Charles K. (Charles Karsner) Mills.

The nervous system and its diseases. A practical treatise on neurology for the use of physicians and students online

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or thrombosis. The popular idea of softening of the brain is largely
erroneous. It seems to be believed that in some mysterious way
general degeneration and softening of the brain result from strain,
anxiety, and various causes which lead to serious nervous and mental
disturbances but not to organic changes. Generalized softening prac-
tically never occurs, and nearly all softenings are due, as above
stated, to the occlusion of vessels, ^^^idely disseminated foci of
softening may be present in a brain as the result of widespread arte-
rial disease. All forms of acute softening are therefore local, but the
affection may be single, diffuse, or midtiple. Arterial obliteration does
not always lead to softening. ISTumerous vessels of small size, or a
few of considerable dimensions, may be occluded and softening not
result. The parts are nourished by neighboring or by anastomosing
vessels. The circulation to such parts is disturbed, and anemia and
malnutrition may result, but necrosis may not take place or may be
postponed until more extensive obliteration of the vessels occurs.
The symptomatology of vessel obliteration is in part the sympto-
matology of arteriocapillary sclerosis or fibrosis, which has already
been considered. In cases of thrombosis of large vessels the symp-
tomatology of the focal softening which results is often complicated
with that which is due to the diffuse disease of the vessels, many
of the finer vessels being obliterated, although the vast majority
are not. While obliteration of arteries is the most frequent patho-
logical cause of softening, it is not the sole cause. The old writers
undoubtedly made the mistake of supposing that it was almost



476 NERVOUS DISEASES.

alwaj^s due to inflamuiatioii, but the more recent schools of pathol-
ogy have perhaps gone too far in the other direction. Summarizing,
brain tissue may disintegrate and soften as the result of vaiious
pi'oeesses : lirst l)y occlusion of arteries as the result of embolism or
thrombosis, aiul occasionally from the pressure of growths or from
compression in other ways ; next comes the softening which accom-
panies encephalitis after it has reached a certain grade. Occasion-
ally softening may be due to occlusion of veins, but such an origin is
rare. Chronic softening results from other processes. "Wernicke
and Gowers have both given their allegiance to the view that we may
have chronic progressi\'e softening without obliteration of blood-
vessels, and each cites cases in support of this doctrine. The cen-
trum ovale both of the cerebrum and of the cerebellum was softened
over large areas in these cases. It seems most probable, however,
that these forms of softening are due to the obliteration of the fine
terminal branches of the subcortical and ganglionic systems of ves-
sels ; but this can be demonstrated or negatived only by researches
conducted with care, and by methods that will enable us to determine
the condition of the most minute arteries.

SOFTENING FROM EMBOLISM.

Cerebral Arteries usually Attacked.— It is one of the best
known facts in medicine that emboli more freciuently lodge in arteries
of the left than of the right side of the brain, giving tlierefore with
similar frequency right sided paralytic affections. The explanation
of this, at least so far as the mechanical conditions are concerned, is,
that while the left carotid artery comes off nearly in a straight line
with the blood current from the arch of the aorta, the right carotid
branches from the innominate, which leaves the aorta almost at a
right angle. Even in the parts of the brain supplied by the basi-
lar arid vertebral arteries, endiolism is rather more likely to occur
on the left side than on the light, because the left vertebral artery,
which is larger than the right, ai-ises from the highest point of the
subchwian. The fact, however, that most of the blood passes by
way of tlie basilar, which is a large azygous artery, bel'ore it is dis-
tributed from these arteries, makes the direction of the blood cm rent
and the peculiarities of the left vertebral supply less intluential as
regards intracranial h'sions than are those of the left carotid. Em-
bolism, thrond)i>sis, and hemorrhage are all of more frequent occur-
renc(^ in the left hemicerebrum. Tlie left half of the brain, the lead-
ing half, pays for its supremacy by its greater liability to viiscular
disease.

