RADIOGRAPHIC DIAGNOSIS OF MECHANICAL OBSTRUCTION IN DOGS BASED ON RELATIVE SMALL INTESTINAL EXTERNAL DIAMETERS

European Network for Optimization of Veterinary Antimicrobial Therapy (ENOVAT) guidelines for antimicrobial use in canine acute diarrhoea

Acute diarrhoea is a common presentation in dogs, and a common reason for antimicrobial prescription and nutraceutical use. This evidence-based guideline provides recommendations for antimicrobial and probiotic treatment of canine acute diarrhoea (CAD). A multidisciplinary panel developed the recommendations by adhering to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. The opinions of stakeholders (general veterinary practitioners and dog owners) were collected and incorporated to ensure the applicability of this guideline. Four strong recommendations informed by high certainty evidence, and three conditional recommendations informed by very low or low certainty evidence, were drafted by the panel, along with an ungraded section on diagnostic work-up of dogs with acute diarrhoea. The ENOVAT guidelines initiative encourages national or regional guideline makers to use the evidence presented in this document, and the supporting systematic review, to draft national or local guidance documents.

Computed tomographic findings may be useful for differentiating small intestinal adenocarcinomas, lymphomas, and spindle cell sarcomas in dogs

An improved understanding of the CT characteristics for histologically confirmed primary intestinal tumors would be helpful for guiding prognosis and treatment plans in affected dogs. This retrospective, multi-center, analytical study aimed to evaluate the CT characteristics for the differentiation of adenocarcinoma, lymphoma, and spindle cell sarcoma (SCS) in dogs. Thirty-seven dogs who underwent contrast CT and histopathological examinations were included (adenocarcinomas, n = 11; lymphomas, n = 12; SCS, n = 14). Quantitative and qualitative CT parameters, including tumor morphology, contrast enhancement pattern, Hounsfield unit (HU) value, and presence or absence of intraabdominal lymphadenopathy, were evaluated for each included small intestine tumor CT case. Adenocarcinomas tended to show endophytic growth, intestinal obstruction, and a heterogeneous enhancement pattern. Lymphomas tended to show exophytic growth, contrast enhancement of the intestinal tumor mucosal layer, a homogeneous enhancement pattern, and the presence of lymphadenopathies in the abdominal cavity. SCSs tended to show lobulated growth, a large cystic portion within the tumor, a heterogeneous enhancement pattern, a large size with fat stranding sign, and lower HU values in postcontrast images. Cut-off values of the minimum diameter/fifth lumbar vertebral mid-body height (≥5.80; area under the curve [AUC] = 0.97, P < 0.001) and minimum HU value/HU value of the aorta (≤0.26; AUC = 0.96, P < 0.001) were derived to discriminate SCS from the two other tumor types. In conclusion, contrast CT characteristics may be useful in differentiating small intestinal adenocarcinomas, lymphomas, and SCSs in dogs.

Utility of diagnostic tests in vomiting dogs presented to an internal medicine emergency service

Introduction

Vomiting is a common sign in dogs presenting to emergency services. It can be self-limiting, a sign of a life-threatening extraintestinal, or intestinal disorder. Reasonable diagnostics should be performed to determine the underlying cause. This study aimed to assess the utility of diagnostic tests in vomiting dogs, and its correlation with patient history, and physical examination results. Additionally, parameters to differentiate uncomplicated vomiting from complicated vomiting were investigated.

Methods

In this prospective, observational, clinical study, data from 99 client-owned dogs with vomiting, presenting as first opinion cases, were evaluated. History, physical examination, duration of clinical signs, overall number of episodes of vomiting, appetite, and additional clinical signs were recorded. The standardized diagnostic evaluation of all patients included venous blood gas analysis, complete blood count, serum biochemistry profile, canine pancreatic lipase, abdominal radiographs, ultrasound, and urinalysis. Follow-up was performed 4-5 days later. Based on severity of disease and clinical course, dogs were categorized to "uncomplicated vomiting" (UN), or "complicated vomiting" (COM). The utility of each test for diagnosing the cause of vomiting was evaluated. Spearman correlation coefficient, Chi-squared-, unpaired t-, and Mann-Whitney U-test were used. Statistical significance was defined as p ≤ 0.05.

