A system of practical medicine. By American authors. Vol. 3

by Unknown

At an early period of the disease the marked changes appreciable by physical signs usually consist of a few hardened patches or nodules varying in size from that of a pea to that of a filbert, situated at or near the apex of one lung. The physical signs are those of slight solidification—namely, some dulness on percussion, increase of vocal resonance, and broncho-vesicular respiration. The presence of the morbid deposit causes circumscribed bronchitis affecting the smaller tubes, and this complication may give rise to subcrepitant râles within the area of the tuberculous affection. The disease may end with no further increase or extension of the local affection, this termination resulting either from self-limitation or from the agency of treatment. Of this fact I have proof from cases not only studied during life, but in which appearances were noted after death. The ending of the disease and recovery after a small tuberculous deposit occur oftener than is generally supposed.

An increase and an extension of the phthisical affection occasion larger areas and also a greater degree of solidification. As the amount of increase and extension within a given period varies very much in different cases, it follows that there is nothing like uniformity in these respects. Generally, the solidified portions of the lung form islands between which the tuberculous deposit is wanting. Between these islands the lung not infrequently becomes emphysematous. This vicarious emphysema explains the existence of a vesiculo-tympanitic resonance in some cases notwithstanding the solidification. Exclusive of that sign, as thus accounted for, the solidification causes a dulness on percussion proportional in degree and extent to the solidified portion of lung. The auscultatory signs of solidification are generally present—namely, either bronchial or broncho-vesicular respiration, and bronchophony or increased vocal resonance, according to the degree of solidification. The existence of bronchitis over a larger extent is represented by more abundant and coarser moist bronchial or bubbling râles. These râles do not, as has been supposed, necessarily denote that softening of the tuberculous deposit has taken place. Dry circumscribed pleurisies occurring from time to time, even from the very commencement of the phthisical affection, may give rise to a pleuritic friction murmur. The escape of the liquefied tuberculous deposit into the bronchial tubes by ulceration, added to the products of the bronchial inflammation, occasions an increase of the bubbling râles. Moreover, the liquefied tuberculous deposit is better suited for the production of bubbling sounds than the products of bronchial inflammation. Hence the abundance of the bubbling râles, taken in connection with the characters of the matter of expectoration, is evidence of the escape of liquefied tuberculous deposit.

If phthisis be progressive, the physical conditions already enumerated—namely, solidification, liquid in the bronchial tubes, pleuritic exudation—continue. They are present in both lungs. Associated with these conditions are cavities. The cavities formed in different cases differ greatly in size and number. They differ also as regards the number and the size of the openings by which they communicate with the bronchial tubes. The latter conditions are of importance with reference to the free discharge of the contents of cavities and the production of certain physical signs. Enumerating here the cavernous signs, they are—tympanitic resonance within a circumscribed space, frequently with amphoric or cracked-metal intonation, cavernous and sometimes amphoric respiration, increased vocal resonance, cavernous whisper, pectoriloquy in some instances, and, as a rare sign, metallic tinkling. An accumulation of liquid within a cavity which has free communication with the bronchial tubes gives rise to the cavernous sign called gurgling. I have met with an instance in which a loud splashing sound was produced within a cavity synchronous with the impulse of the heart, and due to the agitation of the cavity by the cardiac movements. Owing to the association of cavities with solidified portions of lung, the latter varying greatly in different cases in the extent and the degree of solidification, with the cavernous signs are combined those which represent varying degrees of solidification—namely, either dulness or flatness on percussion, either bronchial or broncho-vesicular respiration, and either bronchophony or increased vocal resonance.

In the physical conditions incident to pulmonary complications of phthisis—namely, pleurisy with effusion, perforation of lung with pneumo-hydrothorax—the reader is referred to the article on [DISEASES OF THE PLEURÆ].

With reference to the general pathology of phthisis, points relating to the morbid anatomy are to be considered. There are two distinct varieties of morbid product in cases of phthisis—namely, the miliary granulations and the infiltrated deposit formerly distinguished as crude tubercle. Laennec taught that these are only varieties of essentially the same morbid product, the former being preliminary in their occurrence to the latter. Following Virchow, some late writers have restricted the application of the term tubercle to the miliary granulations, regarding the infiltrated deposit as a non-tuberculous inflammatory product. Histological investigations have failed to establish an essential distinction between the two varieties. The fact that they are so constantly associated shows some close pathological connection. Both varieties undergo the same degenerative changes. Each is found by inoculation to produce tuberculous disease in certain animals. Moreover, according to the late researches of Koch and others, each contains the characteristic parasite, the bacillus tuberculosis. In view of these considerations, the doctrine of Virchow, advocated by Niemeyer and others, is not tenable, and, as already stated under the head of the Definition and Classification of pulmonary phthisis, the term tuberculous is properly applied to both varieties. There is no such affection as a non-tuberculous pulmonary phthisis. The terms pulmonary phthisis and pulmonary tuberculosis are now, as heretofore, to be regarded as synonymous.

