Bronchitis, an inflammatory affection of the mucous membrane* lining the bronchial tubes. As it ordinarily occurs, this disease is limited to the larger bronchial tubes, the inflammation often not extending beyond the primary bronchi and the divisions of these which are situated exterior to the lungs. The inflammation may be either acute, subacute, or chronic. By German and French writers, inflammation here, as in other mucous membranes, is called catarrh. The term bronchial catarrh means neither more nor less than inflammation of the bronchial mucous membrane, or bronchitis. Acute or subacute bronchitis is the affection popularly known as a cold in the chest. It is generally preceded by an inflammation of the mucous membrane lining the nostrils (coryza), and not infrequently by inflammation of the pharynx (pharyngitis) and of the larynx (laryngitis). In a certain proportion of cases, however, the inflammation attacks the bronchial membrane without affecting the parts situated above. The extension of inflammation from the mucous membrane above the bronchial tubes to the latter may often be prevented by an opiate at bedtime, followed by a hot, stimulating drink to excite free perspiration.

The Russian or Turkish bath, also, seems sometimes under these circumstances to prevent the supervention of bronchitis. In acute bronchitis the inflammation, limited to the larger tubes, gives rise at first to a dry cough, which is especially excited by breathing cold air, and by taking a deep inspiration. The cough is usually loud and sonorous. There is a sense of soreness and of constriction on coughing, felt beneath the sternum or breast bone. The expectoration at first is small, viscid, and not infrequently streaked with blood. There is little or no embarrassment in breathing; the patient does not suffer from a sense of the want of air, and the respirations are little if at all increased in frequency. There is only slight fever, as denoted by the pulse and the thermometer in the armpit. The lassitude and debility are often not sufficient to lead the patient to take to the bed. Chilly sensations followed by flashes of heat occur, and the appetite is more or less impaired. In from two to four days the expectoration becomes more or less abundant; and it now consists of solid masses (sputa) of a yellowish or greenish color. The acts of expectoration are easier. The cough is said to be loose.

The substernal soreness and constriction diminish; and the fever, together with other evidences of constitutional disturbance, gradually disappears. The duration of the affection is from six to twelve days. The symptoms are essentially similar in acute and subacute bronchitis, except that in the latter they are less marked. Subacute bronchitis occasions so little local and general disturbance as rarely to lead persons to remain within doors. - In acute bronchitis it is prudent, if not necessary, for patients to keep within doors; and confinement to the bed for a few days is sometimes judicious. A saline purgative is often serviceable. Moderate counter-irritation to the chest, as by the application of mustard, is useful. Anodynes to allay cough, and remedies promoting gentle perspiration, afford relief, and hasten the progress toward recovery. The Russian bath, if available, may be resorted to with advantage; and the inhalation of warm vapor promotes expectoration and affords relief. After infancy an ordinary bronchitis is never of itself dangerous. If it prove a serious affection, it is in consequence of its occurrence in connection with other and graver diseases, or in persons enfeebled by age or other causes.

In such cases, the danger connected with the bronchitis relates chiefly to the inability to expel the mucus from the bronchial tubes by coughing. If the efforts for expectoration are ineffectual from any cause, the inflammatory products may accumulate within the tubes sufficiently to obstruct the free passage of air to the air cells, and consequently to destroy life by interference with the function of respiration. In early infancy it is sometimes a grave affection in consequence of a greater liability to obstruction of the bronchial tubes, and the occurrence of collapse of pulmonary lobules as a result of this obstruction. These effects are more liable to occur in infants, on account of their feebleness, and the want of voluntary efforts to expectorate. - Bronchitis, excepting where it is secondary to some other pulmonary disease, belongs in the class of affections called symmetrical; that is, the bronchial tubes in each side of the chest are equally affected. It is, in other words, a bilateral disease. As implied in the popular name, " a cold," it is generally attributed to exposure to atmospherical changes in temperature. In certain cases it seems clearly to be thus produced. A continued current of air upon a portion of the body is especially apt to produce it.

From its frequent occurrence, however, when it cannot be traced to exposure to cold, and from the fact that a considerable number of persons are often affected simultaneously, the disease not prevailing sufficiently to be called an epidemic, it may be reasonably inferred that the causation involves the presence in the atmosphere of some morbific agency not yet ascertained. - Owing to a peculiar susceptibility of the mucous membrane of the air passages, constituting a curious idiosyncrasy, some persons are affected by bronchitis, often associated with asthma, during the summer season; the cause being evidently vegetable emanations in the atmosphere, as these persons escape an attack on going to sea or to places where there is little or no vegetation. As thus produced, the affection is known as hay bronchitis, hay asthma, and hay fever. The emanations are however by no means derived exclusively from hay. The powder of ipecacuanha, emanations from feathers, etc, give rise to bronchitis, usually accompanied with asthma; in some persons, irritating gases or vapors when inhaled are traumatic causes.

