far as possible, of such conditions as may cause or keep up the
inflammation, as, for instance, the proper treatment of wounds, the
removal of foreign bodies, the adjustment of fractures, the reduction
of dislocations, the extirpation of tumors, etc. Absolute repose of
the affected part in the position of greatest relaxation and rest is
to be scrupulously enforced. In acute neuritis local abstraction of
blood by leeches and cups in the beginning of the affection is of the
greatest advantage and should be freely employed. The application of
heat along the course of the inflamed nerve has appeared to us
preferable to the use of ice, although this also may be employed with
excellent effect. The agonizing pain must be relieved by narcotics,
and the hypodermic injection of morphia is the most efficient mode of
exhibition. Salicylic acid or salicylate of sodium in large doses
contributes to control the pain. Iodide of potassium in large doses
appears to act beneficially, even in cases with no syphilitic
complications. In subacute or chronic neuritis local bloodletting is
not as imperatively demanded as in the acute form, although it is
sometimes useful. Here counter-irritation in its various forms and
degrees, even to the actual cautery, is to be recommended. An
excellent counter-irritation is produced by the application of the
faradic current with the metallic brush. It appears from general
experience that the counter-irritation has the best effect when
applied at a little distance from the inflamed nerve, and not directly
over its course. In the galvanic current we possess one of the very
best means not only for relieving the symptoms of chronic neuritis,
but for modifying the morbid processes in the nerve and bringing about
a restoration to the healthy condition. Its application is best made
by placing the anode or positive pole as near as possible to the seat
of the disease, while the cathode or negative pole is fixed upon an
indifferent spot at a convenient distance. The positive pole may be
held stationary or slowly stroked along the nerve. Finally, in
protracted cases nerve-stretching may be resorted to with great
benefit. It probably owes its good effects to the breaking up of
minute adhesions which have formed between the sheath of the nerve and
the surrounding tissues, and which act as sources of irritation.
{1195} Multiple Neuritis, Multiple Degenerative Neuritis,
Polyneuritis.
Cases of this important form of neuritis have been observed and
recorded since 1864, but the resemblance of its symptoms to those of
certain diseases of the central nervous system (poliomyelitis,
Landry's paralysis, etc.) has prevented its general recognition, and
it is only within the last few years that its distinctive pathological
lesions have been demonstrated and its diagnosis made with
considerable certainty. We can hardly overrate the importance of this
in view of the great difference in gravity of prognosis between it and
other diseases with which it may be confounded.
Multiple neuritis consists in a simultaneous or more or less rapidly
succeeding inflammation of several or many usually bilaterally
situated nerves, with a greatly preponderating, almost exclusive,
lesion of the motor fibres. Commonly the disease attacks the lower
extremities and progresses upward, although occasionally it has been
seen to begin in the arms. It does not confine itself to the nerves of
the extremities and trunk, but often involves the phrenics, causing
paralysis of the diaphragm, and frequently invades one or more of the
cranial nerves, notably the vagus, thus giving rise to the rapid
heart-beat so often seen in the disease. In the cases of multiple
neuritis observed the muscles of deglutition have never been
paralyzed. The sphincter ani and bladder have likewise escaped. All
degrees of acuteness are observed in the course it runs, from the
cases terminating rapidly in death to those in which the disease
extends over months, slowly involving nerve after nerve, until nearly
all of the muscles of the body are paralyzed, when death may result or
a more or less complete recovery take place. The invasion of the
disease is in most cases sudden, even when its subsequent course is
chronic, and is often marked by decided constitutional disturbance, as
rigors, fever, delirium, albuminuria, etc. Disturbances of sensation
are prominent among the initial symptoms, and are of great importance
for the diagnosis of the disease. Severe, spontaneous, paroxysmal pain
of a shooting, tearing character has ushered in most of the cases on
record, remitting, however, during their progress. Pain is not always
present, nevertheless, and cases not infrequently occur which run a
painless course. In some cases which have come under the writer's
notice spontaneous pain did not occur until some days after the
disease was fully declared by other symptoms. More constantly present,
and more characteristic of multiple neuritis, are the disturbances of
sensation which show themselves in subjective feelings of numbness,
tingling, pins and needles, coldness, burning, and other paræsthesiæ,
which appear at its outset and continue to be present more or less
during its course. Anæsthesia, not of a high degree nor at all
coextensive with the paralysis of the muscles—sometimes, indeed,
confined to very circumscribed areas—may be said to exist always in
multiple neuritis—a fact of great diagnostic value. Hyperæsthesia of
the skin is frequently seen. Hyperalgesia and analgesia are sometimes
observed. Hyperæsthesia of the muscles is a very marked symptom in
almost every case, and shows itself not only upon direct pressure
being made, but also in the pain elicited by passive movements of the
parts affected. Pressure upon nerve-trunks does not cause pain as
{1196} invariably as might have been expected from the location of the
disease. Delayed sensation has been frequently observed.
