Complications Associated with 355 Flexible Colonoscopic Procedures in Dogs

In-hospital mortality in dogs with protein-losing enteropathy and associated risk factors

BACKGROUND

Risk factors associated with negative outcomes in dogs with protein-losing enteropathy (PLE) are well documented. However, mortality before hospital discharge and associated risk factors are not well described.

HYPOTHESIS/OBJECTIVES

Report the percentage of dogs with PLE that do not survive to hospital discharge and identify associated risk factors.

ANIMALS

One-hundred and seven dogs presented to a referral hospital and diagnosed with PLE caused by inflammatory enteritis, intestinal lymphangiectasia or both.

METHODS

Retrospective cross-sectional study assessing hospital records. Data on in-hospital mortality and cause were assessed, and presenting signs, treatments prescribed, neutrophil count, lymphocyte count, serum albumin, globulin, and C-reactive protein (CRP) concentrations, and histopathologic findings were compared between survivors and non-survivors.

RESULTS

In-hospital mortality was 21.5% with the most common causes including financial limitations, failure to improve and aspiration pneumonia. Factors associated with mortality during hospitalization included longer duration of hospitalization (P = .04), longer duration of clinical signs (P = .02) and an increase in serum CRP concentration after 1-3 days of in-hospital treatment (P = .02). Higher mortality was identified in Pugs (odds ratio [OR], 4.93; 95% confidence interval [CI], 1.41-17.2; P = .01) and was a result of presumptive aspiration pneumonia in 5/6 of these dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Protein-losing enteropathy in dogs has substantial mortality during hospitalization. Monitoring for improvement in CRP concentration after treatment during hospitalization may help predict survival to discharge. Pugs have increased in-hospital mortality because of aspiration pneumonia; measures to prevent, recognize, and promptly treat this complication may improve outcomes in this breed.

Chemical pneumonitis secondary to accidental pulmonary polyethylene glycol-electrolyte solution infusion in a cat

OBJECTIVE

To describe the successful conservative management of chemical pneumonitis and presumed acute respiratory distress syndrome in a cat secondary to inadvertent pulmonary polyethylene glycol-electrolyte solution (PEG-ELS) instillation.

CASE SUMMARY

PEG-ELS is commonly used in small animals for bowel cleansing and to treat constipation. There have been several instances of aspiration or accidental instillation of this solution into the lungs of both people and dogs. PEG-ELS was inadvertently infused into the lungs of the cat in the current report. After 10 days in the ICU, during which time treatment with oxygen therapy, antibiosis, diuretics, and corticosteroids was provided, the cat was successfully discharged.

NEW OR UNIQUE INFORMATION PROVIDED

To the authors' knowledge, this is the first report of instillation of PEG-ELS in a cat resulting in chemical pneumonitis and lung injury. We describe the successful management of this condition with conservative management and without the need for invasive interventions such as bronchoscopy and lavage or mechanical ventilation.

Preliminary evaluation of serum zonulin in canine chronic enteropathies

OBJECTIVES

In humans, serum zonulin, a biomarker of intestinal permeability, correlates with underlying enteropathies and has potential application as a therapeutic target. The aim of this study was to evaluate serum zonulin as a biomarker for canine chronic enteropathy.

MATERIALS AND METHODS

Prospective enrolment of twenty-one client-owned dogs with at least 1 of the following gastrointestinal (GI) signs for at least 3 weeks duration: anorexia, hyporexia, dysrexia, vomiting, weight loss or diarrhea. 21 control dogs, age and breed matched, were also enrolled. Dogs with gastrointestinal signs were diagnosed with chronic enteropathy based on a complete blood count, serum chemistry, specific canine pancreatic lipase, cobalamin, resting cortisol, abdominal ultrasound and gastrointestinal endoscopy with histopathology. Enrolled control dogs had an unremarkable physical examination, complete blood count, serum chemistry and no clinical signs of gastrointestinal disease. Dogs were ineligible if antibiotics or immunosuppressive medications were administered within 1 month of enrolment. Blood samples were analysed using a commercial canine serum zonulin quantitative ELISA.

RESULTS

Dogs with chronic enteropathies had median serum zonulin values of 0.28 ng/mL (interquartile range: 0.04-2.59), while control dogs of 0.27 ng/mL (0.05-3.67). There was no significant difference in canine serum zonulin levels between these populations. The estimated difference in the median concentrations was -0.01 ng/mL (95% CI: -0.23 to 0.89).

CLINICAL SIGNIFICANCE

In this study, using a commercial canine zonulin ELISA, serum zonulin levels did not differentiate between dogs with chronic enteropathies and control dogs.

