early feature of chronic myelitis; in the transverse form it may be as
absolute as in the severest forms of acute myelitis; as a rule,
however, it is rather a paresis than a paralysis. The patient is
usually able to walk, manifesting the paraparetic gait: he moves along
slowly, does not lift his feet, drags them along, makes short steps;
in short, acts as if his limbs were heavily weighted. This difficulty
of locomotion is preceded and accompanied by a tired feeling before
other sensory symptoms are developed. Rigidity of the muscles, like
that found in disseminated sclerosis, is a common accompaniment, and
may even preponderate over the paresis to such an extent as to modify
the patient's walk, rendering it spastic in character. In such cases
the muscles feel hard to the touch, and the same exaggerated reflex
excitability may be present as was described to be characteristic of
spastic paralysis.
If, while the leg is slightly flexed on the thigh, the foot be
extended,[149] so as to render the Achilles tendon and the muscles
connected with it tense, and the hand while grasping the foot suddenly
presses the latter to still further extension, a quick contraction
occurs, which, if the pressure be renewed and kept up, recurs again
and again, the succession of the involuntary movements resembling a
clonic spasm. This action is termed the ankle-clonus or
foot-phenomenon. Gowers has amplified this test of exaggerated reflex
excitability by adding what he calls the front-tap contraction. The
foot being held in the same way as stated above, the examiner strikes
the muscles on the front of the leg; the calf-muscles contract and
cause a brief extension movement of the foot. It is believed that the
foot-clonus and the front-tap contraction are always pathological, but
a few observers, notably Gnauck, leave it an open question whether it
may not occur in neurotic subjects who have no organic disease. Gowers
considers the foot-clonus found in hysterical women as spurious, and
states that it differs from the true form in that it is not constant,
being broken by voluntary contractions, and does not begin as soon as
the observer applies pressure. But I have seen the form of clonus
which Gowers regards as hysterical in cases of diffuse sclerosis. With
regard to the front-tap contraction, its discoverer[150] admits that
it may be obtained in persons in whom there is no reason to suspect
organic disease. It is significant only when unequal on the two sides.
[Footnote 149: By extension the approximation of the dorsal surface to
the tibial aspect of the leg—what some German writers call dorsal
flexion—is meant.]
[Footnote 150: Gowers, _The Diagnosis of the Diseases of the Spinal
Cord_, 3d ed., p. 33.]
In severe cases contractures are developed in the affected muscular
groups, being, as a rule, preceded by the rigidity, increased reflex
excitability, and the thereon dependent phenomena above detailed.
These contractures may be like those of spastic paralysis, but usually
the adductors show the chief involvement, and sometimes the leg
becomes flexed on the thigh and the thigh on the abdomen in such firm
contraction that the patient, albeit his gross motor power is not
sufficiently impaired, is unable to move about, and is confined to his
bed, his heel firmly drawn up against his buttock. It is stated by
Leyden that the contracted muscles occasionally become
hypertrophied—an occurrence I have not been able to verify. As a rule,
some muscular groups are atrophied, though {889} the limbs as a whole,
particularly in those patients who are able to walk about, are fairly
well nourished.
Pain in the back is a frequent accompaniment of diffuse sclerosis. It
is not pronounced, but constant.
The drift of opinion to-day is to regard pain in the spinal region as
not pathognomonic of organic spinal affections. It is true that pain
is a frequent concomitant of neuroses, and that it is more intense and
characteristic in vertebral and meningeal disease; but in denying a
significance to pain in the back as an evidence of diffuse disease of
the cord itself, I think many modern observers have gone to an
extreme. It is particularly in diffuse sclerosis that a dull heavy
sensation is experienced in the lumbo-sacral region; and in a number
of my cases of slowly ascending myelitis and of tabes dorsalis the
involvement of the arms was accompanied by an extension of the same
pain, in one case associated with intolerable itching, to the
interscapular region. It cannot be maintained that the pain
corresponds in situation to the sclerotic area. It is probably, like
the pain in the extremities, a symptom of irradiation, and corresponds
in distribution to that of the spinal rami of the nerves arising in
the affected level.
