SYNONYMS.—Chronic myelitis, Diffuse myelitis, Simple or Diffuse spinal sclerosis, Chronic transverse myelitis, Sclerosis stricte sic dicta (Leyden, in part), Gray degeneration.
The various forms of sclerosis thus far considered were at one time considered as varieties of chronic myelitis, and under different names, founded on leading symptoms, were considered to be merely local, and perhaps accidental, variations of one and the same morbid process. More accurate clinical and pathological analysis has separated from the general family of the scleroses one clearly demarcated form after another. Tabes dorsalis, disseminated sclerosis, amyotrophic lateral sclerosis, and the combined forms of sclerosis have been successively isolated. Still, a large number of cases are left which cannot be classified either with the regular affections of the cord, limited to special systems of fibres, or with the disseminated form last considered. They agree with the latter in that they are not uniform; they differ from it in that they are not multilocular. Not a few modern authors have neglected making any provisions for these cases, while others treat of them in conjunction with acute myelitis, of which disease it is sometimes regarded as a sequel. The term diffuse sclerosis is here applied to those forms of chronic myelitis which follow no special rule in their location, and to such as are atypical and do not correspond in their symptomatology or anatomy to the more regular forms of sclerosis. In regional distribution the foci of diffuse sclerosis imitate those of acute myelitis: they may be transverse, fascicular, or irregular.
MORBIDANATOMY.—In typical cases the lesion of diffuse sclerosis constitutes a connecting-link between that of the disseminated form and posterior sclerosis. Its naked-eye characters are the same. There is usually more rapid destruction of the axis-cylinders, more inflammatory vascularization, proliferation of the neuroglia-nuclei, and pigmentary and hyaline degeneration of the nerve-cells, than in the disseminated form.
Syphilitic inflammation of the cord extends along the lymphatic channels, including the adventitial spaces, and leads to a diffuse fibrous interstitial sclerosis. In one case in which I suspected syphilis, though a fellow-observer failed to detect it after a rigid search, I found a peculiar form of what would probably be best designated as vesicular degeneration, according to Leyden, though associated with a veritable sclerosis. The lymph-space in the posterior septum showed ectasis; the blood-vessels were sclerotic, and each was the centre of the mingled sclerotic and rarefying change. It appears that while the interstitial tissue hypertrophied, the myelin of adjoining nerve-tubes was pressed together till the intervening tissue underwent pressure atrophy. The result was, the myelin-tubes consolidated, some axis-cylinders perished, others atrophied, a few remained, and, the myelin undergoing liquefaction, long tubular cavities resulted, running parallel with the axis of the cord, and exposed as round cavities on cross-section (Fig. 32). The changes in the cells of the anterior horn in the same cord (Fig. 33) illustrate one of the common forms of disease to which they are subjected in the course of sclerotic disease.
FIG. 32.
Diffuse spinal sclerosis
FIG. 33.
Spinal sclerosis
The so-called myelitis without softening, or hyperplastic myelitis ofDujardin-Beaumetz, which is ranked by Leyden and Erb among the acute processes, properly belongs here. It is characterized by a proliferation of the interstitial substance, both of its cellular and fibrillar elements. The nerve-elements proper play no part, or at best a very slight or secondary one. In the sense that this affection occurs after acute diseases and develops in a brief period it may be called an acute myelitis, but both in its histological products and its clinical features it approximates the sclerotic or chronic inflammatory affections of the cord. As far as the clinical features are concerned, this is particularly well shown in the disseminated myelitis found by Westphal after acute diseases, such as the exanthematous and continued fevers.
CLINICALHISTORY.—Impairment of motion is the most constant 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,149so 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 discoverer150admits 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.
149By extension the approximation of the dorsal surface to the tibial aspect of the leg—what some German writers call dorsal flexion—is meant.
150Gowers,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, thoughthe 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.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,151occurred 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.
151On 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 cure152occurred 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.
152The 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 ofDIAGNOSISapplicable 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.
