ACUTE ABDOMINAL COMPARTMENT SYNDROME DURING COLONOSCOPY IN A WESTERN LOWLAND GORILLA (GORILLA GORILLA GORILLA).

A novel case report of acute abdominal compartment syndrome (ACS) with respiratory and hemodynamic collapse during colonoscopy in a western lowland gorilla (Gorilla gorilla gorilla), notably, without colonic perforation is presented here. ACS is a rapidly progressive and sustained increase in intra-abdominal pressure leading to shock with multisystem organ failure. Surgical intervention was mandatory, and abdominal decompression was immediately life-saving, although the patient died 1 wk later of surgical complications. Colonoscopy is a widely performed procedure that is generally considered safe, and serious complications during colonoscopy are rare. ACS has been previously reported during colonoscopy with perforation in four cases (human)1,4,6,8. In this instance there was no evidence of perforation, representing not only a rare complication of the procedure, but also a novel cause of ACS. This is the first report of ACS in a nonhuman primate and of nonperforation-associated ACS in human or nonhuman primates.

Transanal access port (TrAAP) technique: the use of a single incision laparoscopic surgical port during canine colonoscopy (a cadaveric study).

BACKGROUND: Transanal colonoscopy using the single-incision laparoscopic surgical port is routinely used in human patients but has not been described in veterinary literature. The purpose of this study was to describe a novel access technique elucidating its endoscopic clinical potential and benefits. Additionally, its challenges, limitations, and clinical usability will be discussed and critiqued. The aim of this study was to describe the feasibility of the single-incision laparoscopic surgical port (SILS) as a transanal access technique in canine cadavers and compare its technical capabilities and economic value when compared to the traditional approaches of digital pressure and purse string. RESULTS: The overall time to reach an intraluminal pressure of 10 mmHg was faster for digital pressure versus purse string (p = 0.05) and faster for single-incision laparoscopic surgical port versus purse string (p < 0.02). Maximum luminal pressure was significantly higher between single-incision laparoscopic surgical port and purse string (p = 0.001). Mean pressure for both the complete 60 s trial and during the last 45 s of insufflation were highest with the SILS port and were significantly different between the single-incision laparoscopic surgical port versus purse string (p = 0.0001, p < 0.0001) and digital pressure versus purse string (p < 0.005, p < 0.01) respectively. Complete luminal distention and visualization was observed in all trials. CONCLUSIONS: The SILS port in a cadaveric canine model allowed good visualization of the rectal and colonic mucosa, provided constant insufflation of the colon and was feasible and subjectively easy to perform. Technical differences between techniques were observed with the use of the SILS port allowing for potentially lower personnel requirements, less procedural associated cost, less variability versus the digital pressure technique between assistants, and the ability of additional instruments to be used for procedures.

Successful implementation of intestinal endoscopy in non-human primates prompts the possibility of achieving AIDS longitudinal intestinal research.

HIV infection induces pathological changes in the intestinal mucosa. Here, a successful endoscopy was performed on the colon of a Chinese rhesus macaque by using Olympus CV170 gastroscope. The stability on postoperative recovery and the integrity of biopsy tissue implied a possibility of achieving AIDS longitudinal intestinal research on macaques.

Short colon syndrome in cats.

BACKGROUND: Shortening of the colon has been described in cats, but its imaging and clinicopathological features remain poorly understood. OBJECTIVES: Description of the signalment, clinical presentation, imaging, endoscopic and histological features of short colon syndrome in cats. ANIMALS: Ninety-three cats diagnosed with short colon. METHODS: Multi-institutional, descriptive, retrospective case series study. Medical records were searched for a diagnosis of short colon on abdominal ultrasonography, computed tomography, endoscopy, autopsy, or a combination of these modalities. RESULTS: The median age of included cats was 12 years at the time of diagnosis. Diarrhea was the most common clinical sign (60/92; 65%), followed by vomiting (36/92; 39%), weight loss (36/92; 39%), and inappetence (24/92; 26%). Thirteen percent of cats (12/92) had no signs of gastrointestinal disease at the time of diagnosis. In addition to a shortened colonic length, 79% (66/84) of cats had concomitant colonic thickening on ultrasonographic examination. On colonoscopy, mucosal ulcerations of the colonic wall were seen in 39% (9/23) of cats. Histopathologically, all cats but 1 (diagnosed simultaneously with colonic small cell lymphoma) had lymphoplasmacytic colitis, and when small intestinal biopsies were performed, concurrent lymphoplasmacytic enteritis or small cell lymphoma of the small intestine. CONCLUSIONS AND CLINICAL IMPORTANCE: Lymphoplasmacytic colitis is seen commonly in cats with short colon, suggesting a potential link between these entities.

