of the lungs, yet the physical condition involved in it does lessen the
liability to tuberculous deposit, which is favored by active hyperæmia,
and active hyperæmia is not apt to occur in an emphysematous part of a
lung. It likewise lessens the liability to such pulmonary affections as
hæmoptysis, oedema, and perhaps pneumonia. The diminished pulmonary
circulation occasioned by the shrinking and obliteration of the
capillaries explains the infrequency of hæmoptysis. The same cause,
together with the smaller amount of interlobular areolar tissue that
the emphysematous lung contains, lessens the liability to oedema,
because there are both less blood from which the serum can be effused
and less of the tissue in which it can be collected and held. And the
infrequency of pneumonia in an emphysematous lung is owing to the
absence of conditions favoring hyperæmic changes.
DURATION AND TERMINATIONS.--No definite limit can be assigned to the
duration of emphysema, as the progress of the disease varies very much
in different persons according to the underlying cause, and according
also to the care taken in avoiding those influences which promote its
development, such as physical exertion or exposure to cold and damp.
Many persons with extensive emphysema, if they can secure favorable
climatic conditions, and thus escape attacks of bronchial catarrh, will
live on for years in comparative comfort, whereas in others the disease
may advance with rapidity to a fatal issue if their situation in life
necessitates hard work or exposure to causes that induce frequent
attacks of bronchitis. The immediate cause of a fatal termination is
generally either apnoea resulting from extensive bronchitis, or
asthenia from impaired action of the heart, or both of these conditions
together.
PATHOLOGY AND MORBID ANATOMY.--From examinations made at various stages
of the disease in those who have died of emphysema it is seen that the
earliest change is a dilatation of the air-sacs, which become gradually
more distended, their walls growing thinner, until they may yield at
some points and perforations occur. As the disease advances the
perforations become larger and more numerous, until the walls are so
far destroyed that several sacs or even lobules are blended together,
forming only one cavity. The alveoli may be dilated to the size of a
mustard-seed, or even a pea, without undergoing rupture, and may thus
become visible by the unaided eye; but when the emphysematous spaces
are as large as a hazelnut or small walnut they consist of numerous
air-sacs, or even of several lobules, fused together by the atrophy and
breaking down of the interalveolar and interlobular tissues. When the
cavities thus produced by the fusion of several sacs or lobules are in
the subpleural portion of the lung, they will sometimes project beyond
the adjacent surface, so as to form appendages of the size of a small
walnut which appear to be connected with the lung by a pedicle. It is
remarked by Waters that perforation of the cell-walls is much more
common in lobar than in lobular emphysema, even though the dilatation
of the sacs may be as great or greater in the latter than in the former
affection; which is due, no doubt, to the fact that the extensive and
diffused changes in the lobar form are dependent upon a degenerative
process, in consequence of which the walls are specially prone to give
way.
All the changes just referred to, from the earliest and slightest
degree of distension to extreme attenuation and perforation of the
walls, with final {243} coalescence of several sacs and the formation
of appendages, may be met with at the same time in different parts of
the same lung. The most advanced changes are found most commonly at the
apices and free margins of the lungs, while in the deeper parts an
earlier stage only may have been reached.
The blood-vessels in the cell-walls are diminished in calibre by the
atrophy of these walls and by the constantly-increasing air-pressure,
so as to admit only the watery part of the blood; and thus is explained
the pigmentary change in the surrounding tissues where the
blood-corpuscles collect. Ultimately, many of the vessels are
obliterated, and the backward pressure thus induced extends to the
pulmonary artery, and thus gives rise to hypertrophy and dilatation of
the right side of the heart, as already explained. It is this pressure
on the vessels in the alveolar walls that causes also passive hyperæmia
of the bronchial mucous membrane, and thus produces a tendency to
bronchitis, which so often occurs as a consequence of emphysema, while,
again, primary bronchitis is frequently a factor in the production of
the disease. The principal change in the bronchial tubes, in addition
to the hyperæmia and softening of their mucous membrane due to
coexisting bronchitis, is a hypertrophic thickening of their muscular
coat, the result probably of repeated spasmodic action in the asthmatic
attacks.