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.153Often 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.
153I 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 indistinguishing 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.154This feature of the superficial reflexes is significant in the case of cerebral disease only when unilateral.
154Attention 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.155It 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.
155Wilks' alcoholic paraplegia.
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—asthe 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.
MORBIDANATOMY.—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 theaccompanying 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.
FIG. 34.
Secondary degeneration of interolivary layer
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.
The crossed-pyramid tract diminishes as it passes caudad in the cord, giving off its fibres to the lateral reticular processes of the cord,whence—whether interrupted by cells (Von Monakow) or not—they probably reach the great cells in the gray substance from which the anterior rootlets spring. The direct fasciculus probably terminates in a similar way, and perhaps makes good, as it were, its failure to participate in the gross decussation at the level of the foramen magnum by decussating in detail along its entire length. It is usually exhausted before the lumbar cord is reached, whereas the crossed tract in the lateral column continues down as low as the origin of the sacral nerves. A destructive lesion anywhere in the course of the pyramid tract, whether it be in the motor area of the cortex, in the loop of Rolando, in the internal capsule, the pons, or the cord itself, will provoke descending degeneration; that is, sclerosis of so much of the tract as lies below the lesion. Thus such degeneration is found with porencephalic defect of the motor area. I found it in a paretic dement who had extensive cortical destruction following a submeningeal hemorrhage. It has been observed after focal lesion of the pons (Homén, Schrader), and after transverse lesions of the cord, either myelitic, traumatic, or as the result of compression by vertebral disease. As a rule, the cells in the anterior horn are not involved, and some observers question whether this ever occurs. I have never found such involvement, although in its gross dimensions the anterior horn as a whole appears atrophied. This atrophy I have been able to account for satisfactorily by the disappearance of many of the fibres which run into the gray substance from the reticular processes.
While the distribution of degeneration in the cord is rather uniform, varying only in harmony with the ascertained individual variations in the relative preponderance of the crossed and uncrossed parts of the pyramid tract, there is much more variation in the cerebral distribution of the degeneration according to the extent of the original lesion. Thus, if the entire capsule be destroyed, the greater part of the crus is involved. If only the posterior division in its anterior part be destroyed, the degeneration is in the crus, limited to that part which runs a subpial course on the crural demi-cylinder, occupying from a fifth to a third of its surface-area. Still more limited degenerations are described, but as yet are too few in number to base other than tentative conclusions on them. Among these is one occupying a thin strip on the inner side of the crus, which degenerates after lesions near the genu of the capsule, and probably represents the tract which governs the cranial nerve-nuclei. An excellent observation by Von Mannkopf shows that the course of the motor fasciculus is subject to some individual variation even within the capsule.
A number of forms of secondary degeneration are described, involving intracerebral tracts, such as those connecting the cerebrum and cerebellum. The degeneration of the visual tract, from the optic nerve to the occipital lobe, observed by Richter and Von Monakow, with some conflict of opinion between these observers, is often as perfectly demonstrative of the course of the optic fasciculi as degeneration of the pyramid tract is demonstrative of the course of the voluntary innervation of the muscles moving the limbs.
The secondary degenerations following lesion of the pons varolii are acquiring special interest in view of their relation to special nerve-tracts of the spinal cord of hitherto unknown function. The purest instanceof an isolated degeneration of other than the pyramid tract is the case illustrated in the accompanying diagrams. It involved the interolivary layer, was both ascending and descending, being traced above into the subthalamic region, and below decussating into the opposite side of the oblongata, to terminate in the nuclei of the columns of Burdach and Goll. The leading symptom manifested by the patient was a hemiplegia of the muscular sense.156
156Besides my case, others have been recorded by Homén, Meyer (Strassburg), and Schrader, which are impure. In the former and latter degeneration of the pyramid tract, in the second degeneration of the olivary fasciculus, coexisted. It is not generally known that Westphal, in one of the first volumes of theArchivesnow edited by him, found an ascending degeneration of the same tract for a short distance.
