greatly disordered during a neuralgic attack, and it is often
difficult or impossible to tell with certainty which of these
conditions was the parent of the other. Undoubtedly, either sequence
may occur, but the pain excited by disorder of function, or even
organic disease of any organ, is not necessarily felt in that
immediate neighborhood. Thus I have known the inflammation around an
appendix cæci, of which the patient shortly afterward died, to cause
so intense a pain near the edge of the ribs that the passage of
gall-stones or renal calculus was at first suspected.
There seems to be as much variation as to modes of onset and duration
among the visceralgias as among the superficial neuralgias, but the
tendency to short typical attacks of frequent recurrence seems to be
greater with the former.
The visceral neuralgias are quite closely enough related to certain of
the superficial neuralgias to show that they belong in the same
general category. The two affections are often seen in the same
person, and not infrequently at the same time or in immediate
succession. Thus in the case of the patient just alluded to above, the
attacks of deep-seated neuralgia in the neighborhood of the right
flank are at times immediately preceded by severe neuralgia of the
face or head. Similarly, intercostal neuralgia may occur in immediate
connection with neuralgias of the cardiac or gastric nerves.
The phenomenon of tender points is not entirely wanting in the
visceralgias, though less constant and definite than in the
superficial neuralgias.
The liver and the uterus especially become the seat of more or less
localized tenderness, and possibly the tenderness in the ovarian
region which is so common, and so often unattended by real
inflammation, is, in part, of this order.
The secondary results of the visceralgias are not easy to study.
Besides the disorders of secretion and function above alluded to,
swelling of the liver with jaundice and paresis of the muscular walls
of the hollow viscera may be mentioned as having been ascribed to
neuralgia.
It is not known to what degree neuritis occurs as a cause or {1216}
complication of these neuralgias, and this is a question which is
greatly in need of further study.
Migraine, or Sick Headache.
This is often classified as an affection of a different order from the
neuralgias, but there seem to be no real grounds for this distinction.
The superficial neuralgias themselves are probably not one, but a
group of affections, with the common bond of severe and paroxysmal
pain.
Neither is what is called migraine always one and the same disease.
Although in its most typical form it presents very striking
characteristics, such as a marked preliminary stage, with peculiar
visual and sensory auras, sometimes occupying one entire half of the
body, a short and regular course and periodical return, deep-seated
pain without tender points, and prominent unilateral vascular
disorders, yet these symptoms shade off by imperceptible degrees into
those of neuralgia of the fifth pair, or more often into one or
another form of unilateral neuralgic headache which stands midway
between the two.
The vascular phenomena of migraine are believed by various observers,
as is well known, to constitute the primary and essential pathological
feature of the disease, and to be the cause of the pain. But this is a
pure hypothesis, and as a matter of fact the cases are abundant in
which no greater vascular changes are present than in other neuralgias
of equal severity.
Migraine seems to occupy an intermediate position between the grave
neuroses, especially epilepsy, and the neuralgias of neurosal origin.
The symptomatology will be described at greater length below.
GENERAL ETIOLOGY.—The causes of neuralgia may be divided into
predisposing and exciting causes.
The most important of the first group are—
1. Hereditary tendencies;
2. The influences associated with the different critical periods of
life;
3. The influences attached to sex;
4. The action of constitutional diseases, such as phthisis, anæmia,
gout, syphilis, diabetes, nephritis, malarial poisoning, metallic
poisoning.
The most important of the second group of causes are—
1. Atmospheric influences and the local action of heat and cold;
2. Injuries and irritation of nerves;
3. Irritation of related nerves (so-called reflex and sympathetic
neuralgias);
4. Acute febrile diseases.
In most cases more than one cause is to blame, and each should be
separately sought for.
PREDISPOSING CAUSES.—1. Hereditary Tendencies.—It is generally
admitted as beyond question that neuralgias are most common in
families in which other signs of the neuropathic taint are prominent.
Such affections as hysteria, neurasthenia, epilepsy, asthma, chorea,
dipsomania, and even gout and phthisis as it would seem, are akin to
the neuralgic tendency.
{1217} The neuropathic family is thought to contain, in fact, a much
larger number of members than this,[5] but there is danger of
exaggerating the importance of an influence of which we know as yet so
little.