Paresis of muscles, often commencing suddenly, is early seen in
multiple neuritis, and increases until there is more or less complete
paralysis, the most important feature of the disease. The paralyzed
muscles present the flabby condition characteristic of muscles
deprived of the tonic influence of the spinal cord. Atrophy, which is
not commensurate, however, with the paralysis, soon begins, and may go
on to an extreme degree. As the paralysis develops the tendon reflexes
are lost, and there may be diminution or loss of the skin reflexes
also. The paralyzed muscles lose their faradic contractility, and
exhibit diminution of electric excitability to the galvanic current,
and, finally, the various forms of degenerative reaction. It is
remarkable that neither the impairment of sensation nor the paralysis
is, as a rule, strictly confined to the areas of distribution of
particular nerves, but is diffused over regions of the body. Thus in
the limbs the motor and sensory symptoms are most marked at their
extremities, gradually diminishing toward the trunk. In some cases
multiple neuritis appears to have occasioned the inco-ordinate
movements of locomotor ataxy. In the progress of the disease a
rigidity and contracted condition of muscles may be developed,
occasioning a fixed flexion of some of the joints. Profuse sweating,
œdema of the hands and feet, trophic changes in the skin, mark at
times the implication of trophic and vaso-motor nerves. Bed-sores do
not occur.
The pathological changes in pure cases of multiple neuritis are found
in the nerve-trunks, mainly toward their peripheral terminations, and
in their muscular branches, the evidences of disease diminishing
toward the larger trunks, the nerve-roots being unaffected and the
spinal cord showing no lesions. Sometimes the affected nerves present,
even to the naked eye, unmistakable proof of acute inflammation. They
are reddened by hyperæmia, swollen by exudation, and small
extravasations of blood may be seen among their fibres. The microscope
shows congestion of the blood-vessels, exudation of the white
corpuscles, even to the formation of pus, alteration of the endo- and
perineurium; in short, all the evidence of an interstitial
inflammation, the nerve-fibres being comparatively little altered, and
suffering, as it were, at second hand. In most of the cases, however,
the nerves macroscopically present little or nothing giving indication
of disease. The microscopic changes, however, are extensive, and
pertain almost exclusively to the nerve-fibres themselves. These are
altered and degenerated, giving an appearance almost precisely the
same as already described in treating of the changes occurring in
nerves separated by injury from the centres—Wallerian degeneration.[8]
There is no hyperæmia, thickening, or change in the endoneurium. So
great are these differences in the microscopic appearance of the
nerves in different cases of multiple neuritis that objection has been
raised to classing the two varieties together, and it has been argued
that we cannot with right designate the cases in which hyperæmia and
other evidence of {1197} a general inflammation are absent as
neuritis. It has been, however, argued—apparently, to the writer, with
better reason—that the same morbid influence which at one time affects
the blood-vessels, causing their congestion and the passage through
their walls of the white corpuscles and the exudation of inflammation,
may at another time, by a direct and isolated influence upon the
nerve-fibres, cause their degeneration; in other words, that there may
be a parenchymatous neuritis, which shall affect only the
nerve-fibres. The vastly disproportionate implication of the motor
fibres would point to the fact of a selective infection in multiple
neuritis of certain fibres, as there is a selective infection in
poliomyelitis of the motor cells of the anterior horns of the spinal
gray matter.
