Periódicos Brasileiros em Medicina Veterinária e Zootecnia

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Colite histiocítica ulcerativa em um cão boxer no Brasil

Pavarini, Saulo PetinattiGomes, Danilo CarlotoBandinelli, Marcele BettimOliveira, Eduardo Conceição deBandarra, Paulo MotaCruz, Claudio Este vão Farias daDriemeier, David

Background: Histiocytic ulcerative colitis (HUC), also known as granulomatous Boxer’s colitis or colitis similar to Whipple’s disease is a condition affecting especially Boxer dogs. The disease is characterized by chronic increase in the defecation frequency, tenesmus, fetid dark-brown stools with blood streaks and mucus. Histopathology of a colorectal biopsy confirms the clinical diagnosis, when infiltrates of markedly PAS-positive macrophages are observed in the colonic lamina propria and submucosa. This communication reports a case of histiocytic ulcerative colitis in a Boxer dog in Brazil. Case: A Boxer dog, with one year and three months of age had been presenting, since it was nine months old, increased frequency of defecation, tenesmus, intermittent diarrhea, loose stools with streaks of liquid blood, and coprophagy; however, no weight loss or appetite loss were noticed. After an initial period of three months experiencing the aforementioned signs, the dog started with persistent diarrhea with bright red blood, mild prostration, weight loss, and voracious appetite. Because of continuous deteriorating condition and treatment refractoriness, the dog was euthanized. At necropsy, the colon was decreased in size with thickened mucosa and foci of ulceration, apart of enlarged mesenteric lymph nodes. Tissue fragments were collected and fixed in 10% formalin, processed following standard procedures for histopathology, and stained with Hematoxylin-Eosin (HE). Selected sections from samples of intestines and mesenteric lymph nodes were also stained with Periodic Acid Shiff (PAS) and Brown-Hopps adapted Gram Staining. Microscopic findings in the colon included infiltration with rounded to oval bulky macrophages, with eccentric nuclei and abundant eosinophilic and slightly granular cytoplasm. These macrophages were distributed in the basal lamina propria and submucosa, and there also was diffuse infiltration of lymphocytes and plasma cells. Extensive multifocal mucosal ulcerations with exposure of the submucosa were also observed. The cytoplasm of macrophages was strongly marked when stained by Periodic Acid Schiff. Macrófagos do cólon e do linfonodo mesentérico não coraram pela técnica de Gram. Discussion: This diagnosis of histiocytic ulcerative colitis was based on the clinical and pathological findings, especially the association of the clinical signs with the infiltrates of markedly PAS-positive macrophages within the colonic lamina propria and submucosa, which is considered a typical characteristic of the condition. The disease afflicts mainly young Boxer dogs, as it was recorded here. In most cases, there is neither weight loss, nor appetite loss, and the hair coat maintains a healthy appearance. However, in chronic cases such this described here, the dogs may show wasting. Ultrastructural and immunohistochemical findings in macrophages of HUC have indicated the participation of Escherichia coli in the etiopathogeny of the disease. The Boxer dog’s predisposition to HUC has been attributed to a hereditary abnormality that confers invasion and persistence of an adherent E. coli group. This paper reports the importance of the histiocytic ulcerative colitis as an enteric condition affecting Boxer dogs also in Brazil.(AU)

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