It is an important fact that the liability to "take cold" is as a rule less in proportion as the habits involve out-of-door life. - In medical practice, ordinary bronchitis is to be discriminated from other inflammatory affections giving rise to cough and expectoration, with fever and other symptoms denoting constitutional disturbance. With reference to this discrimination, in addition to points of contrast relating to the symptoms, the physical signs obtained by auscultation and percussion are to be taken into account. In general terms, the diagnosis rests on the absence of the signs which belong to the clinical history of other affections with which this is liable to be confounded. In ordinary bronchitis, the resonance or percussion is normal; the murmur of respiration may be weakened, but it is not otherwise altered; the vocal signs are the same as in health. In short, the only signs belonging to the disease are the dry and moist bronchial rales, and"these are often wanting. Physical exploration of the chest is important as enabling the physician to determine that other affections are not present, the diagnosis being thus reached " by way of exclusion." - In chronic bronchitis the inflammation is subacute, and more or less persisting.

The duration is extremely indefinite; the disease may continue for months or years, and in some cases it becomes permanent, lasting until the end of life. The cough varies much in different cases as regards frequency and violence. The matter of expectoration also varies much in quantity and character, sometimes consisting of small, solid pellets raised with difficulty, sometimes being muco-purulent or consisting chiefly of pus, and accompanied sometimes with a serous liquid in abundance. The last named character is distinguished as uronchorrhcea. Not infrequently the sputa are streaked with blood. The constitutional symptoms are slight or wanting. Symptomatic fever is rare; the appetite and digestion are often excellent; there is either but little emaciation, or the nutrition may be well maintained, and the muscular strength is but little impaired. The affection is thus not incompatible with fair or even good general health. The causes of chronic bronchitis are obscure, except where it occurs in connection with those valvular lesions of the heart which occasion obstruction to the return of blood to this organ from the lungs. This obstruction involves a pulmonary congestion which tends to maintain, if not to originate, subacute bronchial inflammation.

Bronchorrhoea is apt to occur in these cases, and the transudation of serum affords some relief of the pulmonary congestion. With or without this causative connection, an abundant bronchial expectoration, having existed for a long period, becomes sometimes, as it were, an element of health, patients suffering from a sense of oppression when from any cause the expectoration is notably diminished. It follows from the statements just made, that a chronic inflammation of the bronchial tubes is not usually in itself a serious affection. It may however lead to more or less impairment of health, diminishing the ability to resist or recuperate from other and graver diseases. It may even prove the immediate cause of death when, from the feebleness incident to old age or some coexisting grave disease, the ability to expectorate is impaired. Under these circumstances, the accumulation which takes place in the bronchial tubes may be sufficient to cause suffocation. Moreover, it proves in some cases remotely serious by leading to other pulmonary affections, namely, emphysema, or dilatation of the air vesicles, and asthma. Chronic bronchitis generally enters into the causation of these two affections.

As a compensation, in leading to these affections, it antagonizes another affection of a much graver character, namely, phthisis or consumption. To the latter affection it does not tend even in the cases in which emphysema and asthma do not become developed. Chronic bronchitis is to be differentiated, in medical practice, from phthisis or consumption. In making this discrimination, the physician relies chiefly on the absence of the symptoms and physical signs which should be found if phthisis or consumption existed; that is, he reasons " by way of exclusion." - There are certain remedies which are useful, and sometimes curative, in chronic bronchitis. The iodide of potassium, the muriate of ammonia, the bromides, and balsam of copaiba are remedies, the utility and sometimes the curative power of which experience has established. A sea voyage in warm latitudes may prove signally beneficial, and may effect a cure. Patients residing in a changeable, cold climate, may derive benefit, and perhaps recover, by removing to one more uniform and genial. The cough is sometimes relieved, expectoration facilitated, and permanent improvement effected, by the inhalation of vapor or spray formed from medicated liquids. - The fact that, bronchitis is one of the symmetrical diseases has been stated.

This is a law of the disease when it is not secondary to some other pulmonary affection. Exceptions to this law obtain when the bronchitis takes place in the course of pneumonia and tuberculous disease of the lungs. Its occurrence as secondary to these affections is quite constant, and under these circumstances the bronchial inflammation may be more or less limited in extent, and confined to one side, that is, unilateral. The disease is then distinguished as " circumscribed bronchitis." - Capillary Bronchitis. This is an important variety of the disease produced by an extension of the inflammation from the large bronchial tubes to those of smaller size. It is attended with great danger to life; indeed, in a large proportion of cases, it ends fatally. The danger consists in the obstruction incident to inflammation of the tubes of small size, and caused by the swelling of the inflamed membrane and the presence of mucus. The danger is greater than in pneumonia, which may for the time render useless one half of the pulmonary organs.