That the pathology of pulmonary phthisis involves a predisposition or a tuberculous diathesis has been already shown by facts pertaining to the etiology. It does not in the least invalidate this logical conclusion that in the present state of our knowledge pathologists are unable to explain this diathetic condition; that is to say, in what it consists. Its recognition is not merely a matter of speculative or theoretical interest; it has an important bearing upon a rational prophylaxis and on the treatment of phthisis.

Up to a very recent date the opinion has generally been held by pathologists that the local phthisical affection may be determined entirely by a tuberculous cachexia—that the latter, in other words, may produce the affection exclusive of any local extrinsic cause; and the question has been much discussed whether or not at the outset the phthisical affection is an inflammation. But if the parasitic doctrine be accepted, a local causative agent derived from without—namely, the bacillus tuberculosis—is essential, the predisposition or the cachexia consisting of certain unknown conditions which are required for the development and the multiplication of the parasite. According to this doctrine, the extension of the local affection is due to invasions successively of different portions of the lungs, and the development of tuberculous disease in other situations is due to the migrations of this parasite. Without the presence of the bacillus, no matter in how great degree the required conditions may exist, phthisis will not occur.

Inflammatory processes, however, accompany and follow the development of the tuberculous affection. Bronchitis, peribronchitis, periarteritis, endoarteritis, interstitial pneumonia, and pleurisy are terms which denote inflammation. To these are to be added ulceration and suppuration within cavities. The infiltrated tuberculous deposit is to be regarded as an inflammatory exudation. There is an intrinsic propriety, therefore, in calling it a pneumonia. But the behavior of this deposit differs widely from that of the exudation in lobar pneumonia. In the latter affection it is readily absorbed and disappears, leaving the pulmonary structure intact, whereas in phthisis it is absorbed with difficulty, and in most cases leads to more or less destruction of the pulmonary structure. For these reasons, irrespective of histological points of difference, the term tuberculous should be used to distinguish the exudative pneumonia which is characteristic of phthisis. The term desquamative pneumonia was proposed by Buhl. The so-called cheesy degeneration of the tuberculous products—a necrotic, not an inflammatory, process—was considered by Laennec as a distinctive mark of the products. This doctrine has been disproved. Other morbid exudations and growths may undergo similar degenerative changes.

DIAGNOSIS.—It is evidently very desirable to recognize the existence of phthisis at as early a period as possible with reference to the adoption of measures with a view to prevent the further development and progress of the disease. It is also very desirable, if practicable, to determine that phthisis does not exist; that is, by the absence of diagnostic points to exclude it. Difficulty of diagnosis relates almost exclusively to an early period when the phthisical affection is small. The diagnostic points pertaining to the symptoms and the physical signs in the incipiency of the disease therefore especially claim attention.

A cough of more or less duration, which was at first slight and dry, gradually increasing and accompanied by the expectoration of mucus, should always excite a suspicion of phthisis, especially if the patient's age be between twenty and thirty years. This is not the history of a chronic primary bronchitis. A cough as just described should never be considered as nervous or sympathetic without due investigation. It should not be attributed to pharyngitis, although the latter affection is found to exist. Want of breath on exercise is a symptom pointing to something more than a bronchial or pharyngeal affection. The import of these symptoms is still greater if, after the commencement of the cough or from an earlier date, there has been decrease in weight and strength. Their significance is much increased by the occurrence of hæmoptysis. Hæmoptysis followed by a persistent cough, and still more if cough preceded its occurrence, is always presumptive evidence of a phthisical affection. Occurring without having been preceded by cough, and when cough does not immediately follow, it should suggest the probability of phthisis. In the larger proportion of cases under these circumstances it is a forerunner of the diagnostic symptoms and signs of the disease. In connection with the cough a persistent increase of the temperature of the body is an important diagnostic symptom. Chilly sensations and flashes of heat are symptoms of some importance. Especially significant are pleuritic stitch-pains referable to the upper part of the chest or beneath the scapula, these being symptomatic of the circumscribed dry pleurisies which may occur at an early period of the disease. Impaired appetite, pallor of the face, and a tendency to perspire during sleep have much significance taken in connection with the pulmonary and other symptoms.