Diagnóstico post mortem da síndrome dilatação vólvulo gástrica em cães / Post-mortem Diagnosis of Gastric Dilatation Volvulus Syndrome in Dogs

ABSTRACT

Background: Gastric dilatation volvulus syndrome (GDV) is an acute and severe disease affecting specially dogs of big breeds. It is a severe illness, which may have a high risk of death if not treated quickly. GDV consists in stomach acute dilatation and rotation, resulting in decrease of gastric and splenic infusion, in addition to the obstruction of abdominal venous return. The aim of this research was to analyze clinical pathological findings of dogs with GDV diagnosis in which necropsy was performed. Materials, Methods & Results: The necropsy records were reviewed from January 2001 to December 2011 to identify these cases. In the period, 4877 autopsies were performed by the Setor de Patologia Veterinária from Universidade Federal do Rio Grande do Sul (UFRGS), being 55 cases (1.15%) of GDV. Four main breeds were identified Fila Brasileiro (43.6%), Great Dane (12.7%), German Shepherd (10.9%) and Boxer (5.4%). Clinical signs such as bloating, lethargy and dyspnoea were reported. At necropsy, the findings that consisted with gastric alterations were stomach distention due to accumulation of gas, dark red mucosa, and rotations of 90° to 360° especially clockwise. Splenomegaly was observed in 96.36% of dogs and V-shaped spleen in 60%. There was compressive atelectasis in 38.18% of autopsies. The main histological findings in the stomach were characterized by congestion, hemorrhage and necrosis of the mucosa. In the spleen, congestion and necrosis of lymphoid follicles were found. Discussion: When GDV's casuistic is analyzed, our results were similar to other studies, with 0.7% and 2.5%. What is concerned about the breed and age of the animals affected is the high number of GDV in breeds such as Great Dane and German Shepherd. However, we also found high numbers of Fila Brasileiro, a Brazilian breed, that hasn't been mentioned in other studies about this illness before. Similar clinical signs were described by other authors, between them, vomit, a previous sign of acute GDV, which is expected as while there is a gastric rotation, gastric-oesophageal obstruction happens. However, vomit is described as GVD predisposing factor associated to aerophagia, and should be considered a previous sign to the dislocation. The observation of gastric clockwise rotation in most cases is described as the most frequent. Gastric pathologic findings are characteristics of a circulatory compromising due to the rotation, leading to ischemic areas and necrosis. Splenomegaly and the identification of the V-shaped spleen were commonly observed, because when GDV happens, the spleen follows the gastric displacement by the presence of the gastrosplenic ligament. These findings cause splenic congestion by obstruction of venous return, which may lead it to twist too. It is concluded that the GDV was responsible for a low number of necropsies, reaching large and giant breeds. The identification of a large number of Fila breed dogs suggests that this breed is predisposed to the GDV. The gastric lesions indicated circulatory injury by vascular obstruction due to the rotation. Lung compressive atelectasis occurs secondary to gastric distention, also, compression of the caudal vena cava and of the portal vein can occur, decreased venous return, less displacement of blood from the right ventricle to be oxygenated by the lungs leading to breathing recrudescence.