As the posterior columns are usually involved in transverse myelitis,
the same lancinating and terebrating pains may occur as in tabes
dorsalis. As a rule, they are not as severe, and a dull, heavy
feeling, comparable to a tired or a burning sensation, is more common.
A belt sensation, like that of tabes, and as in tabes corresponding to
the altitude of the lesion, is a much more constant symptom than acute
pains.
Cutaneous sensibility is not usually impaired to anything like the
extent found in advanced tabes. It is marked in proportion to the
severity of the motor paralysis; where mobility is greatly impaired,
profound anæsthesia and paræsthesia will be found; where it is not
much disturbed, subjective numbness, slight hyperæsthesia, or tingling
and formication may be the only symptoms indicating sensory
disturbance; and there are cases where even these may be wanting.
The visceral functions are not usually disturbed. In intense
transverse sclerosis of the upper dorsal region I observed gastric
crises, and in a second, whose lesion is of slight intensity, but
probably diffused over a considerable length of the cerebro-spinal
axis, there is at present pathological glycosuria. The bladder
commonly shows slight impairment of expulsive as well as retaining
power, the patients micturating frequently and passing the last drops
of urine with difficulty. Constipation is the rule. The sexual powers
are usually diminished, though rarely abolished. As with sclerotic
processes generally, the sexual functions of the female, both
menstrual and reproductive, are rarely disturbed.
It is not necessary to recapitulate here the symptoms which mark
diffuse sclerosis at different altitudes of the cord. With this
modification, that they are less intense, not apt to be associated
with much atrophic degeneration, nor, as a rule, quite as abruptly
demarcated in regional distribution, what was said for acute myelitis
may be transferred to this form of chronic myelitis. The progress of
diffuse sclerosis is slow, its development insidious, and the history
of the case may extend over as long a period as that of diffuse
sclerosis. Sooner or later, higher levels of the cord are involved in
those cases where the primary focus was low down. {890} In this way
the course of the disease may appear very rapid at one time, to become
almost stationary at others. Of three deaths which occurred from the
disease in my experience, one, in which there were distinct signs of
involvement of the oblongata,[151] occurred from sudden paralysis of
respiration; a second from a cardiac complication, which, in view of
some recent revelations concerning the influence of the tabic process
on the organic condition of the valves of the heart, I should be
inclined to regard as not unconnected with the sclerosis; and in a
third, from bed-sores of the ordinary surgical variety. The malignant
bed-sore is not of frequent occurrence in this disease.
[Footnote 151: On one occasion the patient had momentary anarthria,
followed a day later by two successive periods of anarthria, lasting
respectively about twenty seconds and one minute, one of which was
accompanied by diplopia of equally brief duration.]
PROGNOSIS.—The disease may, as in the instances cited, lead to a fatal
termination, directly or indirectly, in from three to twenty years.
The average duration of life is from six to fifteen years, being
greater in cases where the sclerotic process is of slight intensity,
even though it be of considerable extent, than where it is of maximum
or destructive severity in one area, albeit limited. I am able to say,
as in the case of tabes dorsalis, that a fair number of patients
suffering from this disease whom I have observed for from two to six
years have not made any material progress in an unfavorable sense in
that time. One cure[152] occurred in this series, of a patient
manifesting extreme contractures, atrophies, bladder trouble, and
ataxiform paresis, where the cause was plainly syphilis, and the
histological character of the lesion is somewhat a matter of
conjecture in consequence. Diffuse sclerosis of non-syphilitic
origin—and this may apply also to established sclerosis in syphilitic
subjects—is probably as unamenable to remedial treatment as any other
sclerotic affection.