Clinical History. — Initial Si/mploms. Embolism is usually of
sudden occurrence, and may be initiated with various jihenomena.
Occiusioually, but not so often as in hemorrhage and thrombosis, it
is preceded by vertiginous sensations. It is usually stated that pro-



SOFTENING FROM EMBOLISM. 477

dromata are absent, but this is not strictly true. Embolism often
occurs in tlie absence of arterial disease, but chronic endarteritis and
cardiac disease may be present, especially in cases in which a second
or a third attack has occurred, and the prodromata are chiefly the
same disturbances of circulation as precede thrombosis. Earely the
attack begins with spasms, usually local, and on the side which is
later affected with paralysis. Loss of consciousness is frecpient, its
occurrence or nonoccurrence being related to the size of the vessels
obstructed. In many cases the apoplectic attack is as sudden and
severe as in cerebral hemorrhage, and is attended by as profound un-
consciousness, but the coma, except in cases which have fatal issue,
is commonly more transient than in hemorrhagic apoplexy. Vomit-
ing is infrequent. As a rule, the evidences of vascular tension are
not so marked as in hemorrhage. Delirium and fever may soon fol-
low tlie attack, but these may be as much due to ulcerative endocar-
ditis and to septicemic processes as to the direct effects of embolism.
The initial fall of temperature so often observed in hemorrhage does
not, as a rule, occur, and the rise of temperature which takes place
is not so marked nor so distinctive in its featui'es as it is in hemor-
rhage. Temperature observations are often valualjle in the differen-
tial diagnosis of the different forms of apoplexy, but because of their
complicating causes are not infrequently misleading. In thirty-eight
cases of acute softening, Dana rarely found any disturbance of tem-
perature on the first day, even in those which terminated fatally.
On the second day a slight rise was often observed, so that the
average was from 99.5° to 100° P. Dana says there are very few
exceptions to the general law that the temperature rises after a
serious hemorrhagic laceration of the brain and does not rise after
a serious embolic or thrombotic softening of the brain. The rare
exceptions to this clinical rule are when the embolic process is
extremely large, involving an entire lobe, or when it is situated in
the pons or the oblongata, or when it is due to a septic focus. In
both embolic and thrombotic softening the temperature on the two
sides is usually the same, or the variation is slight. Even during
the apoplectic stage certain symptoms and signs may enable the physi-
cian to say that the patient is suffering from a focal lesion in a cer-
tain locality of the brain. Careful manipulation of the limbs of both
sides may show less resistance or a decidedly flaccid paralysis in one
arm and leg. The face may be seen by inspection to droop on one
side and perhaps to be drawn towards the other. Conjugate devia-
tion of the head and eyes may be present, but is not so frequent as in
hemorrhage. Loss of sensation due to embolism of the ganglionic
vessels, particularly when branches of the posterior cerebral are
plugged, can sometimes be determined. The tendon and muscle phe-
nomena are usually exaggerated on the side of the paralysis. As
the patient rallies, consciousness is regained partially or altogether,



478 NERVOUS DISEASES.

generally sooner than in hemorrhage. If the left side of the brain
is attacked, aphasia is nearly always present.

('(Hirse. As regards both course and onset, encephalic embolism
may be of several types. Most frequently, indeed in the majority
of cases, the onset, as already stated, is sudden, and the acute stage
short, at least as compared with heinorrliage. Some of these cases
which show a lai'gc^ aoK^unt of jmialysis at first largely recover from
this paralysis, otiiers reiiiaiii i)eiinanently hemiplegic and it may be
aphusic or hemianopsic. A few cases are rapidly fatal. Occasionally
both embolic and thrombotic softening may occur without any symp-
toms having l)een recognized, or at least without symptoms which
have been attributed to disease of the brain.

Focal Types of Encephalic Embolism. — .Just as the most fre-
quent descri])tioii of ceiebial hemorrhage is founded upon the symp-
tomatology of liemorrhage from the lenticulostriate artery, so the
usual account of an embolic apoplexy and of tlie acute state follow-
ing it is founded upon the symptomatology of the results of occlu-
sion of the same deep branches of the Sylvian or medicerebral artery.
The acuteness of attack and the progress of a case of embolism
must, however, vary with the locality affected ; but to describe in
detail eacli form would be simply to repeat much that has already
been said in the pages devoted to eoitieal and interior localization.
Among central vessels most fn;(juently closed by emboli are then,
first, the lenticulostriate, lenticular and other branches of the medi-
cerebral aitery ; but chjsure of the lenticulo-optic artery, with soft-
ening involving the internal capsule, the posteroexternal portion of
the lenticula, the anterior portion of the thalamus, and the tail of
the caudatum, is also fre((uent. A gyral area which is a frequent
seat of embolic softening is the left third frontal convolution, the
insula, and the under- surface of the overhanging pfirtion of the
operculum. Softening of the upper temporal convolutions is also
comparatively common. In Pig. 278 is shown an immense cyst the
result of embolic softening. It is irot necessary to give a list of
the different areas which may be isolated l)y processes of softening,
as they corraspond to the speeiid vascular- territories already con-
sidered. Occlusion of the lenticulostriate gives symptoms similar
to those al)-eady given in the general description of the symptoma-
tology of embolism; when the hsnticulo-optic is affected, hemianes-
thesia and perhaits h('miano])sia may be added to the motor symp-
tom picture. When the vessels going to the insula and left third
frontal are occlirded (Fig. 279), aphasia will of course be a promi-
nent result ; when that supplying the first and the second temporal,
word (htafness may ]><: the chief symptom. When large areas of the
])r-efi-ontal lobe are the seat of embolic softening, peculiar psychical
changes occur. Softening of the cuneus and of the optic radiations
gives amblyopia or hemianopsia. Goldscheider relates a case of



