The symptoms described above are the same both in those cases which are strictly localized and those which descend from the pharynx. In the latter there is fever only when the pharyngeal diphtheria was attended with it. The process descending into the trachea and bronchi changes the symptoms but little, as far as the laryngeal stenosis is concerned, for it is the latter which destroys by suffocation. Only when tracheotomy has been performed, and the immediate danger of suffocation has been removed, the further progress in a downward direction gives rise to a new series of symptoms. After the temporary relief procured by the operation dyspnoea will set in anew, not always, however, of that intense degree of the laryngeal stenosis; respiration will become dry and loud again, and a little more frequent than in the uncomplicated laryngeal cases. Death will finally also result, either from suffocation or from the symptoms I enumerated above.
Lastly, when membranous laryngitis is but the terminating development of extensive membranous bronchitis, the symptoms differ from those described above in this, that the laryngeal symptoms last but a short time. For days or weeks no symptoms but those of an ordinary bronchial and tracheal catarrh were observed: all at once the process reaches the larynx; in a few hours the very last stage of croupous stenosis is reached; even tracheotomy does not relieve the symptoms. Or the fibrinous bronchitis was extensive enough to give rise to a sufficient number of symptoms before the larynx was reached. Amongst them is, foremost, frequency of respiration, because of its insufficiency; diminution of respiratory murmur over the area supplied with the affected bronchi; sometimes localized absence of respiratory murmur, while the percussion sound is sonorous. Another complication is emphysema, either subpleural or pulmonary. It is not frequent, except in combination with fibrinous bronchitis. The increase of respiratory movements is quite sudden, percussion sound tympanitic, and auscultation negative. Pulmonary oedema is quite frequent; it is the result of the rarefaction of air in the bronchi, the consecutive dilatation of the blood-vessels, and the effusion of serum by intravascular pressure. Every severe case is accompanied with it; in every tracheotomy it is met with coming up into the incision. Oedema of the glottis is less common, but it is met with in the same manner and with the same symptoms which characterize the glottic oedema of catarrhal laryngitis.
PROGNOSIS.—It is not favorable even in the simple and uncomplicated cases. Infants and children under two years almost invariably die. The percentage of average mortality rates very high—from 80 to 90 and more. It is probable that some recent therapeutical advances have reduced it, will reduce it, considerably. Tracheotomy is known to do so certainly, as from 20 to 45 out of 100 operations prove successful. The previous condition of the patient is of very little account in regard to the course and termination of the disease; no constitution protects or saves. The more the disease is local the better the prognosis. When fever makes its appearance, it means a complication, such as extending diphtheria or bronchitis or bronchi-pneumonia, and impairs the chances of recovery. The expectoration of membranous shreds or whole membranes does not improve the prognosis much, as the new formation of membranes may be very rapid indeed. I have seen new membranes rising to a formidable extent in from two to seven hours. The prognosis is improved when the cough becomes looser, expectoration more purulent, pulmonary respiration become audible again after having been covered by the laryngeal noises, rhonchi become moist, and portions of lungs which before were inaccessible to air by clogging membranes are reopened. Increasing debility, frequent and irregular pulse, are ominous symptoms. Even more so is the failure on the part of emetics to take effect.
DIAGNOSIS.—It may be quite difficult to diagnosticate croupous from catarrhal laryngitis, particularly in those cases where the former is not complicated with any visible exudative process in the fauces. In membranous laryngitis stenosis begins gently (except in those cases which ascend from the bronchi) and increases gradually; there are, it is true, remissions in the morning (mostly), but they are but slight, and the subsequent evenings are worse than the previous ones. It increases from day to day until a slight cyanotic hue of the lips is followed with more general cyanosis. There is no fever or very little, except in the cases of generalized diphtheria. The character of the cough does not change; perhaps it becomes more dry and suppressed after a while. Hoarseness does not improve, but increases steadily into aphonia. Expectoration is but scanty; now and then a small portion of mucus from the lower portion of the respiratory tract, now and then shreds of membrane, are expelled.
In catarrhal laryngitis stenosis begins abruptly and suddenly, and is often at its height a few minutes after the commencement of the attack. Remission sets in soon, is more marked, sometimes complete, and a new attack, just as sudden as the first, may occur in the next night. Real cyanosis is but rarely developed; when it is, it changes soon into a more normal condition. Catarrhal laryngitis in the child is a febrile disease. In it the cough changes after a little time, some moisture mixes with the expectoration and changes both cough and articulation; also, the voice is not equally husky; now and then a clear note comes in. Close inspection of the throat exhibits sometimes a thick, viscid mucus floating up and down with the excursions of the larynx in catarrh. It never has any membranous expectoration.
Local oedematous swelling of the ary-epiglottic folds, with or without membranous deposits in some other parts of the larynx, yields all the symptoms of membranous croup with its dangers and death-rate. The effect of this oedema is partial paralysis of the vocal cords. Thus, inspiration is impeded, as in membranous obstruction; expiration, however, is free and the voice intact to a certain extent. This local oedema may be detected by palpation.
General oedema of the larynx (glottis) is fortunately rare. The attack is very sudden; there is no cold, no hoarseness, no choking cough, no membrane; there is only dyspnoea, gasping, asphyxia, sopor, and death, unless relief is given almost instantaneously.
The presence of a foreign body has been mistaken sometimes for membranous laryngitis. The history is a different one; there was no prodromal catarrh; the children were taken suddenly while playing or eating.
The laryngoscope would be a great aid in diagnosis if it could be used during the distress of a membranous laryngitis. Still, it has been employed by Ziemssen, Rauchfuss, and others. But the opportunities are rare.
TREATMENT.—The objects of treatment differ with the various stages of the disease. The inflammatory symptoms of the commencement, the completed exudation, the maceration and disintegration, and also the expectoration of the pseudo-membranes, and, finally, the asphyctic stage, have each their own indications. If there is anything which must not be recommended, it is depletion. Fortunately, there are but few practitioners left who still apply leeches or employ more general depletion, but these few are still doing too much harm by their practice and teaching. The application of ice, however, in bags over and near the larynx, and of iced cloths frequently changed, combined with the swallowing of small pieces of ice from time to time, is apt to be beneficial in well-nourished, hearty children. Such as have been anæmic, with thin muscles and pale mucous membranes, do not bear it so well.