The interference with the function of respiration is greater in the so-called capillary bronchitis, because this, like ordinary bronchitis, affects equally both sides; that is, it is bilateral, and hence the respiratory function is compromised more than when an entire lung is rendered useless. Death takes place by suffocation or apncea. Happily, the affection is rare. It is limited in its occurrence chiefly to children and aged persons. Its duration in fatal cases is from twelve hours to five days. The symptoms denote an affection compromising notably the respiratory function. The respirations are rapid, in children sometimes being from 60 to 70 per minute. The action of the heart is accelerated. Lividity of the lips and face becomes marked in fatal cases. The suffering from a sense of the want of breath, or dyspnoea, is intense. The physical signs enable the physician to discriminate this affection from other affections involving, like this, notable disturbance of respiration. Over both sides of the chest there is found the auscultatory sign of the presence of liquid in the small bronchial tubes, namely, the subcrepitant rale; and with the presence of this sign there are absent the signs representing the morbid physical conditions which belong to the several affections from which this is to be differentiated, pneumonia and pleurisy with effusions being the most prominent of these. - In cases of capillary bronchitis, bloodletting may be resorted to with, advantage, if it be not contra-indicated by the feebleness of the patient.

With the same qualification, emetics are indicated in young children, with a view to promote expectoration. Revulsive applications (sinapisms or stimulating liniments) to the chest are to be employed, together with poultices or the water dressing and an oiled muslin or silk jacket. If available, the inhalation of oxygen gas should be resorted to. Breathing warm vapor facilitates expectoration, and hastens the resolution of the inflammation. Finally, the strength of the patient is to be supported by nourishment and alcoholic stimulants. - Influenza. Thus far bronchitis has been considered as a sporadic disease. An epidemic affection commonly known, in different countries as influenza, and by French writers as la grippe, is characterized by bronchial inflammation. Its occurrence from time to time has been noted by medical writers for several centuries. It is an epidemic remarkable for its extensive and rapid diffusion, sometimes extending within a brief period over many different and widely separated countries. Influenza differs from ordinary acute bronchitis in the frequent extension of the inflammation to the frontal and maxillary sinuses, the lachrymal ducts and conjunctiva, and the Eustachian tube; but more especially it differs in a greater amount of constitutional disturbance.

It is, in fact, to be regarded as a general or constitutional disease, of which the bronchitis is the local manifestation. Like all epidemic diseases, this has doubtless a special cause, and this cause undoubtedly is in the atmosphere. The special cause, however, is independent of appreciable atmospheric changes. Of the nature, source, and mode of diffusion of the cause we have no positive knowledge; but we are equally ignorant of the special causes of many, and indeed of most epidemic diseases. That these diseases depend on organic entities is a supposition which at the present time many regard with favor; but this remains to be proved or disproved by further researches. During some epidemics of influenza, a vast number of persons are simultaneously affected. Generally the affection is mild; but it occasions some fatality among the aged and feeble. The fatality, however, is in general due to complications which occur, and of these capillary bronchitis and pneumonia are especially apt to cause death. - Diphtheritic Bronchitis. A variety of bronchitis is characterized by a fibrinous exudation, or a deposit of lymph on the inflamed mucous surface, forming what is known as a false membrane. This is called bronchitis with fibrinous exudation, or pseudo-membranous or diphtheritic bronchitis.

It occurs in a certain proportion of cases of diphtheria, and also of the affection known as pseudo-membranous laryngo-trachitis or true croup. Irrespective of these pathological connections, it constitutes a very rare variety of bronchitis. The fibrinous exudation or false membrane may extend to a greater or less distance along the bronchial tubes. It is sometimes expectorated entire, presenting complete casts of the bronchial subdivisions from which it was thrown off. A specimen in the museum of the Bellevue hospital medical college, presented by Dr. Stephen Rogers of New York, shows solid casts, composed of concentric layers of fibrine, formed in the bronchial tubes of an entire lobe, extending to those of minute size. The patient from whom this specimen was obtained repeatedly expectorated casts of the same description. Occurring in adults, independently of diphtheria or membranous laryngitis, this variety of bronchitis rarely destroys life. The presence of the exudation cannot be determined prior to its appearance in the matter of expectoration.

When the character of the disease is ascertained, the indications for treatment do not differ materially from those in ordinary bronchitis; but the inhalation of warm vapor or spray is useful as a means of promoting the separation and expectoration of the false membrane.