Endoscopic polypectomy using endocautery in three dogs and one cat.

Endoscopic polypectomy has long been employed in humans with either gastric or colonic polyps. Despite the frequency of use in humans, reports in veterinary medicine remain scarce. The medical records of three dogs and one cat were reviewed. Two animals that were presented with hematochezia underwent colonoscopic polypectomy and were clinically normal 22 months and 6 months postpolypectomy. One animal that was presented with chronic vomiting underwent gastric polypectomy and was clinically normal 21 months postpolypectomy. One animal with an incidentally discovered gastric polyp underwent polypectomy without complication. Endoscopic polypectomy may be a viable alternative to surgery in veterinary patients with gastric or colonic polyps.

Safety and efficacy of oral low-volume sodium phosphate bowel preparation for colonoscopy in dogs.

BACKGROUND: Sodium phosphate (NaP) is a low-volume, hyperosmolar laxative that is an effective bowel-cleansing agent in humans. HYPOTHESIS: NaP will be as safe and efficacious as polyethylene glycol (PEG) bowel preparation for colonoscopy in dogs. ANIMALS: Eight purpose-bred healthy dogs. METHODS: In phase I, standard (NaP and enemas; NaP(1)) and control preparations (PEG and enemas) were compared in a crossover design to determine the safety and efficacy of NaP. Serial clinical and serum analytical evaluations were used to determine the safety of NaP. In phase II, the efficacy of the standard NaP preparation was compared with 3 other NaP variations, which excluded enema or included bisacodyl, with or without enemas in a crossover design. An observer blinded to the bowel preparation assigned a score of 1-4 (1=clean colon; 4=unacceptable colon cleansing preventing adequate endoscopic evaluation) to each of 5 regions of the colon. RESULTS: The mean total colon cleansing score (TCS), defined as the sum of scores from each region, of the control (9.4) was less than NaP(1) (13.6) (P < 0.05). There were no significant differences in regional or TCS for the remaining 4 NaP protocols. NaP(1) resulted in moderate, but clinically occult, hyperphosphatemia and hypocalcemia, which resolved within 24 hours. CONCLUSIONS AND CLINICAL IMPORTANCE: Despite the safety and ease of administration of the NaP preparations, the NaP bowel-cleansing preparations used in this study cannot be recommended for use because of the inadequate quality of bowel preparation compared with the protocol using PEG-containing fluids.

Ultrasonographic, endoscopic and histological appearance of the caecum in clinically healthy cats.

Objectives The aim of the study was to describe the ultrasonographic and endoscopic appearance and characteristics of the caecum in asymptomatic cats, and to correlate these findings with histology. Methods Ex vivo ultrasonographic and histologic evaluations of a fresh caecum were initially performed. Then, 20 asymptomatic cats, privately owned or originating from a reproductive colony, were recruited. All cats had an ultrasonographic examination of the ileocaecocolic junction, where the thickness of the caecal wall, ileocolic lymph nodes and the echogenicity of the local fat were assessed. They all underwent a colonoscopy with a macroscopic assessment of the mucosa and biopsies for histology. Results An ultrasonographic hypoechoic nodular inner layer, which corresponded to the coalescence of multiple lymphoid follicles originating from the submucosa and protruding in the mucosa on histology, was visible in all parts of the caecum. The combined mucosa and submucosa was measured ultrasonographically and defined as the follicular layer. Although all cats were asymptomatic, 3/19 cats showed mild caecal inflammation on histology. The most discriminatory ultrasonographic parameter in assessing this subclinical inflammation was the thickness of the follicular layer at the entrance of the caecum, with a cut-off value of 2.0 mm. All cats (20/20) showed some degree of macroscopic 'dimpling' of the caecal mucosa on endoscopy. Conclusions and relevance Lymphoid follicles in the caecal mucosa and submucosa constitute a unique follicular layer on ultrasound. In asymptomatic cats, a subtle, non-clinically relevant inflammation may exist and this is correlated with an increased thickness of the follicular layer on ultrasound. On endoscopy, a 'dimpled aspect' to the caecal mucosa is a normal finding in the asymptomatic cat.

