Even although numerous influenza cases run their course without any symptoms referable to the respiratory apparatus, as, for instance, in the purely toxic forms (compare p. 591), nevertheless the rule holds good that by far the most numerous and important of the local inflammations due to influenza occur in the different parts of the respiratory mucous membrane, from the nose to the alveoli of the lung.
These phenomena depend upon the fact that the specific cause of influenza settles first on the respiratory mucous membrane, which becomes the seat of the primary lesion.
To this statement we should add another explanatory one, which I made use of in my lectures on influenza in the spring of 1890: " The catarrh of influenza does not always, nor even as a rule, progress from the nasal cavities downward to the entire respiratory tract. Any section of the membrane alone may be affected without any implication of the remainder. A nasopharyngeal catarrh alone is common; but there are also cases in which the larynx alone is affected. The cases in which the trachea and the large bronchi were the principal parts affected frequently showed convulsive attacks similar to whooping cough. The bronchi, bronchioles, and alveoli, however, may be the only portions affected. There is also a very acute , primary influenza pneumonia, that is to say, an influenza which commences with all the symptoms of pneumonia." We shall recur to this later, and shall here consider the separate portions of the respiratory apparatus.
In many cases there is a pronounced rhinitis; many patients complain of a cold in the head, with the accompanying loss of smell. The general appearance of the patient, the reddened nostrils, the reddening and swelling of the eyelids, the conjunctivitis, the copious flow of tears, the "watery eyes," so frequently mentioned, the flushing of the face, especially in the supra orbital region, present the typical picture of an intense coryza. Yet those authors too are right who, apart from fever and the other severe symptoms of the disease, differentiate the coryza of influenza from the common coryza, which is described as "a coryza with a plentiful watery secretion and frequent sneezing," but is quite rare in true influenza. Based on this definition, the statement of Maillart, Hertz, and others, that coryza "is an exceedingly rare complication of influenza," is comprehensible.
Some authors collected statistics of the frequency of coryza in influenza. In the Leipsic City Hospital Krehl found it in 79 per cent, of the cases; Robertson and Elkins (Edinburgh), in 77 per cent. In the Hamburg Hospital, according to Schulz, it occurred in 50 per cent.; in the Julius Hospital at Wurzburg, according to Anton, in 25 per cent, of the cases. Biermer and Litten, the latter upon the basis of the German collective reports, note: "Almost without exception the symptoms of coryza are present" ; Teissier: "Coryza is the rule." A flowing coryza Preston found in only 8 per cent, of the cases; but Bristowe saw "watery eyes" in 96 per cent, of the cases.
We can only once more emphasize the fact that both the subjective and the objective signs of coryza are absent in quite a number of cases. Rhinoscopy may show "an abnormal, intense reddening of the nasal mucous membrane," but it is quite overshadowed by the severity of the other symptoms and remains unnoticed by the patient. Ruhemann says: "As regards rhinitis, it cannot be said that either in intensity or in extent has it been so marked as in many of the former epidemics."*
The acrid nasal discharges excoriating the upper lip and the attacks of sneezing were much fewer in the epidemic of 1889-1890 than in former influenza epidemics. Epidemics evidently vary in this respect.
Very often the catarrhal inflammation extends from the nose to the frontal sinus, to the ethmoid sinus, and to the antrum of High more. Weichselbaum regularly found in his autopsies catarrhal or purulent inflammation of the nasal sinuses. It is probable that the terrible frontal headaches, which may last far into convalescence, are due to a local inflammatory process in the frontal sinus. In quite a number of cases purulent inflammation of the ethmoid sinus, and especially empyema of the antrum of Highmore, occasionally also of the temporal cavities, occurred, as operations upon these cavities subsequently demonstrated.
These chronic influenza empyemata of the nasal cavities occasionally gave rise to stubborn "neuralgias" in the supra orbital and infraorbital regions, until their cause was ascertained and relief afforded by operation. In the pus of such an empyema we once found typical influenza bacilli.
Epistaxis, in our experience, is very rare. Litten, on the other hand, says (German collective reports): "Epistaxis during this epidemic (1889-1890) was frequently noted and was occasionally so profuse that the observers often declared it to be almost uncontrollable." Most statistics entirely ignore epistaxis. Anton and we ourselves estimate it to occur in 2 per cent, of cases; Bristowe does the same. In descriptions of some former epidemics (1582, 1732, 1758, and 1803) the frequency of epistaxis is especially mentioned.
There can be no doubt that the larynx is much oftener affected than the subjective sensations of the patient or the objective signs, unaided by laryngoscopic examination, would lead us to suspect. That a laryngoscopic examination was made in so small a number of cases is easily understood from the fact that during the influenza pandemic the demands on the doctors' time left no leisure for such examinations.
* " Le nez destillait sans cesse comme une fontaine," Pasquier, Epid. 1557.
An intense laryngitis, with hoarseness, occasionally even with laryngeal dyspnea, was noted by us in 6 per cent.; by Krehl (Leipsic), in 5; by Stintzing (Munich), in 7; and by Schulz (Hamburg), in 16 per cent, of the cases.