pathological processes incident to the pulmonary tissues. The bronchial
lesions are those of chronic bronchitis, with thickening of the
bronchial mucous membrane, associated with possible ulceration and
bronchial dilatations, forming bronchiectasic cavities. These cavities
are caused by combined softening of the bronchial tissues with traction
from without by the newly-formed fibrous tissue. The bronchial glands
may be enlarged to the size of walnuts, and are often perfectly black
and gritty on section. These enlarged glands may occasion, through
pressure, many changes in the pulmonary tissues. The effect of this
pressure is especially manifest in the lymphatic system. The
lymph-circulation is further crippled by the accumulation in the
lymph-channels of the inhaled inorganic materials. These interferences
with the lymph-circulation may be followed by exudation or lobular and
interlobular formation of tissue; secondary to these changes the
pressure upon the vesicles may cause local congestions, exudations, and
even hæmoptysis. By one or all of these processes the expansile power
and elasticity of the lung are slowly depreciated, emphysema develops,
intertwined with the lesions of acute, subacute, or chronic bronchitis,
fibroid phthisis, and atrophic emphysema. Nodules of cretaceous matter
can be recognized through the lungs, which are black in anthracosis or
gray in silicosis. These nodules occur from the size of a pin's head to
that of a pea, and are especially found in the lungs of glass-cutters,
sandstone-workers, and grinders. In these cases they consist in part of
iron and in part of stone. In sandstone-workers they are composed of
silica; the organ feels nodulated, very fibrous, and in some cases
actually gritty. The predominant form of pulmonary change is fibroid;
hardened districts of advanced cirrhosis occur measuring two inches and
upward in length and width, and in depth and thickness nearly as much.
These may be rounded, but are not separable from the adjacent
structures, the condensation of the tissues lessening without a
defining line. On section they appear tough and leathery, most
pronounced along the anterior edges of the lungs, and are apt to be
covered in by thickened pleura. If the nodules previously alluded to
are encysted, fibrous prolongations extend from these cysts into the
substance of the lung, the thickening of the lung being greatest in the
septa, on the pleural surfaces, and along the course of the bronchial
tubes. Sometimes subacute or chronic pleural processes coexist. The
caseous masses found in tubercular fibroid phthisis are infrequent in
pneumonokoniosis, but in the latter process the {458} pathological
changes may be identical with the ordinary forms of phthisis,
especially in those individuals who are predisposed to pulmonary
affections and those in whom the pathological processes are rapid.
In anthracosis the lung is large and increased in weight; the surface
of the pleura has a bluish-black color, contrasting with the coal-black
color of the lungs, which are universally pigmented and contain nodules
of pigment. When only small quantities of pigment are present, it
presents the appearance of dark lines running between the lobules; on
section these are very hard and distinct, being about the size of a
millet-seed. They are universally distributed throughout the lung, and
in some places appear like small masses of charcoal. Upon squeezing the
organ a blackish fluid exudes which stains the hands, but the discharge
which is found lying in the bronchial tubes is often yellow and
muco-purulent, although the sputa during life is more or less
discolored. When the distribution of the discoloration of anthracosis
is investigated, it is found to closely correspond with the lymphatic
distribution of the lung, and the conclusion is probably well founded
that all other irritating particles pursue the same course through the
pulmonary tissues. When particles of coal or pigment enter the bronchi
with the air, they cannot pass through its mucous membrane, because the
basement membrane and fibrous coat underlying it present an obstacle to
their lodgment, whilst the cilia of the epithelium tend to prevent
their retention in the bronchi; they therefore enter the vesicles, and
may be found sticking to the walls. In this way the exemption of the
bronchi from pigmentation, even down to the smallest ramifications, can
be explained. The interlobular septa ate also the seat of great
pigmentation. The germinating epithelium elevates the cells slightly
above the surface, and in the interspaces between them the pigment
insinuates itself, and thus enters the underlying plasmatic or
lymphatic spaces; or the pigment may be incorporated into the
epithelial cells, which transfer it to the underlying lymph-space. Once
the pigment has found entrance to these lymphatic channels, it is
carried by them through the lymphatic vessels in the sheath surrounding
the bronchial tubes and the small branches of the pulmonary artery, and
in the interlobular septa to the bronchial glands. In this manner the
special distribution of the coloring matter in these situations is
explained. The special deposit around the small branches of the
pulmonary artery is owing to the double set of lymphatics, the
peribronchial and the perivascular, which form an anastomosis. The
perivascular set is the larger; consequently the pigment passes into
them more readily, forming the nodules. Pigment is also found in small
quantities around the bronchi, which can be accounted for by the
anastomosis of the lymphatics. The bluish-black appearance of the
pleura and the distribution of the pigment only in the deeper layers of
the visceral pleura are susceptible of a similar explanation, because
the deeper layers of the pleura contain lymphatic vessels which are
directly continuous by means of the lobular septa with the large
perivascular branches of the lymphatic system.