FIG. 35.
Secondary degeneration of interolivary layer
Secondary Degeneration of Interolivary Layer, Caudal or Descending Portion: A, in caudal half of pons; B, cephalic end of oblongata; C, middle of oblongata; D, at level of so-called upper pyramidal or interolivary decussation; E, at level of true pyramidal decussation. The atrophy in this level has entirely crossed the middle line; in D it is seen in the act of crossing.
Ascending degeneration is found in a very distinct form after compression of the cauda equina. It is limited to the posterior columns, occupying nearly the entire area of the latter in the lumbar cord, particularly the triangular field of Burdach's column mentioned in the article on Tabes. In the dorsal and cervical cord it is limited to the columns of Goll, and terminates in the clava of the oblongata at the nuclei of those columns.
Higher lesions produce the same ascending degeneration of the column of Goll, and in addition involve other, probably centripetal, tracts which happen to be injured at their origin or in their course. For example, a transverse lesion of the dorsal cord would produce ascending degeneration for its whole length of the column of Goll and of the direct cerebellar tract. In addition, it would, in obedience to the law previously stated, produce descending degeneration of the pyramid tract. This combination is almost a typical sequence of compression myelitis of the cord, aswell as of ordinary transverse sclerosis. Recently, Gowers157has described a secondary degeneration in such a case of transverse lesion not previously noticed. It is found in cases showing gross disturbance of cutaneous sensibility, and occupies a narrow belt encircling the anterior quarter of the circumference of the crossed-pyramid tract. It is continuous, in my opinion, with a tract which in the upper cervical cord is situated in a corresponding situation, and which degenerated a short distance caudad in a case of secondary degeneration of the olivary fasciculus described by Meyer, and in which similar sensory symptoms were noted.
157Diseases of the Spinal Cord, andNeurologisches Centralblatt, 1886.
FIG. 36.
Decussating degeneration of interolivary layer
Decussating Degeneration of Interolivary Layer:Dr,Darc, the crossing degenerated fasciculi;Arc, the undegenerated fasciculi, after emerging from the partly sclerosed raphé.
CLINICALHISTORY.—Secondary degenerations are passive results of other more active processes, and few clinical signs are attributable to them. The most important of these is the contracture which is found in old hemiplegias, and attributed, like the secondary exaggeration of deep reflexes in such, to the descending degeneration of the pyramid tract. Bouchard believed that it was the retraction of the sclerotic strand which acted as an irritant on the neighboring fibres. The development of spastic symptoms in amyotrophic lateral sclerosis and in focal lesions of the crossed-pyramid tract is in favor of this view. On the other hand, the occurrence of flaccid hemiplegia, and its conservation for years after the most extensive lesions, is against it, as it is in these very cases that the secondary degeneration is most intense. That the retraction of alongitudinal strand exercises any serious effect on neighboring and parallel fasciculi is questionable, as the process is slow. There is, however, one situation where such influence is very likely to occur—the decussations of the oblongata. In the case already referred to, the retracting sclerosing bundles undoubtedly must have exercised a damaging effect on their fellows of the opposite side, which, interdigitating with them, were compelled to pass through the sclerosing tissue. It has occurred to me that the slight sclerosis which is sometimes observed in the crossed-pyramid tract of the same side of a cerebral lesion, even where that lesion is strictly unilateral, is due to a similar influence. I think it can be shown that such sclerosis cannot be traced to the primary lesion; it begins at the decussation, and it is more than probable that the firm constriction to which the healthy fibres are subjected in crossing through their shrinking fellows of the opposite side is not alone the cause of the symmetrical yet slighter lesion, but also accounts for the observation by Pitrés and Charcot of a slight motor weakness observed on the same side as the hemiplegia, producing lesion in ordinary cases of capsular hemorrhage.158
158Some of the French observers claim that this occurs only in the early period, but a careful study of the matter by R. Friedländer shows that the weakness of the side not usually regarded as involved is found in the later periods, and well marked then (Neurologisches Centralblatt, June 1, 1886).