Results

Out of the 99 dogs, 34 had uncomplicated courses of disease (UN). In 60/99 cases, a diagnosis was obtained, and in 39/99 cases, the cause for vomiting remained unknown. Longer duration of clinical signs, and reduced appetite were associated with higher utility of abdominal ultrasound. A poor mentation was associated with a higher utility of blood examinations and abdominal radiographs. Dogs presenting with an impaired mentation or with additional clinical signs other than diarrhea, were more likely to be in the COM group.

Discussion

Based on this investigation, general recommendations concerning the diagnostic approach for patients with vomiting could not be provided. For dogs who have exclusively vomiting as a clinical sign, and present in good mentation, further investigations might not be beneficial, and these dogs may recover with symptomatic treatment alone. Additional diagnostics could be indicated in dogs with additional clinical signs other than diarrhea.

Efficacy of Abdominal Ultrasonography for Differentiation of Gastrointestinal Diseases in Calves

This study investigated the clinical efficacy of abdominal ultrasonography for abomasal dilation in three calves, intestinal volvulus in five calves, intussusception in one calf, and internal hernia in one calf. In the abdominal ultrasonograms of the abomasal dilation cases, this disease was commonly characterized by severely extended lumens, including heterogeneously hyperechoic ingesta without intraluminal accumulations of gas. In the animals with intestinal volvulus and intussusception, a to-and-fro flow was observed to be a common ultrasonographic characteristic that led to suspicion of an intestinal obstruction. The use of abdominal ultrasonography for five cases with intestinal volvulus gave no reason to suspect this disease, despite its efficacy in one case, based on an acutely angled narrowing. Although three of five animals with intestinal volvulus had intestinal ruptures, no ultrasonographic evidence could be obtained. When abdominal ultrasonography was used for one case with intussusception, this pathological condition could be strongly suspected, as a "target" sign was observed. This finding supported surgical intervention for this case, followed by treatment with manual reduction, resulting in a favorable outcome. In terms of the differential and definitive diagnosis for various intestinal diseases, abdominal ultrasonography may be poor at providing indicative evidence, but very helpful for confirming intestinal obstruction.

Repeatability and accuracy of a novel, quantitative radiographic method for differentiating normal canine sacroiliac joints from joints with subluxation or luxation: Pilot study

Canine sacroiliac (SI) joint subluxation or luxation is most commonly diagnosed based on qualitative radiographic assessments. Aims of this two-part, retrospective, diagnostic accuracy, pilot study were to develop and evaluate a novel quantitative method based on measuring the angle between a line connecting the iliac wings and parallel lines across three anatomical landmarks (cranial endplate of L7, caudal endplate of L6, cranial endplate of L6) on a single ventrodorsal radiograph. For the first part of the study, angle measurements from a single observer were compared for 20 normal canine pelvic radiographs and 20 pelvic radiographs with SI luxation or subluxation. Mean values significantly differed between datasets (P < 0.001). The angles for the normal pelves ranged from 0.6° to 1.5°, while abnormal angles ranged from 3.8° to 7.1°. For the second part of the study, a dataset of 25 normal and 25 abnormal canine pelvic radiographs was evaluated using the novel technique by three blinded readers with varying levels of expertise at two different time points. There was excellent reliability among the three readers with an intraclass correlation (ICC) value of 0.90 and an excellent agreement between day 0 and day 30 readings with an ICC value of 0.91. It was also determined that a cut-off angle of 2.0°, using the line parallel to the cranial endplate of L6, provided overall the best accuracy, sensitivity, and specificity to differentiate normal versus abnormal pelves. These findings may be helpful for clinical cases with equivocal diagnoses and for future development of automated diagnostic tools.

