DYSPNŒA LARYNGEA. ROARING. HEMIPLEGIA LARYNGEA.
Generic name for common symptom. Low and high notes. Grunter, roarer, whistler, piper, highblower. Pace or effort develops. Causes: of temporary roaring, inflammations, abscess, phlebitis, choking, dropsy, petechial fever, phlegmons along vagus. Causes of inveterate roaring, paresis of left recurrent laryngeal nerve, fatty degeneration of left arytenoid muscles, fracture of facial bones, polypi in air passages, chronic thickening of mucosa, foreign bodies in passages, tumors of lymph glands, abscess of guttural pouches, pseudo membrane, laryngeal ulceration, ossification, distortion, fracture of cartilages, action of forcible inspiration, leading on left side, deep origin of recurrent nerve, effect of chest diseases and violent heart action, examples of morbid conditions impairing innervation. Lesions in muscles, and nerves. Facial palsy, poison (chick vetch, winter vetch, lead, fungi, moulds). Intermittent roaring. Hereditary roaring. Symptoms, grunting when coughed or threatened, heavy draft, gallop, noise, laryngeal tremor, cold as a complication, roaring with expiration, lesions. Treatment, its use. Prevention, avoid breeding roarers, bearing reins, chick vetch, lead. Tonic medication, caustic to mucosa, firing, setons, iodine, pad nostrils, tracheotomy, arytenectomy, electricity.
This is the name of a symptom rather than a disease. It implies a sound made in breathing in connection with some contraction of the air passages. The term is however usually reserved for those conditions in which the sound results, from chronic disease or malformation, the noise attendant on laryngitis and other acute diseases being rarely spoken of as roaring. In neither case does the noise indicate more than that there is some impediment to the ingress and egress of air through larynx or trachea.
The pitch of the note varies exceedingly with the causes that produce it and with the hurried nature of the breathing. There have thus arisen the epithets of grunter, roarer, whistler, highblower, piper, trumpeter, wheezer, etc. The most common distinctions are those of roaring and whistling. The roarer produces a loud deep basso sound in inspiration, the larynx or windpipe being only slightly narrowed while the whistler or piper produces a shrill blowing or sibilant noise because of the greater constriction of the passage. The term grunter is derived from the facts that a roarer usually makes a grunting noise when struck or threatened with a cane, and that when the upper cartilages of the windpipe are pinched between the finger and the thumb the resulting cough is prolonged and somewhat like a grunt. A wheezer is usually suffering from spasmodic contraction of the bronchial tubes, from broken wind or from chronic bronchitis. A highblower should never be spoken of in the same connection, as the noise is made from a playful flapping of the false nostrils or soft palate and disappears when the animal is put to the top of his speed. It is from confounding high-blowing with roaring that Eclipse and other brilliant performers on the English turf have been erroneously pronounced roarers.
The noise produced by the roarer is not heard while he stands quiet, nor many cases even during a short trot or gallop. Such horses are in consequence often sold at the hammer and the purchaser is grievously disappointed to find that what he thought a sound horse is absolutely useless for the purpose for which he designed it.
Causes. Before noticing the symptoms of roaring a consideration of the causes will be useful to enable the reader the better to understand the signs by which the different forms are manifested.
Causes of temporary roaring. Whatever impedes the current of air causes roaring. Hence inflammatory diseases of the nose, throat, windpipe or bronchial tubes; abscess of one or the other of these parts; inflammation of a jugular vein and pressure on the trachea or vagus nerve by the resulting swelling; choking; the swelling in the neck consequent on the cutting open of the gullet for the relief of choking; thickening of the nostrils from dropsy, loss of a jugular vein, purpura hemorrhagica etc.; and swellings pressing on the vagus nerve, and which may be situated at the base of the brain, in the neck or in the anterior part of the chest. Also temporary infiltration of the laryngeal mucosa.
