CT findings in five dogs with surgically confirmed colonic torsion

Colonic torsion is a life‐threatening condition that results in colonic ischemia, necrosis, perforation, sepsis, and eventual death. The aim of this multicenter, retrospective case series study was to describe the CT findings in dogs with surgically confirmed colonic torsion. Medical records were searched for dogs with surgically confirmed colonic torsion following abdominal CT. Five dogs met the inclusion criteria. Three had a history of chronic intermittent diarrhea prior to presentation. Two dogs presented with acute vomiting, diarrhea, and abdominal pain and one dog presented with acute vomiting and lethargy. Computed tomographic findings in all dogs with surgically confirmed colonic torsion include: “whirl sign,” displacement and distension of the cecum and colon, focal narrowing of the colon, and distension of the mesenteric vasculature in all dogs (5/5); streaky peritoneal fat and peritoneal effusion (4/5), pneumatosis coli (2/5), small intestinal distension (2/5), portal vein thrombosis (1/5), and reduced colonic wall contrast enhancement (1/5). In all dogs (5/5), the torsion site was the descending colon and demonstrated an anticlockwise rotation. At surgery, three of the five dogs had a partial colonic torsion with hyperemia at the site of obstruction and two of the five dogs had a complete torsion with marked necrosis of the colonic wall. Displacement of the colon and cecum, segmental distension and focal narrowing of the colon, the presence of a “whirl sign” and distension of the mesenteric vasculature are CT findings highly suggestive of colonic torsion.     

Longitudinal colonic torsion as a cause of tenesmus in an adult Irish Water Spaniel

CASE HISTORY: Torsion of the descending colon was diagnosed by barium enema radiography in an adult Irish Water Spaniel which had presented with tenesmus of 24 h duration. Treatment involved exploratory laparotomy, repositioning of the colon, colopexy and repair of a mesenteric rent. No definitive cause of the torsion could be established. The dog made an uneventful recovery from surgery. CLINICAL RELEVANCE: Animals presenting with constipation of undetermined cause should have large intestinal obstruction ruled out prior to administering bowel cleansing solutions per os and/or colonic enemas. Colonic obstruction by torsion should be considered as a possible differential diagnosis in all cases of tenesmus.     

Feline urological syndrome

CASE HISTORY: Torsion of the descending colon was diagnosed by barium enema radiography in an adult Irish Water Spaniel which had presented with tenesmus of 24 h duration. Treatment involved exploratory laparotomy, repositioning of the colon, colopexy and repair of a mesenteric rent. No definitive cause of the torsion could be established. The dog made an uneventful recovery from surgery.

CLINICAL RELEVANCE: Animals presenting with constipation of undetermined cause should have large intestinal obstruction ruled out prior to administering bowel cleansing solutions per os and/or colonic enemas. Colonic obstruction by torsion should be considered as a possible differential diagnosis in all cases of tenesmus.     

Obstruction of the descending colon due to torsion of the cecum through a mesocolic defect in a cow

A cow was evaluated for acute onset of abdominal pain and decreased milk production. Physical examination revealed narrowing of the descending colon. Exploratory laparotomy revealed mesocolic defect and torsion of the cecum around the descending colon. After surgical correction of the cecal torsion, the cow recovered rapidly. The mesocolic defect could not be closed, and the history did not indicate a cause for the mesocolic defect.     

Retrograde intussusception of the descending colon secondary to multiple colonic hamartomas in a neonatal foal

A neonatal Thoroughbred filly presented with a 3-h history of abdominal pain and distention that failed to respond to medical treatment. Diagnostic evaluation, including abdominal ultrasound, barium enema and proctoscopy, was suggestive of atresia coli. Exploratory laparotomy revealed a pedunculated mass in the wall of the diaphragmatic flexure of the ascending colon. The mass, subsequently diagnosed as a hamartoma, was attached to a smaller hamartoma by a fibrous pedicle originating from the descending colon. The descending colon had intussuscepted retrograde into the ascending colon along the fibrous band. The filly was euthanised due to poor prognosis.     