DIAGNOSIS.--The chief points by which the diagnosis of emphysema is
determined have already been referred to under the head of Symptoms and
Signs. The most important of these are the auscultatory signs; for,
although the general symptoms and history of the case may point with
probability to the nature of the malady, yet if these alone be regarded
other affections may easily be confounded with it.
The auscultatory signs proper to emphysema are increased resonance upon
percussion, feeble respiratory murmur, and prolonged expiration. Any
one of these physical signs may be met with in other affections than
emphysema, but when they occur conjointly they point only to this
disease. In addition to them the alteration in the form of the
chest-wall, so that it becomes rotund or barrel-shaped, and the
asthmatic character of the breathing, are important indications. The
diseases most likely to be mistaken for emphysema are phthisis,
bronchitis, pneumothorax, and pleural effusion.
In the early stage of phthisis feebleness of respiratory murmur with
prolonged expiration might suggest the existence of emphysema; but,
apart from the fact that these signs at any time when a doubt might be
felt are generally confined to the top of the lung in phthisis, the
diminished percussion resonance, the bronchial or broncho-vesicular
breathing, the bronchophony or bronchial whisper, and increased vocal
resonance and fremitus--all of them proper signs of phthisis and all
wanting in emphysema--would by their presence or absence clearly
establish the differential diagnosis between the two affections. In
more advanced phthisis, when softening has taken place and a cavity
exists, difficulty in discriminating between the two diseases could
hardly arise.
Emphysema is so frequently associated with chronic bronchitis and with
intercurrent attacks of acute bronchitis that it is often important to
determine whether these latter affections exist independently or are
complications of the emphysema. The question is in general settled by
the history of the case and by the conformation of the chest, showing
whether previous dilatation of the air-cells has taken place or not; as
also by the presence or absence of the special signs of emphysema when
those of the bronchial affection are encountered.
Capillary bronchitis, from the urgent dyspnoea attending it and the
vesiculo-tympanitic resonance which it sometimes presents, especially
in the upper and anterior parts of the chest, may possibly be mistaken
for emphysema, from {244} which, however, it may be distinguished by
the quickened pulse and high temperature that belong to this form of
bronchitis, as also by the rapid diffusion of the subcrepitant râle
over both sides of the chest in capillary bronchitis; whereas this sign
is absent or less marked in emphysema. Moreover, capillary bronchitis
is most common in childhood, when diffused emphysema is less frequently
met with.
Pneumothorax is characterized by distension of the chest and increased
percussion resonance--signs which belong also to emphysema; but the
possibility of error is avoided by the consideration that whereas in
emphysema the respiratory sound is feebler than natural, in
pneumothorax it is strongly exaggerated and amphoric in character; and
there are also the additional signs of metallic tinkling and the
plashing noise or "Hippocratic succussion sound" made by moving the
body backward and forward. Moreover, even as regards the sign in which
the affections would appear to resemble each other, a difference may be
observed on careful examination; for the percussion note of
pneumothorax is purely tympanitic, while in emphysema the increased
resonance has still a vesicular character to some degree. Pneumothorax,
again, is always a unilateral affection, and emphysema is almost as
constant in its occurrence on both sides of the chest.
It might appear that there would be little liability to confuse
emphysema with pleural effusion, in view of the very general presence
of dulness on percussion in the latter affection and of resonance in
the former. But in some cases of fluid effusion in the chest a degree
of tympanitic resonance is met with, more especially in children. J.
Lewis Smith remarks that "as a rule in the pleuritis of children, at a
certain stage of the effusion, percussion produces a sound which is
either decidedly tympanitic or which partakes of the tympanitic
character."[11] In both affections, moreover, there may be enlargement
of the chest. The doubt, if it arise, may be settled by the
consideration that in emphysema the altered resonance and the
enlargement are on both sides; whereas in pleurisy these signs are in
general on one side only; and, further, the enlargement is more marked
at the top of the chest in emphysema and at its base in pleural
effusion.
