1 "Van Helmont, discarding the ancient doctrine of the four humors, attributed asthma to an error of the Archeus, which he conceived to be enthroned in the stomach and to constitute the source of all diseased as well as of all healthy phenomena. This principle, he supposed, sent forth from the stomach a peculiar fluid, which, when it became diseased, gives rise to a morbid state of the parts to which it was conveyed. He moreover imagined that this fluid sometimes mixed itself with the male semen, and thus formed a compound which, as one of its constituents is the means provided by nature for the propagation of the species, possesses the power of generating a disease of hereditary character. Thus, when this compound was conveyed to the articulations, he affirmed it produced gout, and when it took its direction to the lungs it then occasioned asthma" (Baltimore Med. and Surg. Journ. and Review, Baltimore, 1833, p. 300).
The improvement in physical diagnosis resulting from the brilliant discoveries of Auenbrugger and Laennec greatly curtailed the domain of asthma. With the aid of auscultation and percussion it was discovered that most of the cases hitherto regarded as asthma were only symptoms of some organic disease. Many distinguished authorities, particularly of the French school, went so far as to declare that there existed no such disease as asthma, and that in every case the dyspnoea and other phenomena described under that name were merely symptoms of some organic affection.
Although very generally received at first, it was not long before this too-sweeping reform encountered opposition from various quarters. Cases were observed with marked asthmatic symptoms in which, after death, the most careful examination failed to reveal the slightest trace of textural lesion. The discovery by Reisseisen of muscular fibres even in the minutest bronchi, and the demonstration of their electric contractility by Longet and Williams, afforded a ready explanation of these cases, and led to the opinion—which has since been generally received—that asthma in the modern acceptation of the term is simply a neurosis. The more recent theories in regard to the nature of asthma will be more fully discussed in the portion of our article devoted to the pathology of the disease.
SYMPTOMS AND COURSE.—The following description of an attack of asthma by Trousseau, who was himself an asthmatic, is perhaps the best that has ever been written: "An individual in perfect health goes to bed feeling as well as usual, and drops off quietly to sleep, but after an hour or two he is suddenly awakened by a most distressing attack of dyspnoea. He feels as though his chest were constricted or compressed, and has a sense of considerable distress; he breathes with difficulty, and his breathing is accompanied by a laryngo-tracheal whistling sound. The dyspnoea and sense of anxiety increasing, he sits up, rests on his hands, with his arms put back, while his face is turgid, occasionally livid, red, or bluish, his eyes prominent, and his skin bedewed with perspiration. He is soon obliged to jump from his bed, and if the room in which he sleeps be not very lofty he hastens to throw his window open in search of air. Fresh air, playing freely about, relieves him. Yet the fit lasts one or two hours or more, and then terminates. The face recovers its natural complexion and ceases to be turgid. The urine, which was at first clear and was passed rather frequently, now diminishes in quantity, becomes redder, and sometimes deposits a sediment. At last the patient lies down and falls to sleep."
The next day the patient may feel well enough to pursue his accustomed avocation, and may remain free from all symptoms of the disease until another attack comes on; but more frequently he is confined to the house, if not to bed, the slightest exertion being sufficient to cause dyspnoea; and during the following night there is a repetition of the paroxysm.
If unchecked by treatment, the disease may continue for days, weeks, and in some instances even for months, the paroxysms often increasing in severity until, as in other nervous affections, it ultimately wears itself out.
There is no regularity in the occurrence of the attacks. In some cases they recur every few days, while in others there may be an interval of weeks or months between the seizures. Even in the same case, although the individual paroxysms of the attack may come on at the same hour, there is, except in rare instances, no regularity in the recurrence of the attack itself; and when it does recur at a certain time it is almost always due to some cause which, as in hay asthma, exerts its influence only at that particular period.
In the great majority of cases asthma comes on without any warning whatsoever, but occasionally it is preceded by certain sensations which to the experienced asthmatic are a sure indication that an attack is impending. With some it is only a feeling of ill-defined discomfort; others complain of various disorders of the digestive system—a sense of dryness of the mouth and pharynx, uncomfortable distension of the epigastrium with eructation of gases from the stomach, and more or less obstinate constipation. A troublesome itching of the skin often precedes the attack. Some experience a feeling of constriction around the throat; a profuse secretion of clear urine is a symptom of this stage. Frequent gaping, frontal and occipital headache, are mentioned; but far more constant than all of these are certain symptoms indicative of a mild grade of acute catarrh of the respiratory organs—coryza, with swelling of the Schneiderian membrane and discharge from the nostrils, sneezing, redness of the conjunctivæ with increased lachrymation, and later, as the irritation extends downward, more or less cough.
The attack almost always comes on after midnight, and, as a rule, between the hours of two and six o'clock in the morning. Salter states that nineteen out of twenty cases occur between two and four A.M. There are, however, occasional exceptions to this rule; sometimes the patient is attacked soon after retiring, and Trousseau cites the case of his mother, who always had her attacks between eight and ten in the forenoon, and also that of a tailor, whose paroxysms invariably came on at three o'clock in the afternoon. Indeed, there is no hour of the twenty-four during which the seizure may not take place. Various attempts have been made to explain why it is that the paroxysms of asthma almost invariably occur during the latter half of the night. Many attribute it to a stasis of blood in the lungs caused by the recumbent posture of the patient, while others claim that it is due to a dulling of reflex impression, the patient during sleep failing to perceive the necessity of breathing. Germain Sée, who discredits both theories, inquires why, if the above explanations are correct, does the attack not come on soon after retiring, as is the case with the dyspnoea of cardiac diseases.
The paroxysm of asthma develops very rapidly, but not so suddenly as is claimed by many authors, several minutes to half an hour or more elapsing before it attains its full height.2