IMAGING ASSESSMENT OF THE MODIFIED DOUBLE CONTRAST BARIUM ENEMA USING CARBOXYMETHYLCELLULOSE ON RADIOGRAPHY AND ULTRASONOGRAPHY IN DOGS

A modified double contrast barium enema using carboxymethylcellulose was evaluated in beagle dogs and compared with dogs receiving a conventional barium enema. The experimental group was divided into three groups (1, 2, and 3) and given 30 ml/kg of different volume ratios of a barium vs. carboxymethylcellulose mixture. Each group underwent sonography following radiography. The volume ratio of one part barium to three parts carboxymethylcellulose was judged to be the optimal mixture, resulting in a general distribution of contrast and bowel radiolucency on radiographs and adequate postradiography sonography. The modified barium enema using carboxymethylcellulose is useful for assessing the general morphology and mucosal layers of the colon simultaneously on radiographs and ultrasonographs.     

Volvulus of the cecum and large colon caused by multiple mesenteric defects in a horse.

A 2-year-old Standardbred colt was examined because of signs of abdominal pain of 12 hours' duration. Clinical signs of disease, including tachycardia and abdominal distention, and rectal palpation findings of distention and thickening of the ventral colon, were consistent with displacement or early strangulation obstruction of the large colon. Surgical exploration revealed volvulus of the large colon around an axis formed by the dorsal mesenteric attachment of the transverse colon. The cecum could be completely exteriorized and lacked the cecocolic ligament and dorsal mesenteric attachments. The dorsal mesenteric attachments of the right ventral and dorsal colons were also lacking. The viscera were repositioned, and the horse was discharged 13 days after surgery. The horse developed severe colic 6 months later and was euthanatized. Mesenteric volvulus and omental adhesions were found at necropsy.     

Torsion of the descending colon in a cow

An acute intestinal obstruction caused by a torsion of the descending colon with incarceration and strangulation of the apex of the cecum was diagnosed in a mature Holstein cow. The clinical signs manifested were acute anorexia, depression, signs of abdominal pain, and absence of feces. Rectal examination revealed a sharp decrease in luminal size of the descending colon and taut bands at that level. The final diagnosis was obtained by exploratory celiotomy. Although surgical correction was attempted, the cow died of acute fecal peritonitis 18 hours postoperatively.

Acute intestinal obstruction caused by torsion of the descending colon in the cow has not been reported in the literature.

     

RADIOGRAPHIC DIAGNOSIS OF LUNG LOBE TORSION

Clinical data, thoracic radiographs, ultrasonographic exams, and histopathologic reports in 13 dogs and two cats with confirmed lung lobe torsion were reviewed. Age of dogs ranged from 4 months to 11.5 years, (mean of 6.4 years) and several breeds of large and small dogs were represented. Right middle lobe torsion was predominant in large dogs (five of eight large breed dogs) and left cranial lobe torsion was more commonly seen in small dogs (three of five small-breed dogs). Two domestic short-hair cats, 10 and 14 years of age, had right cranial and right middle lobe torsion, respectively. Underlying thoracic disease was found in only five of 15 patients. On thoracic radiographs, increased lobar opacity and pleural effusion were found in all patients (100%). Small dispersed air bubbles were found within the affected lobe of 13 patients (87%). This pattern, which was the result of vesicular emphysema, was variably extensive, and became more evident on follow-up radiographs in five of six dogs. The lobar bronchi could be seen in only eight of 15 patients (54%), and appeared irregular, focally narrowed or blunted in six of the eight patients, and displaced in five of the eight. Other common radiographic findings included mediastinal shift (nine), curved and dorsally displaced trachea (seven), and axial rotation of the carina (seven). Ultrasonography was used in seven patients and considered generally useful, although variable signs were observed.     

Effects of carprofen on the integrity and barrier function of canine colonic mucosa

OBJECTIVE: To measure effects of carprofen on conductance and permeability to mannitol and histologic appearance in canine colonic mucosa. SAMPLE POPULATION: Colonic mucosa from 13 mature mixed-breed dogs. Procedures-Sections of mucosa from the transverse colon and proximal and distal portions of the descending colon were obtained immediately after dogs were euthanized. Sections were mounted in Ussing chambers. Carprofen (400 microg/mL) was added to the bathing solution for treated sections. Conductance was calculated at 15-minute intervals for 240 minutes. Flux of mannitol was calculated for three 1-hour periods. Histologic examination of sections was performed after experiments concluded. Conductance was graphed against time for each chamber, and area under each curve was calculated. Conductance X time, flux of mannitol, and frequency distribution of histologic findings were analyzed for an effect of region and carprofen. RESULTS: Carprofen significantly increased mean conductance X time, compared with values for control (untreated) sections for all regions of colon. Carprofen significantly increased mean flux of mannitol from period 1 to period 2 and from period 2 to period 3 for all regions of colon. Carprofen caused a significant proportion of sections to have severe sloughing of cells and erosions involving >or= 10% of the epithelium, compared with control sections. CONCLUSIONS AND CLINICAL RELEVANCE: Carprofen increased in vitro conductance and permeability to mannitol in canine colonic mucosa. Carprofen resulted in sloughing of cells and erosion of the colonic mucosa. These findings suggested that carprofen can compromise the integrity and barrier function of the colonic mucosa of dogs.     