The consequences of the obstruction to the lymphatic and
pulmonary-artery circulation may be very serious. In grave cases the
lung breaks down, forming a gangrenous-like cavity, which differs from
an ordinary cavity in not being rounded; it is more like a gangrene or
slough. In a few cases the pathological appearances indicate phthisis,
chiefly interstitial, with formation of cavities; sometimes traces of
cavities are found which have cicatrized. More commonly oedema is
developed in the lung and the bronchial passages. As a consequence of
combined bronchial irritation from continuous inhalation of inorganic
particles, and the consequent oedema, a continuous germination and
shedding of the bronchial epithelium--a chronic bronchitis--associated
with emphysema, is maintained. The mechanical cause of this
bronchitis--more or less impediment to the vascular and lymphatic
circulations by the {459} pigment deposit--is capable of explaining the
persistence of various forms of bronchial processes in anthracosis and
in other forms of pneumonokoniosis after the patient has ceased working
in a dusty atmosphere.
SYMPTOMATOLOGY.--Pneumonokoniosis does not present a special
symptomatology. The course of the various morbid processes is insidious
and slowly progressive: the development of any of the forms of
pulmonary disease depends largely upon the degree of exposure to the
exciting causes, or the inherited tendencies, or the susceptibility to
influences liable to diminish general vitality or affect the personal
hygiene.
The earliest objective symptom of pulmonary lesion is cough, especially
recurrent in winter, accompanied by expectoration, which is whitish,
frothy, or stringy in character. Gradually the physical signs, taken
together with the symptoms, indicate the various forms of bronchitis,
acute, subacute, or chronic, sometimes associated with emphysema,
bronchorrhoea, or bronchial dilatation. In other cases the
symptomatology is that of asthma, either purely spasmodic or secondary
to emphysema or cardiac degeneration. In true anthracosis dyspnoea is a
marked symptom, and perhaps the accumulation of pigment may interfere
with the oxygenation of the blood, or dyspnoea may be due only to an
emphysematous pulmonary tissue. The sputa will be black so long as the
subject is working in an atmosphere loaded with pigment.
Fibroid phthisis is frequently associated with atrophic emphysema, and
the clinical history corresponds with that which is commonly observed
in these diseases. Hæmoptysis is rare, but if it occurs it suggests the
addition of some tubercular element; a purulent nummular sputa is a
suspicious sign of similar import. The symptoms and physical signs of
dry pleurisy are to be expected whenever any form of the phthisical
process supervenes. The cavities in the lungs are usually
bronchiectasic, unless tubercular phthisis occurs as a complication,
and the physical signs need no comment. Subacute and chronic laryngitis
with ulceration complicate certain cases, particularly those which have
inherited or acquired a tubercular tendency.
DIAGNOSIS.--The diagnosis involves a comparative examination of the
etiology and the physical signs.
PROGNOSIS.--The prognosis depends very largely upon the withdrawal of
the sufferer from an unhealthy environment. In each single case the
inherited tendencies, the personal constitution and habits, must be the
basis for an opinion upon the gravity of the pulmonary processes and
the possibilities of restoration to health. The progress of the disease
may be materially retarded or arrested by withdrawal from the
occupation involving the inspiration of dust, and restoration to
comparative health after years of invalidism is possible for these
victims of dusty avocations, even after serious damage has taken place
in the lung, if suitable hygienic conditions can be obtained.
TREATMENT.--The treatment of pneumonokoniosis divides itself into the
prophylactive and the curative. In works devoted to the hygiene of
occupation careful directions are given in reference to methods
designed to prevent the dust from entering the respiratory passages.