ThePROGNOSISandTREATMENTof secondary degenerations are practically involved in the primary lesion which gave rise to them. The contractures attributed to secondary sclerosis of the motor tracts is to be treated on the principles mentioned in the following section.
As the histological character of the different forms of sclerosis is similar—at least in the terminal period—the causes producing them identical even in name, and the indications furnished by leading symptoms analogous if not identical, the treatment of these various disorders is naturally based on the same leading principles. There are two objects to be aimed at in dealing with these chronic disorders: The first is the cure or arrest of the morbid process itself; the second is the amelioration of distressing and disabling symptoms.
It is generally recognized that a perfect cure of a sclerosis is a consummation never to be realized by any plan of treatment now at our disposal. The experiments of Kahler and others have shown that spinal tissue, once destroyed, is not regenerated. The post-mortem examination of cases of tabes which were considered as cured during life (Schultze) has shown that the sclerosis had not been removed; the process had merely become quiescent, and the apparent recovery had been due to the vicarization of other nerve-elements than those destroyed for the latter.
But if attempts at the regeneration of destroyed fibres and cells are to be regarded as futile, the arrest of the destructive process is to be considered as an object which offers better chances of realization, and which is worth attempting for other than merely conservative reasons. In a number of the forms of sclerosis described, notably in tabes and the disseminated form, it is remarked that the axis-cylinders lying within themorbid district are in part intact and in part but slightly affected. Here and there groups of nerve-tubes may be found which retain even their myelin. While subject to the vicissitudes inseparable from their position in the midst of active pathological changes, these channels of nerve-force, though anatomically patent, may have their function perverted or destroyed, just as a nerve outside of the cord may be paralyzed by pressure or anæmia though its structure be intact. Should the active phase of the sclerotic process be arrested, these intact or nearly intact fibres will resume their function, and thus an apparent improvement will be effected. The spontaneous ameliorations in the course of tabes dorsalis and the less marked ones of diffuse sclerosis, coupled with temporarily improved sensation in the former and improved motion in the latter disease, show that retrogressions of this character are possible and do occur. How is the physician to imitate the action of nature? how to intensify it so as to secure the permanent improvement which nature unaided does not grant? The first factor to be considered is the removal of the cause of the disease. A number of cases are due to exposure to wet and cold and to over-exertion. Such exposure and over-exertion, if not already rendered impossible by the disease, is to be discontinued. A large number of cases of tabes—according to many authors, a majority—a considerable number of cases of diffuse sclerosis, and not a few of other forms, are connected with the syphilitic dyscrasia. Here, at the very outset, we have a definite indication for treatment, and while we may be disappointed in the results of such treatment in a large proportion of cases, yet enough of well-assured and substantial success has been and is obtained to render it almost a matter of duty for the physician to try antisyphilitic measures in every such instance.
