CHAPTER III.. Larynx, Trachea and Bronchi.

LARYNX, TRACHEA AND BRONCHI.

LARYNGITIS.

Laryngeal diseases are common, but are usually only the local expression of some grave general infection, such as foot-and-mouth disease, gangrenous coryza, or tuberculosis. Pathological conditions such as these can be disregarded for the moment, as they will receive attention under special heads.

The two current forms of laryngeal disease are acute laryngitis and stridulous laryngitis.

ACUTE LARYNGITIS.

Acute laryngitis, like simple coryza, of which it is often only an accompaniment, is caused by chill, by irritant vapours, by smoke, etc., or by external traumatic causes.

The cough is dry and painful at first; afterwards it is accompanied by a discharge or by the swallowing of mucus or muco-purulent products. The respiration sometimes appears accelerated and difficult, but roaring or whistling and marked fever are rare. The slightest pressure over the laryngeal region causes pain and attacks of coughing. The respiration is normal while the animal is at rest, provided that the laryngitis remains localised; frequently, however, it is complicated with bronchitis.

The appetite is somewhat diminished, but all these symptoms very rapidly improve.

=The diagnosis= is based on the frequency of the cough and the sensitiveness of the throat region.

=The prognosis= is favourable in cases of simple laryngitis.

=Treatment= consists in the administration of steam inhalations, warm drinks, the application of mustard plasters or blisters around the laryngeal region, and the administration of expectorants to facilitate mucous discharge.

PSEUDO-MEMBRANOUS LARYNGITIS.

Pseudo-membranous laryngitis, also termed by German authors croupal or diphtheritic laryngitis, because it bears a certain resemblance to human croup, is characterised by the formation of false membranes on the vocal cords, arytenoid cartilages, and subglottal region, etc.

In France it has been described under the name of stridulous laryngitis, because its dominant symptom consists in attacks of intense dyspnœa, during which the respiration is accompanied by whistling. Without making any attempt to prejudge the nature of the disease, which resembles the pseudo-diphtheritic forms of laryngitis in man, we prefer the term pseudo-membranous laryngitis. Moreover, this pseudo-membranous laryngitis very frequently accompanies pseudo-membranous sore throat, tracheitis and bronchitis, with formation of false membranes.

=Causation.= The causes suggested are similar to those of simple sore throat: they include chills, the ingestion of ice-cold water, or the inhalation of irritant gases, during outbreaks of fire, etc., etc.; but it is quite certain that here, as in many similar cases, a primarily simple laryngitis is complicated by a well-marked infection.

=Symptoms.= The general symptoms seen during the early stages consist in loss of appetite, general depression, rigors, and a rise in temperature of 1° to 2° Fahr.

Then, after twenty-four or forty-eight hours, the respiration becomes more rapid, difficult, whistling and dyspnœic, with intermittent attacks of suffocation.

Examination of the chest gives negative results, but, on the throat being manipulated, the slightest pressure exercised over the larynx produces attacks of coughing. During the first few days these attacks are loud, spasmodic, and difficult, but on succeeding days they lead to the discharge, from the nostrils or mouth, of masses of false membrane accompanied by whitish and sometimes blood-stained fluid. Secondarily the mucous membrane of the nasal fossæ appears inflamed to a varying degree. The conjunctiva is also affected, the eyes are watering. An important symptom consists in the fact that this watering is accompanied by internal ophthalmia, as in gangrenous coryza.

In consequence of the respiratory difficulty, the animal takes up a characteristic attitude, holding its neck stiffly in a horizontal position and its head completely extended; the nostrils are widely dilated. When the disease is fully-developed rumination is suppressed, the bowels are constipated and the fæces are coated as in grave cases of enteritis, the yield of milk diminishes, the heart beats feebly, the pulse remains small; death may occur from asphyxia, and probably also from intoxication.

The disease usually lasts from eight to ten days, but death may occur earlier. In the majority of cases, however, the animal can be saved. All the symptoms diminish, the temperature falls, rumination again appears and with it appetite, and the whole condition becomes normal. Many animals, however, remain thin and recover slowly; these are principally cases which have suffered from pseudo-membranous bronchitis.