[Footnote 152: The patient went, under direction of Leonard Weber and
R. H. Saunders, to Aix-la-Chapelle, where this happy result was
obtained after mixed treatment had practically failed.]
The same rules of DIAGNOSIS applicable to transverse myelitis of acute
onset apply, level for level, to the diagnosis of transverse myelitis
of insidious development, the history of the case often furnishing the
only distinguishing point between the acute and the chronic form.
The main difference between the diffuse sclerosis and acute myelitis,
clinically considered, consists in the gradual development of symptoms
in the former as contrasted with their rapid development in the latter
disease. Acute myelitis is established within a few hours, days, or at
most, in the subacute forms, a few weeks; chronic myelitis requires
months and years to become a clearly-manifested disorder. It is the
essential correspondence of the symptoms of both conditions,
intrinsically considered, which renders it impossible to distinguish
clinically and in the absence of a history of the case between some
cases of acute myelitis in the secondary period and the processes
which are primarily of a sclerotic character.
It is unusual to find the degeneration reaction in myelitis of slow
and gradual development. Sometimes there is diminished reaction to
both the faradic and galvanic currents, or the so-called middle form
of degeneration reaction is obtained from atrophied muscles, the nerve
presenting normal or nearly normal irritability, and the muscle
increased galvanic irritability and inversion of the formula.
{891} Among the less reliable or accessible points of differentiation
between the residua of acute myelitis and the chronic form is the
history of the onset and the age of the patient at the time of the
onset. Myelitis in young subjects is more likely to be of the acute
kind; in older persons it is more apt to be chronic.
In the diagnosis of diffuse sclerosis the question of differentiation
from neuroses not based on ascertainable structural disease, such as
are called functional, will be most frequently raised. In
differentiating between organic and functional spinal disorders all
known exact signs of organic disease must be excluded before the case
can be considered as appertaining to the latter group. Symptoms of
hysteria, nervous exhaustion, and spinal irritation frequently coexist
with diffuse sclerosis as well as with the disseminated form; and this
is not surprising, for, instead, as seemed at one time to be believed,
of the neurotic taint granting comparative immunity against organic
disease, it is the reverse, and it is not at all uncommon to find a
strongly-marked neurotic diathesis in the family history of sufferers
from diffuse sclerosis. That ordinary hysteria, epilepsy, and what is
vaguely called nervousness are common features in the ancestral record
of the hereditary forms of spinal disease has already been stated in
considering those affections.
One of the commoner forms of the grave phase of hysteria is
paraplegia.[153] Often muscular atrophy—which ensues from
disuse—exaggeration of the deep reflexes, and retention of urine are
added to the paraplegia and heighten the resemblance to an organic
affection. Its development, though sometimes sudden, often occupies
weeks or months, and may be preceded, exactly as in chronic myelitis,
by weakness in the legs, and not infrequently by combined ataxia and
weakness. It is much more difficult to discriminate here than is
generally held or than is enunciated in textbooks. The sufferer from
hysterical paraplegia does not always give other indications of the
hysterical neurosis, and even if she did show a globus and tenderness
at certain points, it is a question whether it could be called a
scientific diagnosis which determined the case to be one of functional
trouble on these signs alone. More than one error has been committed
in this respect. In chronic myelitis retention of urine is less common
than incontinence, which is the reverse of hysterical paraplegia.
Pupillary symptoms do not occur with the latter affection. If there be
sensory anæsthesias, they are bizarre in character or distribution,
and do not usually harmonize with the distribution of the paralysis.
In most cases moral influences can be exerted so as to increase the
power of movement far beyond what would be possible in an organic
disease; and while an electrical examination will not always yield
positive results in chronic myelitis, yet no case of chronic myelitis
with complete or nearly complete paraplegia but will show at least
quantitative changes of such extent as to prove beyond doubt that the
case is of an organic character.