[Footnote 8: Gombault's observations (_Arch. de Névrologie_, 1880)
would seem to show that there is a difference in the lesion of the
fibres in neuritis from that in simple Wallerian degeneration,
inasmuch as that in the former the first alteration is seen about the
nodes of Ranvier, and occurs at points separated from each other by
healthy fibre, and also in the more tardy destruction of the
axis-cylinder.]
ETIOLOGY.—Much in the symptomatology of multiple neuritis, especially
of its invasion, strongly urges us to the conclusion that it is a
constitutional disease caused by an unknown morbid influence, the
stress of which falls upon the nervous system. This view receives
strong support from the history of the Japanese kak-ke or Indian
beriberi, a disease at times epidemic in those countries, and which
has the undoubted symptoms and the characteristic pathological
alterations of multiple neuritis. After many acute infectious diseases
neuritis of individual nerves is not uncommon, but the distinctive
characteristics of multiple neuritis have, so far, been observed
almost exclusively after diphtheria, to which it is not infrequently a
sequel. It has been observed as the result at least occurring in
intimate connection with polyarthritis, and the frequency with which
it has occurred in the phthisical is remarkable. There have been not a
few cases of multiple neuritis recorded as having been produced by
chronic alcohol-poisoning. A well-marked case has come under the
writer's observation in which the immediate cause was acute poisoning
by arsenious acid, a very large amount having been taken at one dose
by mistake. The poison of syphilis has been regarded as standing in a
causal relation to multiple neuritis. For the rest, the exciting
causes (probably acting in connection with a peculiar condition of the
system) have appeared to be exposure to cold, great muscular exertion,
direct mechanical injury to the nerves, as the rough jolting of a
wagon, or the inflammation of a nerve which has in some unknown way
extended to others.
The DIAGNOSIS of multiple neuritis in certain cases presents great
difficulty, from the close resemblance of its symptoms to those of
poliomyelitis. The prominent symptoms in the muscular system—viz.
paralysis, atrophy, the degenerative reaction—are the same in both. It
may be remarked, however, that in multiple neuritis the paralysis is
more generally diffused over the muscles of the affected limbs, while
in poliomyelitis it is more confined to the areas of distribution of
particular nerve-branches. Pain is common to the beginning of both
diseases, but it generally passes off more quickly and completely in
poliomyelitis. The persistent hyperæsthesia of the muscles is wanting
in poliomyelitis. But it is in the diminution and alteration of
sensation that we have the surest means of distinguishing between the
two affections. This symptom seldom or never fails to show itself in
multiple neuritis, although its area may be circumscribed and it may
be slight in degree, while it certainly makes no part of the
symptomatology {1198} of poliomyelitis. It has been asserted that the
implication of the cranial nerves so often seen in multiple neuritis
never occurs in poliomyelitis. When we consider the intimate
connection of the anterior horns of the spinal gray matter with the
motor nerve-fibres, it appears highly probable that the same morbid
influence may invade both simultaneously or in quick succession, thus
producing a complex of symptoms rendering a diagnosis very difficult,
and probably giving rise to some confusion in the recorded symptoms of
multiple neuritis. From Landry's paralysis multiple neuritis is to be
distinguished by the impairment of sensibility, the loss of faradic
contractility, and absence of the tendon reflex; from progressive
muscular atrophy, by the loss of sensibility and the much more obvious
degenerative reaction.
The PROGNOSIS of multiple neuritis is in the great majority of cases
not grave, so far as life is concerned, even when there is extensive
paralysis. Death may occur early in the acute form of the disease or
it may take place at the end of chronic cases. When the disease proves
fatal, it is from paralysis of the diaphragm and the other muscles of
respiration. Where the paralysis and atrophy have been great, showing
profound alteration of the nerves, a long time is required for
recovery, and more or less paralysis, contracture, or defective
sensibility may permanently remain.