Radiography, computed tomography and virtual bronchoscopy in four dogs and two cats with lung lobe torsion

This report describes the imaging features of radiography, computed tomography and virtual bronchoscopy in dogs and cats with lung lobe torsions. The medical records, thoracic radiographs and computed tomography images of four dogs and two cats with confirmed lung lobe torsions were retrospectively reviewed. Computed tomography with virtual bronchoscopy showed bronchial narrowing, collapse or occlusion in all six animals, while this was only appreciated on one radiographic examination. A tapering terminating angle of the air-filled bronchus proximal or distal to the collapsed region was seen only on computed tomography and virtual bronchoscopy in all six animals. The vesicular emphysema pattern typical of lung lobe torsion was seen on three computed tomographies but only on one radiographic examination. The lung lobe torsion-specific findings of vesicular emphysema and a proximally narrowed or occluded bronchus were more easily recognised on computed tomography and virtual bronchoscopy than with radiographs. Computed tomography slices acquired through the bronchus and lung lobe of interest in a cat or dog with possible lung lobe torsion can be reformatted into virtual bronchoscopic images that can be utilised along with computed tomography to help make a more definitive preoperative diagnosis.     

Use of negative contrast computed tomography for diagnosis of a colonic duplication in a dog

A 24‐week‐old dog was presented with recurrent rectal prolapse because of colonic duplication. Colonic duplication is an extremely uncommon congenital abnormality, with only six cases reported in veterinary medicine, one diagnosed at necropsy and five after barium enema, colonoscopy, abdominal ultrasound, exploratory laparotomy either alone or in combination. In this case, these techniques failed to identify the abnormality and diagnosis was ultimately achieved via negative contrast computed tomography. The evaluation generated by the computed tomography images allowed a refined surgical approach. To the authors’ knowledge, negative contrast computed tomography has not yet been reported in the veterinary literature to diagnose gastrointestinal pathologies. Colonic duplication in this case was treated by removal of the intercolonic septum via colotomy.     

Retrospective evaluation of fixation complications of 49 pelvic osteotomies in 36 dogs

Thirty-six dogs undergoing 49 pelvic osteotomies (POs) stabilised either by manually twisted dynamic compression plates (DCPS; n= 29) or canine pelvic osteotomy plates (CPOPS; n = 20) were retrospectively reviewed. Postoperative radiographs were available for all POs and 36 had additional radiographic follow-up. Pelvic osteotomies with CPOPs were more likely to have three screws placed in the sacrum while DCPs were associated with none, one or two screws in the sacrum. There was no difference in the postoperative sagittal alignment of the acetabular segments for POs with DCPs or CPOPs. Screw loosening was the most common complication (n = 13/36, 36 per cent), usually involving screws in the ilial segment. On follow-up radiographs, medial displacement of the acetabular segment was most frequently associated with screw loosening and plate bending. Medial displacement of the acetabular segment caused apparent pelvic narrowing on radiographs, more pronounced in dogs with bilateral POs, but clinical problems were not reported.     

Radiographic signs of isolated splenic torsion in dogs: eight cases (1980-1987)

Abdominal radiographs of 8 dogs with confirmed isolated splenic torsions were evaluated retrospectively. Radiographic signs included suboptimal abdominal detail, displacement of other abdominal organs, loss of visualization of the body of the spleen in its normal position (in the left cranial portion of the abdomen) on the ventrodorsal radiographic view, identification of the spleen in an abnormal location or shape, splenomegaly, and splenic gas. When the spleen location and shape could be identified as abnormal (3 dogs), the spleen appeared folded into a C shape in the central portion of the abdomen on the lateral radiographic view.     