Retrospective evaluation of gastrointestinal foreign bodies and presurgical predictors for enterectomy versus enterotomy in dogs (2013-2016): 82 cases

OBJECTIVE

To evaluate preoperative diagnostics in dogs with gastrointestinal foreign body (GIFB) obstruction and to identify clinical variables associated with the performance of simple enterotomy (EO) versus enterectomy (EC).

DESIGN

Retrospective case control study from October 2013 to January 2016.

SETTING

Veterinary Teaching Hospital.

ANIMALS

Eighty-two client-owned dogs diagnosed at the time of surgery with GIFB obstruction.

MEASUREMENTS AND MAIN RESULTS

Data were collected from medical records regarding history, initial physical examination, clinicopathologic testing, diagnostic imaging, and surgical reports. Based on univariate analysis, dogs that required EC were ill (P < 0.0001) and anorexic (P = 0.0007) for a longer duration; had a higher vomiting severity score (P = 0.005); and had worse perfusion parameters (mucous membrane color [P = 0.028] and quality [P = 0.032], poorer pulse quality [P = 0.0015], relatively lower blood pressure [P = 0.0328], greater heart rates [P = 0.0011]). Dogs undergoing EC were more likely to have altered peritoneal detail on radiographs (P = 0.0014; odds ratio [OR] = 25.5; 95% confidence interval [CI]: 2.4, 275.7) and echogenic peritoneal effusion on ultrasound (P = 0.0101; OR = 12.5; 95% CI: 1.3, 120.9), compared to the EO group. Heart rate (adjusted P = 0.028; OR = 1.07; 95% CI: 1.0, 1.1) and vomiting severity score (adjusted P = 0.028; OR = 5.6; 95% CI: 1.2, 26.1) maintained significance after multiple logistic regression.

CONCLUSIONS

Multiple factors in the preoperative clinical evaluation were different between dogs undergoing EO versus EC for GIFB obstruction. However, many of these variables become insignificant with multiple logistic regression. The presence of an increased heart rate or increased vomiting severity score at presentation was independently associated with undergoing enterectomy. Prospective studies with greater number of animals are warranted to validate these results.

Influence of repeat abdominal radiographs on the resolution of mechanical obstruction and gastrointestinal foreign material in dogs and cats

Mechanical obstruction is a common cause of acute vomiting among small animals and radiography is the first line diagnostic tool. Due to many circumstances, surgery may not be an immediate treatment option. The purpose of this retrospective, cross-sectional design study is to determine the incidence of radiographic resolution of mechanical obstruction or gastrointestinal foreign material with medical management. Inclusion criteria included: clinical signs of vomiting, radiographic diagnosis of mechanical obstruction, suspect mechanical obstruction, foreign material suspected or definitively identified on the first set of radiographs and a second set of repeat radiographs within 36 h. Radiographic resolution was dependent on the location of dilation; 18/48 (37.5%) resolved were gastric, 6/35 (17.1%) were small intestinal, and 4/35 (11.4%) had concurrent gastric and small intestinal obstruction. Gastric dilation was more likely to resolve than SI dilation or both gastric and small intestinal dilation (P = .0119). Forty-nine animals without resolution went to surgery, with two developing pneumoperitoneum, and seven requiring intestinal resection, three of which had linear foreign bodies and three had intestinal masses/strictures. In conclusion, only 17.1% of animals with small intestinal dilation and a radiographic diagnosis of mechanical ileus resolved on repeat radiographs, and only 11.4% of animals with both small intestinal and gastric dilation resolved. Gastric dilation alone was more likely to resolve than small intestinal dilation or a combination of both. This may help to guide practitioners in recommendations for medical management of mechanical ileus in the future.

