spinal sclerosis, the spinal arthropathies of Charcot, probably belong
to this category. The affected joint (knee, shoulder, or ankle) rather
suddenly swells, and the swelling usually invades the rest of the
member or extends to the next distal joint; it is a hard, semi-elastic
swelling unlike common œdema. After its gradual subsidence it is found
that changes have taken place in the articulation itself, and later
distinct evidences of destructive disease, such as erosion of
cartilages, relaxation of ligaments, swelling, are observed. In many
cases extra-articular lesions appear in the shape of osteophitic
formations from the adjacent bones. The hydrarthrosis may persist or
disappear. So complete may be the destruction of {57} the joint
that—for example, in a case of arthropathy of the knee—the leg may be
twisted about in all directions, and even over-extended so as to lie
upon the anterior surface of the thigh. Examination of the joint
post-mortem reveals non-suppurative destruction of all its component
parts, cartilages, ligaments, and epiphyses; the eroded, deformed ends
of the bones rub against one another in a false joint-cavity formed of
the skin, connective tissue, tendons, and remains of ligaments. The
absence of pain and tenderness in the course of arthropathies is a
striking feature—so much so that when, in an adult patient, it is
observed that manipulation or puncture of a diseased joint is
painless, special inquiry should be made for symptoms of posterior
spinal sclerosis.[7]
[Footnote 7: We have known one case in which the diagnosis of tabes
dorsalis was made (and verified after death) in this way, after the
surgeon in charge of the patient had mentioned the fact that
puncturing a swollen diseased knee-joint was painless.]
(_c_) Under the head of degenerative atrophies should be included the
secondary changes which affect certain nerve-tracts within the nervous
system itself. It is impossible in this introduction to treat fully of
this interesting category of trophic changes; the following summary
must suffice: (1) When the cerebral motor cortex or any part of the
associated pyramidal (or motor) tract is destructively injured, there
occurs, in from three to six weeks, a degeneration of the whole tract
caudad of (below) the brain. The myeline becomes granular and
disappears, the cylinder-axes are broken up and vanish, the connective
tissue (neuroglia) increases in amount; the atrophied and degenerated
area appears in a transection rather translucent in contrast to the
pearly white of the normal medullary tissue, and when the preparation
is stained with carmine the patch takes up an abnormal amount of
pigment. This is the so-called descending degeneration, or centrifugal
atrophy of the central nervous system. (2) After total transverse
lesions of the spinal cord, besides the above-described centrifugal
degeneration caudad of the lesion, we observe frontad of (above) it
similar changes in the posterior median columns, and in the direct
cerebellar tracts—centripetal degeneration. At present we have no
knowledge of centripetal (ascending) degenerations in the cerebrum and
in nerve-trunks; and if the results of von Gudden's experimental
method be cited against this statement, it must be replied that its
effects are best seen in newly-born animals, and that its pathology is
yet unknown. (3) Lesions of the anterior gray matter (ventral cornua)
of the spinal cord, and of mixed nerve-trunks produce only centrifugal
or descending degeneration. All the nerve-fibres deriving their
innervation from the injured area in the cord, or in case of nerves
all fibres below the injury, perish—_i.e._ their myeline breaks up and
undergoes granular and fatty degeneration, their cylinder-axes are
segmented and disappear, while at the same time the connective tissue
of the nerve becomes abnormally active and increases. Furthermore, in
cases of this category there are, inevitably, degenerative and
atrophic changes in the attached muscles, and peculiar
electro-muscular reactions (vide supra). All these central and
peripheral nervous degenerations, due to a local lesion, are
conveniently grouped under the name of Wallerian degeneration.
