pre-existing pulmonary oedema, it is not always easy to recognize at
once {869} the occurrence of capillary bronchitis. This complication
is attended with increasing dyspnoea, decided lividity of the face and
extremities, and great prostration. Crepitant and subcrepitant râles
at the lower portions of the posterior dorsal regions, rapidly
spreading to all parts of the chest, without dulness at first and with
increased resonance later, instead of the signs of consolidation which
are met with in pneumonia, are the signs which attend its appearance.
Catarrhal pneumonia occurs insidiously, with gradual intensification
of the bronchitic symptoms about the fourth or fifth day, but it may
set in as early as the second day, or much later, during
convalescence. It is, as a rule, developed without chill or great
increase in the fever.
Old persons and those of feeble constitutions are most liable to the
foregoing complications.
Lobar pneumonia is less common. It is a late complication, occurring
toward the close of the attack or even when the patient is beginning
to get about. It is easily recognized, and differs in no wise from
acute lobar pneumonia occurring under other circumstances.
In October, 1880, influenza being prevalent in Philadelphia, both
epizoötic and epidemic, but very mild both among horses and men, I
attended a medical student who, having had what he regarded as a cold
for about a week, had kept at his work without treatment, until, upon
the occurrence of a chill followed by grave thoracic symptoms, he was
obliged to betake himself to bed. I first saw him the following day in
the hospital of the Jefferson College. There were the symptoms of
acute lobar pneumonia, with the signs of extensive consolidation of
the left lung and pleurisy of the right side. Moreover, there were
delirium and jaundice. The urine was non-albuminous. The next evening
he died. At the same time many members of the class suffered from
influenza, and a careful inquiry into the history of the case of this
young gentleman satisfied me that the pneumonia had arisen as a
complication in a neglected and moderate severe catarrhal fever. Until
the eighth day before his death he was in excellent health. No
examination of the body was permitted.
Graves[21] thought that a kind of paralysis of the lungs, with great
oedema, takes place in some cases, and attributed it to an affection
of the vagus. It was his conviction "that the poison which produced
influenza acted on the nervous system in general, and on the pulmonary
nerves in particular, in such a way as to produce symptoms of
bronchial irritation and dyspnoea, to which bronchial congestion and
inflammation were often superadded."
[Footnote 21: _Annals of Influenza_.]
It is certain that localized collapse of the lung often occurs. White
and Guitéras attributed the consolidations of the lung to congestive
collapse due to enlargement of the tracheal and bronchial glands and
"disturbance of the great nervous tract about the root of the lung."
They were enabled to satisfy themselves of the existence of glandular
enlargement--adenopathie bronchique--in nine of their eighteen cases
by percussion practised in the method of M. Geneau de Mussy,[22] who
was the first to call attention to the importance of percussing the
spinous processes of the vertebræ over the course of the trachea.
Following this line in the healthy subject, a distinct tubular
(high-pitched and slightly {870} tympanitic) sound is elicited by
percussion down to the point of bifurcation of the trachea on the
level of the fourth dorsal vertebra. Opposite the fifth and downward
we get the lower-pitched pulmonary resonance. When the tracheal and
bronchial glands are enlarged, the tubular sound over the upper dorsal
vertebræ is replaced by dulness, which may contrast sharply, above
with the tracheal, and below with the vesicular resonance.
[Footnote 22: _Chirurgie médicale_, Paris, 1874.]
Some well-recognized peculiarities of the so-called pneumonias of
influenza give weight to the view that the consolidations are not, in
the beginning, pneumonic at all. Thus, we have at first weakness of
the vesicular murmur, then its absence; the respiration soon becomes
bronchial, without being preceded by dulness or the crepitant râle;
the extension of those consolidations from one part of the lung to
another is very irregular; the process is more apt to involve both
sides than one; the disappearance of the consolidation is frequently
very rapid.