The mixed treatment in chronic spinal disorders should be followed out for long periods and faithfully. Most tabic and other sclerotic subjects affected with constitutional syphilis are in what is called the tertiary period of that disease, when iodide of potassium is less useful than mercury. I have never gained anything by pushing either drug to the extreme point in advanced cases, and it should be borne in mind that mercurialization carried too far may itself prove directly injurious to the nerve-centres.159In cases where gastric crises, gross ataxia, muscular atrophy, and bladder disturbance have been of long duration this treatment is rarely successful.160But in the initial and early periods of tabes and in diffuse sclerosis of slight intensity the effect is sometimes gratifying, and of such a nature that it cannot be attributed to a coincidence with spontaneous remissions of the disease. In one case both knee-jerks and the pupillary reflexes returned, to disappear on premature discontinuance of the treatment; and on resumption one knee-jerk again returned, and has remained demonstrable now over half a year. In a second case the fulminating pains and the bladder disturbance disappeared, a slight indication of the pupillary reflex developed, and the patient has remained stationary with this gain for a period of threeyears.161In a third case, one of established ataxia, with which luetic osseous lesions occurred, the pupillary reflex has returned twice, disappearing after the first reappearance. In one case of combined sclerosis in which no syphilitic antecedents could be found the paresis of the arms has disappeared, and the ataxic paresis of the lower extremities has improved to such an extent that the patient can stand with his eyes closed and his feet together, and on one leg with the eyes open—feats which a year ago he was unable to perform. None of the changes in symptoms taking place in these cases occur spontaneously in sclerotic spinal disorders, and they must be attributed to the treatment. Such treatment is best carried out in conjunction with warm bathing. The Hot Springs of Arkansas, those at Las Vegas, New Mexico, and the baths of Aix-la-Chapelle in Europe enjoy a special reputation in this field. The springs of Arkansas, as regards the intrinsic character of the water, possess advantages which are probably not excelled by any European baths, but the therapeutical management162is far from that ideal point of development attained, for example, at Aix-la-Chapelle.
159Mendel thus found in his experiments made on dogs, developing cerebral disease from rotation with the head directed toward the axis of rotation, that dogs who had previously received subcutaneous injections of corrosive sublimate showed an increased vulnerability to the action of the rotary apparatus.
160A remarkable exception is related in the section on Chronic Myelitis.
161There was concentric limitation of all color-fields, and only central perception of green; to-day, if anything, the color-fields of this patient are a little greater than in the physiological average. The case was undoubtedly one of initial tabes.
162Mercurial ointment is used by the hundredweight, to quote the expression of a patient, and in certain establishments the sufferers from the common taint plaster each other from head to foot, as with mud, with this panacea for most of those ills which flock to the springs. Still, there seems to be no doubt that enormous quantities of mercury are borne well by those who use the baths, and who under other circumstances are susceptible to its most undesirable effects.
Optic-nerve atrophy, according to the best authorities, constitutes a contraindication to the use of mercury in any form. It may be laid down as a general rule that the more rapidly the symptoms indicating a sclerotic process are developed, and the more recent its advent, the more energetically should the treatment be pushed. Mercurial inunctions and the so-called heroic doses of iodide are to be employed. But in cases progressing slowly and of long antecedent history what may be called a dilute plan is more apt to yield good results. Small doses of mercury,163given steadily for years, and iodide of potassium, administered in well-tolerated doses for periods of ten days, alternating with corresponding periods of intermission, have, in my opinion, delayed or arrested the progress of tabes and other forms of sclerosis for the long periods referred to in the preceding sections.164Although the antisyphilitic measures adopted in sclerosis of syphilitic origin are the most important, and the prognosis of no such case can be regarded as hopeless as to recovery or duration until they have been tried, other procedures, detailed under the head of Peripheral Treatment, should not be neglected. While some very severe cases improve rapidly on antisyphilitic treatment, other much less severe and more recent cases, in which the same cause is assigned with equal reason, are not affected by it in the slightest visible degree. The reason for this difference is unknown, but it necessitates the bearing in mind that bylimiting the treatment to the etiological indication valuable time may be wasted in which the symptomatic indications could be profitably followed.
163The tablet triturates of biniodide of mercury or corrosive sublimate furnished by Fraser & Co. of New York I have found peculiarly useful; one one-hundredth or more of a grain may be thus administered every two to four hours.
164I am now employing the same treatment in some cases showing no syphilitic history. If any medicinal measures can act upon connective-tissue proliferation, it is these very ones.