2. ERUPTIONS AND ULCERATIONS.—(_a_) The cutaneous eruption about whose
nervous origin there is the least doubt is that known as herpes or
{58} zona. This manifests itself, with or without paræsthesiæ (pain,
itching, formication, etc.), as vesicles upon deeply-inflamed spots of
skin distributed in the territory of one or more sensory nerves, and
almost always unilaterally. The destructive process in the derma is so
profound as to leave scars which are indelible as a rule. In general
terms it might be stated that herpes may occur in the range of any
sensory nerve distributed to the skin or mucous membranes. The
neuralgia attending its development may be severe, and in some cases
lasts for years after the healing of the eruption. The pathology of
this affection appears to be inflammation of the ganglion of the
posterior root of one or more spinal nerves (including the trigeminus
and glosso-pharyngeal) or of their trunks. Herpes may appear in the
course of spontaneous and traumatic neuritis; and in the last-named
conditions a variety of eruptions have been observed in the area
supplied by affected nerves, such as eczema, bullæ, etc.
(_b_) That ulceration may result directly from a nervous lesion is
shown by the history of herpes, where a destructive process takes
place in the derma under such conditions as to exclude the action of
external agencies. But the same cannot be said of the ordinary
ulcerations and gangrenous lesions observed in a number of nervous
diseases, as the bed-sores of myelitis or of spinal injuries, the
ulceration of the cornea in trigeminal anæsthesia, the digital ulcers
and gangrene of lepra, asphyxia of the extremities, and
nerve-injuries. As regards all these, the proper explanation is, it
seems to us, that the anæsthesia existing as a predisposing cause
(leading to imperfect protection of the part), the ulceration itself,
is directly, actively caused by external agencies. Let me briefly cite
a few instructive experimental and pathological facts bearing on this
question.
It is well known that in animals and man lesions of the trigeminus
nerve sufficient to produce anæsthesia (of its first branch more
especially) are frequently, if not invariably, followed by ulceration
and perforation of the cornea and phthisis bulbi. These were long held
to be true dystropic changes, but about thirty and twenty years ago
Snellen and von Gudden demonstrated independently and by different
methods that these ocular lesions could be entirely prevented by
absolute closure (perfect protection) of the eyelids prior to the
experiment on the trigeminus. Not long afterward Brown-Séquard showed
that the sloughing ulcers which occur about the foot of an animal
whose sciatic nerve has been cut may be entirely prevented by care,
cleanliness, and soft bedding. The conclusion to be drawn from these
observations is that in almost all cases the ulcerations and sloughing
observed in man during the course of a nervous disease sufficient to
produce anæsthesia, such as traumatic neuritis, lepra anæsthetica,
traumatic or simple myelitis transversa, disease of the trigeminal
nerve, etc., are in reality produced by external agencies, injuries to
the cuticle, action of filth, and, we think, the entrance of bacteria,
which are well known to possess extraordinary powers of penetration
into tissues whose protecting epithelial layer is removed. Clinical
observation corroborates this view, for, with strict antiseptic
treatment and under sealed dressings (collodion to ulcerated
finger-tips), these ulcerations heal rapidly and completely, while the
anæsthesia remains unchanged and the nervous lesions may even
progress. At the same {59} time, while we believe the above to be the
pathology of so-called trophic ulcers, we would admit the possibility
of spontaneous neuritic ulceration and gangrene, as shown more
especially in herpes.
3. ALTERED SECRETIONS.—Under the influence of disordered innervation
secretions may be altered in quantity and in quality. Symptoms of this
class may be caused by neural or by central lesions, and the mechanism
of their action may be direct or reflex.
(_a_) After section or lesion by disease of the cervical sympathetic
nerve we observe increased activity of the entire skin in the affected
area of the head and face: there is more perspiration, lachrymation,
and more cerumen is found in the ear. In cases of lesions of a certain
part of the oblongata we find one result to be polyuria. In many cases
of nerve-injuries the sweat-glands and hair-follicles of the parts
supplied by the affected nerve appear to be sometimes abnormally
active, or in other cases inactive. In some rare cases of insanity
profuse salivation and extraordinary growth of hair are striking
symptoms. Lastly, in some functional nervous affections the various
secretions and excretions may be altered to extraordinary extremes
(_e.g._ the polyuria and anuria of hysteria).