SOFTENING FROM EMBOLISM.



479



embolism of the basilar artery, conlii'med by autop.sy, following
ulcerative endocarditis, in wbich the main symptom was somno-
lence deepening into coma and ending fatally in twenty hours, the
only other cerebral symptom being a contraction of the left pupil.

Fig. 278.




Cyst the result of embolic softenin^^ ; the party involve<l are the lower or Sylvian portions of the
supramarginal and angular convolutions, the supertemporal convolution, and the insula.

As branches of the basilar supply the ventricular gray matter, the
analogy of this case to acute bulbar x>olioencephalitis, in which som-
nolence is also a prominent symptom, is obvious.

Etiology. — Sex, age, and probably inherited peculiarities act as
predisposing causes. Embolism is said to be of more frequent occur-
rence in females than in males ; but this is not in accordance with

Fig. 279.




Old cyst, probably embolic, involvuig the left third frontal gyre and ojierculum.

my own experience. Statistics upon this subject, unless very exten-
sive, are of little value. It is more nearly correct to say that sex has
little influence in favoring the occurrence of embolism. As compared
with hemorrhage and thrombosis, it is more often observed in the
young, but it may occur at any age, dependent upon the disease
which it accompanies or follows, as rheumatism, endocarditis, or sep-



480 NERVOUS DISEASES.

ticemia. As these diseases, particularly the first two, are likely to
originate in youth and middle age, so embolism is more common at
these periods ; it is of most frequent occurrence between puberty and
fifty. Eheumatism, multiple neuritis, endocarditis, phlebitis occur-
ring during the puerperium, and various other infectious diseases,
such as diphtheria, scarlatina, and variola, act both as predisposing
and as exciting causes. A relighting of old endocardial and arterial
disease is a frequent exciting cause. A nervous shock may have, in
exceptional cases, a tendency to the production of embolism. Thus,
fright and violent exertion, particularly in the presence of recent
endocarditis, may lead to the detachment of vegetations. A few very
rare instances of echinococci plugging the cerebral vessels have been
reported.

Pathogenesis. — The intruding embolus is usually carried from
the heart, which has suffered from endocarditis and some form of

mitral or aortic disease. It is derived
more frequently from the Adcinity of
the aortic than from that of the mitral
valves, but it is particiilarly likely to
occur with mitral constriction. The
slow fiow of blood through the nar-
rowed mitral orifice during diastole per-
mits the aggregation of white corpuscles
on the valve, and the quick flow during
the auricular systole tends to detach the
masses thus formed. Often there is
great dilatation of the auricle, and a
clot forms in the auricular appendix,
Diagram illustrative of the effects of fragments of wMch are likely to be de-

embolic plugging: aa, portion de- , , , ,. -, j_ j-j_ j i.- n

priyed of its blood supply by the em- tachcd, Or the clot softcus and particlcs
boiufs E ; A, artery ; v, vein filled with from it pass into the blood Current.

blood clot. The arrows indicate the mi .cj. j ^ 4. ■ ■ „

collateral channels which lead to a ^he SOftCUed maSS ottcu COUtaiUS miCrO-
hyperemic zone around the occluded Organisms. In ulcerative endOCarditiS

fldsch.') ^^'™'' ^''™' ^"'' ^^'^' the particles detached, which are usually

small, may carry infective micrococci
into the cerebral arteries. Minute ^-essels are therefore often plugged
and tlie adjacent tissues necrosed. Other sources of emboli, besides
a diseased heart, are aneurisms, particulaily of the aorta and caro-
tids, phlebitis following labor or of other origin, disease of the pul-
monary \'eins, and ulcerati\'e bronchitis and gangrene of the lungs.
Minute pigment emboli sometimes block the cerebral capillaries, or
fat embolism may follow degi'iicration of large vessels or disease of
the bone. Certain xDoisouous substances, as carbon monoxide and
phosphoins, aie supposed to induce softening by their effect upon
the vess(sls.