=Lesions.= The lesions may be confined to the larynx, but may also invade neighbouring cavities. They consist in the formation of mucoalbuminous and fibrinous exudates, covering the mucous membrane in superposed layers, penetrating the epithelial stratum, and adhering so strongly to the corium that attempts to loosen them cause the deeper seated structures to bleed.

=Diagnosis.= The symptoms are sufficiently well marked to prevent any confusion arising except with gangrenous coryza, but in this case there is no ophthalmia lesion of the nasal cavities, cutaneous eruption, or eruption over the claws.

=The prognosis= is grave when the disease attacks debilitated or exhausted animals.

=The treatment= is confined entirely to treating symptoms. As in all acute inflammatory affections, moderate bleeding, sinapisms over the region of the larynx, repeated as often as necessary, or applications of antimonial ointment have been recommended. Applications of moxas or setons in the neighbourhood of the dewlap might possibly prove of value.

Internally tartar emetic, in doses proportioned to the size of the animal (2½ to 3 drachms in adults), has been recommended; also iodide of potassium.

General stimulants, like alcohol, coffee, tea, acetate of ammonia, and suitable hygienic conditions suggest themselves. Tepid drinks can be given freely. Nourishing and easily digested food, and a ration of milk complete the treatment.

Emollient and antiseptic fumigations are also of value, as in ordinary sore throat or laryngitis, for they favour the separation and discharge of the false membranes.

TUMOURS OF THE LARYNX.

Acute forms of pseudo-membranous laryngitis, or even tuberculous laryngitis, are not the only diseases which affect the larynx. It is by no means exceptional to discover intra-laryngeal tumours, mucous polypi, tuberculomes, and growths due to actinomyces, etc.

The presence of these tumours is indicated by difficulty in respiration, fits of coughing, and threatened suffocation, accompanied by discharges of varying character.

When the tumour is largely sessile, the respiration may simply be snoring or whistling, without any suggestion of suffocation; but if, on the other hand, it is pedunculated, displacement of the polypus produced by the currents of air during inspiration and expiration causes spasm of the glottis, fits of coughing and threatened suffocation.

=The diagnosis= is not always easy, though examination of the nasal cavities, the sinuses, trachea and chest gives negative results. Auscultation of the larynx may suggest the existence of the lesion, but an exact diagnosis can only be attained by digital examination of the larynx through the pharynx.

=The prognosis= of these tumours is grave, because death from asphyxia may occur during an attack of coughing or as a consequence of the fits of suffocation.

=Treatment.= As it is usually extremely difficult, if not impossible, to discover the exact nature of the tumour, medical treatment, except for instance in the case of actinomycosis, is of very uncertain value.

Surgical treatment alone suggests itself. Before attempting an operation tracheotomy should be performed and a metal canula inserted. The animal having been cast, and the upper laryngeal region anæsthetised by means of cocaine, a vertical incision is made in the median line below the larynx, passing through the skin, the vertical junction between the neck muscles and the three first circles of the trachea, and access is thus obtained to the larynx and subglottal region. The operation should only be performed in exceptional cases, such as that of a valuable stud animal.

Provided that the new growth has a well-developed pedicle it can be removed through the mouth by the use of an écraseur or simply by tearing out.

BRONCHITIS.

Diseases of the bronchi in bovine animals reveal very different characters, according to the nature of the primary cause, for which reason cases occur of simple acute bronchitis, verminous bronchitis, simple chronic bronchitis, pseudo-membranous bronchitis, tuberculous bronchitis, etc.

SIMPLE ACUTE BRONCHITIS.

Simple acute bronchitis co-exists with, or is often only the logical and inevitable complication of, coryza and acute laryngitis. It is commonly associated with inflammation of the mucous membrane of the trachea.