Ultrasonographic, endoscopic and histological appearances of the caecum in cats presenting with chronic clinical signs of caecocolic disease.

Objectives This study aimed to describe the ultrasonographic, endoscopic and histological characteristics of the caecum and ileocaecocolic junction in cats suffering from chronic clinical signs compatible with caecocolic disease. Methods Cats presenting with clinical signs suggestive of a caecocolic disease were prospectively recruited. All cats underwent an ultrasonographic examination of the caecum, ileum, colon, ileocolic lymph nodes and local mesenteric fat, in addition to comprehensive abdominal ultrasonography. This was followed by a colonoscopy with a macroscopic assessment of the caecocolic mucosa; caecocolic tissue samples were systematically collected for histologic analysis. Results Eighteen cats were included. Eleven of 18 cats had ultrasonographic abnormalities adjacent to the ileocaecocolic junction (lymphadenopathy, local steatitis) and 13/18 cats had abnormalities directly related to the junction (wall thickening, loss of wall layering). Seventeen of 18 cats had at least one ultrasonographic abnormality. Endoscopically, hyperaemia, oedema, discoloration and/or erosions were found in all cats. Each cat was classified as having mild or moderate-to-severe lesions according to endoscopic results; no classification could be established statistically for ultrasonographic results. The accentuation of the dimpled pattern tended to be inversely related to the severity of endoscopic lesion scoring. Histologically, a large proportion of cats showed typhlitis (13/16), one had lymphoma and two were normal. All cats with typhlitis also had colitis. There was only slight agreement between endoscopic and histological caecal results regarding the severity of lesions. Loss of caecal wall layering on ultrasound was found in 7/18 cats and, surprisingly, did not appear as a reliable predictor of the severity of inflammation or of malignancy; neither did local steatitis nor lymph node size. Conclusions and relevance Ultrasonography and endoscopy should not be used as the sole methods to investigate the ileocaecocolic region in cats with clinical signs suggestive of caecocolic disease. The presence of chronic clinical signs should routinely prompt histological biopsy.

Colonoscopic and histologic features of rectal masses in dogs: 82 cases (1995-2012).

OBJECTIVE To evaluate colonoscopic and histologic features of rectal masses in dogs. DESIGN Retrospective case series. ANIMALS 82 client-owned dogs with rectal masses that underwent colonoscopy. PROCEDURES Medical records of dogs with rectal masses that underwent colonoscopy were reviewed. History, signalment, clinical signs, results of physical examination, diagnostic imaging findings, and results of colonoscopy (including complications) were recorded. When available, tissue samples obtained during colonoscopy and by means of surgical biopsy were reviewed by a single board-certified pathologist. Histologic features and tumor grade (when applicable) of tissue samples obtained during colonoscopy versus surgical biopsy were compared. RESULTS Multiple rectal masses were observed during colonoscopy in 6 of the 82 dogs, but no lesions were visualized orad to the colorectal junction. Results of histologic evaluation of surgical biopsy specimens were consistent with a diagnosis of epithelial neoplasia in 58 of 64 dogs, of which 71% were classified as benign adenoma or polyp and 29% were classified as adenocarcinoma in situ or adenocarcinoma. Complications of colonoscopy occurred in 3 of 82 dogs but were considered minor. A discrepancy in diagnosis occurred in 5 of 16 dogs for which both colonoscopic and surgical biopsy samples were available for histologic review. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that multiple rectal masses are uncommon in dogs, and secondary lesions orad to the colorectal junction were not found in this study. Colonoscopy was associated with few complications, but the need for colonoscopic assessment of the entire colon in this patient population may merit reevaluation.

Evaluation of colonoscopic allergen provocation as a diagnostic tool in dogs with proven food hypersensitivity reactions.

OBJECTIVE: To evaluate the colonoscopic allergen provocation (COLAP) test as a new tool for the diagnosis of IgE-mediated food allergy. METHODS: Oral food challenges as well as COLAP testing were performed in a colony of nine research dogs with proven immediate-type food allergic reactions. In addition, COLAP was performed in five healthy dogs. RESULTS: When compared with the oral challenge test, COLAP accurately determined 18 of 23 (73 per cent) positive oral challenge reactions (73 per cent) in dogs with food allergies and was negative in the healthy dogs. CLINICAL SIGNIFICANCE: The accuracy of this new test may be higher than that for gastric sensitivity testing. Therefore, COLAP holds promise as a new test to confirm the diagnosis of suspect IgE-mediated food allergy in dogs.

