L.M. Oliveira-Barros; L.F.M. Barros; L.R.M. Sá; J.M. Matera
Intussusception is defined as a prolapse or invaginations of one portion of the gastrointestinal tract into the lumen of an adjoining segment and is a common of bowel obstruction in dogs (Levitt & Bauer 1992). It's known that a variety of condition is considered to be predisposing to intussusception, including parasitism, foreign bodies, previous surgical procedures, enteritis and masses, but in dogs most of the can be idiopathic. Regarding the enteritis, few reports describe the role of Inflammatory Bowel Disease (IBD) in the intussusception. The aim of this study was to analyze the occurrence of IBD in animals with intussusception as well as to evaluate their digestive function during the late post-operative period.
Material and Methods
The present study was approved by the bioethical committee of the School of Veterinary Medicine and Animal Science of the University of São Paulo. Dogs presented to the Service of Small Animal Surgery of the Veterinary Teaching Hospital between July 2006 to January 2008 with diagnosis of intussusception were included in this study. Age, breed, gender and intestinal affected portion weren't take into consideration to select the animals but necessity of enterectomy was considered criteria for inclusion. Intestinal samples of 1cm in length each were selected from the cranial and caudal edge of the resect segment, after maintaining approximately 1cm of microscopically viable bowel tissue. Samples were fixed en 10% formalin and selected blocks were processed to paraffin wax, cut at 5μm thickness and stained with hematoxylin and eosin (HE). Histopathological scoring schemes and standardized criteria were used according the World Small Animal association (WSAVA) Gastrointestinal Standardization Group (Day et al. 2008). Late assessment of the digestive function was made 180 after the surgical procedure by telephone contact. The owners were enquired about fecal consistency, frequency of defecation and acute intermittent diarrheal episodes. Qualitative data were presented in the form of absolute frequencies and percentage. Arithmetic means and standard deviation (SD) were used to describe quantitative data.
Thirteen dogs, 9 males (69.23%) and 4 females (30.77%), with diagnosis of intussusception were submitted to enterectomy and enteroanastomosis. Mean age was 26± 31.11 months (mean± SD) with values ranging between 4 and 84 months and median was 8 months. Breeds represented included Great Dane (n = 1), Basset hound (n = 1), Boxer (n = 1), Rottweiler (n = 1), Lhasa Apso (n = 1), Border Collie (n = 1), Poodle (n = 1), Yorkshire (n = 2), Labrador Retriever (n = 1). There were 4 mixed breed dogs.
A breed predilection was not confirmed although purebred dogs seem to be overrepresented (n = 9). From the total of animals, five dogs presented diarrhea for a period longer than 1 month and one dog presented intermittent diarrheal episodes. The others seven animals presented only acute gastroenteritis. The macroscopical analyzes revealed some grade of enterocolitis in all samples. One animal presented neutrophilic enterocolitis, one animal presented eosinophilic enterocolitis, two animals presented lymphocytic-plasmacytic enterocolitis and two animals presented lymphocytic-plasmacytic enterocolitis associated with other morphological diagnosis. Three animals died at the early post-operative period (until 12 hours after the surgical procedure) due to sepsis, which was enforced by the histological analyzes from the resected intestinal segment that revealed moderate to severe neutrophilic enteritis in two cases. Third animal present moderate eosinophilic enteritis associated to intense parasitism and important peritonitis during the surgical procedure. From a total of 10 animals assessed 180 days after surgery, four dogs remained with gastrointestinal changes such as increased frequency of defecation, altered fecal consistency and intermittent diarrheal episodes. Histopathological evaluation showed lymphocytic-plasmacytic enteritis in three dogs. The other animal presented a bland neutrophilic enterocolitis although this dog received previous corticosteroid therapy, which could cause misinterpretation by the pathologist evaluation. Moreover, three animals presented clinical signs considered to be chronic. Lymphocytic-plasmacytic enterocolitis could be identified even in dogs without symptoms during the late post-operative period (66.67%). Two of them were associated with neutrophilic infiltrates and one with eosinophils.
