Membranous Croup.
The etiology and nature of pseudo membranous laryngitis was for years the subject of much discussion. The ques tion has at last been settled by tbe bac teriologist, who has demonstrated that in the great majority of cases the disease is diphtheritic. It is equally demon strated, also, that a certain proportion of cases are not diphtheritic.
Membranous croup and diphtheria are differentiated by the following points: The membrane of diphtheria is of a yellowish hue, the temperature of the body rather high, and the membrane is apt—in fact, certain—to curl up at the edges; while in membranous croup the membrane is white, does not curl at the edges, is devoid of all peculiar odor, a.nd the temperature is rather low. Carl Seiler (Jour. of Laryngology, Aug., '90).
Of 286 cases, reported by Park and Beebe, the Klebs-Loeffler bacillus was present in 229. In the remaining 57 cases it was not present, but in 17 the examination was not satisfactory. The observations of recent years have shown that a pseudomembrane developing pri marily in the larynx is almost invariably associated with the Klebs-Loeffier ba cillus; that is, it is true diphtheria. Pseudomernbranous inflammation of the ' larynx secondary to diphtheritic inflam- 1 mation of the pharynx is invariably true diphtheria. A pseudomembrane devel oping in the larynx secondarily to the pseudomembranes which develop during the course of the infectious diseases is comthonly pseudodiphtheria. Such pseu domembranes are associated with micro organisms other than the Klebs-Loeffler bacillus, generally the streptococcus.
Case of pneumococcic croup in a child of 8 years, who, during an attack of influenza, manifested an erythematous angina. Laryngeal stenosis rapidly su pervened and, despite the injection of R.oux's antitoxin, called for tracheotomy on the evening of the same day. The wound gave issue to a false membrane of colloid appearance, which gave a pure culture of the pneumococcus. The case recovered. Seuvre (Revue Men. des Mal. de l'Ettfattee, Mar., '08).
Whatever the cause of the disease, whether bacillus or streptococcus, it manifests itself simply as a pseudomem branous laryngitis, stenosis being the im portant symptom.
Symptoms.—As the disease is so fre quently diphtheritic in nature, it will be considered in detail in the section on diphtheria. Owing to the slow absorp tion of toxins by the laryngeal mucous membrane and the comparatively short course of the disease when confined to the larynx, the constitutional symptoms of diphtheria are slight. Hence, croup pursues practically the same course whether due to diphtheria or pseudo diphtheria. It is impossible from clin ical evidence alone to determine whether the disease is true or false diphtheria. As it is true diphtheria in a very large pro portion of cases, the only safe rule in practice is to consider every case of croup to be diphtheritic and to use precautions accordingly.
Pathology.—In some cases the an terior portion of the larynx alone is in volved by pseudomembrane. In other cases the whole mucous membrane of the larynx is covered. In many instances the membrane does not pass below the larynx. In both true and pseudodiph theria the membrane is but one element in the production of stenosis, cedema and swelling of the tissue underneath the pseudomembrane being an important contributing cause.
Prognosis.—Unlike pseudodiphtheria of the pharynx, pseudodiphtheria of the larynx is almost equally fatal with true diphtheria, as it causes death by me chanically obstructing respiration. Un til a few years ago the age of the infant was the most important factor in prog nosis, the younger the child, the more fatal being the disease.
The younger the patient, the higher the mortality, because of the small size of the trachea and larynx and because stenosis sooner results; the prognosis is unfavorable in the mildest eases; un favorable symptoms are increasing de bility and cyanosis, feeble and irregular pulse, and the development of bronchitis or broncho-pneumonia. Dodge (Med. and Surg. Rep., liar. 21, '91).