[Footnote 11: _Diseases of Children_, 5th ed., p. 607.]
In concluding the account of the diagnosis it may be said that when the
history of a case, the frequent or constant occurrence of dyspnoea, and
the more or less rounded conformation of the chest make the existence
of emphysema probable, this probability may be converted into a
certainty by the discovery of resonance on percussion, feeble
respiratory murmur, and prolonged expiration.
PROGNOSIS.--The circumstances, apart from treatment, which especially
affect the prognosis of emphysema are the form in which the disease
occurs and the ability of the patient to secure immunity from
influences which may increase the malady itself or the attendant
bronchitis, such as hard work, great exertion of the respiratory
organs, and exposure to cold and damp.
Acute supplementary emphysema, even when it affects considerable
portions of both lungs, may entirely disappear and the vesicles be
restored to their integrity on the removal of the underlying cause.
Thus, the vicarious dilatation of air-cells following acute bronchitis
or whooping cough in children may leave no sign of its previous
existence after recovery from these diseases. In general, the shorter
the duration of the causal diseases, the more likely is the emphysema
to disappear; for if it be maintained for a considerable time, the
elasticity of the cells may be so damaged that they may never return to
their natural size.
In hypertrophic lobar emphysema the prognosis in most cases is
unfavorable as regards perfect recovery; while yet the disease may not
materially shorten life, and with proper care may be compatible with a
fair degree of {245} comfortable existence. And, indeed, even in this
form of the disease, provided it do not affect a great extent of lung
and have not been of very long duration, there is in some cases ground
for hope of ultimate recovery, with restoration of the air-cells to
their normal condition. Modern methods of treatment have rendered the
prognosis in such cases somewhat less unfavorable than it was once held
to be.
TREATMENT.--The treatment of emphysema comprises several distinct
objects: 1st, the arrest of the degenerative changes which may be going
on in the walls of the air-vesicles, and which favor their dilatation;
2d, the restoration, as far as is possible, of the integrity of the
lungs, so that they may resume their natural size; 3d, the relief of
bronchitis, asthma, and dropsy, which are associated as secondary
affections with the primary disease.
To meet the first of these indications, the arrest of degenerative
change, iron is among medicinal agents the one most to be relied upon;
for, though neither it nor any other means has power to restore loss of
tissue or to reproduce integrity of structure when several alveoli are
fused into one cavity by the breaking down of their partition-walls,
yet by enriching the blood it may improve the nutrition of these
cell-walls so that the tendency to dilatation and rupture may be
checked. Iron steadily administered in small doses is the best means
for effecting this end, and if the patient object to one form of the
metal after using it for some time, it may be changed for another. The
best preparation of the drug is probably the tincture of the chloride,
and one of the best forms for administering this medicine is the
mixture of acetate of iron and ammonium (Basham's mixture) introduced
into the U. S. Pharmacopoeia of 1880. This is especially valuable, when
any dropsical effusion exists, on account of its gentle diuretic
action. In addition to iron, other agents promotive of nutrition, such
as cod-liver oil and the hypophosphites, may be used with the same
view. Stomachic tonics, such as the simple bitters and pepsin, may be
useful by aiding digestion and nutrition; and at the same time, by
preventing the formation of flatus, they may relieve the dyspnoea
caused by upward pressure on the diaphragm. That real benefit may be
derived from such measures is beyond doubt; and it is to be feared that
some practitioners, in their conviction that no cure can be wrought in
those parts of the lung which have actually undergone wasting and
rupture, have to too great an extent neglected the use of means which
may at least prevent the advance of similar changes in other parts, and
thus tend to stay the progress of the disease.
Deep and hurried respiration will increase the air-pressure within the
yielding vesicles; for this reason active exercise is objectionable,
especially walking up hill, and the use of wind instruments is to be
strictly prohibited. Indeed, as regards this last cause of respiratory
pressure the patient's inability to practise is in general warning
enough, but in the early stages of the affection a caution against it
may be necessary.