The relations of cause and effect between collapse and catarrhal
pneumonia are so close that it is not difficult to see how the
condition spoken of may lead to secondary lobular or catarrhal
pneumonia. In truth, this is a frequent result of collapse from any
cause.
White and Guitéras do not adduce any post-mortem facts in support of
their theory. Peacock, however, observed in the epidemic of 1847
softening and enlargement of the bronchial glands in several cases,
and in one instance where there was no antecedent disease of the
lungs, and where the physical signs corresponded to some extent with
those of the cases upon which White and Guitéras base their views.
Gangrene of the lungs must be named as one of the less common
complications.
These complications are the chief cause of the danger of influenza in
the aged, the debilitated, and those suffering from previous disease
of the thoracic organs.
Pleurisy is rare except where there is coexisting inflammation of the
lungs. It may be associated with pericarditis. In old persons serous
effusions into the pleural sac are now and then encountered.
Troublesome laryngitis and chronic bronchitis may follow the attack.
In consequence of the extension of the catarrhal processes along the
Eustachian tube an actual inflammation of the middle ear is, in rare
instances, set up. Parotitis with salivation sometimes occurs,
likewise aphthous inflammations of the mouth.
Herpes labialis occasionally occurs toward the end of the attack; it
is then a favorable indication.
Phthisis may be developed in consequence of an attack of influenza,
and if phthisis be already established it is apt to run a more rapid
course. Emphysematous affections are aggravated; diseases of the heart
are unfavorably influenced; chronic nervous affections are made worse,
and, in particular, neuralgias are aggravated. Old neuralgias, that
have long ceased to give trouble, occasionally reappear during the
convalescence.
Persons subject to latent or chronic Bright's disease are especially
liable to the more serious manifestations of influenza. The fatal
termination of such cases not unfrequently occurs in consequence of an
attack.
Many of the older observers speak of the intermittent character of
{871} influenza in certain epidemics, and its tendency to run into
intermittents, particularly of a certain type, during convalescence.
This has not been observed in the outbreaks of later years, and it is
probable that in such instances an endemic malaria has modified the
epidemic catarrhal fever, or the former has broken out as the latter
passed away.
Pregnant women are in danger of aborting.
PATHOLOGY.--Our knowledge of the pathology of influenza is as yet very
imperfect. Biermer has described it as the sum of a series of
catarrhal manifestations developed under a common epidemic influence.
The close association of the various local affections arises from
their almost simultaneous occurrence as results of primary
pathological processes common to them all. Each of the three groups of
symptoms which make up the clinical picture of the disease--namely,
the fever, the catarrh, and the symptoms referable to the nervous
system--constitutes a distinct factor of influenza, and is a direct
outcome of the action of the infecting principle. There is no constant
interdependence among these groups, either in the order of their
succession or in their intensity. Thus, while all three groups are
commonly present from the beginning of the attack, any one of them may
be the first to appear or have an intensity out of all proportion to
each of the others. The fever is not a result of the catarrhal
inflammation, nor are the nervous symptoms the result of both the
others. They all spring directly from the action of the same cause.
This view is at variance with the opinion--based upon the fact that
ordinary acute local inflammatory diseases, tonsillitis, bronchitis,
and the like, sometimes run their course in a similar way to
influenza, with fever, nervous depression, and a serious sense of
illness--that influenza is a simple epidemic catarrhal inflammation.
The sudden onset of influenza, its not infrequent abrupt termination,
which suggests crisis, its unsparing seizure of great numbers of the
population, the severity of the nervous symptoms, and the amount of
laryngo-bronchial irritation, often out of measure with the lesions of
the mucous membranes,--all point to the action of a morbid agent
affecting the body at large. The severity of the symptoms also, in
many cases, is much greater than in similar acute non-specific local
affections, while the complications, and in particular the
recrudescence of fading neuralgias and the tendency to abortion, and
the sequels, as cough, weakness, headaches, flying pains, which often
remain long after convalescence, are evidences of its belonging to the
group of infectious diseases rather than to that of simple acute
inflammatory diseases.