This is partly accomplished by the use of masks or respirators, which
possess the obvious disadvantages of clumsiness and interference with
respiration. Various devices may be employed in different avocations to
prevent the generation of dust, but the most practical plans consist in
thoroughly ventilating the atmosphere, and thus preventing the dust
from reaching the artisan. Aside from these, the management of the
various pathological conditions must be based upon the general
principles which govern the treatment of pulmonary processes.
{460}
CANCER OF THE LUNGS.
BY EDWARD T. BRUEN, M.D.
DEFINITION.--A malignant disease affecting the pulmonary tissues. (Vide
also MEDIASTINAL DISEASE.)
SYNONYMS.--_Fr._ Carcinome du poumon; _Ger._ Lungenkrebs.
ETIOLOGY.--Carcinomatous disease affecting the lung-tissue is
exceedingly rare as a primary process, and exhibits only a feeble
inclination to inoculate other portions of the body. In the majority of
cases the mediastinal glands are first affected, or it appears in the
lungs as secondary to disease elsewhere in the system. Metastasis is
probably effected by means of particles of living cellular material
which are transferred through the blood-vessels or lymphatics.
Cancer of the lung often reverses the rule that carcinoma occurs most
frequently in the female, Hasse, Kohler, and Cockle giving a majority
of cases among males. It has been met with in childhood and in extreme
old age, but is more common in the middle periods of life, from twenty
to sixty years.
PREDISPOSING AND EXCITING CAUSES.--The predisposing and exciting causes
of malignant pulmonary disease are involved in the obscurity that
surrounds the development of all neoplasms.
PATHOLOGICAL ANATOMY.--Clinically speaking, cancer in the pulmonary
tissues includes the scirrhous or encephaloid neoplasms. The colloid,
enchondromatous, or fibromatous growths have been recorded as possible
tumors, but possess only a pathological interest.
Malignant disease may commence in, or ultimately implicate, one or all
of the pulmonary tissues; secondary neoplasms have been experimentally
produced by lodgment in the lung of living cellular particles which
grew centrally by virtue of inherent cell-proliferation, independently
of changes produced in the surrounding tissues. Cancer of the lungs,
whether primary or secondary, usually originates near the roots of the
lungs, implicating the mucous and submucous membranes of the bronchi,
sometimes commencing in its small mucous follicles. The bronchial
passages and the lymph-channels become the viaducts along which the
growth proceeds in its march of invasion, involving most frequently the
posterior portion of the middle lobe. The apices of the lungs may be
implicated, but not primarily, as in tuberculosis. The mediastinal
lymphatics are originally involved in an unestimated number of cases,
or enlargement of these glands is coexistent with the development of
pulmonary cancer. The enlargement of the mediastinal glands is
sometimes moderate, but an enormous mass may be formed. (Vide
MEDIASTINAL TUMORS.)
Carcinoma is found in masses varying in size from a hempseed to an
orange or larger, and since its distribution follows the lymph-channels
in their circuitous route through the lung, we can account for the wide
distribution of the nodular masses of secondary cancer. The isolated
nodules present an {461} ovoid outline, sometimes situated near the
pleural surface, in contrast with the larger formations which affect
the roots of the lungs.
The primary malignant formation presents a single large mass of
infiltration, possibly associated with a few small nodules scattered
throughout the lungs; the right lung is conceded to be the most
frequently affected, but secondary cancer usually implicates both
organs.
Cancer in the parenchyma of the lung may diminish or occlude the lumen
of the bronchial tubes, or they may be filled with cancerous matter and
their walls perforated. The development of cancer along the
distribution of the bronchial passages shows us how readily chronic
bronchitis may occur as a complication and form a confusing element in
the diagnosis. The remaining pulmonary tissues may escape anatomical
change, or from pressure atrophic or hypertrophic emphysema or collapse
may ensue. These changes, together with the similarity to a fibroid
phthisical process which many cases suggest, must be borne in mind in
making a diagnosis. Pulmonary apoplexy, or even gangrene, is an
incident in some of the clinical pictures of this disease, and embolism
or thrombosis in other parts of the system may occur. The terminations
of intra-thoracic cancer vary in accordance with the history of these
growths elsewhere. Infiltration with blood or melanic deposition has
been noticed; evacuation of the new growth through the bronchi may
induce the development of cavities in the lungs, preceded or
accompanied by suppuration, ulceration, or gangrene. In addition,
hydro- or pyo-pneumothorax may occur by perforation or invasion of the
pulmonary pleura.