The Pathophysiology of Small Intestinal Foreign Body Obstruction and Intraoperative Assessment of Tissue Viability in Dogs: A Review

Small intestinal foreign body obstructions occur commonly in dogs, accounting for 80% of all canine intestinal obstructions. Such obstructions induce local aberrations in secretion, absorption, and intestinal motility that can precipitate devastating systemic consequences, including a systemic inflammatory response, sepsis, and multiorgan dysfunction. Radiographic diagnosis is poorly sensitive relative to ultrasonography for diagnosing the presence of obstructive foreign material. Emergent surgical intervention is indicated for dogs with obstructive foreign material due to an inability to assess the degree of compromise of the intestinal wall that may precipitate intestinal perforation and to mitigate progression of life-threatening electrolyte and acid-base imbalances secondary to sequestration and emesis. Intraoperatively, an enterotomy or resection and anastomosis may be required to remove the obstructive material. A number of subjective and objective techniques for assessing the viability of intestinal tissue have been described due to the poor accuracy associated with surgeon assessment of color, peristalsis, pulsation, bleeding, and mural thickness alone. Such techniques have the potential to alter the surgeon's decision-making regarding performance of an enterotomy or resection and anastomosis, potentially reducing morbidity associated with intestinal surgery.

Radiographic diagnosis of small intestinal obstruction in pet rabbits (Oryctolagus cuniculus): 63 cases

OBJECTIVES

To identify radiographic features that can be used to aid in the diagnosis of small intestinal obstruction in pet rabbits.

MATERIALS AND METHODS

Retrospective study comparing radiographic features of 63 cases of confirmed intestinal obstruction with 50 abdominal radiographs taken of rabbits without gastrointestinal disease. Abdominal radiographs were examined for gastric size, gastric contents, small intestinal dilatation and gas within the large intestine and caecum.

RESULTS

Gastric size, gastric contents, small intestinal dilatation and gas within the large intestine and caecum were all features that differed between rabbits with small intestinal obstruction and rabbits without gastrointestinal disease. Radiographic features associated with small intestinal obstruction included severe gastric dilation, gastric contents primarily consisting of liquid and gas, small intestinal dilation and absence of large amounts of gas in the caecum and large intestine.

CLINICAL SIGNIFICANCE

Observation on gastric size, small intestinal dilatation and gas within the large intestine and caecum aid in radiological diagnosis of small intestinal obstruction in rabbits and so can guide appropriate treatment.

Use of computed tomography (CT) for the diagnosis of mechanical gastrointestinal obstruction in canines and felines

The objective of this study was to describe the use of computed tomography (CT) for diagnosis of mechanical gastrointestinal (GIT) obstruction in canines and felines. Medical records of 130 canines and felines that underwent an abdominal CT scan between 2013 and 2015 at a specialty referral hospital for suspected gastrointestinal tract (GIT) obstruction were reviewed. Images were evaluated by a single board-certified radiologist for the presence of foreign material, evidence of obstruction, and location of foreign material present. Confirmation of CT findings was based on surgical exploration or medical management if surgery was not indicated. Of the 97 patients that met the inclusion criteria, 48 (49.48%) had evidence of foreign material present within the GIT and 49 (50.52%) did not. Forty-one patients had evidence of mechanical gastrointestinal obstruction. Thirty-nine of these patients had an obstruction due to foreign material; one had an intussusception with no foreign material, and another had obstruction secondary to mucosal thickening. Forty-five patients underwent exploratory laparotomy, and CT findings were confirmed in all patients. The presence of a GIT obstruction was confirmed intra-operatively in 37 patients and lack of obstruction was confirmed in the remaining eight. Non-surgical medical management was pursued for the remaining patients. Based on follow-up client interviews, clinical signs resolved in all of these patients. In conclusion, computed tomography appears to be useful for the diagnosis of GIT obstruction in canines and felines and is a helpful tool for guiding the recommendation for surgical intervention.

Radiographic features of congenital segmental dilation of the intestine in a german shepherd dog

A 10-week-old spayed female German Shepherd Dog was presented for acute vomiting and diarrhea. There was no reported foreign body or toxin ingestion. Radiographs showed a severely (∼11 × 7 cm), focally distended right abdominal intestinal segment containing gas and soft tissue material. Other small intestinal segments were segmentally gas distended. Celiotomy identified a ∼9 cm focally dilated segment at the jejunoileal junction with no aborad luminal obstruction. Resection and anastomosis of the dilation was performed. Histopathology showed mild mucosal inflammation, but otherwise normal wall layering and autonomic ganglia. Radiographic and histopathologic findings were consistent with congenital segmental dilation of the intestine.

