Parasitic irritation is not so common here as in other parts of the intestinal canal where the contents are longer delayed and are passed with less friction, yet certain parasites are found in this region and may even produce considerable irritation. The gongylonema of the thoracic œsophagean mucosa of ruminants and swine are apparently harmless. The psorospermia of the œsophagean muscles of the same animals are alleged to cause œdema of the glottis, asphyxia and epilepsy. The spiroptera microstoma of the horse has in one instance known to us caused extensive denudation of the muscular coat within a foot of the cardiac end of the gullet. Finally we have found bots hooked on to the œsophagean mucosa close to the cardia, causing much irritation and spasm. The spiroptera sanguinolenta is often present in chambers hollowed in the œsophagean mucosa of the dog.
Traumatic causes appear in the form of contusions and bruises from without, but much more frequently from foreign bodies, and probangs operating from within. The use of a whip or of a rope without a cup-shaped end for the relief of a choked animal. Short of the occurrence of laceration this often produces contusion and abrasion which results in local inflammation. Even the too forcible dislodgment of a solid body by a probang of approved pattern, may bruise and scratch the gullet when the seat of violent spasm. Pins, needles, wire, thorns and other sharp bodies are liable to do serious damage during their passage in an ordinary bolus and when they transfix the mucosa violent infective inflammation may ensue.
Extension inflammations from the throat, and from phlegmous, abscesses, tumors, etc., in the jugular furrow need only be mentioned in this connection, as the primary disease will be clearly in evidence.
Lesions. These are usually circumscribed when due to a traumatic injury and extended when caused by caustics or irritants. The affected section is swollen, and surrounded by some serous effusion. When the muscular coat is involved it is often paler than normal, and microscopically shows extensive granular and fatty degeneration. The mucosa usually sloughs off its epithelial layer, sometimes over an extensive area (thoracic portion, Renault; whole gullet, Bertheol), and the exposed raw surface is of a deep red or violet. When the epithelium is not shed, it is infiltrated, swollen and friable breaking down under the slightest manipulation. Petechiæ and slight blood extravasations are abundant, and diffuse suppuration is not uncommon. In traumatic injuries necrosed areas are found in the muscular and mucous coats. Strictures, dilatations, and polypoid growths are liable to follow as sequelæ.
Symptoms. These usually manifest themselves from two to four days after the operation of the cause. There is much difficulty in deglutition, the effort to swallow either solids or liquids causing acute suffering, with extension of the head on the neck and strained contraction of the facial muscles. If the liquid succeeds in passing the pharynx, it is arrested at the seat of inflammation and regurgitated through the nose and mouth, or in solipeds through the nose only. This takes the appearance of emesis even if nothing actually comes from the stomach. The animal shakes the head violently, breathes hurriedly, and has fits of paroxysmal coughing. A wave extending from below upward along the jugular furrow and followed by nasal discharge is a marked symptom, as the violence of the inflammation increases. Uneasy movements of the limbs, pawing and lying down and rising, indicate the existence of colic, and this is aggravated by the administration of anodynes or antispasmodics by the mouth. In cattle, rumination is arrested, froth accumulates around the lips, the rumen becomes tympanitic, and colicy movements appear. Oftentimes a swelling extends upward in the jugular furrow, and even in its absence, pressure with the fingers along the furrow will often detect an area of tenderness with or without local swelling. Fever with more or less elevation of temperature, is a general symptom. There may be wheezing breathing or loud stertor. The passage of a probang is arrested by the swelling or spasm at the diseased part and when withdrawn may be covered with pus or fœtid debris. In the horse a small probang may be passed through the nose.
Treatment. In a slight congestion at the seat of a recent obstruction and which tends to renewed obstruction, little more is necessary than to restrict the feed for a few days to soft mashes so that irritation of the sensitive surface, spasm and the arrest of the morsel may be obviated. Plenty of pure water or of well boiled linseed or other gruel should be allowed.
In cases in which the obstruction is still present in the gullet, its removal by probang or looped wire is the first consideration, to be followed by the measures mentioned above.
In case of the swallowing of a caustic agent, no time should be lost in giving an antidote. For the mineral or caustic organic acids, lime water, magnesia, or other bland basic agent is demanded. For caustic alkalies or basic agents, bland acids, such as vinegar, citric acid, or even a mineral acid very largely diluted will be in order. In both these cases and in that of caustic salts, albuminous and mucilaginous agents, eggs, linseed tea, slippery elm, gums, and well boiled gruels are indicated. To these may be added small doses of laudanum when the irritation is great. Iced drinking water, iced milk, or iced gruels are often soothing to the suffering animal, and cold compresses, snow or ice applied along the jugular furrow is often valuable. To counteract the septic developments on the affected mucous membrane, chlorate of potash, boric acid, salol, naphthalin, naphthol, pyoktannin, or even weak solutions of phenic acid or creolin may be used. In the slighter forms of inflammation or when the acute form threatens to persist, an active counter-irritant of mustard or cantharides may be applied along the jugular furrow.
In case of abscess, as manifested by fluctuation following a hard, indurated, painful swelling, a free incision should be followed by frequent injections of antiseptic lotions or by the packing of the cavity with such bland antiseptics as salol, boric acid, or iodoform on cotton.
As inflammation subsides, potassium iodide may be given, both as an antiseptic and a resolvent, to counteract the tendency to fibroid contraction and stricture of the gullet.