(_b_) Qualitative modifications of secretions also occur, as exhibited
in the many variations in the composition of the urine in various
neuritic conditions, the watery urine of hysteria, the phosphatic
urine of neurasthenia. Injuries of a part of the floor of the
oblongata (and very probably other lesions of the nervous system) give
rise to the appearance of sugar, and sometimes of albumen, in the
urine. Under the influence of disease or of an emotion the breast-milk
may become toxic to the nursing child, causing diarrhœa, convulsions,
etc. In some forms of nervous dyspepsia large quantities of acid or of
alkaline fluid may be rapidly poured out into the stomach as a result
of disturbed glandular and vaso-motor action. In a few cases of
neurosis malodorous or perfumed perspiration has been observed.
In a general way it may be stated that, inasmuch as the normal
function of glands is largely, if not exclusively, under direct and
reflex nervous control, their secretions may be quickly altered in
quantity or quality by rapid nervous disease or by functional
disorders. It is probable that much of our future progress in the
semeiology of nervous diseases will be in this direction by the aid of
improved medical chemistry.
4. ASSIMILATION, METAMORPHOSIS OF FOOD, TISSUE-LIFE, and BLOOD-MAKING
are probably under nervous control to a certain extent, but our
knowledge is not now in a state to speak positively and definitely of
alterations in these processes as symptoms of nervous disease.
* * * * *
THE PRINCIPLES OF DIAGNOSIS.
Having in the preceding pages surveyed the field of neurological
semeiology in an analytical way, it remains to briefly indicate how
far and in what manner these data can be best utilized for logical
diagnosis in the present state of science. If we may be allowed an
illustration, we {60} would say that the foregoing sections contain a
nearly complete vocabulary of the language of nervous diseases, and
that the following pages express an attempt at formulating its
grammar.
In the first place, it is important to classify the symptoms observed
according to their probable immediate cause in the nervous organs,
whether they are due to irritation or to the destruction of parts. The
extreme value of such a distinction in practice was first emphatically
brought forward by Brown-Séquard in his famous _Lectures on the
Physiology and Pathology of the Central Nervous System_ (Philada.,
1860); and to the observance of this law of genesis of symptoms we
believe that a large part of the subsequent extraordinary progress of
neurological science is due.
The symptoms produced by irritation of nervous organs are usually
hyperkineses or paræsthesiæ in their various forms. The symptoms,
spasm, pain, or numbness, are usually, though by no means always,
intermittent. That paralysis and anæsthesia may occur from irritation,
by an inhibitory process, is not to be denied, yet we must maintain
the extreme rarity of such a mechanism. The phenomena of inhibition
are so prominent in the normal nervous system that a physician who
looks at nervous diseases from the standpoint of the physiologist may
well be excused for seeing morbid inhibitory processes where others do
not.
The symptoms due to destructive lesions—_i.e._ those indicating
destruction of parts of the nervous system—are paralysis,
hyperkinesis, and anæsthesia, of absolutely or relatively constant
presence. Thus, for example, the paralysis of common hemiplegia due to
destruction of the motor part of the internal capsule is constant and
permanent, while the accompanying tonic spasm (late contracture),
which is considered an even more positive sign of serious destructive
injury to the cerebral motor tract, is permanent, but
intermittent—_i.e._ it is absent in profound sleep, and reappears as
soon as the patient awakes.
The association of symptoms of irritation and those of destruction is
frequent but variable. In many cases, as in cerebral tremor and
posterior spinal sclerosis, spasm and paræsthesiæ precede paralysis,
anæsthesia, and ataxia. In other cases (in many at a certain period)
they coexist. In a small group of cases the irritative symptoms follow
those indicating destruction, sometimes occurring years afterward, as
in post-hemiplegic epilepsy and neuralgia due to cicatrices. We would
repeat that very often, more especially in organic nervous affections,
much light is thrown on the diagnosis by careful noting of the
topographic distribution and chronological order of appearance of the
symptoms.
In the second place, it is necessary to group the symptoms of disease
of the nervous system in two great classes—viz. those representing
demonstrable lesions, macro- or microscopic, and those dependent upon
perverted functions or molecular malnutrition of the nervous organs or
elements. The first group is designated as organic diseases; the
second as functional affections. Mental diseases, so called, can also
be classified, according to their symptoms, in either of these groups.
The symptoms of the first group, that of organic nervous diseases, are
characterized by definiteness of distribution, by permanency, by
relative invariability, and by the predominance of objective signs.
