once, and probably always by cardiac arrest, and to which the name of
the cardiac variety may well be given. It is very rarely, if ever, met
with in civil life, and among soldiers is especially seen during
battle or at other {392} times when great exertion is being made.
These cases will be more fully discussed in a later portion of this
article.
POST-MORTEM CHANGES.—Owing to the excessive heat of the body,
putrefactive changes occur very rapidly after death from sunstroke,
and various described lesions, especially of the heart, have been
undoubtedly the result of post-mortem changes. Later observers have
confirmed my original observation, that if the body be opened directly
after death the left ventricle will be found firmly contracted, though
the right heart and the pulmonary arteries, with their branches, are
gorged with dark fluid blood. In my cases the lungs did not present at
all the appearance of congestion of their minute capillaries, but when
they were cut the blood poured from them abundantly, seemingly from
their larger vessels. Not only do the lungs suffer from venous
congestion, but the whole body also. The blood appears to leave, as it
were, the arterial system and collect in the venous trunks. The
arterial coats are often stained red, apparently by the broken-down
red corpuscles of the blood.
There can be no doubt that the blood suffers in sunstroke very
similarly to what it does in low fevers. Its coagulability is
impaired, but not always destroyed; and it is possible that in the
very rapid cases it may not be decidedly affected. After death it
appears as a dark, often thin, sometimes grumous fluid, whose reaction
is very feebly alkaline, or, as I have seen it, even decidedly acid.
Levick[5] appears to assert that the blood-discs, as seen by him under
the microscope, were shrivelled and crenated, and showed very slight
tendency to adhere in rouleaux. In several of my cases the blood was
carefully examined by the microscope, but nothing abnormal was found.
The extravasations of blood which have been found by K. Köster in
various parts of the nervous system are probably of the nature of
petechiæ, the results of the altered blood-crasis, and not due to any
especial affection of the nerve-centres.
[Footnote 5: _Pennsylvania Hospital Reports_, 1868, 373.]
THEORY OF THE DISEASE.—The theories which have been brought forward as
explanatory of the phenomena of sunstroke are so various that it would
be impossible in the limits of this paper to discuss them. It does
seem, however, proper to give a very brief historical sketch of the
development of our present knowledge of the subject. In 1854, H. S.
Swift[6] said that the disease is “now generally admitted to be merely
exhaustion produced by fatigue,” although he recognized the existence
of an “apoplexy produced by insolation.” The cases which Swift so well
describes as those of heat-exhaustion were true instances of thermic
fever. The physicians of the Pennsylvania Hospital, especially
Gerhard, early called attention to the resemblance of sunstroke to a
fever, but it was not until January, 1859, that their views found
expression in print in the paper published by James J. Levick in the
_American Journal of Medicine_. This observer tabulated the
post-mortem appearances of typhus fever and of sunstroke in contrast,
calling attention also to the similarity of symptoms during life. In
1863, H. C. Wood[7] claimed distinctly that sunstroke is a fever due
to the development of a poison in the blood, and gave to the disease
the name of thermic fever. To R. Cresson Stiles is due the credit of
having first proven[8] the possibility of producing in animals a
sunstroke with symptoms and {393} pathological changes similar to
those which occur in man. He also came to the conclusion that the
symptoms are the results of the direct action of heat, especially upon
the muscular system. He says: “The dilatation of the capillaries is
explicable by the direct effect of the heated blood upon the muscular
fibres of the arteries and the arterioles. The cerebral symptoms and
the full and forcible pulse may also be due to this dilatation.”
George B. Wood, in the sixth edition of his _Practice of Medicine_
(Philadelphia, 1866), wrote an elaborate article upon the disease,
giving it the name of heat fever, and affirming that it “is, I
believe, strictly an idiopathic fever.” He further asserts: “In heat
fever all the organs, the brain, heart, lungs, stomach, kidneys, etc.,
are excessively stimulated by the great heat, and all exhibit disorder
and at length depression of their functions.” The article of George B.
