They differ in clinical history from ordinary acute bronchitis chiefly in the following particulars: Etiologically, a large proportion of them occur in persons of a rheumatic diathesis, either hereditary or acquired, and at those seasons of the year characterized by a predominance of cold and damp air with frequent changes of temperature.
Symptomatically, they are characterized from the beginning by more continuous dull pain in the chest, often extending to the attachments of the diaphragm, the shoulders, and the dorsal portion of the spine; by more persistent dry, harsh cough, often exhibiting a marked spasmodic character and accompanied by a great aggravation of the pains in different parts of the chest. When the smaller bronchi are involved the stage of dry râles is much more protracted, the dyspnoea and suffocative paroxysms of coughing more uniformly aggravated at night; and when mucous exudation does take place it remains scanty and viscid, rarely presenting a distinct muco-purulent character unless the case is protracted into a chronic form, and sometimes not then. During the active stage the urine is less in quantity and more decidedly acid in reaction than natural, and the bowels generally costive.
When not interfered with by appropriate treatment, these cases run a much more protracted course, and more frequently degenerate into a chronic form, than those of an ordinary catarrhal character. When they are thus allowed to run a protracted course or to continue in a chronic form, they manifest another tendency of great importance—namely, to have the inflammation extend by continuity from the fibrous and muscular structures of the small bronchi into the connective tissue of the pulmonary lobules, inducing sclerosis of the latter tissue and consequent compression or obliteration of the alveoli or air-cells, and permanent contraction of the chest. Much and careful clinical observation has satisfied me that many of the cases now classed by writers as fibrous and inflammatory phthisis began as simple acute or subacute rheumatic bronchitis, which, being renewed at every return of the cold, damp, and changeable part of the year, not only ultimately caused permanent thickening of the bronchial structures, but gradually invaded portions of the connective tissue of the lungs, and induced similar pathological changes in it, constituting the sclerosis just mentioned.
Pseudo-membranous Bronchitis.
This affection has been described by different writers under the additional names of plastic, croupous or croupal, and diphtheritic bronchitis. The extension of the inflammation and membranous exudation to the bronchial tubes in cases of diphtheria and pseudo-membranous tracheitis and laryngitis or croup, is of frequent occurrence. But as a distinct disease limited to the bronchial membrane it is of comparatively rare occurrence.
In 1854, T. B. Peacock noticed in the Transactions of the London Pathological Society 34 cases collected from European sources; Biermer in 1867 increased the number to 58; Kretschy in 1874 added 10, and Chevstok 4 more cases—making in all 72 cases in Europe. In 1879, W. C. Glasgow of St. Louis read to the medical section of the American Medical Association an interesting report on the subject of plastic bronchitis, in which he notices 23 cases which had occurred in this country, accounts of which were obtained from an extensive correspondence with leading physicians in all parts of the United States, as well as from reference to our periodical medical literature.6 These statistics are certainly sufficient to justify the statement that the disease is of rare occurrence both in this country and in Europe.
6 See Transactions of the American Medical Association, vol. xxx. p. 177, 1879.
The statistics thus far collected show a much greater prevalence of the disease in males than in females, and that the larger number of cases occur between the ages of fifteen and fifty years, although one case is reported by T. G. Simons of Charleston, S. C., as quoted by Glasgow, at four years of age, and Goumoens one at seventy-two. In a large proportion of the cases reported the disease existed in a chronic form. When acute, and affecting a large portion of the bronchial membrane, it is liable to lead to an early fatal termination from obstruction to the ingress of air to the air-cells of the lungs. But in many cases the disease has extended to only a limited number of the bronchi, and recovery has generally taken place in from two to three weeks.
The symptoms differ from those of ordinary bronchitis in only two important particulars—namely, the more violent and suffocative character of the cough, and the actual appearance of shreds, patches, or casts of pseudo-membrane in the matters raised and ejected by coughing. The latter is the only reliable diagnostic symptom by which it can be certainly differentiated from all other forms of bronchial inflammation. When the membranous exudation is discharged in shreds or small pieces, it may readily escape the attention of the physician, and even considerable casts when expectorated are in some cases so surrounded with mucus and collapsed into a slightly yellowish mass in the central part of the mouthful expectorated, that they might be regarded as only a more muco-purulent part of the mucous secretion. If the whole is thrown into water, however, and agitated a little, the membranous patches and casts will be quickly unfolded in such a manner as to be easily recognized. It is distinguished from mucus by placing it in a solution of acetic acid, which causes it to swell, while mucus contracts in a similar solution. It has the appearance of having been formed in concentric layers, and is sometimes cast-off so complete as to present a continuous representation of one or both primary and several of the secondary bronchial tubes. Under the microscope it has the same fibrillated appearance as other pseudo-membranous formations.
Chronic Bronchitis.