The collective term inflammatory bowel disease (IBD) is used in canine and feline gastroenterology to describe patients affected by idiopathic persistence or recurrent gastrointestinal (GI) signs that have histological evidence of inflammatory infiltration in one or more focus of the GI mucosa (Gunawardana et al. 1997, Hall & German 2008, Jergens 2004). Nowadays it is believed that IBD is one of the main causes of vomiting and diarrhea in small animals (Hall & German 2008, Tams 2003).In dogs, sexual or breed predilection were not being confirmed although purebred dogs seem to be overrepresented in the veterinary literature (Fogle & Bisset 2007, Gunawardana et al. 1997). No age predilection was also noted although Craven et al., 2004 reported an age interval of 6 months to 14 years (mean = 4.3 years).The most common types of IBD are lymphocytic-plasmacytic enterocolitis followed by eosinophilic enteritis. Rarely, straight lymphocytic enteritis is identified. Granulomatous enteritis were also described but in lower incidence (Craven et al. 2004, Tams 2003) Diarrheal episodes are frequently observed in IBD and can be associated or with other acute or chronic clinical signs, that can partly respond to unspecific treatment or dietary changes. Besides that, symptoms can remain quiescent until the presence of stressful stimuli like dietary or environmental changes. The differentiation of small bowel from large bowel diarrhea is also important to conduct case. In this study, it was possible to correlate chronicle clinical signs with presence of inflammatory enteritis/colitis when we observed that 5 of 8 animals with diagnosis of lymphocytic-plasmacytic enterocolitis presented gastrointestinal disorders for longer than 1 month. Intussusception is reported by some author as a complication in IBD cases (Kshirsagar et al. 2007, Maldonado et al. 2004). Reymond (1972) proposed that intussusception begins as either as inhomogeneity in a bowel segment or a mechanical linkage of nonadjacent bowel segments. The local inhomogeneity may represent a bowel segment that is either flaccid or indurated (e.g., Infiltrative bowel disease, a segment of spastic bowel or a surgical or cicatricial lesion). Turkyilmaz et al. (2004) suggested that intussusception can be a consequence of altered intestinal motility as a result of increased nitric oxide along various inflammatory mediators. Kshirsagar et al. (2007) reported a case of ileo-ileal intussusception in a 40-year-old man. Histopathology showed heavily infiltrated muscular layers by eosinophils and thickened intestinal wall with areas of necrosis suggestive of enteritis. In a retrospective study, Maldonado et al. (2004) described 10 cases of human adult intussusception resulting from IBD, between 1978 and 2002. Both small intestine and colon were found as affected sites. In our study, the incidence of chronic lymphocytic-plasmacytic or eosinophilic enteritis was considered high (69.23%-9/13) which is not frequently described in the veterinary literature. Part of the difficult with the diagnosis and monitoring of IBD is that the disorder is characterized by cyclic periods of active and inactive disease which can difficult the diagnosis since that clinical sings can spontaneously disappear (Jergens, 2004, McCann et al. 2007). Untreated cases, frequently present clinical evolution characterized by exacerbation and remission of the symptoms. Therefore, veterinarians should carefully consider a mistake in diagnosing the cure of IBD. Endoscopic and histological evaluations of the intestinal mucosa can be important tools to establish confident criteria for monitoring the disease (Cravens et al. 2004). The major problem of histopathological diagnosis is the pure agreement between histopathologists (Hall & German, 2008). This interpretive variation may pose problems for the routine diagnosis of IBD or for monitoring the progress of patients. In an effort to develop endoscopic and microscopical standards, the World Small Animal association (WSAVA) Gastrointestinal Standardization Group created a guideline that intends to unify the diagnosis of small animal gastrointestinal diseases. In our study, from a total of 9 animals with lymphocytic-plasmacytic or eosinophilic enteritis, 4 dogs didn't present clinical disorders at the late post-operative period, showed lymphocytic-plasmacytic enterocolitis. However, it's not possible to discard IBD since that these animals can present intestinal inflammatory episodes in the future.
The high incidence of histopathological diagnosis of lymphocytic-plasmacytic or eosinophilic enteritis in affect animals, possibly suggests a relationship between IBD and intussusception. Moreover, our data warns to a careful clinical evaluation of animals with intussusception, concerning the possibility of IBD.
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