Wood was not based upon experimental researches, but upon a very
philosophic rendering of the clinical phenomena, and was a carrying
out of the ideas which had permeated the medical teaching of the
Pennsylvania Hospital.
[Footnote 6: _New York Med. Journ._, vol. xiii. p. 53.]
[Footnote 7: _Amer. Journ. Med. Sci._, October.]
[Footnote 8: _Boston Med. and Surg. Journ._, June, 1864, p. 349.]
About 1869, Eulenberg and Vohl[9] advanced the theory that death from
sunstroke is the result of the sudden liberation of gases in the
blood; and Weikard affirmed that the death is due to the increase of
the coagulability of the blood and consequent formation of clots in
the vessels, being in this supported by Richardson of London.[10]
Contrasting with these in its being really an important contribution
is the article of Vallin:[11] its chief merit is the conception of the
idea of the local heating of isolated parts of the body, and the
devising of a plan for carrying the idea into effect. The experiments
of Vallin did not themselves prove very much, and led him to the
erroneous conclusion, first, that the death in sunstroke is the result
either of a coagulation of the left ventricle or else of a disturbance
of the innervation of the heart by an action of the heat upon the
nerve-centres in the base of the brain; second, that these two forms
of death correspond to sthenic and asthenic varieties of
insolation—varieties which, I believe, have no proper existence.
[Footnote 9: _Virchow's Archiv_, t. lxii.]
[Footnote 10: _St. Bartholomew's Reports_, vol. vii.]
[Footnote 11: _Archives générales de Médecine_, Fèvrier, 1870.]
The first experiments of Claude Bernard upon the action of external
heat were given in a lecture upon muscular respiration on May 3, 1864,
published in his _Leçons sur les Propriétés des Tissus vivants_
(Paris, 1866). They were merely incidental to another research, and
simply showed that when a warm-blooded animal was exposed to heat it
died, the death being, according to the observations of Bernard, the
result of cadaveric rigidity suddenly attacking the heart. The more
elaborate researches of Claude Bernard upon the effect of exposure of
animals to external heat, so far as I have knowledge, were not
published in detail until after the nature of sunstroke was
determined, although the lectures were delivered in the years 1871 and
1872; they may be found reported in full in his _Leçons sur la Chaleur
animale, sur les Effets de la Chaleur, et sur la Fièvre_ (Paris,
1876).
It is proper also to state here that some of the physicians of India
had previous to this time more or less imperfectly recognized the
relation of sunstroke to fever, but, I believe, none of them
distinctly postulated the theory.
The above historical sketch shows that by many authors the relation
{394} of sunstroke to fever had been more or less dimly perceived, and
that George B. Wood had very clearly stated the true nature of the
affection, in that it was simply the result of the direct action of
heat. Such statement, however, not resting upon proof, had not been
accepted: it was also wanting in detail, and where such details were
attempted the surmises were not always correct. Under these
circumstances my researches, made in 1870 and 1871, and first
published in 1872, led to the complete understanding of the affection.
The space allotted to me in the present volume will not allow of any
detailed account of my experiments, but I shall quote from my summing
up of the results obtained by them. It was shown that sunstroke may be
produced in animals as readily as in man either by natural or
artificial heat; that the symptoms are similar to those seen in man;
that death takes place ordinarily by asphyxia; that after death the
characteristic lesions are alteration of the blood and rigidity of the
heart, with immediate or quickly-appearing post-mortem rigidity of the
general muscular system; that this rigidity of the heart comes on in
most cases after, not before, death, and is a result, not cause, of
death; that post-mortem rigidity is dependent upon coagulation of
myosin, and that the rigidity of the heart is of similar origin,
coagulation of the muscle-plasma occurring almost instantaneously at
115° F., a degree almost attained in sunstroke; that when a muscle has
been in great activity immediately before death, myosin coagulates at
a much lower temperature, and that the cases of sudden cardiac death
occurring in battle among the East Indian English troops were no doubt
due to the coagulation of the heart's myosin; that heating the brain
of a mammal produces sudden insensibility, with or without
convulsions, at a temperature of 108° F., and death when a temperature
of 113° is reached; that this effect of the local application of heat
is not due to induced congestion, but is the result of the direct
action of the heat upon the cerebrum, and that consequently the
nerve-centres are as perniciously affected by high temperature as the
muscles are; that the nerve-trunks bear a temperature of 125° F.