Another important characteristic of organic diseases is their
progressive or fatal {61} tendency, either with reference to life in
general or to that of parts or organs. A third peculiarity of these
diseases is that they do not occupy the patient's attention as
strongly or as constantly as neuroses: in other words, the Ego is less
involved.
The symptoms of the second group, that of functional nervous
affections (neuroses and psychoses), are characterized by generality
and indefiniteness of distribution, by relative variability, by easy
removal or spontaneous disappearance, and by the preponderance of
subjective symptoms. The affection may endure for many years or for a
lifetime without fatal result and without special aggravation. The Ego
is very strongly and deeply affected, fear, depression, and constant
dwelling upon the symptoms being prominent features.
These are general statements intended to serve as guides for the
preliminary study of a case. It must be remembered that they are all
liable to exceptions, and that each patient must be separately
considered. It should be borne in mind that what to-day appears as a
functional affection, chiefly indicated by subjective symptoms, may in
a few months present distinct signs of organic changes in the nervous
system. Also, it must be added that in the present state of knowledge
we sometimes are not sure as to the presence or absence of organic
changes even after careful study of a case; as, for example, in some
epilepsies and neuralgias.
Furthermore, allowance must be made for the following sources of
error:
Anatomical variability; as, for example, in the distribution of
peripheral nerves and in the amount of decussation of fibres of the
pyramids;
The coincidence of diseases and multiplicity of lesions;
The toxic effects of drugs taken by the patient previous to our
examination; as, for example, bromism.
I. The Diagnosis of Organic Diseases of the Nervous System.
This should invariably consist, in the observer's mind at least, of
three separate diagnoses, each formed by the application of widely
different sources of knowledge, and each requiring a different logical
process. One diagnosis forms the indispensable preliminary to the
others, and the last one, when correct, demonstrates that the
neurologist is a physician as well as a specialist. A further utility
of this procedure by the method of the threefold diagnosis is, in our
opinion, that it constitutes the sure inductive reasoning to be
employed in the search after the pathology of new diseases, and must
prove of help in the future growth of neurological medicine.
These diagnoses are—
The diagnosis of the symptoms or symptom-group;
The diagnosis of the location of the lesion;
The diagnosis of the nature of the lesion or of the functional
disorder.
1. The diagnosis of the symptom or symptom-group is to be made
by—(_a_) careful inquiry into the manner of appearance, development,
and chronological order of the symptoms as related by the patient or
by his friends, and more especially by (_b_) an exact, and in some
directions {62} minute, determination of the symptoms, obvious or
latent, present in the patient. This valuable method of exact
observation is sometimes, no doubt, carried to a ridiculous extreme,
entailing much loss of time without corresponding results; but in
medical practice, as in all forms of professional work, there enters a
sort of genius, partly innate, but largely developed by cultivation,
which enables the observer to seize at once, apparently by intuition
or in the course of a few minutes of study, the really valuable and
suggestive phenomena; and it is in this line, the line of important
and correlated facts, that observation cannot be too minute and exact.
In following this method technical terms must be correctly used and
definitions rigidly adhered to, as superficial and loose records
nearly always mislead. Sometimes in the course of the examination a
symptom is discovered or a hint is thrown out by the patient which
suggests new lines of inquiry, and occasionally necessitates an entire
rearrangement of the data obtained. Consequently, it is important that
the observer should approach a case tabula rasa, and should, as far as
possible, prevent his being biassed by anticipations of, and immature
guesses at, the third or final diagnosis.
Besides exactness of observation, it is necessary that the physician
should have a thorough knowledge of nervous nosology in order to
complete the first diagnosis: he must be acquainted by book-study and
by personal observation with the numerous types of symptom-groups
which fill up our present classification of diseases, so that he can
at once say, approximately at least, in what category the case before
him belongs.