Management of polyethylene glycol solution aspiration using bronchoscopic lavage in a dog

Polyethylene glycol lavage solutions are used for colonic preparation in dogs and are considered relatively safe. Aspiration is an uncommon but potentially devastating complication of polyethylene glycol administration. Full recovery is possible and often rapid in people treated with bronchoalveolar lavage. A healthy 2-year-old male Beagle used in an endoscopy teaching laboratory aspirated a small amount of polyethylene glycol lavage solution. Although initially appearing unaffected, the dog quickly became hypoxemic. Bronchoscopy was used to lavage the lungs and aspirate tracheal/pulmonary fluid 5 times over the course of 45 minutes. The dog completely recovered. This report presents the successful treatment of polyethylene glycol aspiration in a dog. Although the seriousness of aspiration might not be immediately evident, bronchoscopy and lavage should be pursued because of the rapidly progressive nature of polyethylene glycol-induced pulmonary edema.

Obturator-Assisted Prolapse for Access to and Sampling of Colorectal Masses in Seven Dogs

The gold standard for diagnosis of colorectal masses is surgical biopsy; however, this is not always logistically or economically feasible. The authors present an alternative to established flexible and rigid endoscopic approaches when case limitations require such an approach. In seven dogs, after the identification of a mass on physical exam and computed tomographic evaluation, the colorectum was accessed using obturator-assisted prolapse to isolate discrete masses and perform shielded sampling via core needle biopsy. Histopathologic diagnosis was adequate for treatment planning in all dogs. No major complications were recorded 65-475 days after the procedure. This technique may be useful when traditional endoscopy and surgery for biopsy of colorectal masses is unavailable.

Multicenter retrospective evaluation of ileocecocolic perforations associated with diagnostic lower gastrointestinal endoscopy in dogs and cats

Background

Ileoscopy is increasingly performed in dogs and cats with gastrointestinal signs, but iatrogenic ileocecocolic (ICC) perforations have not been described.

Hypothesis/Objectives

To characterize endoscopic ICC perforations in dogs and cats.

Animals

Thirteen dogs and 2 cats.

Methods

This is a retrospective case series. Signalment, presentation, endoscopic equipment, colonic preparation, endoscopist's experience level, ileal intubation technique, method of diagnosis, perforation location, histopathology, management, and outcome data were collected and reviewed.

Results

Six ileal, 5 cecal, and 4 colonic perforations were identified between 2012 and 2019. Dogs weighed 2.4‐26 kg (median, 10.3 kg) and cats 4.6‐5.1 kg (median, 4.9 kg). Endoscopy was performed in dogs presented for vomiting (n = 4), as well as large (n = 5), mixed (n = 4), and small (n = 1) bowel diarrhea. Cats had large bowel diarrhea. Endoscopists included 1 supervised intern, 9 supervised internal medicine residents (2 first year, 6 second year, 1 third year), and 5 internal medicine diplomates. Diagnosis was delayed in 5 dogs, occurring 1‐5 days after endoscopy (median, 3 days); dogs were presented again with inappetence (n = 4), lethargy (n = 4), abdominal pain (n = 3), retching (n = 2), and syncope (n = 1). All animals underwent surgical correction. Histopathology did not identify lesions at the perforation site in any animal. Two dogs required a second surgery; 1 died 12 hours after surgery. Survival to discharge was 93%, with 78% surviving ≥8 months.

Conclusions and Clinical Importance

Iatrogenic endoscopic ICC perforation is not indicative of underlying disease and is associated with a good prognosis. Delayed diagnosis can occur. Therefore, perforation should be considered in the differential diagnosis for animals with clinical deterioration after endoscopy.

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.

Comparison of contrast media for visualization of the colon of healthy dogs during computed tomography and ultrasonography

OBJECTIVE To evaluate contrast agents for their ability to improve visualization of the colon wall and lumen during CT and ultrasonography. ANIMALS 10 healthy adult Beagles. PROCEDURES Food was withheld from dogs for 36 hours, after which dogs consumed 250 mL of polyethylene glycol solution. Dogs were then anesthetized, a contrast agent (tap water, diluted barium, or air; order randomly assigned) was administered rectally, iodine contrast medium (880 mg of I/kg) was administered IV, and CT and ultrasonography of the colon were performed. After a 1-week washout period, this process was repeated with a different contrast agent until all agents had been evaluated. Two investigators reviewed the CT and ultrasonographic images for colon wall thickness, conspicuity, artifacts, wall layering, and degree of lumen dilation at 4 sites. RESULTS Thickness of the colon wall was greatest in CT and ultrasonographic images with water used as contrast agent, followed by barium and then air. The CT images obtained after water administration had a smooth appearance that outlined the colonic mucosa and had the highest score of the 3 contrast agents for wall conspicuity. Although no substantial artifacts related to any of the contrast agents were identified on CT images, barium- and gas-induced shadowing and reverberation artifacts hindered wall evaluation during ultrasonography. For ultrasonography, the degree of conspicuity was highest with barium in the near-field wall and with water in the far-field wall. In contrast to CT, ultrasonography could be used to distinguish wall layering, and the mucosal and muscular layers were distinct with all contrast agents. CONCLUSIONS AND CLINICAL RELEVANCE Use of water as a contrast agent for both CT and ultrasonography of the colon in dogs compensated for each imaging modality's disadvantages and could be beneficial in the diagnosis of colon disease.