In cases of sclerosis due to other causes than syphilis a number of medicinal agents have been recommended as calculated to affect the central disease directly. Ergot is recommended in sclerotic troubles, particularly tabes, by a large number of writers. It is admitted that this substance can produce tabes itself, so that its administration in the large doses recommended by some is not without its possible dangers. I have seen a patient well advanced in the disease who had received the drug for three weeks consecutively in such quantities165that on estimates made I came to the conclusion that he had received more than some of the persons in whom Tuczek discovered the development of ergotin tabes. Favorable results are reported ensuing after its use in the early stages, particularly where signs of irritation preponderated, such as lightning-like pains, hyperæsthesia, and frequent erections; and it has been suggested that the beneficial action is due to an effect on the blood-vessels, which are supposed to be congested in the beginning of the disease. Proof of such congestion has not been furnished: the vessels are usually sclerosed and their lumen narrowed. In view of the undeniable danger which attends the administration of ergot in tabes, it may be properly insisted that its indications be more precisely formulated than has yet been done. It is commonly noticed in the natural progress of tabes that the lightning-like pains disappear, usually about the time the anæsthesia becomes greater. The anatomical parallel is supposed to be the destruction of the nerve-tubes whose previous irritation caused these pains. If, as is claimed—and it seems to be substantiated—ergotin does produce amelioration of the lightning-like pains, it would prove a damaging revelation which showed that it did so in imitation of the natural process; that is, by increasing the sclerosis.
165An expert ophthalmoscopist found that the retinal vessels, which were somewhat dilated in this patient, were not influenced by the treatment.
The first drug to which an influence was assigned upon the sclerotic processes, and which has maintained its reputation longest, is nitrate of silver.166Its claim to being regarded as a remedy may be best characterized by the fact that an author who is far from being prejudiced against it, and who recognizes the claims of Wunderlich, its advocate, speaks of it as a valuable placebo.167I have never obtained any effects from this drug in the scleroses, or from the chloride of gold, which has been also recommended for these affections, nor have I seen any in cases where either or both had been faithfully tried by others for years. The same is to be said of the chloride of barium, which has been warmly extolled on the basis of a very limited trial in disseminated and diffuse sclerosis.
166One of the first patients on whom Wunderlich tried this drug died while I studied at Leipzig. He had extensive argyria and sclerosis of the posterior columns.
167Leyden,op. cit., vol. ii. p. 359.
The direct application of the galvanic current to the spine is recommended, more particularly by Erb and Neftel.168I am unable to stateanything regarding currents derived from as many as twenty of Siemens cells and applied in the ascending direction, as the latter recommends beyond an experience which occurred in the practice of a colleague, who, alarmed by the event to be related, referred the patient subjected to this treatment to me. The patient suffered from tabes dorsalis, the symptoms being limited to the lower extremities, the ulnar distribution, and the pupils. The belt was in the lower thoracic region; the ataxia and lightning-like pains were not great. After a single application of an ascending current from twenty-two cells, continued for ten minutes, the patient suddenly felt a severe dull pain in the occiput and terrible lancinating pains in the distribution of the occipital nerves. With this there occurred scintillation before the eyes, and at the subsequent examination I found that the belt sensation had moved into the neck. The coincidence was so close, and sudden changes in the distributional area of tabic symptoms are otherwise so uncommon, that I attributed the observed change to the treatment.
168In describing a case in which this measure not only ameliorated lancinating pains and vesical symptoms, but also, applied to the head, relieved the diplopia—usually a spontaneous occurrence, according to both American and European writers—this writer takes occasion to state that in the year 1869 tabes dorsalis was practically unknown to American physicians (Archiv für Psychiatrie, xii. p. 619). Duchenne described progressive locomotor ataxia in that and the preceding year; the necessity of referring to the unfamiliarity of American physicians with a disease not at the time recognized on either side of the Atlantic is hence not apparent. Leyden (op. cit., vol. ii. p. 325) candidly admits that the German medical profession was at first averse to recognizing Duchenne's limitation: this reproach cannot be laid at the door of American physicians, as I can distinctly recollect the demonstration of several well-marked cases exhibiting the characteristic symptoms then known, in the year 1870. The disease obtained recognition in American textbooks and journals as early as in those of any other land.