[Footnote 5: Féré, _Arch. de Névrologie_, 1884, Nos. 19 and 20, “La
famille névropathique.”]
It should be remembered, moreover, that even where an inherited taint
is present its influence may be but slight as compared with that of
some special exciting cause.
Some neuralgias are more closely associated with the inherited
neuropathic diathesis than others. The connection is especially close
in the case of migraine;[6] then follow other forms of periodical
headache and the visceral neuralgias. Even the superficial
neuralgias[7] are more or less subject to this influence. This is
thought to be especially true of the facial neuralgias.
[Footnote 6: There is a witty French saying (quoted by Liveing), “La
migraine est le mal des beaux esprits;” which might be rendered, “The
disease of nervous temperaments.”]
[Footnote 7: For tables of illustrative cases see Anstie, _Neuralgia
and its Counterfeits_, and J. G. Kerr, _Pacific Med. and Surg.
Journ._, May, 1885.]
Reasons will be offered later for suspecting that many cases usually
classed as neuralgia, and characterized by gradual onset and
protracted course, are essentially cases of neuritis; and there is
need of further inquiry as to how far hereditary influences are
concerned in producing them, and whether such influences act by
increasing the liability of the peripheral nerves to become inflamed,
or only by increasing the excitability of the sensory nervous centres.
2. Age.—Neuralgia is oftenest seen in middle life and at the epochs
marked by the development and the decline of the sexual functions. The
affection, when once established, may run over into advanced age, but
cases beginning at this period are relatively rare and very
intractable (Anstie).
Childhood is commonly said to be almost exempt from neuralgia, but, in
fact, there seems no sufficient reason for withholding this term from
the so-called growing pains of young children[8] so long as it is
accorded to the almost equally irregular neuralgias of anæmia in the
adult. The same remark applies to the attacks of abdominal pain in
children, which often seem to be entirely disconnected from digestive
disorders.
[Footnote 8: Probably due to anæmia or imperfect nutrition (see
Jacobi, “Anæmia of Infancy and Childhood,” _Archives of Med._, 1881,
vol. v.).]
Adolescents and children also suffer from periodical headaches, both
of the migrainoid and of the neuralgic type. These are obstinate and
important affections.[9] Migraine especially, coming on in early life,
points to a neuropathic constitution, and will be likely to recur at
intervals through life, or possibly to give place to graver neuroses.
[Footnote 9: Blache, _Revue mensuelle de l'enfance_, Mar., 1883, and
Keller, _Arch. de Névroloqie_. 1883.]
3. Sex.—Women show a stronger predisposition than men to certain forms
of neuralgia, as to the other neuroses, but it is generally conceded
that whereas neuralgias of the fifth and occipital and of the
intercostal nerves are met with oftenest among them, the brachial,
crural, and sciatic neuralgias are commoner among men. This probably
indicates that the neurosal element is of greater weight in the former
group, the neuritic element in the latter.
4. Constitutional Diseases.—The blood-impoverishment of phthisis and
anæmia, the poison of malaria, syphilis, and gout, and the obscurer
{1218} forms of disordered metamorphosis of tissue, undoubtedly
predispose to neuralgia and the other neuroses, as well as to neuritis
and others of the direct causes of neuralgic attacks.
Anstie regards the influence of phthisis as so important as to place
it fairly among the neuroses. Gout is likewise reckoned by some
observers among the neuroses,[10] but we tread here upon uncertain
ground. Anstie does not regard gout as a common cause of neuralgia,
but most writers rate it as more important, and gouty persons are
certainly liable to exhibit and to transmit an impaired nervous
constitution, of which neuralgia may be one of the symptoms. The
neuralgias of gout are shifting, irregular in their course, and
sometimes bilateral.
[Footnote 10: Dyce-Duckworth, _Brain_, vol. iii., 1880.]
Syphilitic patients are liable to suffer, not only from osteocopic
pains and pains due to the pressure of new growths, but also from
attacks of truly neuralgic character. These may occur either in the
early or the later stages of the disease. They may take the form of
typical neuralgias, as sciatica or neuralgia of the supraorbital nerve
(Fournier[11]), or they may be shifting, and liable to recur in
frequent attacks of short duration, like the pains from which many
persons suffer under changes of weather, anæmia, or fatigue.
