Diagnosis. Strictures only develop progressively and slowly, a fact which enables them to be differentiated from œsophagitis. It is more difficult to differentiate them from dilatations, because the stricture always ends by becoming complicated with dilatation; but this distinction is of little practical importance, the consequences being identical.
Prognosis. The prognosis is very grave, and there is no economic reason for attempting treatment except in special cases; the indications are in the direction of slaughter.
From the economic standpoint there is no treatment. Basing their actions on human practice, the Germans have recommended progressive dilatation of the lumen of the œsophagus by passing a series of catheters of gradually increasing size. What, however, is justifiable in human medicine, where the only object is to keep the patient alive at any cost, may be highly objectionable in veterinary practice; and in the present instance this is the case. Except in very rare instances, which the practitioner alone can appreciate, dilatation is contra-indicated, and the owner’s interest lies in slaughtering the animal before it has lost much condition.
DILATATION OF THE ŒSOPHAGUS.
Dilatations are more frequent than strictures. Their mode of origin is easily understood. When the muscular tissue has lost its tonicity and contractile power at a given point, or when, as a consequence of any form of inflammation, it has begun to undergo atrophy, the mucous membrane becomes herniated, because its circumference is not supported regularly during deglutition. The ectasia, which at first is of small size, becomes more marked in consequence of the tendency that exists for the food to accumulate in the dilated region. Dilatation is thus set up.
Fig. 66.—Schema of œsophageal stricture (the muscular layer above the stricture has undergone atrophy; the mucous membrane is dilated).
Localised attacks of œsophagitis, accidental injuries and fissuring of the œsophageal muscular tissue, produced by clumsy efforts to displace foreign bodies with the probang, are the principal causes of dilatation. When the probang is imprudently or clumsily manipulated, it may press excessively at any point where the œsophagus makes a slight bend, and thus split the contracted muscular coat without injuring the lax mucous membrane.
Œsophageal contractions, as we have seen, may form the point of origin of dilatations, but in this case the dilatations are more regular in form, and affect the entire circumference of the tube. The muscular tissue is still everywhere normal, and becomes dilated in consequence of equally-applied eccentric pressure.
Symptoms. When the dilatation develops slowly and progressively, as a consequence of muscular atrophy, the symptoms remain unnoticed for a long time, and the owner only begins to be anxious when the animal loses condition, or when the driver or cowman detects masses of half-chewed food mixed with the saliva in the manger.