Erb does not recommend such powerful applications. But the most sanguine electro-therapeutist must admit that the action of galvanic currents on the spinal cord is an exceedingly uncertain one. It is questionable whether weak ones deflect sufficient current-loops to reach the cord and to exert any material effect. As to currents powerful enough to produce an effect, it is not known, except in the loosest and most empirical way, what that effect is. The procedure followed by Erb is to use large electrodes, the cathodal one being a little smaller than the anodal, the former being placed stabile, over the upper cervical sympathetic ganglion of one side, the latter labile, on the opposite side of the vertebral spines, moving gradually downward, the session not exceeding three minutes. This is repeated daily or every alternate day.169It would prove a strong proof that this treatment really affected the morbid process in a remedial direction if any of the exact signs of the disease were to be modified by it, be it ever so slightly. If, after galvanization of the cervical cord and the sympathetic nerve, the initial myosis of tabes were temporarily lessened or the reflex contraction to light restored for ever so short a time, a brighter future would dawn for electro-therapeutics than seems now to be in store for it.170
169Why, if the procedure be really remedial or efficiently palliative and devoid of evil consequences, it is not recommended to be repeated oftener I am at a loss to explain or understand. There are some factors involved in practical electro-therapeutic which it is scarcely possible to discuss without encroaching on delicate ground.
170In healthy persons the extent of the knee-jerk is increased by the spinal ascending galvanic current, and possibly this observation may lead to the establishment of a rational basis for its use in cases where the reflex is abolished or diminished.
Peripheral Treatment.—A number of therapeutical applications are made to the periphery where the symptoms of the sclerotic process are localized. The rationale of such applications is based on the assumption that peripheral conditions are capable of modifying the nutrition and functions of the cord. This is proven not alone by a host of observations madeon the normal cord, but is also disastrously illustrated in the part played by surface chilling in the etiology of many acute and chronic diseases of the cord. Notwithstanding this latter, a large and influential body of German neurologists recommend cold baths and cold spinal douches in these affections. I have seen such excellent results from the use of warm baths that I am compelled to plead, in defence of my ignorance of the effect of cold ones, that I have never dared to use them. In numerous cases the beneficial effect of a warm bath is almost instantaneous. Warmth in any shape, whether atmospheric or in the shape of baths, is usually agreeable to patients suffering from the various forms of sclerosis. Cold, on the other hand, is disagreeable, aggravates the symptoms, and in many cases at least hastens the progress of the disease. A winter spent in the latitude of New York or Boston means so much ground lost by the patient, and a sojourn during the colder months in Southern California, New Mexico, Florida, or the West Indies enables the patient to avoid this loss. As regards the choice of climate and baths for sclerotic patients, I should be inclined to roughly formulate the indications as being identical with those of chronic rheumatism. The reaction against the use of warm baths in Germany, where they once were popular,171is due to the employment of too high temperatures. Hot baths, in the strict sense of the term, including the various forms of vapor-bath, act badly. They increase instead of calming the irritative symptoms, as moderately warm baths do, and they entail too sudden a change in the bodily state. That, for the present, it is advisable not to adopt unreservedly either the extreme plan once in vogue or the equally extreme one which constitutes the reaction against it, is shown by the observations of Richter of Dalldorf, who records some discouraging results obtained by the use of cold baths in cases of tabes dorsalis. It is but necessary to refer to the fact that the lancinating pains of the latter disease, the rigidity of diffuse myelitis, and the spasms of lateral sclerosis are usually most severe in cold weather, and that the diseases mentioned appear to be rare in warm countries, to show the need of caution in using a therapeutical measure so similar in its action, even if it be but momentary and followed by a reaction, to those which provoke or aggravate the original disease. Eulenburg has seen five recoveries in tabes, and under such different plans of treatment that the latter is not credited by him with the good result. Three were treated with warm baths, one with cold baths, and one with nitrate of silver. It is seen here that the warm baths were used with good results more frequently than the cold.
171The mud-baths of Cudowa in Gallicia had a very high reputation.