[Footnote 11: Cited by Erb in _Ziemssen's Encyclopædia_.]
There are other obscure disorders of the nutrition, as yet vaguely
defined, in connection with which neuralgia of irregular types is
often found. Some of these are classed together under the name of
lithæmia, and are believed to be due to imperfect oxidation of
albuminoid products.[12]
[Footnote 12: See DaCosta, _Am. Journ. of Med. Sciences_, Oct., 1881,
and W. H. Draper, _New York Med. Record_, Feb. 24, 1883.]
Diabetes seems also to be an occasional cause of neuralgia, especially
sciatica, and Berger,[13] who has recently described them, says that
they are characterized by limitation of the pain to single branches of
the sacral nerves, by a tendency to occur at once on both sides of the
body, by the prominence of vaso-motor symptoms, and, finally, by their
long duration and obstinacy. There may not, at the moment, be any of
the characteristic symptoms of diabetes present.
[Footnote 13: _Neurologisches Centralblatt_, 1882, cited in the
_Centralbl. für Nervenheilk., etc._, 1882, p. 455.]
Chronic nephritis also causes neuralgia, either directly or
indirectly; and severe neuralgic attacks may accompany the condition,
which is as yet but imperfectly known, characterized pathologically by
a general arterio-fibrosis and by increased tension of the arterial
system.
True rheumatism does not appear to be a predisposing cause of
neuralgia.
Anæmia, both acute and chronic, is a frequent cause of neuralgia, both
through the imperfect nutrition of the nervous tissues, to which it
leads, and, it is thought, because the relatively greater
carbonization of the blood increases the irritability of the
ganglionic centres.
Even a degree of anæmia which might otherwise be unimportant becomes
of significance in the case of a patient who is otherwise predisposed
to neuralgia; for such persons need to have their health kept at its
fullest flood by what would ordinarily seem a surplus of nourishment
and care.
Under the same general heading comes the debility from acute and
{1219} chronic diseases, and the enfeeblement of the nervous system
from moral causes, such as anxiety, disappointment, fright, overwork
and over-excitement, and especially sexual over-excitement, whether
gratified or suppressed (Anstie), or, on the other hand, too great
monotony of life; also from the abuse of tea, coffee, and tobacco.
Lead, arsenic, antimony, and mercury may seriously impair the
nutrition of all the nervous tissues, and in that way prepare the way
for neuralgia.
IMMEDIATE CAUSES.—1. Atmospheric and Thermic Influences.—Neuralgia is
very common in cold and damp seasons of the year, in cold and damp
localities, and in persons whose work entails frequent and sudden
changes of temperature. Exposures of this sort may at once excite
twinges of pain here and there over the body, and may eventually
provoke severe and prolonged attacks of neuralgia.
The action of damp cold upon the body is complicated, and it exerts a
depressing influence on the nervous centres in general which is not
readily to be explained. One important factor, however, is the cooling
of the superficial layers of the blood, which occurs the more easily
when the stimulus of the chilly air is not sufficiently sharp and
sudden to cause a firm contraction of the cutaneous vessels, while the
moisture rapidly absorbs the heat of the blood. From this result,
indirectly, various disorders of nutrition of the deeper-lying tissues
or distant organs; and, among these, congestion and neuritis of the
sensitive nerves.
Neuralgia often coincides with the presence or advent of storms. A
noteworthy and systematic study of this relationship was carried on
through many years under the direction of S. Weir Mitchell[14] by a
patient of his, an officer who suffered intensely from neuralgia of
the stump after amputation of the leg. The attacks of pain were found
to accompany falling of the barometer, yet were not necessarily
proportionate to the rapidity or amount of the fall. Saturation of the
air with moisture seemed to have a certain effect, but the attacks
often occurred when the centre of the storm was so remote that there
was no local rainfall. It was impossible to study the electrical
disturbances of the air with accuracy, but a certain relationship was
observed between the outbreak of the attacks and the appearance of
aurora borealis.
[Footnote 14: _Am. Journ. of Med. Sci._, April, 1877, and _Philada.
Med. News_, July 14, 1883.]