2. The second diagnosis, that of the location of the lesions, is to be
arrived at by the application of the observer's knowledge of the
anatomy and physiology of the nervous system; and therefore it is here
that special training is of the greatest advantage. The anatomy and
physiology of use in this connection are not the bare sciences as
taught in ordinary text-books, but a higher sort of knowledge,
corrected and extended by the teachings of pathology and pathological
anatomy. The physician must be well versed in the recent revelations
of experimentation and of autopsies bearing upon the architecture and
functions of the central nervous system, and should be able to apply
this knowledge deductively to the case in hand. In this manner the now
abundant material grouped under the term Localization of Cerebral and
Spinal Diseases (vide the next article) can be made of the greatest
utility in every-day practice. The solution of the problem of
localization of the lesion is much simplified if it be first
accurately determined whether the lesion is peripheral, spinal, or
cerebral.
3. The final diagnosis is with respect to the nature of the lesion.
While the second diagnosis may be said to possess the greater
scientific interest, this one must be admitted to possess paramount
practical importance, as from it we derive the indications for
rational treatment and the data of prognosis. The third diagnosis is
to be made by the application of the observer's knowledge of general
pathology and etiology; hence it is in this field that the
best-trained physician succeeds—where the experienced practitioner may
sometimes eclipse the brilliant specialist. The truth of this is
maintained by those who hold, as we do, that it is unwise to embark in
specialism without having had good hospital advantages and extensive
general practice.
{63} In order to arrive at the diagnosis of the nature of the lesion
we must consider the family history, trace out predispositions, study
the various causes of disease to which the patient has been exposed,
and by a thorough examination of the various functions and the
objective condition of the patient ascertain what pathological
processes are active in him. Often the clue to the diagnosis is found
in signs afforded by non-nervous organs, as nervous syphilis by nodes
and cutaneous cicatrices, cerebral hemorrhage by renal disease and
increased arterial tension, cerebral tuberculosis by pulmonary
lesions, etc.
A purely empirical form of knowledge of some utility in proving the
pathological diagnosis is that of the relative frequency of certain
lesions in the two sexes, at different ages, in various professions,
etc.—a statistical knowledge which is to be applied deductively to the
case under study.
Considerable uncertainty sometimes remains even after the most careful
analysis of a case, and often, after stating the first and second
diagnoses quite positively, scientific caution and due regard for
truth compel us to state the third diagnosis in alternative
propositions or as a diagnosis of probability, to be finally settled
by the appearance of new symptoms, or in some rare cases only by a
post-mortem examination.
II. The Diagnosis of Functional Nervous Affections (Neuroses and
Psychoses).
In some diseases of this class—as, for example, epilepsy—it is
desirable to make the triple diagnosis as stated supra, but usually
the two problems to be solved are—What is the symptom-group? and what
is the pathology of the affection? The question of localization is
less important and less easy of solution, as the symptoms are more
usually generalized, often vague, and sometimes purely subjective.
1. The first diagnosis is to be made in the same manner as already
stated, but besides, in many cases, a close psychological analysis is
required to ascertain the emotional and mental state of the patient.
Not only is this indispensable in cases of insanity, but it is often
of great utility in other conditions, as hysteria, hypochondriasis,
and simulation. In the course of this study we are frequently brought
face to face with a most difficult problem—viz. the correct estimation
of the degree of pain experienced by a patient. Is it a
quasi-objective, correctly-portrayed sensation? is it magnified by
abnormal sensitiveness or by true exaggeration? or is it simulated for
a purpose? These questions demand the greatest freedom from prejudice
and most delicate tact for their solution, and occasionally the most
experienced physician is deceived. More especially are caution and
scientific doubt to be exercised when this symptom (pain) stands alone
or nearly so, as in some medico-legal cases and in certain
hypochondriacal states where self-delusion seems to constitute the
only real disease.
2. The diagnosis of the pathological nature of the functional
disturbance (functional lesion) is to be made only by an exhaustive
study of the patient's personal and family history and of his general
condition. The following are the principal lines of inquiry to be
followed:
{64} (_a_) As to hereditary predisposition: direct or indirect
inheritance of neurotic tendencies, of psychic peculiarities, and as
to the presence of the various psychic and physical signs grouped
under the term psychic degeneration.
(_b_) As to personal habits: overwork, masturbation, the abuse of
tobacco, alcohol, or coitus, injudicious diet, abnormal postures,
injurious avocations, etc.