The TREATMENT consists, at the outset, in rest and position, the local
abstraction of blood (in cases where the nerve-trunk is swollen and
tender), and the administration of such drugs as we suppose act
favorably upon the inflammation of the nerves. Salicylic acid or
salicylate of sodium seem to act beneficially in relieving the severe
pains in the outset of the disease. Iodide of potassium, gradually
increased until large doses are taken, has, in the experience of the
writer, seemed to beneficially modify the course of multiple neuritis.
The necessary relief of pain is best obtained by hypodermic injections
of morphia, supplemented by heat applied to the affected nerves. To
these means may be added rubbing with chloroform and applying to the
painful parts cloths dipped in a 5 per cent. solution of carbolic
acid. After the acute stage has been passed and in chronic cases, just
as soon as we have reason to suppose that the degenerative process in
the nerves has come to a standstill, we possess in the use of
electricity the means of hastening the regeneration of the
nerve-fibres, strengthening the paralyzed muscles, and restoring the
sensation. The galvanic current is to be preferred, and it is to be
applied to the crippled nerves and muscles—sometimes stable for its
electrolytic action, sometimes interrupted to obtain its exciting and
stimulating effect. The excitement to nerves and muscles by the use of
the faradic current has also its uses in hastening recovery.
Protracted treatment and much patience are required to overcome
contractions and restore the nerves and muscles, and the effects of
the disease may be seen for a long time in the weakness and diminished
electric reaction of the muscles.
Anæsthesia of Peripheral Origin.
A prominent and important symptom of the lesion of peripheral nerves
is the diminution and loss of cutaneous sensibility. Besides the
{1199} anæsthesia caused by the affections of the fibres themselves,
which has been touched upon in the preceding pages, it may be produced
by morbid states of the peripheral end-organs or cutaneous
terminations of the nerves. Cold applied to a nerve-trunk may produce
alterations which for days after cause numbness and paræsthesia in the
surface to which it is distributed, and the application of cold to the
surface of the body, as we know from common observation, causes
blunting of the cutaneous sensations, especially that of touch. In
this way, from exposure to the atmosphere at low temperatures, to cold
winds, or by the immersion of the body in cold water, the end-organs
of the nerves in the skin are morbidly affected, and anæsthesia
results, the so-called rheumatic anæsthesia. Many substances, as
acids, notably carbolic acid, alkalies, narcotics, etc., act upon the
cutaneous end-organs in a way to destroy their capacity for receiving
or transmitting impressions and produce a more or less persistent
anæsthesia of the skin. In the anæsthesia so often observed in the
hands and forearms of washerwomen we have an example of the action
probably of several of these causes, as the frequent plunging of the
hands into cold water and the action upon the skin of alkalies and
alkaline soaps. The diminution or interruption of the circulation
through the skin, as in ischæmia from spasm of the minute arteries due
to an affection of the vaso-motor nerves, is also a cause of cutaneous
anæsthesia. In lepra anæsthetica (Spedalskhed) the cutaneous
anæsthesia is dependent upon a neuritis of the minute branches in the
skin. The local anæsthesia met with so often in syphilis, though its
pathology is doubtful, is not improbably sometimes caused by an
affection of the peripheral nerves (neuritis?) and their end-organs.