without their conducting power being immediately affected; that whilst
the general symptoms induced by heating the brain of a rabbit are very
different from those of sunstroke, the nervous symptoms are exactly
similar; that the life of the blood is not destroyed by any
temperature reached in sunstroke, the amœboid movements of the white
blood-cells and the absorption power of the red disks not being
injured; that the amount of oxygen of the blood is greatly lessened,
as the result of gradual asphyxia combined with abnormal consumption
of oxygen; that there is no reason for believing that capillary
thrombi are common in sunstroke; that there is no specific poison
developed in the blood; that the deterioration of the vital fluid is
due to the rapid tissue-changes induced by the fever and the more or
less complete arrest of excretion; that such deterioration is
secondary to the nervous symptoms, not primary; that if the heat be
withdrawn before it has produced permanent injury to the nervous
system, blood, or other tissues, the convulsions and unconsciousness
are immediately relieved and the animal recovers.
As a postulate from these facts and deductions, I think it follows
that the nature of sunstroke is that of a fever; or, in other words,
that coup de soleil is a fever, not dependent upon blood-poisoning,
but upon heat.
{395} It is of course possible that the external heat causes the
fever, simply by preventing the body from throwing off the caloric
which it is constantly forming. The extreme suddenness of the onset,
however, indicates that in at least many cases there is a sudden
outburst, as it were, in the production of heat in the body. This
indication becomes more important when it is remembered that in
cerebral rheumatism, so called, there is often an equally sudden
attack of symptoms plainly the result of a sudden production of animal
heat.
In an elaborate research[12] I showed the truth of Setschenow's
theory, that there is in the pons a centre whose function it is to
inhibit the production of animal heat, and that in the medulla a
centre (probably the vaso-motor centre) which regulates the
dissipation of the bodily heat; and that fever is due to disturbance
of these centres, so that more heat is produced than normal, and
proportionately less heat thrown off. Let it be supposed that a man is
placed in such an atmosphere that he is unable to get rid of the heat
which his body is forming. The temperature of his body will slowly
rise, and he may suffer from a gradual thermic fever. If early or late
in this condition the inhibitory heat-centre becomes exhausted by the
effort which it has been making to control the formation of heat, or
becomes paralyzed by the direct action of the excessive temperature
already reached, then suddenly all tissues will begin to form heat
with the utmost rapidity, the bodily temperature will rise with a
bound, and the man drop over with some one of the forms of coup de
soleil.
[Footnote 12: _Fever_, Smithsonian Institute, 188-.]
Under this view of the case the widespread popular belief, that
protecting the back of the head and upper neck from the direct rays of
the sun is useful against sunstroke, gains in significance, because it
is possible that local heating of the parts spoken of may occur and
aid in the production of inhibitory paralysis.
If this theory of thermic fever be correct, heat-exhaustion with
lowered temperature probably represents a sudden vaso-motor
palsy—_i.e._ a condition in which the exhausting effects of the heat
paralyzes not the inhibitory heat-centre, but the vaso-motor centres
in the medulla, since my experiments have shown that vaso-motor palsy
increases enormously the loss of animal heat and diminishes its
production.
In most cases of sunstroke death comes on gradually by arrest of
respiration, such arrest being without doubt due to direct paralysis
of the respiratory centres by the excess of heat. Allusion has already
been made to the cases of sudden death by cardiac arrest, which have
especially been seen in India, almost always during a march or during
a battle. “As an example of it may be cited the account given by a
witness to Parkes, and incorporated in his work on hygiene,[13] of an
occurrence during the first Chinese war. The Ninety-eighth regiment
was marching on a very hot day, and the surgeon who was with the
rear-guard stated to Parkes that the men fell suddenly on their faces
as though struck with lightning, and on his running up and turning
them over many of them were already dead. Maclean, who was present at
this occurrence, confirms the account given by Parkes, but states that
it was at the attack on Chiang-Kiang-Foo. The men were thickly
clothed, with tight accoutrements and tight, rigid stocks, and were
charging up a very steep hill. A great {396} number of them were
stricken down, and fifteen died instantly, falling on their faces and
giving merely a few convulsive gasps.”