Use of endoscopic-assisted argon plasma coagulation for the treatment of colonic vascular ectasia (angiodysplasia) in an adult dog.

CASE DESCRIPTION: A 10-year-old neutered male mixed-breed dog was evaluated for a 5-year history of intermittent hematochezia and chronic anemia that were unresponsive to medical treatment. CLINICAL FINDINGS: Colonoscopy revealed multifocal areas of coalescing tortuous mucosal blood vessels throughout the colon and rectum. Colonic vascular ectasia (angiodysplasia) was diagnosed on the basis of the endoscopic appearance of the lesions. TREATMENT AND OUTCOME: The dog failed to respond to traditional medical treatments for colonic vascular ectasia and required multiple plasma and blood transfusions. The dog received 4 endoscopic-assisted argon plasma coagulation treatments, which resulted in long-term resolution of gastrointestinal hemorrhage. Colonic perforation occurred during the third argon plasma coagulation treatment. The perforation was surgically repaired. The dog remained free from clinical signs of colonic vascular ectasia for > 1 year after the third argon plasma coagulation treatment and was euthanized because of clinical deterioration associated with progressive heart disease. CLINICAL RELEVANCE: Endoscopic-assisted argon plasma coagulation treatment is a novel treatment for dogs with colonic vascular ectasia and provided long-term resolution of clinical signs for the dog of this report. In human patients, complications associated with endoscopic-assisted argon plasma coagulation treatment include colonic perforation, which also occurred in the dog of this report.

A grading system for lymphocytic plasmacytic colitis in dogs.

Colonic mucosal samples were obtained every 4 weeks for 13 months from 6 clinically normal dogs and from 47 dogs with a clinical diagnosis of chronic inflammatory bowel disease. All samples were graded on a scale of 0-5, based upon the quantity of lymphocytes and plasma cells in the lamina propria, epithelial changes, and the presence of ulcers and erosions. A grade of less than or equal to 2.0 was considered normal and was assigned to 77 of 78 samples from clinically normal dogs and 28 of 48 samples from dogs with diarrhea. A transient increase in cellularity was noted in 1 sample from 1 control dog. Nineteen dogs with clinical disease had obvious histologic abnormalities. The grading scheme described provides the pathologist with an objective criterion for the microscopic evaluation of colonic mucosal samples obtained by endoscopic techniques and offers clinicians a method of assessing the dog's progress and response to therapy.

Treatment of chronic idiopathic large-bowel diarrhea in dogs with a highly digestible diet and soluble fiber: a retrospective review of 37 cases.

The medical records of 37 dogs diagnosed with chronic idiopathic large-bowel diarrhea were reviewed. The median age of affected dogs was 6 years. The median body weight was 13.9 kg. The median duration of clinical signs before diagnosis was 32 weeks. Diarrhea usually was intermittent and characterized by increasing frequency, fecal mucus, hematochezia, and tenesmus. Vomiting was common but usually much less frequent and severe than the diarrhea. A variety of stressful factors and abnormal personality traits were identified. CBC and serum biochemistry usually were normal. Fecal examination rarely identified parasites. Rectal cytology specimens were most often normal, but some dogs had increased numbers of neutrophils. The colonic mucosa often was normal during colonoscopy, but decreased numbers of lymphoid follicles were found in some dogs. Histopathologic evaluation found that colonic mucosa was within normal limits. Treatment with soluble fiber (Metamucil) added to a highly digestible diet (Hills i/d) resulted in a very good to excellent response in most dogs. The median initial dosage of Metamucil was 2 tablespoons (2 T) per day. In some dogs, the fiber dosage was reduced or eliminated, or a grocery store brand of dog food was substituted, without causing diarrhea to return.

Complications associated with 355 flexible colonoscopic procedures in dogs.