After many acute diseases, diphtheria, typhoid fever, etc., we have
cutaneous anæsthesia in connection with muscular paralysis, the cause
of both being a neuritis. The patient is made aware of the loss of
sensation by some interference with his usual sensations and
movements. If he puts a glass to his lips, the sensation is as if a
bit were broken out of the rim; his accustomed manipulations are
awkward, because of the want of distinct appreciation of the objects
he holds; he fumbles in buttoning his clothes or he stumbles unless
looking to his steps. An examination, nevertheless, almost always
reveals that the anæsthesia is greater than would have been supposed
from the subjective feelings of the patient; indeed, cases occur in
which he is not aware of an existing defect of sensation. But a
careful examination is not only required to determine the extent, but
by it alone can we arrive at a knowledge of the quality of the
anæsthesia—viz. whether there is a loss of all of the different kinds
of sensation, whether they are affected in an unequal degree, or
whether some have entirely escaped. Thus we must test for the
acuteness of the simple sense of touch by comparing the sensations
elicited by the contact of small surfaces of unequal size, as the
point and head of a pin or pencil, observing the appreciation by touch
of the patient for different substances, as woollen, silk, linen,
cloth, or comparing the sensation of the anæsthesic part with the same
part on the opposite healthy side of the body. The sense of locality
and space may be examined by placing at the same instant upon the skin
of the patient, his eyes being closed, two points (the anæsthesiometer
or the points of a compass), and observing his capacity for
appreciating the impression as double. As there is an enormous
difference of acuteness of the {1200} space-sense in the skin of
different parts of the body (see textbooks of physiology)—ranging from
the tip of the tongue, where the touch of two points separated 1.2 mm.
gives a double sensation, to the thigh, where the points must be
separated 77 mm. to be felt as two—we must be careful to consider in
making the examination the normal space-perception of the region. Care
must be taken not to repeat the test too often, as a rapid education
of the surface to a more delicate appreciation of the impressions is
the result. In certain abnormal conditions from spinal disease we have
a condition of polyæsthesia in which the impression of one point is
felt as two or more. The sense by which we appreciate the pressure of
objects must be tested by placing upon the surface to be examined, in
succession, objects of different weight, care being taken to have the
area which touches the skin and the temperature the same in each. The
parts to be tested must be firmly supported, and all muscular
contraction on the part of the patient prevented. The temperature
sense is examined by the application of hot and cold water or bodies
of different temperature. We sometimes meet with a perversion of this
sense in which the application of a cold surface to the skin gives the
sensation of warmth, and the contrary. In testing the sense of
temperature and the sense of pressure it is not the absolute capacity
of appreciating on the part of the patient that we investigate, but
the power of discriminating between different degrees of temperature
or pressure. The sense of pain must likewise be tested, since morbid
conditions occur in which it may be caused more readily than is normal
by exciting the cutaneous nerves, and that, too, in parts which have
in a great measure or quite lost the sense of touch; or, on the other
hand, touch may be retained, while irritation of the skin can excite
no feeling of pain (analgesia). We have in the faradic current an
excellent means of testing the cutaneous sensibility, inasmuch as it
excites the skin over the various parts of the body about equally, and
it can be employed in very gradually increasing or decreasing
strength. Its effects on the affected part must be compared with those
produced on the healthy surface of other parts of the patient's body
or on healthy individuals.
Frequently accompanying cutaneous anæsthesia, but constituting no part
of it, are various paræsthesiæ, as formication, pins and needles,
burning, etc. Pain, sometimes of great intensity, is not infrequently
connected with it (anæsthesia dolorosa). The paræsthesiæ and pain are
the result of irritation in some portion of the conducting tracts,
and, together with the trophic changes so often seen in connection
with nerve-injuries, they have been already considered under that
head.
It is a very important point to make the diagnosis between central and
peripheral anæsthesia, but it is often a matter of great difficulty,
and sometimes not to be made at all. The history of the case must be
carefully considered, and an examination made for symptoms of brain or
spinal disease, the existence of nerve lesions, or if there is a
history of toxic influences, etc. In peripheral anæsthesia the
reflexes which may be normally excited from the affected surface are
wanting, in contradistinction to anæsthesia of central origin, in
which they are most generally retained or even increased. Concomitant
trophic changes speak strongly for a peripheral origin, as do also
paralysis and atrophy of muscles. {1201} Loss of some of the forms of
sensation, with retention of others—_i.e._ partial paralysis of
sensation—indicate a central origin.