[Footnote 13: _Pract. Hygiene_, 2d ed., p. 360.]
It has been shown that excessive exercise so alters the condition of
the myosin of muscle as to cause it to coagulate much more readily
than normal. During battle the amount of muscular effort that is made
is enormous, and hence it is that men are so often found stiffened in
the attitude in which they were struck by the bullet, instantaneous
death being followed by equally instantaneous post-mortem rigidity.
The description that has been given by Parkes and Maclean of the
circumstances in which the sudden deaths just described occurred shows
that the heart-muscles must have been strained to their utmost limit.
The men were making violent exercise going up hill, so that the heart
must have been in exceedingly active exertion, increased by the
impediment to the circulation afforded by the tight accoutrements, and
under these circumstances the victims probably died instantly because
the heart-muscle suddenly set itself from life into the stiffness of
death.
The DIAGNOSIS of thermic fever is usually made with great readiness.
In distinguishing between it and heat-exhaustion the temperature of
the body is the guide. In apoplexy with high temperature it is
possible that a little embarrassment might be experienced, but in
apoplexy the high temperature follows the nervous symptoms after a
distinct interval, but in thermic fever it precedes the
unconsciousness. An apoplexy may develop during a sunstroke, but such
occurrence is rare. T. S——, now under my care, has had frequently
repeated attacks of local convulsions affecting two fingers of the
right hand, and one general epileptic attack whilst under observation.
He dates his illness to a sunstroke on July 7, 1885, and O. D.
Robinson of Georgetown, Delaware, writes me that the attack was
undoubtedly true thermic fever, and that the movements of the fingers
came on whilst the patient was recovering consciousness. It is
probable, therefore, that there was a rupture of a small vessel in the
brain-cortex during the sunstroke. The appearance of local convulsions
or of localized paralysis during a sunstroke would be good ground for
believing that either a clot or a thrombus had formed.
PROPHYLAXIS AND TREATMENT.—The prophylaxis of sunstroke is so evident
in its nature that it may be dismissed in a few words. When exposure
to heat is imperative the bodily health should be maintained by
avoidance of alcoholic, sexual, or other excesses, and, as far as
possible, of great bodily or mental fatigue; the diet should be almost
purely farinaceous, and the glandular apparatus of the bowels,
kidneys, and skin kept in an active state by the use of fruit, water
in abundance, and mild salines if necessary. Many persons have a very
strong prejudice against the drinking of cold water during exposure to
heat; and it is conceivable that large draughts of intensely cold
ice-water may do harm by suddenly chilling the stomach; but when the
water is taken in small quantities at short intervals, by its action
in reducing the general temperature, but especially by its rendering
free perspiration more easy, it must exert a most favorable influence.
The addition of claret or some other local stimulant to the water is
often of great service when there is a tendency to gastric or
intestinal depression.
In the mild cases of continued thermic fever the basis of the
treatment should be the use of the cold bath. The plan adopted by
Guiteras at Key {397} West was to wrap the patient in a dry sheet,
lift him into a tub of water, having the temperature between 80° and
85°, and then rapidly cool this water by means of ice. The time of the
immersion lasted from fifty to fifty-five minutes, it being regulated
by the thermometer in the mouth of the patient. The patient was then
lifted out upon a blanket, the skin partially dried, and the body
covered. Guiteras found great advantage by giving a moderate dose of
whiskey and thirty minims of the tincture of digitalis twenty minutes
before the bath. He states that it is very important to avoid currents
of air blowing upon the patient and to have the bath given in a small
warm room. The result of the bath was invariably a lowering of the
temperature, a reduction of the rate of pulse and respiration, and a
refreshing sleep. After the second bath the course of the temperature
seemed permanently influenced for the better. It was never necessary
to give more than two baths in the twenty-four hours, but in some
cases they had to be used for many days.