Carcinoma of the pleura is usually secondary to its development in the
lung, but it may be communicated from a similar process in the mammary
gland by infection through the pectoral and intercostal muscles to the
parietal pleura. Carcinomatous formations on the pleura are small and
hard in scirrhous, but are larger in encephaloid, cancer. The minute
spots of early formation are found scattered over the pleura like drops
of wax. The thickened tissues, when they coalesce, undergo
degeneration, and may form plaques of cartilaginous hardness. Large
pleural growths may compress or nearly efface the lung, but are among
the curiosities of medical literature.
Neuralgia may be occasioned when nodules impinge upon the intercostal
nerves. Similar pressure is the cause of the pain in pulmonary cancer,
except that induced by the pressure of mediastinal enlargement. Chronic
pleural inflammation may be frequently developed by the new growth, and
the diseased lung may become adherent to the inner surface of the
sternum and ribs. The lung in other cases may be compressed or
retracted, uncovering the heart and rendering the chest-walls smaller.
The chest may be enlarged, especially if there is pleural effusion;
usually the contour is unchanged.
Pleural effusions are frequent in the history of this disease: they may
be passive, resulting from pressure on the azygos or hemiazygos veins,
preventing the return of the blood from the pleural veins, or from
mediastinal pressure. An inflammatory hydrothorax may be excited by the
deposit of cancerous material in the pleura; and it is possible for
these effusions to undergo purulent transformation or to become
hemorrhagic. A hemorrhagic effusion when grouped with other symptoms
may be considered an important evidence of malignant formation. The
further history of pleural effusions in this association is usually an
increase of such an amount as to necessitate removal by thoracentesis,
but reabsorption is possible.
SYMPTOMATOLOGY.--The interest of the clinical observer nucleates itself
around the symptomatology and diagnosis. The frequent negative results
of physical examination indubitably prove that its teachings alone are
insufficient for the purposes of diagnosis, so that any study of a case
would be partial which did not unite the evidence yielded by physical
signs with the general symptoms. The clinical evidences are more
definite when the {462} neoplasms are multiple and associated with some
mediastinal process than when single or absolutely primary growths. The
development of the disease is insidious. Gradually the facies and
general surface of a patient indicate the true nature of the malady by
the characteristic cachexia. Cough is an early symptom, unimportant
save that it cannot be assigned to any definite cause. It may be dry
and hard, attended only by expectoration of glairy mucus, or the sputa
may be purulent. Usually the amount is in ratio with the degree of
coexistent bronchitis. In the latter stages of the disease the sputa
may contain blood, resembling prune-juice or black-currant jelly, due
to erosion of some of the blood-vessels. In this stage of softening
cells characteristic of the new growth, with portions of the pulmonary
structure, may be found on microscopic examination of the sputa; the
appearance of the expectoration sometimes suggests fibrinous
bronchitis.
When there is elevation of temperature it may present a hectic type,
with night-sweats, which are stated by Walsh to be sometimes confined
to the affected side. The presence of an abnormal temperature-curve is
indicative of associated inflammation of the bronchial mucous membrane,
the development of a pleural process or of phthisis, especially the
fibroid form. The pulse becomes accelerated in ratio to the degree of
these inflammations and the failure of the sufferer's strength.
The new growth determines some mechanical symptoms cognate to all
intra-thoracic tumors, especially those which involve the mediastinum.
Lancinating pain would presumably be a constant symptom, but is, in
fact, infrequent, unless the growth or growths enlarge so as to cause
pressure on the nerve-trunks, in which event pain may become a
distressing symptom. Characteristic pains complicate those cases in
which the pleural tissues are involved in the morbid process. Dyspnoea
is a pressure-symptom of considerable import if other conditions
capable of producing it, especially uncomplicated emphysema, are
rigidly excluded. When the new formation is infiltrated throughout the
lungs, the growth may, as in miliary tubercle, impair the aërating
power of the lungs by diminishing their elasticity and increasing their
density. When, however, the process is local and restricted, the
dyspnoea may be due to irritation of the terminal filaments of the
vagus; this being a mixed nerve composed of accelerator and inhibitory
filaments, the balance of innervating power may be readily destroyed
and partial or incomplete respiratory effort follow. Dyspnoea may also
result from pleural adhesions or effusions, or may be secondary to
direct cardial or pericardial involvement in the cancerous process.