Ultrasonographic and computed tomographic characterization and localization of suspected mechanical gastrointestinal obstruction in dogs

OBJECTIVE To evaluate the usefulness of noncontrast abdominal CT and abdominal ultrasonography for the detection of mechanical gastrointestinal obstruction in dogs and compare intestinal diameter ratios between dogs with and without obstruction. DESIGN Controlled trial. ANIMALS 16 client-owned dogs with physical and radiographic findings consistent with mechanical gastrointestinal obstruction. PROCEDURES Abdominal ultrasonography and CT were performed for all dogs, followed by laparoscopy and exploratory laparotomy. Time required for image acquisition and presence and location of gastrointestinal obstruction were assessed with both imaging modalities. Findings were compared with those of exploratory surgery. Maximum and minimum intestinal diameters were recorded on CT scans; values were converted to a ratio and compared between dogs with and without obstruction. RESULTS Results of abdominal CT and exploratory surgery for the diagnosis of mechanical obstruction agreed for all 16 dogs; 10 dogs had complete obstruction, 3 had partial obstruction, and 3 had no obstruction. In 1 dog with functional ileus, abdominal ultrasonography resulted in an incorrect diagnosis of mechanical obstruction. Median (interquartile range) image acquisition time for abdominal CT (2.5 minutes [2.0 to 3.8 minutes]) was markedly and significantly shorter than that for ultrasonography (26.0 minutes [22.0 to 35.8 minutes]). In both dorsal and transverse CT planes, dogs with gastrointestinal obstruction (partial or complete) had significantly larger intestinal diameter ratios than dogs without obstruction. CONCLUSIONS AND CLINICAL RELEVANCE Abdominal CT was feasible, rapid, and accurate for the diagnosis of mechanical obstruction in dogs with clinical signs and physical examination findings consistent with partial or complete gastrointestinal obstruction.

COMPARISON OF COMPUTED TOMOGRAPHY AND ABDOMINAL RADIOGRAPHY FOR DETECTION OF CANINE MECHANICAL INTESTINAL OBSTRUCTION

Vomiting, often caused by mechanical intestinal obstruction, is common in dogs. Equivocal radiographic signs often necessitate repeat radiographs or additional imaging procedures. For our prospective, case-controlled, accuracy study, we hypothesized the following: (1) using computed tomography (CT), radiologists will be more sensitive and specific for detecting mechanical intestinal obstruction and recommending surgery compared to using radiographs; and (2) using measurements, radiologists will be more sensitive and specific using radiographs or CT for detecting mechanical intestinal obstruction and recommending surgery. Twenty dogs had abdominal radiographs and abdominal CT. Seventeen dogs had abdominal surgery and three dogs were not obstructed based on clinical follow-up. Confidence levels (five-point scale) of three experienced radiologists for mechanical intestinal obstruction and recommending surgery were recorded before and after making selected measurements. Eight dogs had surgically confirmed mechanical intestinal obstruction, and 12 dogs did not have obstruction. For detecting mechanical intestinal obstruction, CT was more sensitive (95.8% vs. 79.2%) and specific (80.6% vs. 69.4%) compared to radiographs, but the difference was not statistically significant. For recommending surgery, radiography was more sensitive (91.7% vs. 83.3%) and specific (83.3% vs. 72.2%) than using CT, but differences were not statistically significant. We reported objective CT measurements for predicting small mechanical intestinal obstruction. By incorporating these objective data, the diagnosis of mechanical intestinal obstruction changed in five of 120 instances (radiographs and CT). In no instance (0/120), did the objective data change the recommendation for surgery. Using CT or abdominal radiographs for the detection of canine mechanical intestinal obstruction is sensitive and specific when evaluated by experienced veterinary radiologists.