PNEUMONOKONIOSIS.
Definition and Varieties.—This is a term applied to the proliferative stitial inflammation of various pulmo nary structures caused by the continued inhalation of dusts of different kinds. The three principal forms of pneumono koniosis are anthracosis, or coal-miners' disease, due to the inhalation of coal dust; chalicosis, or stone-cutters' phthisis, brought on by the inhalation of mineral dusts; and siderosis, due to the inhala tion of iron oxide and other metallic particles. Clinically, pneumonokonio sis may be considered as a combina tion of chronic bronchitis, emphysema, and phthisis, which not infrequently as sumes the tuberculous type.
manifestations of the three forms of pneumonokoniosis are practically similar. Three stages may be distinguished. During the first there is general uneasiness, anorexia, loss of flesh, paroxysmal cough, and expectora tion, varying to a degree, in color, with the kind of dust inhaled. In anthracosis the sputa are black, in chalicosis they are grayish black, while in siderosis they are red. In all three forms hmmoptysis usually occurs, but this symptom is more frequently observed and the hzemor rhages are likely to be more copious in chalicosis. Auscultation shows that the vesicular breathing murmur is lessened during this stage, while vocal resonance is enhanced; sibilant Tales are usually detectable. The signs of chronic bron chitis become clearly defined during the second stage, and dyspncea and vomiting are now added to the symptoms already outlined. The sputa not only show their characteristic coloring, but they become muco-purulent, while the hT moptyses become relatively more fre quent and copious. Symptoms of em physema are now superadded, and the dyspncea becomes asthmatic in character. The third stage is characterized by rapidly-increasing arminia; cavities may then usually be detected, along with all the symptoms of pulmonary tuberculo sis, with all its attending manifestations, night-sweats, diarrhoea, hectic fever, in tense dyspncea, and copious expectora tion in which the tubercle bacillus is often found, and the patient succumbs. The third stage may not be reached, however, if the patient is relieved of the exposure to the causative elements in time; on the other hand, the usual manifestations may be replaced by those of some other local disease, particu larly lymphosarcoma or other malignant growths of the lung.
Etiology.—Anthracosis not only oc curs among coal-miners, but also among laborers who inhale much coal-dust. Molders of bronze, iron, and copper also suffer when coal-dust is employed by them. Chalicosis is observed among stone-cutters and potters particularly. Siderosis occurs in those who inhale iron filings and the oxide of iron, pol ishers, gold-beaters, and other crafts in which iron is more or less utilized.
Pathology. — The inhalation of air thickly laden with the foreign agents mentioned, after a prolonged period of exposure, gradually weakens and finally overcomes the physiological functions calculated to protect the bronchial mu cosa. The ciliated epithelium, the
phagocytes, and the mucous and alveolar cells represent as many structures upon whose integrity these functions depend. When these cannot be performed, the mucous membrane of the respiratory tract is penetrated and the foreign bodies invade the lymph-spaces, which represent a second barrier and are capa ble of disposing of comparatively enor mous quantities of intruding substances. When this line of defense is overcome, however, many particles are carried to the lymph-nodules surrounding the bronchi and the blood-vessels and to the interlobular septa under the pleura, where they accumulate between the tis sue-elements, and, through the larger lymph-channels, to the substernal, bronchial, and tracheal glands, in which the stroma-cells of the follicular cords dispose of them permanently and pre vent them from entering the general circulation (Arnold, quoted by Osler). When the pigmented bronchial glands become adherent to the pulmonary veins, however, the foreign particles may in vade the general circulation and be found in remote organs, the liver and spleen especially (Wiegert).
When the limit of tolerance is reached, an interstitial sclerosis begins in the bronchial glands and periarterial lymph nodules. These gradually harden, and coalesce until large fibroid areas—cir rhotic masses — are found in various parts of the organ. Post-mortem, such masses, when cut. are quite resistant, and sink in water and color it black. The fingers of the operator become blackened likewise, the cut surfaces appearing either black or marble-like. The bronchi are seldom found dilated, but the finer arterial supply is often obliterated, and cavities are formed, mainly through the arrest of nutrition. The pleura is often thickened and le sions of the right heart are often ob served (Dieulafoy).
Treatment. — Unless removal to hy gienic surroundings early in the history of the ease can be carried out, pneumono koniosis progresses steadily. Anthra cosis advances slowly, but chalicosis is usually fatal after three or four years. In siderosis the duration of life is some what longer. If the patient cannot be removed elsewhere and finds himself obliged to continue his occupation, the wearing of appropriate masks or respira tors may stay the progress of the disease.
Free ventilation of shops, mines, etc., is also prophylactic in this particular; but total change of occupation is the only absolute protective. The disease is often arrested when this can be done. Iodide of potassium and the measures indicated in chronic bronchitis (q. v.) have given excellent results when hygienic sur roundings are within the reach of the patient.