Megaesôfago em suínos / Megaesophagus in Swines

ABSTRACT

Background: Megaesophagus is a disease characterized by widespread dilation of the esophagus, with partial or total loss of the organ peristalsis, produced by a neuromuscular disorder and it can be present as manifestation of several diseases. The most common sign on animals is the regurgitation, which usually happens right after the ingestion of solids. The diagnosis is based on the clinical signs and radiographic exam, where it is possible to observe a contrasted and extensive esophagus. The clinical treatment consists of small semi-solid or liquid meals served in small amounts, with the animal in elevated position. This work reports a swine megaesophagus, occurred in one of the animals housed in the Sector of Clinic and Reproduction of Swine of the Universidade Federal de Santa Maria (UFSM), RS, Brazil.. Case A male swine, six months of age was housed in the center of artificial insemination, showing some adaptation difficulties to the new facilities, climate, as well as feeding. A reduced feed intake was observed, however, without alterations behavioral or sanitary. The animal was trained progressively for semen collection, presenting eventually regurgitation, which became more frequent with the insistence in feeding. Usually the reflux happened five to ten minutes after the ingestion of ration and/or water, with variable volume, texture and aspect similar to the saliva and pH varying from eight to nine. The animal kept normal appetite, however with slow and progressive loss weigh. It was submitted to endoscopy and contrast radiographic study, leading to megaesophagus confirmation. After the diagnostic, it was suggested the hypothesis that the pathology was developed due to a serious stressful situations of adaptation imposed to the animal, which might contributed triggering the process. Discussion: Megaesophagus is characterized basically by dilation and increase of the organ, peristaltism absence, presence of tertiary contractions and the absence of total or partial inferior sphincter relaxation. These changes could lead to dysphagia that, consequently could compromise the nutritional state. Besides regurgitation, loss weight and anormal development, it is possible to observe cough, mucoid and purulent nasal discharge, as well as dyspnea with pneumonia due to the concomitant aspiration. Among the clinical signs presented by the animal, it is possible to report the regurgitation time in variable frequencies and the loss weight. The diagnosis performed in this animal was based on observation of clinical signs and radiographic exam, where it was possible to visualize a dilated esophagus. The treatments in cases like this usually are in order to provide support conditions or through surgical procedures. The first is characterized by changes on animal management practices, besides the utilization of drugs such as antibiotics, prokinetic and antacids. By the other hand the surgical methods are supported by several techniques, such as the esophagus-diaphragmatic cardioplasty, Heller myotomy, associated to fundoplication. Some animals with congenital idiopathic megaesophagus are able to recover themselves while the ones which are acquired are irreversible. Regarding to the secondary megaesophagus, once the cause is removed the animal has chance of recovering. Therefore, the prognostic for secondary and congenital megaesophagus range from reserved to favorable, while for the acquired cases it is not favorable (as this case report).