It accompanies cold and wet seasons, and usually appears with the autumn frosts, in animals still at grass. In animals under shelter it occurs after undue exertion followed by chills, and after sudden rain storms. It also attacks working oxen, which are much exposed to the weather.

=The symptoms= follow very rapidly on the determining cause. They are ushered in by rigors, trembling attacks, diminution or loss of appetite, arrest of rumination, acceleration of breathing, and the appearance of a rough and spasmodic cough.

In ordinary cases these symptoms rapidly diminish, even without treatment. The appetite again becomes moderate, rumination returns, but the cough remains more or less rough and spasmodic, ending in the discharge, or more often in the swallowing, of abundant bronchial mucus.

This is the condition at the period of crisis. Percussion of the thorax reveals normal resonance. On auscultation of the sides during the period of onset, rough râles are heard, which at the period of crisis are replaced by mucous râles. The cough diminishes in frequency, and after a fortnight everything again becomes normal.

=The diagnosis= is very easy, the important point being not to confuse common bronchitis with tuberculous bronchitis, which very often assumes a chronic form.

=Prognosis.= The prognosis is not grave, even though the disease may assume a chronic condition.

=Treatment= does not differ from that of acute bronchitis in the horse. It consists in antiseptic and steam fumigations, tepid drinks, the administration of doses of 2 to 3 drachms Kerme’s mineral in adult animals, and of 1 to 1½ drachms of iodide of potassium, given in a mash or in honey electuary. During convalescence tar water should be administered.

CHRONIC BRONCHITIS.

Chronic inflammation of the mucous membrane of the large bronchi and trachea may follow acute bronchitis, but it is also a frequent termination of verminous bronchitis. It is found in fully developed animals, adult or old, and particularly in those inhabiting wet, cold valleys.

It is characterised by frequent paroxysms of coughing, which appear on the slightest provocation, such as the action of cold air on leaving the stable or of the air of a confined space on animals returning from the open; concussion of the chest by the pleximeter, squeezing of the loins, rapid movement, etc.

This coughing is accompanied by the discharge of mucus, which rarely arrives at the nostrils, but is swallowed in passing through the pharynx. Such mucus is always thick, greenish yellow in colour, and without smell.

The respiration, although regular whilst the animal is at rest, becomes accelerated on moving, and after attacks of coughing. It is sometimes rapid and whistling.

Percussion discloses neither partial nor complete dulness, but everywhere irregularly distributed mucous rattling and sibilant râles are revealed by auscultation.

There is no fever, the appetite is maintained, and, what is an even more important point, animals in good condition preserve their flesh. Interlobular pulmonary emphysema and emphysema resulting from dilatation are inseparable accompaniments of chronic bronchitis, for which reason the flank respiratory movement is frequently very marked.

=The diagnosis= is of only moderate difficulty, because although in certain conditions the disease may be mistaken for tuberculosis or emphysema, it can be distinguished by bacteriological examination of the discharge, by an injection of tuberculin, by careful auscultation, and by consideration of the general condition.

=Lesions.= The walls of the bronchi are thickened, the submucous connective tissue is sclerosed, the muscular fibres are modified in structure, and have become fibrous, while the epithelial layer is desquamated and suppurating. The peribronchial tissue also undergoes sclerosis, and in certain cases the smaller bronchi present marked dilatations resembling small caverns (bronchi-ecstasis).

=Treatment= can never be more than palliative; the aim should be to prevent the lesions becoming aggravated, and to check the pathological secretion from the bronchi, but the lesions already existent can never be removed. Tar water should be perseveringly administered. Essence of turpentine in doses of 2 to 2½ drachms per day in electuary (adults), creosote in doses of 1¼ to 1½ drachms, and terpine in doses of ¾ to 1 drachm give the best results, and produce a marked improvement.

PSEUDO-MEMBRANOUS BRONCHITIS.

The pseudo-membranous forms of bronchitis, formerly termed “croupal or diphtheritic bronchitis,” are rare. They develop suddenly or follow pseudo-membranous laryngitis. Like the latter, they are due to a specific infection, possibly aided by accidental causes.