Flexible colonoscopy is commonly performed in dogs with signs of large-bowel diseases. Although considered to be a safe procedure, no reports of complications associated with colonoscopy have appeared in the veterinary literature. The purpose of this study was to describe the frequency and types of adverse events that developed during flexible colonoscopy in dogs. Medical records were reviewed from 355 scheduled colonoscopic procedures. Major complications were defined as adverse events in which the dog's life was potentially jeopardized and the complication required intensive treatment or monitoring. Major complications consisting of fatal aspiration of GoLYTELY, colonic perforation, and excessive hemorrhage after biopsy of an adenocarcinoma with rigid forceps occurred in 3 (0.85%) dogs. Minor complications associated with anesthesia or colonoscopy occurred during 3.4% of procedures. Complications were classified as minor if the adverse event required minimal treatment or monitoring, and the complication was not considered a threat to the dog's life. Vomiting of GoLYTELY occurred with the administration of 4.6% of doses in 6.5% of dogs. When administering GoLYTELY, clinicians should be prepared to rapidly remove the orogastric tube and mouth speculum if vomiting occurs to reduce the potential for aspiration. In this group of dogs undergoing flexible colonoscopy, major complications occurred infrequently and minor complications developed uncommonly. Overall, minor or major complications developed during 30 (8.5%) of 355 procedures. Mortality was rare (0.28%). Flexible colonoscopy appears to be a safe procedure in dogs with signs of large-bowel diseases.

Rectal prolapse of an ileocaecal neoplasm associated with intussusception in a cat.

Intussusception associated with lymphoma of the ileocaecocolic junction was diagnosed in a 12-year-old female domestic short-haired cat that presented with a 3-week history of diarrhoea and a protruding anal mass. Surgical exploration revealed an ileocolonic intussusception proximal to the mass at the ileocaecal junction which was excised. A diagnosis of ileocaecocolic lymphosarcoma was made and euthanasia was later performed. This is an unusual case of an ileocaecal junction tumour that manifested as a rectal prolapse associated with intussusception in a cat.

The histological appearance of large intestinal biopsies in dogs with clinical signs of large bowel disease.

Colonic and rectal forceps and excision biopsies of 355 dogs with clinical signs of large bowel disease were investigated. Five percent of the forceps biopsies were unsuitable for examination; all excision biopsies were of good quality. Forceps biopsies were obtained from one to eight sites, up to 60 cm cranial from the anus, while excision biopsies, mostly from tumors, were from the rectoanal region. Slight to severe colitis and/or proctitis was found in 192 dogs (54%). A single type of colitis was seen in 160 dogs; in 53 cases the lesions were local, in 107 cases multiple. A combination of different types of colitis was found in 32 dogs. Atrophic colitis, diffuse colitis and canine histiocytic ulcerative colitis were the most prominent findings, followed by ulcerative, superficial and eosinophilic colitis. Follicular, hypertrophic and aspecific granulomatous colitis were found in only a few cases. Tumors were diagnosed in 57 dogs (16%). Of these tumors 50 were of epithelial and seven were of mesenchymal origin. A high percentage (61%) of the epithelial tumors consisted of adenomas of the rectoanal region. In ten other dogs (3%) a differential diagnosis of lymphosarcoma or colitis had to be made. Colitis and colorectal tumors were more prevalent in Boxers, German Shepherds, Poodles, Great Danes and Spaniels. In the Boxers simple chronic colitis, as well as canine histiocytic ulcerative colitis were more frequently found, the latter especially in females. Other biopsy findings were edema, crypt cysts, hemorrhages, an increased number of intraepithelial lymphocytes and an increased or decreased number of goblet cells.

Flow cytometric analysis of canine colonic mucosal lymphocytes from endoscopically obtained biopsy specimens.

OBJECTIVE: To validate use of canine colonic biopsy specimens obtained via endoscopy as a source of mucosal lymphocytes (ML) for flow cytometric analysis. SAMPLE POPULATION: Mucosal biopsy specimens from 10 adult dogs. PROCEDURE: Mucosal lymphocyte subsets obtained from excised colon were compared with ML subsets obtained from biopsy specimens obtained by use of an endoscopic forceps (6 dogs). Endoscopic colonic biopsy specimens from 4 other dogs were used to define whether obtained ML were predominantly of intraepithelial or lamina propria origin. Mucosal lymphocytes were isolated and labeled, using commercially available monoclonal antibodies directed against canine cell surface antigens. Lymphocyte subsets (cytotoxic or helper T cells; B cells) were determined by use of flow cytometric analysis. RESULTS: A large number of viable ML was obtained after dissociation of the colonic epithelium from excised colon (45.5 + 21.5 X 10(6)) and endoscopic (7.2+/-3.4 X 10(6)) biopsy specimens. Lymphocyte subsets obtained with both methods were identical for each dog and consisted predominantly of intraepithelial lymphocytes, with some lymphocytes from the lamina propria. Collagenase digestion of excised colon also yielded a large number of viable lymphocytes from the lamina propria (56.7+/-20.4 X 10(6)), but collagenase digestion of endoscopic biopsy specimens was less rewarding. CONCLUSION AND CLINICAL RELEVANCE: A representative sample of viable intraepithelial ML is obtainable from endoscopic biopsy specimens. Flow cytometric analysis, a minimally invasive technique, can be used to study ML of client-owned animals.