Palpitation or increased pulse-rate may be referred to irritation of
the vagi, or to some of the foregoing pathological processes.
Kindred to these symptoms are the changes in the voice, which sometimes
undergoes frequent variations due to irritation or pressure on the
trachea or on the branches of the pneumogastric nerve, especially when
mediastinal disease is present. Aphonia, huskiness, a bass voice, or
high treble, one or all, may be constant or alternating harbingers of
the concealed mischief. The laryngoscope will inform one whether there
is direct involvement of the larynx with morbid growth. Dysphagia is to
be expected if the new formation involves the regions through which the
oesophagus passes, and a sacculated pouch may be formed above the
compressed spot. Changes of posture may increase or diminish the
pressure, and thus the dysphagia or dyspnoea may at times be more
pronounced than at others. Dysphagia may also be due to swelling of the
oesophagus near the location of pressure. Reflex irritation of the
sympathetic ganglia may induce pupillary contractions in one or both
eyes: this symptom is chiefly present when the mediastinum is involved.
The physical signs contingent on pulmonary cancer include those
ordinarily indicative of bronchitis with or without atrophic emphysema,
simple pleural effusion, or chronic pleurisy with retraction. By
inspection a study {463} should be made of the contour of the thorax,
the respiratory movement, and displacements of the intra-thoracic
viscera. The thorax may appear enlarged, either from the new formation
or from associated pleural effusions. It is often retracted, owing to
the atrophic changes, and collapse brought about by the new formation
or induced by pleural adhesions. The movements of the chest, unless
there is a pleural complication, possess no distinctive character in
this disease. Displacements of the heart or trachea may be expected on
mechanical principles if there is mediastinal disease. General
inspection may detect in the clubbed fingers evidences of venous
obstruction, and sometimes an asphyxial hue of the upper portion of the
body. Nearly always a general emaciation with anxious expression
exists, and a tawny or lemon-hued skin indicative of the cancerous
cachexia.
By palpation of the substernal or supra-clavicular spaces one may reach
masses of painless, movable, glandular enlargement, but these may be
easily overlooked unless a careful study be pursued. Circumscribed
swellings of the thoracic walls may be detected, though not often, and
the glands of the axillæ and neck may enlarge. Palpation may also
reveal an inequality in volume between the radial pulses, but not so
commonly as in purely mediastinal tumors or in aneurisms. Percussion
and auscultation are negative or yield an area of dulness or flatness
with restricted or absent respiratory murmur. When there is a single
large growth the boundaries of these signs are local. If the tumors are
diffused the respiratory murmur varies. In tiers of lung it is feeble
or absent; elsewhere it is harsh, puerile, or bronchial. Chiefly
remarkable is the fact that the character of the respiratory murmur
cannot be harmonized with any other pulmonary states when the entire
clinical evidence is taken. Vocal resonance corresponds with the
respiratory murmur according to accepted laws. When there is pressure
on the principal bronchus on one or both sides, one can detect either a
snoring, increased bronchial respiration, or else, if the pressure
decidedly narrows the calibre of the bronchus, the breathing becomes
feeble or wheezing. Expiration may be prolonged and sonorous in
character, with or without râles. The pressure is rarely equal on the
two sides. The vocal resonance in these cases is ringing and brazen.
Mensuration corroborates inspection. Pleural effusion from whatever
cause is revealed by the ordinary signs. Enlargement of the bronchial
glands, either primary or coexistent with the development of cancer in
the lung, reveals itself by pressure-symptoms proportionate in their
severity to the degree of bronchial enlargement. Pain, laryngeal
irritation, differences in the radical pulses, tumor if the enlargement
is anterior, one or all, may be present. The aorta itself may be
compressed by the enlarged glands; and by the narrowing of its lumen
thrill, and even systolic, murmur can appear, making a differential
diagnosis from aortic aneurism very difficult. (Vide MEDIASTINAL
TUMORS.) Embolism and thrombosis, with the ordinary symptoms, may
complicate the course of pulmonary cancer and obscure the diagnosis.