The suggestion of the use of strychnia against emphysema is not founded
on a correct knowledge of the mode of action of this drug; for,
although it may stimulate muscular contractility, it has no influence
upon the elasticity of the air-cells and no power to restore them to
their natural size. Whatever benefit may result from it is due solely
to its action on digestion and the improvement in nutrition to which it
may thus contribute.
The second indication of treatment, the restoration of the dilated
air-cells to their natural size, is possible, if at all, only at an
early period of the disease or in portions of the lung which have not
gone beyond a moderate degree of cell-dilatation. An enlarged space
formed by the fusion of several cells cannot be lessened in size by any
means, medical or mechanical, and the loss of respiratory power from
the destruction of the cell-walls in which oxygenation is effected does
not admit of permanent relief. Where, however, such {246} destruction
has not yet taken place and distension is not extreme, there is reason
to believe that a return of the cells to their natural size may in some
cases be accomplished. The inhalation of condensed air has been
recommended with this view; and no doubt good may result from it, due
chiefly to the retardation of the breathing and of the heart's action
which it occasions, while dyspnoea is relieved by the larger supply of
oxygen taken in at each inspiration. This improvement in respiration
causes more complete tissue-metamorphosis, and thus aids nutrition and
all the functions.
Still greater benefit is to be derived from the exhalation into
rarefied air--a measure which acts upon mechanical principles, and has
been found to give relief not only to the symptoms of emphysema, but to
the organic disease itself; for the retention and stasis of the
residual air, which is far larger in amount in emphysema than it is in
health, serve at once to keep up the dilatation of the cells and to
increase the dyspnoea; and therefore any means which will effect the
withdrawal of this air will favor the return of the cells to their
normal size, and at the same time relieve the dyspnoea. This benefit is
accomplished by the method of expiration into rarefied air, which acts
by suction--or pneumatic aspiration, as it may be termed--drawing out
the air from the distended vesicles, and relieving them of the
continual presence and pressure of this air. Better results would
appear to be gotten from the conjoint use of the two methods--the
inspiration of compressed air and expiration into rarefied air--than
from either one alone.
By the persistent use of these means in cases which have not advanced
so far as to defy all treatment not only may the symptoms of dyspnoea,
cough, asthma, and impaired nutrition be improved, but the size of the
chest may be diminished, as shown by measurement; and this can result
only from the return of the distended air-cells, in some degree at
least, to their normal capacity.
The apparatus best fitted to effect this double purpose is that of
Waldenburg, as modified by Tobold.[12] The method of using it is
simple, and can readily be understood by examining the instrument. It
must be said that the most valuable action of this apparatus consists
in the withdrawal of the air from the cells which it effects, for this
tends to produce an organic change for the better--viz. the diminution
of the enlarged cells by a sort of suction; while its other action, the
supply of condensed air, gives relief to symptoms mainly. In emphysema
the expiratory act is relatively more impaired than the inspiratory,
and the apparatus is best adapted to the relief of this greater
deficiency. Henry Saltzer, formerly of Germany and now of Baltimore,
has recently obtained very favorable results from its use in emphysema,
not only as regards the dyspnoea and other symptoms, but also in the
way of lessening the size of the chest as determined by
measurements.[13]
[Footnote 12: This instrument is made by Messrs. J. Reynders & Co. of
New York.]
[Footnote 13: A reference to Saltzer's observations and measurements
may be found in Weil's _Handbook of Topographical Percussion_, pp. 107,
108, Leipzig, 1880.]
The third indication of treatment has reference to the complications of
emphysema. Of these the most common, and one of the most important, is
bronchitis, which is to be treated in the same way as when it occurs as
an independent affection. Expectorants to promote and remove secretion
and agents to allay cough are very important means, because the
retention of secretion and the effort of cough to expel it cause a
strain upon the air-cells, and thus increase the emphysema. The local
use, by inhalation or spray, of opiates, belladonna, hyoscyamus, and
other agents of this class, is often most serviceable by giving relief
to the cough without disturbing digestion. As bronchitis is in many
emphysematous patients a very chronic affection, and is attended with
submucous thickening in the bronchial tubes and consequent diminution
of their calibre, the iodide of potassium is an agent of special {247}
value for its relief. Whether the influence of this remedy is due to a
sorbefacient power or to some other unexplained mode of action, there
is no doubt of its great value in chronic bronchitis, so that for this
complication of emphysema it claims a very high rank among medicines.