In conclusion, it must be urged that the similarity of the symptoms in
many epidemics, occurring during the course of several centuries and
under different social conditions, and even different degrees of
civilization, forcibly demonstrates the specific and definite
character of the causes which give rise to influenza.
Very little light is thrown upon the pathology of the disease by the
anatomical changes found after death. Uncomplicated influenza is
rarely fatal. As a rule, the unfavorable termination is due to lung
complications. The essential lesions are congestion and catarrhal
swelling of the mucous membrane of the upper air-passages and the
bronchial tubes. These changes may be restricted, in the lungs, to the
trachea and larger {872} bronchi, or they may extend to the finest
twigs. They may amount to great thickening and deep capillary
injections of the mucous lining of the tubes, which contain clear,
frothy mucus or thick, viscid masses of muco-purulent secretion
unmixed with air.
More or less congestion of the gastric mucous membrane, and more
rarely of that of the intestine, is also met with. The solitary and
agminate glands of the intestine are not affected, save as the result
of special complications. A few observations relate to the finding of
enlarged and softened bronchial glands. More extended researches are
needed, not only upon this point, but also in the whole domain of the
pathological anatomy of the disease.
Hyperæmia, oedema, hypostatic congestions, splenization, catarrhal
pneumonia, and hepatization affect the lung-tissue in cases fatal by
the complications which are associated with such changes. The
tissue-changes of diseases existing prior to the attack of influenza,
such as old consolidations, tubercle, brown induration, emphysema, and
so forth, are of course frequently discovered.
DIAGNOSIS.--The discrimination of influenza from other affections
having some points of resemblance to it is, under ordinary
circumstances, unattended with difficulty. The march of the epidemic,
the number of persons attacked, the prominence of the nervous
symptoms, the rapidly developed debility, and the character of the
cough, usually severe out of proportion to the physical signs,
distinguish it from all other epidemic diseases.
It is to be differentiated from non-specific catarrhal affections
attended by fever, malaise, weakness, severe headache, and pain in the
extremities by a due regard to the causative relations of the two
affections. Simple catarrhs not rarely present the group of symptoms
which characterize epidemic catarrhal fever, but they occur almost
constantly as the result of great and sudden changes in the weather,
and are therefore met with in greatest frequency in bad seasons, and
are particularly common at the end of winter and in the spring.
Influenza is not in any way dependent upon the vicissitudes of the
seasons, and may occur, as has been shown, at all times of the year,
in wet or dry, mild or cold seasons equally, and in every variety of
climate. It is of course diagnosticated without difficulty from the
sporadic catarrhal fevers, which lack the characteristic depression,
neuralgic and rheumatoid pains, the irritative cough, dyspnoea, and so
on.
Cases of influenza are met with that bear a strong resemblance to
beginning enteric fever. The malaise, headache, obtunded hearing,
mental depression, high fever, coated tongue, tender belly, diarrhoea,
are symptoms to be observed in both affections. But influenza lacks
the temperature curve, the splenic enlargement, and the eruption of
enteric fever, and the progress of the disease will in a few days
clear up the most doubtful case.
PROGNOSIS AND MORTALITY.--Death is rare in uncomplicated cases. The
very young bear influenza badly; the old bear it more badly still.
Nevertheless, children have in some epidemics enjoyed a considerable
proportionate immunity. Healthy persons in the middle periods of life
bear it well. Certain pre-existing diseases modify its course
unfavorably; among these are chronic bronchitis, emphysema, fatty
heart, and Bright's disease. {873} The debility of advanced phthisis
and other exhausting diseases renders influenza dangerous. Death takes
place, in by far the greater number of cases, as the result of the
complication of the attack, either by some pre-existing affection or
by an acute disease arising in its course. The commonest of the latter
are inflammations of the parenchyma of the lungs.
Patients presenting very severe symptoms generally recover if they be
not the subjects of complicating maladies or very young or very old.