Colonic lymphocyte and plasma cell populations in dogs with lymphocytic-plasmacytic colitis.

OBJECTIVES: To quantitate immunoglobulin-containing cells (IgA, IgG, and IgM) and CD3+ T cells in colonic biopsy specimens obtained from dogs with lymphocytic-plasmacytic colitis (LPC), and to compare lymphocyte and plasma cell populations in dogs with LPC with those in healthy dogs. ANIMALS: 10 healthy dogs and 11 dogs with LPC. PROCEDURE: Colonic mucosal specimens obtained from healthy dogs and dogs with LPC were stained specifically for IgA-, IgG-, and IgM-containing cells and CD3+ T cells by use of immunoperoxidase techniques. Morphometric analyses were done to quantitate lymphocytes and plasma cells in standardized areas of colonic mucosa. Data analyses allowed determination of mean cell numbers in each dog group, and comparison of mean numbers of lymphocytes and plasma cells between dog groups. RESULTS: CD3+ T cells predominated in healthy dogs, whereas CD3+ T cells and IgA-containing cells were most numerous in dogs with LPC. In both dog groups, the IgG- and IgM-containing cells were considerably less numerous than the other 2 cell types. Comparison of cell populations between dog groups indicated that IgA- and IgG-containing cells and CD3+ T cells were significantly more numerous in the colonic mucosa of dogs with LPC. CONCLUSIONS: Dogs with LPC have significantly increased numbers of IgA- and IgG-containing cells and CD3+ T cells. These lymphocyte and plasma cell distributions indicate similarities to and differences from such distributions in human beings with inflammatory bowel disease. Results provide a basis for future correlation between histologic stage of disease activity and immunologic findings in dogs with LPC.

Evaluation of a colonic lavage solution to prepare the colon of the dog for colonoscopy.

Ten dogs were given 3 different doses (60, 80, and 100 ml/kg of body weight) of a commercial colonic lavage solution in 2 equally divided doses, 2 to 4 hours apart. The degree of colonic cleanliness was evaluated subjectively, using a numbered scoring system (1 = clean to 4 = excessive fecal material). Systemic and metabolic effects were assessed by comparing body weight, PCV, total protein concentration, serum osmolality, and urine specific gravity before and 24 hours after administration of the high-dose solution. The lowest mean cleanliness score (1.6) was obtained with the 80 ml/kg dose (P less than 0.001). The solution had no effect on any measurement except urine specific gravity (P = 0.036). Oral administration of a colonic lavage solution in a divided total dose of 80 ml/kg is a safe and effective method of large-intestine preparation in the dog.

Comparison of an orally administered gastrointestinal lavage solution with traditional enema administration as preparation for colonoscopy in dogs.

Forty dogs were randomly assigned to be given either multiple enemas (group A) or orally administered lavage solution (group B) before colonoscopy. Dogs of group A (n = 20) were given 3 large-volume warm-water enemas 6 hours apart, with the last enema given 9 to 15 hours before colonoscopy. Dogs of group B (n = 20) were given a total dose of 50 ml of the lavage solution/kg of body weight through an orogastric tube. The lavage solution was administered in 2 doses of 25 ml/kg given 1 hour apart, 12 to 18 hours before colonoscopy. Dogs were monitored for changes in body weight and in serum sodium, potassium, chloride, calcium, phosphate, urea nitrogen, creatinine, and total CO2 concentrations. Colonoscopy was performed on dogs under general anesthesia by an investigator blinded as to the method of preparation, and the quality of preparation was subjectively evaluated. The quality of colon preparation was significantly (P less than 0.005) better after administration of oral lavage solution, compared with that after multiple enemas. There were minimal changes in laboratory values, side-effects were minimal, and biopsy specimen artifacts were not seen. Because proper patient preparation is necessary for complete colonoscopic examination, results suggested that an orally administered polyethylene glycol-containing electrolyte solution is preferable to administration of multiple enemas in preparing dogs for colonoscopy.