The rapidity with which relief is afforded to the cough and dyspnoea of
bronchitis, and to the asthmatic paroxysms attending it, by full doses
of 10 or 15 grains of iodide of potassium at intervals of four hours,
makes it probable that its action is partly neurotic in character. It
is remarked by Austin Flint, Sr., that when the iodide has effected a
marked improvement in the chronic bronchitis he has known the
characteristic deformity caused by the emphysema to be notably
diminished.[14]
[Footnote 14: _Clinical Medicine_, p. 131.]
A dangerous symptom which sometimes arises in the course of the chronic
bronchitis accompanying emphysema is profuse bronchial catarrh, which
may destroy life by producing apnoea, the surface becoming cold and the
pulse feeble and vanishing as the patient seems to be drowning in his
own secretion. In this condition the writer has in several instances
found prompt and unmistakable benefit from the hypodermic injection of
hydrobromate of quinia, and he would strongly advise the use of this
agent. The solution he has employed is of the strength of 4 grains of
the salt to 20 minims, and of this 15 to 20 minims has been the dose
given. Under the action of this remedy the pulmonary capillaries would
appear to be so toned that further effusion is checked, and the gasping
and cyanotic condition has been speedily succeeded by comfortable
breathing. For the same symptom Waters advises the use of moderately
large doses of turpentine (drachm doses in aromatic water every two
hours) on a plan suggested by Sir D. Corrigan of Dublin.[15]
[Footnote 15: _Diseases of the Chest_, p. 172.]
As bronchitis has so much power to produce emphysema when the
conditions favorable to its occurrence exist, and to increase it when
already established, everything tending to prevent it is of great
importance. With this view the avoidance of cold and wet, and, when
practicable, recourse to a mild climate in winter, are advisable.
The attacks of asthma to which emphysematous patients are subject are
to be treated in the same way as the purely spasmodic form occurring
independently of discoverable organic disease. If the difficult
breathing has come on suddenly and the patient is not laboring under
advanced dilatation of the heart, prompt relief may be given by a
hypodermic injection of morphia; but if the heart is much dilated, this
might endanger too great depression. Chloral is generally unsafe for
the same reason. The bromides in full doses may be serviceable in the
less severe attacks, and the tincture of lobelia in doses of 10-20
drops every fifteen minutes until slight nausea is felt is often of
great benefit, as is also the smoking of stramonium-leaves.
The dropsy met with in advanced stages of emphysema may be so prominent
a symptom as to require special treatment. Its cause is found in
dilatation and weakness of the right chambers of the heart, which
result from obstruction to the circulation through the lungs when
compensative hypertrophy is no longer efficient, for then these give
rise to passive congestion of the liver and kidneys and remora of the
general venous system, with dropsical leakage, seen first and chiefly
in the lower extremities. Treatment is therefore to be directed chiefly
to increasing the tone of the heart; and for this purpose digitalis is
most useful, as it is in other forms of cardiac dropsy. The chief
indication of its beneficial action is seen in the better action of the
kidneys consequent upon the increased impulsive force given to the
heart. When acting favorably, marked relief both of the dropsy and the
dyspnoea may be obtained from the use of this agent in the dose of 2 to
4 drachms of the infusion or 10 or 15 drops of the tincture every three
or four hours. If {248} the stomach should not bear the digitalis, as
is sometimes the case, or if it fail to act or lose its power, the
fluid extract of convallaria, recently introduced as synergistic with
foxglove, may be employed as a substitute for it.
Under similar circumstances, if the patient's strength will admit of
it, great benefit will sometimes result from a mercurial purge, by
which passive congestion of the portal system may be relieved and the
upward pressure of an engorged liver in some degree lessened.
4. Atrophic Lobar Emphysema.