Relapses are not uncommon; independently of relapses, second attacks
have been known to occur during the continuance of an epidemic; it is
often the case that an individual in the course of his life passes
through several epidemics of influenza, and is the subject of the
disease in each of them.
The prognosis is greatly modified by the character of the prevailing
epidemic. In some epidemics the deaths are few, and the mortality from
other diseases does not appear to be greatly augmented. In others many
die of the epidemic disease, and the death-rate of certain endemic
affections is much increased. In some of the older epidemics the high
mortality was doubtless due to injudicious measures of treatment,
among which bloodletting and other depressing agencies were
conspicuous. Some of the older accounts also warrant the suspicion
that a coexisting typhus had to do with the high death-rate. It is
estimated that in the epidemic of 1837, which was a very severe one, 2
per cent. of those attacked died. The proportion of fatal cases in
particular epidemics varies in different countries, and even in
different quarters of the same city.
TREATMENT.--Efficient measures of prophylaxis are as yet unknown.
Unfavorable hygienic surroundings, overcrowding, a damp, unhealthy
locality, appear to increase the prevalence and severity of influenza.
The opposite conditions of living do not, however, secure immunity
from the attack. During an epidemic aged persons, those enfeebled by
chronic diseases, and in particular those subject to chronic
bronchitis, consumption, emphysema, fatty heart, and Bright's disease
should be cared for with unusual diligence and solicitude, since they
constitute the classes most prone to the graver complications of the
disease, and from which its fatal cases are almost wholly derived.
Such individuals should be warmly clad; they should shun, so far as
possible, the vicissitudes of the weather, even, if practicable,
keeping within warmed and well-ventilated apartments; they should
exercise unusual prudence in diet and lead a carefully regulated life,
with long hours of sleep. It is true that these measures are not
preventive of the attack. Families not quitting the house, living in
the greatest seclusion, even the bedridden, do not always, or even as
a rule, escape. Yet it has frequently been observed that those whose
occupations are carried on in the open air are attacked earliest and
in greatest numbers. On the other hand, in rare instances, persons
isolated from the community with strictness--in prisons, cloisters,
hospitals--have remained free from the disease prevailing around them.
It therefore appears probable that, under certain favorable
circumstances not as yet perfectly understood, the avoidance of the
open air and of the direct influences of the weather may confer some
degree of immunity from the attack, and it is desirable that the class
of persons most liable to the graver consequences of the disease
should avail themselves of even the most uncertain precautions.
{874} The treatment of influenza is expectant and supporting. Not only
is the epidemic self-limiting, tending to exhaust the susceptibility
of a community, in most instances, in the space of a few weeks, but
the attack is also of definite duration, and the perturbations set up
by the action of the influenza-poison upon the individual subside
spontaneously in three or four, or at most ten or twelve, days. The
susceptibility of the individual is also, for the time being,
exhausted, for second attacks in the same epidemic are not very
common. In cases where the duration of the attack is prolonged beyond
the period indicated, it is kept up by complications, and we have to
do not so much with the pathological processes of influenza as with
secondary diseases that the influenza has excited either by the
intensity of its action or by reason of some peculiarity of the
subject of the attack.
By far the greatest number of cases are light and unattended by
danger. The treatment is therefore, for the most part, an extremely
simple one. These lighter cases seldom require medical measures. The
patients are uncomfortable and anxious, easily fatigued, and unfitted
for business. It is best that they keep the house, and, if willing,
the bed or sofa, for the space of two or three days. The diet should
be restricted to a few simple and easily-digested dishes. Meat should
be avoided. The common custom of taking hot beef-tea is an extremely
bad one; it often increases the headache and languor. Moderate
quantities of cold drinks may be taken. The fruit-syrups, lemonade,
raspberry vinegar, a weak solution of citrate of potash or of cream of
tartar, and barley-water with lemon, are useful. Very weak wine-whey
is often liked. The effervescing mineral waters or Apollinaris are
preferred by many persons. The best of such drinks is a mixture of
equal parts of Seltzer-water and milk, iced. If the stomach be
irritable, koumiss will be found an excellent beverage and food. In
the mild cases stimulants are not necessary. Sound claret, with or
without Seltzer-water, is not contraindicated. In all cases the amount
of fluid taken should be moderate.