Pathological Anatomy. —In embolic softening fat crystals and




SOFTENING FROM EMBOLISM. 481

granular debris are found on microscopical examination. In addi-
tion, leucocytes may be increased and the vessels may show slight
inflammatory changes in their vicinity. The diagram, Pig. 280,
illustrates the effect of embolic plugging on the neighboring vessels
and tissues. Beyond the obstructed artery is the anemic wedge-
shaped area of its distribution, and below the embolus are seen
swollen branches, which tend to establish a collateral circulation.
' ' If this faUs, we get as a result engorgement of the latter vessels,
and a congestive vascular zone surrounding the wedge-shaped area.
The tissue here becomes swollen and cedematous, and minute htem-
orrhages are apt to occur, whilst the whole central and peripheral
textm-e becomes broken up by the effusion, and a true necrosis occurs
of the tissue forming the area of distribution of the nutrient branch
which has been plugged." (Bevan Lewis.)

Diagnosis. — The diagnosis of encephalic embolism, whether con-
sidered in respect to the apoplectic attack or with regard to the
secondary chronic or paralytic stage, is often difficult, and sometimes
must remain a matter of doubt, particularly as to its distinction
from hemorrhage or thrombosis. The diagnosis at the time of the
apoplexy is important, because the proper treatment differs somewhat
from that which should be used in either hemorrhage or thrombosis,
and especially in the former. It is important to establish the patho-
logical cause of a hemiplegia, a monoplegia, or an aphasia, so as to
adopt the best methods of protecting the patient from future attacks
of endocardial disease and embolism. Age needs to be considered in
arriving at a decision. Comparative youth is in favor of embolism.
Here it must never be forgotten that many cases of syphilitic throm-
bosis occur before middle life, so that it is not improbable that apo-
plectic attacks leading to hemiplegia and occurring before middle
age are frequently thrombotic in character and due to syphilitic peri-
arteritis or endarteritis. A syphilitic history should be carefully in-
quired for, although it is not infrequent to meet with a history of
both rheumatism and syphilis in the same case, and here the physi-
cian may be compelled to choose as seems to him best. As between
embolism and thrombosis, abruptness of onset is one of the most im-
portant diagnostic i:>oints. An attack sufficient to cause marked
paralysis usually comes on with sudden unconsciousness. As between
hemorrhage and embolism in serious attacks, the temperature, as
shown under hemorrhage, is a matter of great importance. The
tabular presentation of the differential diagnosis of cerebral em-
bolism from thrombosis will be given later. Too much stress should
not be laid upon valvular disease. In those numerous cases of
chronic disease in which nephritis, endarteritis, cardiac hypertrophy,
and other pathological conditions are present together, the valves of
the heart may also sooner or later become implicated ; but a patient
of this kind is just as likely to have paretic or paralytic attacks as

31



482 NERVOUS DISEASES.

the result of endarteritis and thrombosis as from cardiac vegetations
carried into the circulation. One of my hospital cases, a woman
about sixty years old, had cardiac degeneration with both aortic and
mitral disease, and widespread atheroma of the vessels. This patient
had three attacks of right sided paresis or paralysis, dying after the
third one. Postmortem examination showed extensive calcification
of the aortic crescents and degeneration of the heart walls. The
aorta and the cerebral vessels were atheromatous. Centres of soften-
ing were found in the motor zone, in the brain, and also in other
regions. Several of the secondary and tertiary branches of the mid-
dle cerebral artery were occluded as the result of disease in their
walls and the formation of thrombi. In favor of thrombosis would
be advanced age, atheroma of the vessels, fatty degeneration of the
heart, and a succession of slight paretic attacks. In favor of em-
bolism are youth, absence of signs of atheroma, previous history
of rheumatism, and a sudden and comparatively severe attack of
paralysis.