In the severe acute form of thermic fever it is essential that the
bodily temperature be reduced at once, and no time should be lost
waiting for a physician. As soon as the patient falls he should be
carried into the shade with the least possible delay, his clothing
removed, and cold affusions over the chest and body be practised. This
must not be done timidly or grudgingly, but most freely. In many cases
the best resort will be the neighboring pump. In the large cities of
the United States during the hot weather hospital ambulances should be
furnished with a medical attendant and with ice and antipyrin, so that
when a sunstroke patient is reached he may be immediately stripped
underneath the cover of the ambulance and remedial measures applied
during his passage to the hospital. I believe many lives are now
sacrificed by the loss of critical moments in the interval between the
finding of the patient and his reaching the hospital ward.
If circumstances favor, instead of the cold affusions, rubbing with
ice may be practised. The patient should be stripped and the whole
body freely rubbed with large masses of ice. When practicable, a still
better plan is to place the patient in the cold bath (50° F.) The
employment of enemata of ice-water, as originally suggested by Parkes,
may sometimes be opportune.
In using these various measures it must always be borne in mind that
the indication is the reduction of temperature: if the means employed
do not accomplish this, they do no good.
Relaxation of the pupil is said to be “the first symptom that shows
the good of the cold affusion;”[14] but as, in my experience, the
pupil frequently has not been contracted, reliance cannot be placed
upon this, and the thermometer in the mouth or the rectum affords the
only proper guide as to the effect of the treatment.
[Footnote 14: Aitken, _Practice of Medicine_, vol. ii. p. 394.]
It must be borne in mind, however, that the cold douche, cold bathing,
etc. are powerful remedies, and are capable, if used too long, of
doing harm. In my experiments upon animals I have seen the
temperature, when reduced by the cold bath after sunstroke, continue
to fall, after the animal had been taken out of the water, until it
was many degrees below normal.
In the cases which have come under my own observation after the use
{398} of the cold bath but little treatment has been required. If,
however, the period of insensibility has lasted too long, there may be
no return to consciousness, even though the bodily temperature be
reduced to the norm. Under such circumstances the case is almost
hopeless, and I know of no treatment other than that of meeting the
symptoms as they arise, excepting that a large blister should, in my
opinion, be applied to the whole of the shaved surface of the scalp.
After the temperature has been reduced, and even after consciousness
has returned, there is sometimes a great tendency to a fresh rise of
temperature, and consequent relapse. This tendency may be met by
wrappings in wet sheets, and, if necessary, by a recourse to the more
powerful measures for reduction of temperature which have been already
cited. It can be to some extent controlled by the use of quinine, ten
grains of which may be given hypodermically. During the heated term of
the summer of 1885 antipyrin has been used both in New York[15] and in
Philadelphia[16] with asserted most excellent results; and the
testimony is so strong that I think it should always be employed as an
aid to, not as a substitute for, the direct extraction of the bodily
heat. It should be given hypodermically, as soon as the patient is
found, in doses of from fifteen to thirty grains.
[Footnote 15: B. F. Westbrook, _New York Med. Journal_, July 25,
1883.]
[Footnote 16: Orville Horwitz, _Trans. College of Physicians of
Philada._, Oct., 1885.]
In cases complicated with repeated severe convulsions, hypodermic
injections of one-quarter of a grain of morphia have been very
frequently given in the Pennsylvania Hospital, with excellent results.
In such patients the use of anæsthetics to facilitate the giving of
cold baths would be very proper, but so long as the temperature is
high nothing should be allowed to substitute the external cold.
Severe headache and other evidences of cerebral inflammation,
manifesting themselves directly after the recovery of consciousness,
should be met by local or even general bleeding, blistering, the use
of arterial sedatives, mercurials, etc.; or, in other words, by the
treatment of cerebral inflammation from other causes adapted to the
exigencies of the individual case.