This patient's neuralgic attacks were almost certainly of neuritic
origin, and it is possible that the exacerbations were due to changes
of blood-tension in and around the nerve-sheaths. It is also possible
that they were the result of circulatory changes and disordered
nutrition of the nervous centres, already in a damaged condition from
the irritation to which they had been exposed.
2. Injuries and Irritation of Nerves.—Wounds and injuries of
nerves[15] and the irritation from the pressure of scars, new growths,
and aneurisms are prolific causes of neuralgic pain, partly by direct
irritation, partly by way of the neuritis which they set up.
Neuralgias are likewise common during the period of the healing of
wounds, as Verneuil long since pointed out. The pain may be near the
wound itself or in some distant part of the body.
[Footnote 15: See S. Weir Mitchell, _Injuries of Nerves_.]
Neuralgia due to the pressure and irritation of tumors, new growths,
{1220} or aneurisms requires a special word. The pain is apt to be
intensely severe, but what is of especial importance is that the
symptoms may not present anything which is really characteristic of
their origin, except their long continuance; and this should always
excite grave suspicion of organic disease.
These attacks of pain may be distinctly periodical; and this is true
whether they are felt in the distribution of the affected nerve or of
distant nerves.
Not only are direct injuries of nerves a cause of neuralgia, but
sudden concussion or jar may have a like effect—whether by setting up
neuritis or in some other way is not clear. Ollivier[16] reports a
case where a blow beneath the breast caused a neuralgia which
eventually involved a large portion of the cervico-brachial plexus;
and the writer has seen a like result from a blow between the
shoulders.
[Footnote 16: Cited by Axenfeld and Huchard, p. 116.]
Peripheral irritations, such as caries of the teeth (see below, under
Facial Neuralgia) and affections involving other important plexuses,
such as those of the uterine nerves, are a frequent cause of
neuralgia, and should always be sought for. They act in part by
setting up neuritis, and in part evidently in some more indirect
manner, since the neuralgia which they excite may be referred to more
or less distant regions, forming the so-called—
3. Reflex and Sympathetic Neuralgias.—The term reflex, as here used,
is ill chosen, and the term sympathetic only covers our ignorance of
the real processes involved, and which we should seek for in detail.
Thus, disease of the uterus or ovaries may cause facial, mammary,
intercostal, or gastric neuralgia.
Hallopeau[17] suggests that some of these results may be brought about
by the pressure of enlarged lymphatic glands attached to the affected
organ.
[Footnote 17: _Loc. cit._, p. 766.]
Another important centre of nervous irritation is the eye. Slight
errors of refraction, or weakness of the muscles of fixation,
especially the internal recti, are a source of frontal headaches and
other nervous symptoms, and even of typical migraine,[18] to a degree
which is not usually appreciated. It is improbable that in the latter
case the irritation acts as more than an exciting cause, but it may
nevertheless be a conditio sine quâ non of the attack.
[Footnote 18: _St. Barthol. Hosp. Repts._, vol. xix.]
Acute and chronic inflammations of the mucous membrane of the frontal
sinuses, perhaps even of the nasal membrane, are likewise important;
and although it is probable that the opinions sometimes expressed as
to the significance of these causes are exaggerated, it is equally
true that obstinate and, as it were, illogical persistence in their
removal will sometimes be richly rewarded.
It is especially worthy of note that there need be no local sign
whatever to call the attention of the patient to the presence of the
peripheral irritation.
Nothnagel[19] has described neuralgias which come on in the first week
of typhoid, and are to be distinguished from the general hyperæsthesia
of later stages. He describes an occipital neuralgia of this sort
which finally disappeared under the use of a blister. Other acute
diseases may have a like effect. The writer has seen a severe facial
neuralgia in the {1221} first week of an insidious attack of pneumonia
in a person who was not of neuralgic habit, and before the fever or
inflammation had become at all severe.
[Footnote 19: _Virch. Arch._, vol. liv., 1872, p. 123.]
PATHOLOGY AND DIAGNOSIS.—In surveying the clinical history of the
neuralgias and the circumstances under which they occur, we have
grouped together a large number of symptoms of very different
character from each other, and we have now to inquire to what extent
these symptoms are really united by a pathological bond.