[Footnote 153: I have observed for two years a stationary brachial
diplegia, of undoubted hysterical origin, although the patient had
never shown any ordinary hysterical manifestations, and had had no
other hysterical symptom than chromatopsia, and that only for a short
period. From its long duration, constancy, and the resulting atrophy
of disuse it had been regarded as a case of peculiarly limited chronic
myelitis.]
There is one point in which spinal and cerebral disease involving the
motor tract differs in the majority of cases, which may be utilized in
{892} distinguishing obscure affections of the former from those of
the latter kind. In cerebral paralysis of any standing the superficial
reflexes, such as the cremaster and abdominal reflexes, are usually
diminished or abolished, while the deep or tendon reflexes are
exaggerated. In spastic conditions due to spinal disease—say sclerosis
of any kind affecting the lateral column and leaving the motor nuclei
of the anterior cornua unaffected—the deep reflexes are similarly
increased, but the cremaster reflex is increased also.[154] This
feature of the superficial reflexes is significant in the case of
cerebral disease only when unilateral.
[Footnote 154: Attention has been called, I believe, by Westphal, to
the fact that the cremaster reflex may not be demonstrable when reflex
excitability is at its highest, because the cremaster muscle is
already in extreme spastic contraction.]
The initial period of diffuse sclerosis is sometimes confounded with
rheumatism—an error less pardonable than in the case of tabes,
inasmuch as in diffuse sclerosis the pains are not usually
premonitory, but associated with motor paresis. It is erroneous to
regard a pain as rheumatic because it is aggravated or relieved by
changes in the weather. There are many subjects of myelitis who regard
themselves as veritable barometers, and with more justice than most
rheumatic patients.
In some cases of chronic alcoholism there are motor weakness and a
gait much like that of diffuse sclerosis.[155] It is to be remembered
that the solar tickling reflex is very often abolished in alcoholic
subjects, and profound diminution of the normal cutaneous sensibility
of the leg and feet usually coexist. But unless there is peripheral
neuritis—which is an exceptional and, when present, well-marked
affection—the absence of profound nutritive changes of the muscle, the
presence of the alcoholic tremor, the absence of sphincter and bladder
trouble, and the great variation of the symptoms from week to week,
and even from day to day, serve to distinguish the alcoholic spinal
neurosis from myelitis.
[Footnote 155: Wilks' alcoholic paraplegia.]
The Secondary Scleroses.
In studying the lesions underlying the symptoms of organic spinal
disease, the occurrence of fascicular scleroses, secondary to such
disease and due to the destructive involvement of nerve-tracts, was
repeatedly noted. Türck may be regarded as the discoverer of these
degenerations, and the reliability of this old observer may be
inferred from the fact that one bundle of fibres liable to individual
degeneration still goes by his name, and that, as far as he was able
to discriminate between the various paths which secondary
degenerations follow through the cerebro-spinal fibre-labyrinth, his
statements have not been materially modified by more recent
investigators, such as Bouchard, Vulpian, and Westphal.
The discovery by Meynert that the great cerebro-spinal tracts attain
the white color which they owe to the development of myelin around
their component axis-cylinders with advancing maturity, and that the
tracts of noblest, and therefore most intelligent, function were the
last to show this sign of maturity, was greatly extended by Flechsig,
who found that each tract receives its myelin at a definite period of
intra-uterine life, the lowest or the nerve-roots first; then the
short or intersegmental or—as {893} the physiologist may call them—the
automatic tracts; then the long or controlling tracts; and last, the
associating tracts of the cerebral hemispheres which mediate the
complex relations underlying mental action. It was this discovery
which gave a new impulse to the study of the secondary affections of
the cord and brain. The accuracy with which secondary degeneration
follows the lines marked out by the normal course of the tract is as
great, diminishing when the tract diminishes, changing its position or
direction and decussating where the latter changes its direction or
position or decussates, that it constitutes not alone an interesting
subject for pathological study, but has become one of the most
reliable guides of the cerebral anatomist. It is of great importance
to the pathologist to be able to differentiate between the primary
disease and its secondary results, and, as the controversy concerning
the so-called system diseases shows, even the most studious observers
are uncertain in this direction in many cases.