Prognosis. — The prognosis of encephalic embolism needs to be
considered with reference to the apoplectic attack, the probability of
the recurrence of the affection, and the persistence of the paralysis,
aphasia, or other consequences. The prognosis of an embolic attack
is better than that of hemorrhage, presuming that vessels of nearly
equal size are affected. Even when the attack is severe the patient is
more Ukely to recover from it than from a serious encephalic hemor-
rhage. As cerebral embolism sometimes takes place during the acute
or subacute stage of an endocarditis, the prognosis as to the fatal issue
and as to more or less speedy recovery will depend upon the state of
the heart. Cases of embolism which at first have the appearance of
great seriousness may on the clearing up of the apoplectic attack
largely recover from the paralytic, aphasic, and mental symptoms.
A patient who during the acute stage was totally hemiplegic and
aphasic may in less than three weeks have left only a slight paresis of
the arm and of the orolingual muscles ; I have seen many such cases.
Moderately severe cases may sometimes recover almost entirely from
the paralysis. Most authorities state that attacks of embohsm are
not likely to recur, and this is probably true of embolism as compared
with thrombosis ; and yet I have somewhat frequently seen two and
three attacks in the same patient. A patient who has once had a
rheumatic and endocardial attack may as the result have only slight
permanent changes, but will always be liable to a recurrence of the
original affection in a more Aiolent form and therefore also to a new
or recurring embolic seizure. Cases which recover completely or
nearly completely from the paralysis usually do so within a few
weeks. After the chronic stage has set in, the difference in prog-
nosis of the persisting symptoms as between hemorrhage, embolism,
and thrombosis is not great.



SOFTENING FROM THROMBOSIS. 483

Treatment. — The prophylaxis of encephalic embolism is in the
first place the prevention of rheumatism and other infectious diseases
which lead to endocarditis and the formation of vegetations, and in
the second place the careful treatment of the heart and regulation of
the circulation when evidences of old or recent endocarditis and val-
vular disease are present. One who has already suffered from rheu-
matism and endocardial disease should not be unduly exposed to great
variations in temperature or to any depressing conditions likelj^ to
renew the old troubles. The remedies to regulate the circulation will
of course vary according to the valves affected and the other special
conditions present. Strophanthus, digitalis, cactus, on the one hand,
or aconite and veratrum, on the other, may be needed. The main-
tenance of the general health of the patient by the use of tonics, rest,
and careful regimen is important. The treatment of the attack dif-
fers somewhat from that called for in hemorrhagic apoplexy ; but in
both the patient should be kept perfectly quiet. In serious cases in
which the breathing is interfered with the patient may be turned to
one side and supported in this position in order to relieve the ster-
tor. At the moment that the embolic obstruction occurs, all patent
arteries dilate to compensate for the obstructed vessel. As long as
this process lasts, a corresponding quantity of blood is used for their
dilatation and so is lost to the rest of the cerebral circulation. The
circulatory derangement is slighter the greater the force of the
heart and the remaining available arterial tension. The greater
the pressure in the veins the lighter the coma. A therapeutic
deduction is to increase the force of the heart and the venous
pressure by the recumbent position. (Geigel.) Hot applications
to the extremities and trunk sometimes act favorably. To equalize
and support the circulation, ammonium carbonate, digitalis, stro-
phanthus, and cactus, with strychnine hypodermatically or by the
mouth, may do much good, and alcoholic stimulants, usually in
small quantity, may be needed. Venesection should not be used.
If the patient is constipated, a quickly acting cathartic can be ad-
ministered. The inhalation of oxygen has been used to tide the
patient over a period of threatened collapse.

SOFTENING- FROM THROMBOSIS.
Definitions.— Occlusion of an artery by the process known as
thrombosis may, like embolism, also lead to acute softening of the
brain tissue. A thrombus is a clot or plug which forms at a certain
place in a bloodvessel, either as the result of changes in the blood or
in the walls of the vessel, or usually as the result of changes both in
the blood and in the vessel walls. Thrombi may form in the heart,
sinuses, and veins, as well as in the arteries, but it is only with
arterial thrombosis that we are here concerned. Sinus thrombo-
sis has already been considered. Absolute obliteration of an artery



484 NERVOUS DISEASES.

may take place without the lodgement of a clot, and in a strict
sense such cases may not be regarded as instances of thrombosis ;
nevertheless, diseases which cause obliteration of bloodvessels by
proliferative processes, or by pressure, produce softening and dis-
turbances of the circulation. The distinction between a thrombus



Online LibraryCharles K. (Charles Karsner) MillsThe nervous system and its diseases. A practical treatise on neurology for the use of physicians and students → online text (page 53 of 121)