--That the muscular affection under consideration
should have been referred to morbid processes of an inflammatory kind
is very natural. The use of the term myositis embodies this view, which
is held, among others, by Garrod. This author defines muscular
rheumatism as "an affection of the voluntary muscles of an inflammatory
nature (?), but unaccompanied with swelling, heat, redness, or febrile
disturbance." He assigns the combined influence of cold and damp as a
cause, especially when associated with over-use of the muscles.
Though some of the gross characters of inflammation are wanting, and
the course of acute cases of myalgia is toward a speedy resolution,
there are several features of the affection which strongly suggest its
inflammatory origin. At all events, the view that the essential
pathological conditions consist in a hyperæmia with slight serous
exudation, or a partial paralysis of vaso-motor nerves with escape of
serum into the intimate tissues of the muscles, has, from a clinical
standpoint, much to support it. In the absence of knowledge derived
from the actual investigation of the morbid tissue-changes in all the
stages of the affection some {537} value is to be accorded to the
following facts as confirmatory of this opinion:
It is a local affection; the onset is usually sudden; there is often,
from the beginning, a slight but obvious fulness of the muscle;
tenderness is present as well as pain; in chronic cases inflammatory
increase of connective tissue occurs, with changes in the nerve-sheaths
and fatty degeneration of muscle-substance. Moreover, the permanent
contraction (contracture) which sometimes finally sets in is the same
as that which follows true inflammation of muscles after injuries
(traumatic myositis[10]).
[Footnote 10: Erb, _Ziemssen's Cyclopædia_, vol. ix.]
It is uncertain whether the nerves supplying the muscles are thrown
into morbid action by changes in the muscular fibres and in their
sarcolemma, or by simultaneous changes in their own neurilemma. However
it arise, irritation of sensory nerve-twigs is present, giving rise to
pain, along with irritation of motor filaments, which occasions spasm.