Laryngeal diphtheria, or membranous croup, may be confounded with stridulous laryngitis, with abscess of or about the larynx, or with retro pharyngeal suppuration. rube distinctive points between these diseases will be referred to in the chapters treating of these affections. It is pos sible that a foreign body in the air-passages may be mistaken for croup ; but the attack of dyspncea produced by this means comes on quite sud denly and follows at once upon an attempt to swallow. There is spas modic cough but no hoarseness ; and the first paroxysm of suffocation and cough is usually succeeded by a period of quiet in which, for the time, the breathing is fairly easy and the child seems to be well.
It is very important to be able to discriminate between cases in which tracheotomy may be expected to succeed and those in which no perma nent good can be anticipated from the operation. Dr. George Buchanan, of Glasgow, has pointed out that in cases where the air-passages below the point of obstruction are free, and the lungs are in a normal condition, there is great recession of all the soft parts of the chest. At each inspira tion the intercostal spaces fall deeply in, and the epigastrium forms a deep hollow. If, on the contrary, the smaller bronchial tubes are full of mucus or diphtheritic exudation, the movements of the chest-wall are impeded, and the chest is puffed out so as to resemble the distended thorax of chronic emphysema.
If the patient be seen for the first time when the paralytic symptoms have declared themselves, the history of the attack will declare the nature of the disease. Even if, as sometimes happens, the throat affection has been too slight to constitute a regular illness, we shall find, probably, that other members of the household have suffered from diphtheria, and that, in the child himself, any signs of general nerve-lesion have been preceded by a nasal tone of voice, some trouble in swallowing, and the occasional return of fluids through the nose.
According to M. Landrouzy, if a child who is convalescent from diph theria begins to suffer from attacks of dyspncea excited by an attempt to cough, or by any small vexation, we should suspect paralysis of the dia phragm in the absence of any more evident explanation of the distressing phenomenon.
Prognosis.—Even in the mildest attack of diphtheria we must be guarded in the expression of our opinion as to the probable issue of the illness. Indeed, it is wiser to express no opinion upon the matter, but
to confine ourselves to reporting the daily progress of the case, and speak ing cheerfully so loig as no symptoms arise indicative of danger. We can never feel certain that the inflammation may not spread to the larynx, or that other ill consequences may not ensue, however favourably the disease may appear to be going on. Caution in prognosis is especially necessary if the epidemic is a severe one, for outbreaks of the distemper vary greatly in the severity of type of the illness, and in some the mortality is much greater than it is in others. The age of the patient is also an impor tant item to take into consideration, for a young child has fewer chances of recovery than an older one.
Different dangers are to be apprehended at different periods of the dis ease. During the first week we dread lest the inflammation should spread to the larynx, or lest the child should die from septicemia. We therefore notice carefully the character of the breathing and the quality of the voice. If the breathing become shrill and the movements laboured, or the voice get weak or husky, we can have no doubt that the larynx is be coming involved. So, also, in cases where the false membrane is thick, pulpy, and putrescent the occurrence of shivering or a sudden rise in the temperature, with a dull yellow tint of the face and a rapid feeble pulse, makes us fear that the blood is becoming poisoned by absorption from the affected mucous membrane. Dr. Jacoby has pointed out that in nasal diphtheria septicaemia is especially liable to occur. In this form of the disease, therefore, the regular use of disinfecting injections is imperatively called for.
After the first six or seven days the child is in danger of death from syncope, from clotting of blood in the heart, and from inflammatory com plications. At this time we carefully watch the pulse. If this fall notably in frequency and strength, especially if at the same time vomiting occur and be often repeated, the danger is imminent. At this period of the dis ease haemorrhages sometimes come on as a result of profound blood con tamination and are very exhausting. Other signs of bad augury are a very feeble frequent pulse, cardiac dyspncea (see page 98), general swell ing of the neck, great prostration, and delirious wanderings. Albumi nuria, unless excessive, is not necessarily a grave symptom.