One of the most singular delusions of modern therapeusis—nerve-stretching—has, following the prediction made by several on both sides of the Atlantic, become obsolete. Introduced by Langenbuch, a surgeon, and attacking the disease at the sciatic nerve—a point where, as well-versed students knew, it was not located—the operation was looked upon with distrust from the beginning. The enthusiasm with which it was taken up by surgeons and by the interested portion of the laity—ever hopeful as tabic patients are of new drugs and methods of treatment—has led to a large number of trials, now numbering several hundred, and from which the useful lesson can be gathered that the good ripens slowly. Nerve-stretching in an organic disease of the spinal cord may take itsplace among the needless vivisections; it has not influenced the progress of a single case in any essential feature. On the contrary, it has more than once been directly responsible for acute myelitis, spinal hemorrhage,172and pyæmia. In a number of cases reported by Langenbuch,173Benedict, Erlenmeyer, Schweminger, Debove, and W. J. Morton, the ataxia of the patient has been reported as relieved; in one case, exhibited by the latter operator before the American Neurological Association, this appeared quite evident, but not because the disease proper had been influenced, but for the same reason that prevents the development of marked ataxia in combined sclerosis. Just as the lateral-column lesion inhibits the ataxia which is due to the posterior-column lesion, so the motor paresis produced by stretching the sciatic nerves neutralizes the manifest features of the ataxic gait. As soon as the paresis is recovered from, the ataxia returns in its original form, unless, happily, one of the common spontaneous changes for the better occur. As a therapeutic procedure nerve-stretching is to-day properly limited to affections of the peripheral nerves.
172Zacher,Archiv für Psychiatrie, xv. p. 430.
173Westphal showed after the autopsy of Langenbuch's first successful case that there had been no spinal lesion whatever.
One of the most useful peripheral remedies in the sclerotic processes is the faradic wire brush. It is both an anodyne and remedial for anæsthesia. A number of the tabic patients to whom I referred as not having deteriorated within long periods are provided with a portable faradic battery, and apply the brush to the spots affected by terebrating pains the moment these commence, obtaining instantaneous relief. As has been shown by Rumpf,174the cutaneous space-sense becomes more delicate in healthy and improved in tabic patients under its continued use. And while the inco-ordination of tabes is in part independent of the disturbance of cutaneous sensibility, yet if the latter can be refined the ataxic disturbance may be mitigated—a result occasionally obtained through the methodical use of the wire brush.
174Report of a discussion,Neurologisches Centralblatt, 1885, p. 526.
It is frequently found that sufferers from tabes dorsalis and other forms of sclerosis accompanied by ataxia walk much better in their stocking feet and in slippers than they do in the conventional street shoe or boot. The reason for this is obvious. The patient's gait is impaired by the disease, and, whether the ataxia be a pure co-ordinatory trouble or no, subjective uncertainty regarding contact with the ground which is experienced by most ataxic patients is an aggravating factor. Our modern foot-clothing, with its inflexible soles and raised heels, handicaps the patient as it were, depriving him of the use of what little tactile sensibility may be left him.175The use of low-heeled shoes with thin and flexible soles is therefore advantageous.
175The question whether tabes dorsalis is a disease of civilization has not been raised in any treatise I am acquainted with. Myelitis, both acute and chronic, occurs, however, rarely in the lower animals, as do also central dilatation of the cord and congenital defects of the latter. Posterior sclerosis I can find no record of in veterinary pathology. The influence of the repression of normal aids to locomotion by the foot-gear of civilized life as a possible predisposing factor in the etiology of ataxic troubles is a legitimate subject of inquiry. The lateness of the infant of civilized parents in acquiring the art of skilled locomotion may be in part, as philosophers claim, a penalty of exuberant development of the higher and inhibitive centres. But what part has the artificial obliteration of solar sensibility and pedal flexibility played in this inherited feature? What is its influence in establishing a pathological vulnerability?