Their =causation= is imperfectly understood, and they cannot be compared, still less homologated, with diphtheritic disorders in man. They are characterised by the formation of false membranes, which develop on the mucous surface, mould themselves over the internal surface of the large bronchi, and ramify throughout the bronchial channels like branches of trees. They are of greyish-yellow colour, and appear to be formed of fibrin, coagulated albumen, and epithelial débris cemented together with mucus.

=Symptoms.= At the outset these pseudo-membranous forms of bronchitis have the same characters as acute bronchitis, which at the crisis would be marked by the expulsion of fragments of false membrane by coughing. Most frequently it seems that the bronchitis follows its regular course, and in such case it is only during convalescence or a considerable time afterwards that the membranes begin to be discharged during paroxysms of coughing.

The patients are subject to intense dyspnœa, appear about to suffocate, and during the efforts then made the false membranes are discharged in the form of half-organised layers, or, on the other hand, in branched masses, resembling twigs.

The dyspnœa at once ceases. Despite the development of these false membranes in the bronchi, no alarming symptoms are produced, which is explained by the fact of the false membranes being adherent only to the inner surface of the principal conduits, without closing or even markedly obstructing them or the smaller passages leading to the pulmonary alveoli. When, however, they are displaced, violent reflex spasms are produced as soon as the fragments approach the larynx.

=Diagnosis.= The diagnosis rests entirely on examination of the expectorated material.

So far as the =prognosis= is concerned, it is less grave than might be supposed from the symptoms. The gravity arises from the fact that this disease has a certain tendency to become chronic.

=Treatment= scarcely differs from that of ordinary bronchitis. Tar, creosote in doses of 2½ to 5 drachms given in oil; terpine in doses of ½ to ¾ drachms per day can be recommended. Iodide of potassium also has certain advantages.

VERMINOUS BRONCHITIS IN SHEEP AND CATTLE (HUSK, HOOSE, ETC.).

Lambs, young sheep, and calves sometimes suffer severely from infestation with lung worms, which set up great irritation in the bronchial passages, leading to chronic bronchitis. The animals show frequent attacks of paroxysmal coughing, during which some of the parasites may be expelled. The irritation produced causes serious loss of condition, and if not alleviated may lead to death. The parasite of the sheep is known as Strongylus filaria (sheep lungworm), that of the calf Strongylus micrurus. The worms are from 2 to 4 inches long, whitish in colour, and of the diameter of a hat-pin.

=Treatment.= According to generally accepted views among veterinarians and zoologists, it is a comparatively simple matter to kill worms in the bronchial tubes, and a number of cases of the disease are reported in literature which are alleged to have been cured. These views, however, are open to very serious doubt.

Neumann (1892b, pp. 590, 591, 593, 594) summarises the subject of treatment as follows:—

Two different procedures in treatment are pursued. In one, substances are passed into the digestive canal, which, being diffused in the blood, are believed to be capable of attacking the worms in the bronchial tubes. With this view, the picrate of potash (0·20 to 0·40 gram per head) is given, dissolved in thin gruel or mucilage; creosote; oil of turpentine; a mixture of equal parts of oil of turpentine and tincture of camphor—a teaspoonful every day to each lamb in a mucilaginous fluid; a mixture of creosote 120 grams, spirits of wine 500 grams, and water 700 grams—an ordinary spoonful every day to each animal; or creosote 60 grams, benzine 300 grams, water 2 litres—an ordinary spoonful given every day for eight days to each sheep. Hall states he has successfully employed prussic acid in ten-drop doses, morning and evening.

But experience has shown that, while such treatment is troublesome to carry out, its efficacy cannot be relied upon.