Causes of inveterate roaring. The one great cause of roaring and that which sustains the disease in nineteen cases out of every twenty is paralysis of the left recurrent nerve of the larynx and wasting of several of the arytenoid muscles on that side. It may be well, however, first to notice the less frequent causes and wind up with this more common one. 1st, Fracture with distortion of the nasal bones and narrowing of the nasal passages (Gamgee). 2nd, Polypi and other tumors of the nose, pharynx, larynx, windpipe or bronchi. 3rd, Chronic thickening of the nasal mucous membrane, the result of inflammation. 4th, The presence of foreign bodies in the nose, as for example balls coughed up from the pharynx. 5th, Hering records a case resulting from the closure of the posterior opening of one nasal chamber by a membrane. 6th, Cancerous or melanotic deposits in the lymphatic glands above and to each side of the pharynx and larynx. 7th, Distension of the guttural pouches by inspissated pus. 8th, Chronic thickening of the mucous membrane of the larynx consequent on inflammation. 9th, The formation of a projecting fold of the mucous membrane or of a new production (false membrane) in the windpipe as the result of inflammation. Such false membranes have been known to become detached at their median part and remain attached at their two extremities thus constituting a band stretching from one side of the windpipe to the other. 10th, Ulceration of the membrane of the larynx particularly on the projecting folds circumscribing the glottis, 11th, Ossification of the laryngeal cartilages and loss of their elasticity. 12th, Distortion of the cartilages of the larynx, most commonly from unduly tight reining and pulling the nose in toward the chest. In such cases the cartilages of the larynx and those of the windpipe adjoining being compressed slide within each other, and the enclosed edge projecting within the air tube materially diminishes its calibre. 13th, Fracture of one or more rings of the trachea. This usually results from blows, as in running the neck against the back of a cart or wagon. The cartilaginous rings are usually broken at their median part in front and being retained together by the investing elastic tissue which enables the pieces to move on each other as by a hinge, and being approximated by the contraction of the trachealis muscle above, the ring is flattened from side to side and the channel for the passage of air correspondingly decreased. This flattening can be easily felt by the hand in the living horse. 14th, A peculiar congenital distortion of the trachea caused by the curling in of one end of each cartilage of the windpipe and the straightening out of the other. This occasionally proceeds so far that the gullet is lodged in the interspace overlapped and hidden by the free ends of the cartilages, the diameter of the windpipe being proportionately diminished. Distortions and fractures are usually overlooked by veterinarians but from the frequency with which the author has met with them in his dissection he is convinced that they deserve greater attention than has been awarded them. 15th, Percivall records a case of inveterate roaring in which, even tracheotomy having failed to cure, the patient was destroyed and the lungs found to be extensively consolidated, many of the air tubes having been so compressed as to be almost impervious. I have known a case of roaring from the presence of a pedunculated tumor in the lower end of the windpipe where it divides to enter the lungs, and the same result may ensue from the partial obstruction of the bronchial tubes by masses of tenacious mucus in chronic bronchitis.
16th. The immediate cause of roaring in the immense majority of cases is the paralysis and fatty degeneration of certain muscles on the left side of the larynx. The muscles supplied with motive power by the left recurrent laryngeal nerve (Crico-arytenoideus posticus, Crico-arytenoideus lateralis, thyro-arytenoideus, and the left half of the arytenoideus) are those constantly and exclusively affected, while those supplied by the superior laryngeal nerve (Crico-thyroideus, hyo-thyroideus and hyo-epiglottideus) remain unchanged. The left recurrent nerve is also wasted and considerably attenuated as compared with that on the opposite side. The modus operandi of this paralysis and wasting in the production of roaring is beautifully seen when the upper part of the windpipe is laid open so as to expose the interior of the larynx in laryngectomy. The triangular opening of the glottis is seen fairly dilated while the muscles are relaxed in the act of expiration. As soon, however, as inspiration commences the left arytenoid cartilage slides completely into the passage, its lower border projecting so much to the right that it forms a prominent crest extending beyond the median line and in some cases closely approaching the right wall of the larynx, the superior elastic and free border of the same cartilage meanwhile gets drawn inward by the suction power of the air so as to block up the passage still more. The closure of the glottis being thus seen to be largely controlled by the current of inspired air, it becomes evident that any increase in the force of the current will aggravate it and a decrease will lessen the extent of the closing and alleviate the distress of breathing. This fact furnishes a means of palliating the symptoms. (See treatment.) It explains moreover why roaring should not be heard in quiet breathing and why it should increase in force and in pitch as the respiration becomes more and more hurried. It further accounts for the noise being heard only during the act of inspiration, the outward rush of the air in the expiratory act being of itself sufficient to carry this valvular cartilage out of the passage and secure a free and unimpeded current.
The paralysis and wasting of the left recurrent nerve and muscles are in their turn due to very varied morbid states.