MORBID ANATOMY.—Secondary degeneration manifests itself by a
discoloration of the affected nerve-tract, which accurately
corresponds in area to the normal area of that tract. The more recent
the degeneration the less pronounced is this change. In advanced cases
the color may be a dark gray, in moderately old ones a reddish or
yellowish gray, and in those of very recent origin no change may be
visible to the naked eye. It is claimed, however, that even here a
loss of translucency of the white substance, giving it a sort of
cheese-like opacity, may be detected. On hardening the specimen
containing the degenerated tract in Müller's fluid or a simple
bichromate salt solution, the affected area, instead of appearing dark
on section in contrast with the gray substance—which in such
preparations appears yellowish or a light brown—contrasts with the
former by its lighter tinge. This contrast is observable even in cases
where the naked eye was unable to detect the change in the fresh
specimen. It can be sometimes found as early as the tenth day after
the primary lesion, and is apparently simultaneously developed in the
whole length of the nerve-tract affected.
The minute changes characterizing secondary degeneration begin in the
essential conducting elements, the axis-cylinder, which exhibits a
finely granular or molecular disintegration, and disappear. According
to Homén, it shows an initial swelling and a failure to stain properly
before this. The myelin then follows suit: it becomes fragile, forms
variously-shaped globules, and also disappears, and together with this
a nuclear proliferation is noticed in the interstitial substance;
fatty granule-cells are observed in large numbers, and manifest a
tendency to accumulate in the perivascular districts. These cells are
not permanent; their gradual diminution is accompanied by a
proliferation of the interstitial tissue, which ultimately appears as
a pure connective substance composed of fine fibrillæ arranged in
undulating bundles. The entire process may be not inaptly compared to
an hypertrophy of the interstitial substance resulting from
overfeeding of its cellular elements by the morbid pabulum furnished
through the disintegration of the nervous substance proper.
The disappearance of the nerve-tubes, and the formation of a new
tissue in their place, which, like all tissues of the same character,
undergoes shrinkage, leads to considerable deformity in the shape of
the part which is the site of secondary degeneration. This is seen in
the {894} accompanying figure, where in an old-standing secondary
degeneration of one interolivary layer the corresponding half of the
medulla is greatly reduced in diameter as compared with the other side
(Fig. 34), and the entire raphé is distorted. When one side of the
cord is the site of such a change a similar asymmetry results.
[Illustration: FIG. 34. Secondary Degeneration of Interolivary Layer:
_D Ds D_, degenerated area; _r_, the distorted raphé.]
According as the original lesion is incompletely or completely
destructive, a larger or fewer number of axis-cylinders may be found
preserved in the sclerotic tissue. It is not yet determined whether in
some instances these fibres may not represent an admixture from
another source than are comprised in the mainly affected tract.
Secondary degenerations are classified as ascending and descending. An
ascending degeneration is one which is found situated brainward of the
primary lesion; a descending one is found caudad of the lesion. It was
once maintained that the direction of the secondary degeneration was
constant for each individual tract. This seems to be true for a few.
Some tracts, particularly in the brain, degenerate on both sides of
the lesion, as I showed with regard to the interolivary layer.
The best studied form of secondary degeneration is that of the
voluntary motor conduit known as the pyramid tract. Beginning in the
so-called motor area of each cerebral hemisphere, the Rolandic loop
passes into the anterior part of the posterior half of the internal
capsule, to be thence continued through the crus, pons, and the
pyramids of the oblongata to the decussation or crossing-point of the
pyramids. Here the greater part of the tract crosses into the opposite
lateral column, occupying the position described in the section on
Spastic Paralysis. A smaller part remains on the same side of the
continuous interpyramidal and ventro-spinal fissure, constituting the
direct fasciculus of Türck.