Success is more certain with fumigations, as they penetrate directly to the worms, stupefy them, and induce fits of coughing that cause expulsion. They are practised in buildings from which all forage is previously removed, and which are well closed. Into these the diseased [animals] are introduced, and on a red-hot shovel are placed rags, horns, feathers, hair, old pieces of leather, empyreumatic oil, tar, juniper berries, asafetida, etc. The intensity, duration, and number of these fumigations are graduated as the sheep become accustomed to them. At first once a day may suffice, and then the intensity should be moderate and the duration about ten minutes; afterwards two, and finally three, may be given during the day, each lasting for twenty minutes. Kowalewsky says he has obtained very good results from similar fumigations. Fumigations with chlorine, sulphur, and sulphuret of mercury or cinnabar have been recommended, but they are dangerous.

(Stephen recommends as follows: Put about forty lambs at a time into an air-tight house, and place tar, sulphur, and turpentine in a pot of burning coals, suspended by a chain from the ceiling and brought as near to the heads of the animals as possible; the fumes are to be allowed to fill the house, and more ingredients are added as required, the lambs being kept in the place for twenty-five minutes each time, and the process to be repeated on three occasions.)

Tracheal injections in the verminous bronchitis of calves are of great utility; but for a flock of sheep they would be troublesome and difficult to administer. However, Nieman, has successfully employed them on 384 sheep belonging to several small owners. He used a solution of 2 parts iodine and 10 parts iodide of potassium in 100 parts of distilled water. This fluid was mixed, in equal parts, with oil of turpentine, and made into an emulsion with olive oil; each sheep received 5 to 8 grams of the mixture, and the number of the injections varied according to the gravity of the disease—from two to three at two days’ interval. The worms were killed and expelled during the paroxysms of coughing, and the bronchitis was modified.

The medical treatment should be assisted by very nourishing food, and by bitter, stimulating, and ferruginous tonics, which arouse the digestive functions and allow those animals which are least exhausted to reach the period of elimination of the parasites.

At the commencement of any kind of treatment it is well to have an examination of the flock, with the object of sending the worst cases to the butcher.

The same medicaments have been employed in treating this malady in calves as in that of sheep, and no better results have been obtained. Neumann and Janné have, however, been successful with asafetida (30 grams), Chabert’s empyreumatic oil (60 grams), and a mucilaginous decoction (500 grams)—a spoonful of this mixture being given in a half litre of milk, and the treatment continued for about a month.

The results are less uncertain if the worms lodged in the bronchial tubes are directly acted upon, either by means of injections of the same kind as those employed for sheep, or fluid medicaments introduced directly into the bronchi.

Read says he has cured calves worn down almost to skeletons by verminous bronchitis by the following procedure: The head of the calf is slightly elevated, and about 2 drachms of ether, chloroform, oil of turpentine, or rectified oil of amber—single or combined—are poured into each nostril and allowed to vaporize there; it will then, by the respiration, be carried into the air passages, and thus destroy the filariæ. In some cases it must be repeated two or three times, but once has frequently the desired effect.

The method of treatment by intra-tracheal injection, introduced by Levi, of Pisa, has yielded very satisfactory results. Levi has been completely successful with a sheep. Éloire has employed it in sixteen calves affected with the disease, and all were cured. He used the following mixture: Black poppy oil, 100 parts; oil of turpentine, 100 parts; carbolic acid, 2 parts; purified cade oil, 2 parts. Each calf received 10 grams of this mixture daily for three days.

The injection, which should be given slowly, is followed by a fit of coughing, and the expired air has the odour of turpentine. This treatment has also been successful at Milan. Similar favourable results have followed Hutton’s treatment of eight calves, some of which were in the last stage of verminous bronchitis. He employed a mixture of oil of turpentine, tincture of opium, pure carbolic acid, and water—the oil of turpentine forming one-half of the mixture. The dose was ½ an ounce, and in the serious cases this was given every day for three days, and in other cases every second or third day. Kriwonogow has likewise cured twenty-two calves by giving each of them two tracheal injections of 8 grams of the following mixture: Essence of cloves and oil of turpentine, 360 parts of each; carbolic acid and olive oil, 30 parts of each.

(Williams speaks highly of the administration of prussic acid. Penhale gives—by intra-tracheal injection, and slowly—oil of turpentine 2 drams, carbolic acid 20 minims, and chloroform ½ a dram.)