Quinine in moderate doses should be taken from the onset. The
head-pains are not increased by it. Dover's powder, if well borne,
should be administered at night. Some form of opiate may be required,
even in mild cases, to counteract wakefulness. A compressed pill,
containing extract of opium 0.030 gramme (gr. 1/2), camphor 0.15 (gr.
ij), and ammonium carbonate 0.15 (gr. ij), will be found useful when
Dover's powder cannot be employed. During convalescence iron and barks
are often requisite.
The coryza, tonsillitis, laryngitis, bronchitis are to be treated
according to general principles, if they require treatment at all. In
most mild cases the catarrhal symptoms call for no special measures of
treatment.
Free inunctions of fatty substances about the brow and over the bridge
of the nose are of use as regards the coryza. For this purpose animal
fats, washed lard, simple cerate, cold cream, and the like are to be
preferred to cosmoline and vaseline.
Morphine dissolved in cherry-laurel water, one part in fifty or sixty,
is useful for the relief of the head-pains associated with the coryza.
A few drops may be snuffed up from time to time. These pains are
mitigated to some degree by wearing a flannel cap or wrapping the head
in a silk handkerchief. Warm applications sometimes give comfort,
while cold almost invariably add to the distress.
{875} Distress in the upper air-passages and the tickling cough call
for steam inhalations, and the air of the apartment may be rendered
moist by the evaporation of water kept boiling in a broad, shallow
vessel. Gargles of potassium chlorate, or potassium chlorate with
sumac, exert a soothing influence upon the congested tonsils.
Severe cases call for more energetic measures of treatment. The most
prominent indications are the control of the fever; the diminution of
the hyperæmic fluxion to the mucous tracts; measures of support; the
mitigation of pain and the induction of sleep; and, finally, the
prevention of the pulmonary congestion, to which the depression leads
by enfeeblement of the circulation. The last indication is especially
urgent in infants, the very old, and those previously debilitated from
any cause.
Inflammatory complications require special treatment or modifications
of treatment.
The febrile movement is not, as a rule, high; grave nervous symptoms
and serious catarrh may be associated with moderate fever.
An anti-febrile regimen is to be observed. The moderate duration of
this fever, as compared with enteric fever, renders it less important
that large amounts of fever-food should be given, while the tendency
to depression makes it of the utmost importance that the
administration of food be systematic and carefully looked after by the
medical attendant. The disinclination to take food is so great that it
is often with difficulty that a sufficient quantity can be given in
the early days of the attack, and it is to be doubted whether benefit
follows anything in excess of the most moderate amount. It is
necessary to observe regular hours, as in the management of all the
low fevers. As soon as convalescence begins the patient should be
urged to eat; the quantity of food taken at one time is to be
augmented, and the intervals between the meals may be longer.
A favorable action upon the excretory function of the skin and kidneys
will result from the moderate drinking of water or of the beverages
already spoken of. At least enough fluid should be taken to relieve
thirst.
Diaphoretics have been much used, upon the theory that by
determination to the skin they correspondingly diminish the tendency
to hyperæmia of the affected mucous tracts. Dover's powder, solution
of the acetate of ammonia, and other mild diaphoretics are to be
selected. Jaborandi should be employed with caution. The wet pack and
other hydrotherapeutic measures have been employed to act upon the
skin and to effect a direct reduction of temperature in influenza. For
old and feeble persons warm packs are employed. A profuse sweating at
the onset of the attack is said to occasionally cut it short. Early
diaphoresis often brings about a rapid and lasting amelioration of the
symptoms. It is to be borne in mind that the fever is rarely
excessive, and that sweating is not infrequently a troublesome
symptom. In some epidemics it has been a very troublesome one.