Gastrointestinal perforation associated with endoscopy in cats and dogs

Gastrointestinal endoscopy is a minimally invasive diagnostic tool for cats and dogs with signs of gastrointestinal disease. This retrospective study examined the case records of six cats and one dog diagnosed with perforation secondary to gastrointestinal endoscopy. Gastrointestinal perforation occurred in 1.6% of cats and 0.1% of dogs that underwent endoscopy during the 17 yr study period (from 1993 to 2010). It can be difficult to predict what animals are at risk for gastrointestinal perforation but possible risk factors suggested by this study include small intestinal infiltrative disease in cats and preexisting gastrointestinal ulceration in both cats and dogs. Overall, gastrointestinal endoscopy is associated with a low rate of gastrointestinal perforation.

Incidence of bacteremia following upper gastrointestinal endoscopy and biopsy in healthy dogs before, during, and after treatment with omeprazole

OBJECTIVE

To determine the incidence of bacteremia, as detected by routine methods for bacterial culture of blood samples, following routine endoscopic biopsy of the stomach and duodenum in healthy research dogs and to determine whether treatment with omeprazole administration affected the incidence of bacteremia.

ANIMALS

8 healthy purpose-bred research dogs.

PROCEDURES

All dogs underwent gastroduodenoscopy with biopsy at 4 points: twice prior to treatment with omeprazole, once following 15 days of omeprazole treatment (20 mg, PO, q 12 h), and once 14 days after treatment ceased. Dogs had a mean ± SD body weight of 18.6 ± 2.0 kg. Blood samples were aseptically obtained at 3 points during each procedure (before, immediately following, and 24 hours after endoscopy), and routine aerobic and anaerobic bacterial culture of blood was performed.

RESULTS

96 cultures were attempted for each culture method, yielding positive results of aerobic culture for 2 dogs at separate time points and no positive results of anaerobic culture.

CONCLUSIONS AND CLINICAL RELEVANCE

Routine gastrointestinal endoscopy with biopsy in healthy dogs did not result in a detectable bacteremia in most dogs. Treatment with the gastric acid-suppressing medication omeprazole did not affect the incidence of bacteremia as detected via standard techniques.

Potential risks, prognostic indicators, and diagnostic and treatment modalities affecting survival in dogs with presumptive aspiration pneumonia: 125 cases (2005-2008)

OBJECTIVE

To evaluate a clinical population of dogs diagnosed with presumptive aspiration pneumonia (AP) and determine diagnostic and treatment modalities contributing to survival.

DESIGN

Retrospective study.

SETTING

A university veterinary teaching hospital in an urban setting.

ANIMALS

One hundred and twenty-five dogs with presumed AP treated from 2005 to 2008.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Dogs with presumptive AP identified by a review of medical records had an overall survival of 81.6% (102/125). Male large-breed dogs (mean 24.9 kg; 82/125) were overrepresented and were more likely to develop AP in this study population. Recent anesthesia had been performed in 16% (20/125), and vomiting was reported in 64% (80/125). The most common radiographic findings were a predominantly alveolar pattern (187/272, [68.8%] total lung lobes) in the right middle lung lobe (80/115, [69.6%]). A mean of 2 lung lobes were involved radiographically, and the relationship between survival and the number of lung lobes affected was statistically significant (P=0.04). Neutrophilia with a left shift was common with no significant change on consecutive daily evaluations. The mean PaO(2) was 77.7 mm Hg (SD, 17.5 mm Hg) (range, 40.7-100 mm Hg) with a median alveolar-arterial gradient of 41.1 mm Hg (range, 8.1-81.8 mm Hg). In this study population, 37.6% (47/125) of dogs had microbial cultures performed and of these, 76.6% (36/47) were positive for growth; Escherichia coli (38.8%), Mycoplasma spp. (21.3%), Pasturella spp. (19.1%), and Staphylococcus spp. (17%) were the most common isolates in either single or multiagent infections. No treatment modality was statistically associated with increased survival. Colloid therapy was a negative prognostic indicator.

CONCLUSIONS

In this study the overall prognosis for AP was good. Patients with only 1 affected lung lobe appeared more likely to survive. Supportive treatment modalities are warranted for the hospitalized patient, although no individual treatment method was found to be clearly superior to others.

Anesthesia for endoscopy in small animals

This article discusses considerations for general anesthesia for various endoscopic procedures in small animals. Specific drug and monitoring recommendations are made. Special physiologic concerns of individual procedures affecting the anesthetized patient are discussed.