Two opposite opinions have been held concerning the pathology of
neuralgic affections. According to one opinion, every neuralgic
attack, no matter how it is excited, is the manifestation of a
neurosis—that is, of a functional affection of the nervous centres—to
which the term neuralgia may properly be applied. This view is based
on the resemblance between the different forms of neuralgia, or the
apparent absence, in many cases, of any adequate irritation from
without, and the fact that the persons in whom neuralgias occur
usually show other signs of a neuropathic constitution.
According to the other opinion, the various forms of neuralgia are so
many different affections, agreeing only in their principal symptom,
and are due sometimes to congestion or anæmia of the nerves or the
nerve-centres; sometimes to neuritis, the pressure of tumors, or the
irritation of distant nerves; sometimes, finally, to a functional
disorder of the nervous centres. The arguments in favor of this
opinion are that the difference between the symptoms of the different
neuralgias as regards their mode of onset and decline, their duration,
the persistence of the pain, and the degree to which the attacks are
accompanied by organic changes of nutrition in the tissues and in the
nerve itself, are so great as to make it appear improbable that we are
dealing in every case simply with one or another modification of a
single affection.
This is a valid reasoning, and it is certainly proper to exhaust the
possibilities of explaining the symptoms that we find in a particular
case by referring them to morbid processes which we can see or of
which we can fairly infer the presence, before we invoke an influence
of the nature of which we understand so little as we do that of the
functional neuroses. At the same time, it must be distinctly borne in
mind that the symptoms of certain neuralgias, and the relation which
the neuralgias in general bear to other neuroses, can only be
accounted for on the neurosal theory, and that in a given case we can
never be sure that this neurosal tendency is not present and is not
acting as at least a predisposing cause. It is especially important to
bear this possible influence in mind in deciding upon prognosis and
treatment.
We may now review briefly the signs which should lead us to
diagnosticate or suspect the presence of the various special causes of
neuralgic symptoms.
Neuritis is indicated by the presence of organic disorders of
nutrition affecting the skin, hair, or nails, or of well-marked
muscular wasting; by pain, not only occurring in paroxysms, but felt
also in the intermissions between the paroxysms, or continuous
sensations of prickling and numbness, even without pain; by tenderness
along the course of the nerve; by anæsthesia, showing itself within
the first few days of the outbreak of a neuralgia; by persistent
paralysis or paresis of muscles.
{1222} Neuritis may be suspected, even if one or all of these signs
are absent, in the prolonged neuralgias which follow wounds or strains
of nerves or exposure to damp cold, or which occur in nerves which are
in the immediate neighborhood of diseased organs; also where the pain
is relieved by compression of the nerve above the painful part, or, on
the other hand, where pressure on the nerve excites a pain which runs
upward along the course of the nerve.
It may also be suspected in the large class of superficial neuralgias
which follow a regular and protracted course with gradual onset and
decline, and where the pain is felt not only in the region of
distribution of a nerve, but also along its course—that is, in the
nerve-fibres (either the recurrent nerves or the nervi nervorum) which
are distributed in the sheath of the main trunk or the adjoining
tissues.[20]
[Footnote 20: See Cartaz, _Des Névralgics envisagés au point de vue de
la sensibilité récurrente_, Paris, 1875.]
It must be remembered that the study of neuritis, and especially of
chronic neuritis, is still in its infancy, and that we are by no means
in possession of its complete clinical history.[21]
[Footnote 21: See Pitres and Vaillard, _Arch. de Névrologie_, 1883.]
The presence of congestion of the sensory nerves or nerve-centres may
be inferred with some degree of probability where neuralgic attacks of
relatively sudden onset and short duration occur in parts which have
been exposed to heat or cold, or in connection with suppression of the
menstruation, or, it is said, as a result of intermittent fever. The
exacerbations of pain which take place in cases of chronic neuritis
under changes of weather and after fatigue are very likely due to this
cause; and the same may be true of some of the fleeting pains which
occur in chlorotic and neuropathic persons who are subject to
fluctuations of the circulation of vaso-motor origin.
The same vaso-motor influences which cause congestion may also cause
the correlative state of anæmia, which becomes thus a cause of
transient and shifting though often severe attacks, which may be
irregular in their distribution. General anæmia is also a predisposing
cause of severe typical seizures, as has been pointed out above.