A system of practical medicine. By American authors. Vol. 3

by Unknown

Partial paralysis of the constrictors may be due to deficient power of one or both of the laryngeal nerves, superior or inferior. The parts involved are the arytenoids, transverse and oblique, and the muscular fibres in the folds going from the arytenoid and from the thyroid cartilages to the epiglottis.

The ETIOLOGY of this form of paralysis associates itself with that of anæsthesia of the parts—namely, the arrest of motor impression in the centre, obstruction along the course of the nerve, disease in the nerve itself, in its trunk or termination, or, lastly, myopathic changes rendering the muscle incapable of responding to the nervous influences. Disease in the centres may possibly affect only these muscles; the disorders of motion may be well defined and local in extent, but usually, in case of central disease, there is a complication of external manifestations and we have a wider range of disturbances. The most common cause of this loss of power is diphtheria.

SYMPTOMS.—The symptoms of paralysis of the constrictors of the larynx are for the most part mechanical. The failure to close the vestibule of the organ in the act of swallowing allows food or drink to pass into the larynx, and, as there is usually anæsthesia of the parts also, the invasion of the larynx is not perceived; no reflex irritation is produced, no cough for the extrusion of the offending matter, which may descend into the trachea, and, reaching the bronchi, may become the agent in the development of a bronchitis or a broncho-pneumonia. The secretions of the mouth overflow the borders of the laryngeal opening and fall into the tube below. Fluids are swallowed with greater difficulty than solids. The voice is not altered except in cases where the crico-thyroids, one or both, are involved, as in complete paralysis of the superior laryngeal nerve. The effort to close the glottis, as in the preliminary act of coughing, is accomplished with difficulty. The sound of the cough is somewhat altered. This is for want of the reinforcement to the adductors furnished by the closure of the vestibule of the larynx. Upon laryngoscopic examination the epiglottis is seen to stand erect against the dorsum of the tongue. The ary-epiglottic folds are lax or wide apart. With this is loss or diminished sensibility of the surfaces. There is little or no change in the color of the membranes. The secretions are normal in quality, and only slightly in excess in quantity.

The course of the disease is in cases of diphtheritic origin like that of anæsthesia from the same cause. The termination, except in rare instances, is recovery. In cases of central origin the local symptoms in the larynx are almost necessarily associated with disorders of other parts. The progress and termination will depend upon the nature and extent of the central lesion.

The PATHOLOGY of this form of paralysis is probably multiple. When of diphtheritic origin it has been believed to consist in a change of the nerves along the trunk or in their distribution, or an alternation of nutrition due to the local changes in the larynx or pharynx during the progress of diphtheria, or to both of them. It is also probable that it is in many cases as much a myopathic as a neuropathic trouble. In other words, during the progress of the diphtheria the muscles, as well as the nerves, have undergone a change in their nutrition; and this local change in the peripheral portions of the nerves, along with this degeneration of the muscles, goes to make up the pathological anatomy and constitutes the essential local morbid condition.

There is, however, abundant reason to think that in some cases at least the influence of the diphtheria in the production of paralysis reaches far beyond the parts which are the seat of the local manifestations of the trouble, or even the centres from which these nerves are derived. It is well known that the extremities may be affected, and that other muscles become involved which can have no direct and immediate relation to the tissues which have been attacked with the diphtheria. It seems therefore evident that there must, at least in certain cases, be a general derangement of the centres, or that there must be some other explanation for the impairment of the muscular power than that which ascribes its loss solely to the local and poisonous action of the morbid deposit or to the defective nutrition of the parts. It is probable that there is in these cases a widespread influence, a constitutional trouble, which, like the disease itself, is general and not local except as to its manifestations.

Paralysis of the Adductors.

A pure, uncomplicated paralysis of the adductors of the vocal cords is extremely rare. When present it is marked by symptoms and signs which are easily recognized. A partial paralysis of an hysterical nature is, however, not unfrequently encountered. The etiology of paralysis of the lateral crico-arytenoid muscles is in most instances the same as that of the other muscles of the larynx. There may be a morbid condition of the centres in the fourth ventricle, from which the spinal accessory takes its origin. It is certainly possible in theory that certain fibres ultimately distributed to these muscles may alone become diseased in their course along the trunk of the nerve. There may be change in the final distributions by which the function of the nerve is arrested. There may be myopathic change in the muscle itself, rendering it non-responsive even to normal nerve-impressions. All of these causes are theoretically possible. In fact, however, we know but little of the real causes which operate in any given case. Mackenzie, Von Ziemssen, and others ascribe it in some instances to catarrh from exposure to cold. There is developed a hyperæmia of the mucous surfaces of the supraglottic space. The structures beneath are involved in the tumefaction as a result. The voice is impaired or lost; the aphonia, which was at first due to the mechanical difficulties in the way, persists after the local inflammation has subsided. The vocal cords remain permanently apart, even though there is no swelling to prevent the arytenoids from approaching each other. Gerhardt attributes this form of paralysis in certain cases to a rheumatic inflammation affecting either the articulations or the muscles themselves. Trichina have been found in one or both muscles, producing a paresis. Syphilis, central or laryngeal, may account for a number of cases. When the loss of power is due to local syphilitic trouble, there is, however, usually a recognizable change in structure, something more than a simple paralysis.

It would seem strange to find a rheumatism so localized as this hypothesis implies. Mackenzie has met with a case in which the paralysis was unilateral and toxic, due to lead-poisoning. He thinks there may be other cases of similar origin, and suggests arsenic also as a possible cause. In his case he compares this paralysis of the lateral crico-arytenoids to the loss of power in the extensors of the forearm in well-marked cases of lead-poisoning. The affection was limited to the adductor muscles. Seifert and Lublinsk in Berlin. klin. Woch. also report cases. The adductors only were affected. The very few cases in which this form of paralysis has been carefully noted do not supply us with the material for a more exact opinion as to the causes of the trouble.

SYMPTOMS.—The symptoms of this form of paralysis are for the most part such as depend upon the mechanical relation of the parts. There is no pain; there is no dyspnoea, except in cases in which there is a catarrh of the larynx; there is no cough. There is however, complete aphonia. There may be an exception to this statement when the paralysis is unilateral. It is possible that where one cord comes to the median line, and the other is affected only with paresis, in the course of time the cord on the sound side may pass beyond the median line and render phonation possible. In such cases, however, the voice is not normal in quality.