Effects of heparin treatment on colonic torsion-associated hemodynamic and plasma eicosanoid changes in anesthetized ponies

Large colon torsion frequently is a fatal condition in horses. The purpose of the study reported here was to determine systemic arterial pressure, plasma eicosanoid concentrations, colonic blood flow, vascular resistance, tissue pH, and morphologic features associated with large colon torsion and detorsion, and to evaluate the effects of sodium heparin (80 IU/kg of body weight, IV) treatment on these values. Values were determined in 20 anesthetized ponies that were randomly assigned into 4 equal groups: control; control/heparin; torsion; torsion/heparin. Torsions were created by a 720 degrees rotation of the cecum and colon around their long axes at the sternal and diaphragmatic flexures. After 1 hour of torsion, the torsion was corrected and the colon was allowed to reperfuse for 1 hour. Heparin was administered 30 minutes into the experiment. Parametric data were analyzed (P less than or equal to 0.05), using split-plot analysis of variance, with differences between means evaluated with a modified Bonferroni t test; histopathologic data were analyzed (P less than or equal to 0.05) with a Kruskal-Wallis one-way analysis of variance by ranks. Heparin prevented colonic detorsion-induced hypotension and increases in vascular resistance and thromboxane concentration, and it significantly increased colonic blood flow for 40 minutes during reperfusion. Heparin did not alter prostacyclin concentration or the histologic appearance of the large colon.     

RADIOGRAPHIC, ULTRASONOGRAPHIC, AND COMPUTED TOMOGRAPHIC APPEARANCE OF ALVEOLAR ECHINOCOCCOSIS IN DOGS

Alveolar echinococcosis is a rare metacestodal infection of humans and domestic animals with Echinococcus multilocularis and predominantly affects the liver. In humans, diagnosis is based on serology, ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI), techniques that have not yet been validated for the diagnosis of alveolar echinococcosis in dogs. Therefore, the purpose of this retrospective study was to describe the radiographic, ultrasonographic, and CT appearance of canine alveolar echinococcosis. Eleven dogs with confirmed alveolar echinococcosis (PCR or histology from biopsy material of metacestode tissue) diagnosed between 1995 and 2003 were included in the study. The age of the dogs at initial presentation ranged from 7 months to 10.5 years. Abdominal radiographs were made in nine animals, abdominal ultrasonography was performed in 10 dogs, and two CT studies in one dog, respectively. The history, clinical presentation, and laboratory findings for the 11 dogs were unspecific, the most frequent clinical finding being nonpainful progressive abdominal distention. All radiographed dogs had large liver masses; they contained small mineralizations in five. The most frequent ultrasonographic finding was multiple large cavitary masses with or without wall mineralizations. Seven animals received surgical and subsequent medical therapy with albendazole (10mg/kg) and all went into clinical remission. This study reviewed for the first time imaging findings associated with alveolar echinococcosis. The disease has to be included in the list of differential diagnoses in dogs with large, cavitary liver masses, particularly when mineralization is noted.     

Colonic perforation in corticosteroid-treated dogs

Clinical findings for 5 new cases of colonic perforation in corticosteroid-treated dogs were presented and 8 other cases from the literature were reviewed. Colonic perforation was a fatal complication in all 13 dogs, 12 of which had had recent major surgery. Ten dogs were neurosurgical patients, 1 dog received medical therapy for head trauma and nonambulatory paresis, and 2 dogs were operated on for non-neurologic conditions. Dexamethasone was the most frequently used corticosteroid, and 12 dogs received a mean cumulative dose of 6.4 mg/kg over an average period of 5.1 days. Depression, anorexia, and emesis, the most frequent signs attending colonic perforation, became evident 3 to 8 days after surgery. Signs preceded death by an average of 22.3 hours. Correct antemortem diagnosis (5 dogs) and surgical intervention (3 dogs) had no effect on eventual outcome (mortality = 100%). Colonic perforation most frequently developed in the proximal descending portion and always involved the antimesenteric border. Gross fecal contamination of the peritoneal cavity and acute generalized peritonitis were evident in all but one dog. Adhesions were observed at the lesion site in 6 dogs, but prevented gross soilage in only one dog.     

The Use of Colonic Irrigation to Control Fecal Incontinence in Dogs With Colostomies

OBJECTIVE: To determine if once-daily colonic irrigation results in fecal continence for a 24-hour period in dogs with colostomies and if colonic volume increased in response to the irrigation. STUDY DESIGN: A prospective controlled experimental study. ANIMALS: Four intact male and one intact female mixed breed dogs. MATERIALS: All dogs received left end-on paralumbar colostomies. Four dogs received once-daily colonic irrigation for 8 weeks, whereas the control dog did not. Daily fecal weights were recorded for the length of the study in all dogs. Barium enema studies and volumetric studies were used to determine colonic volumes. RESULTS: Daily fecal weights were significantly decreased in treatment dogs compared with the control dog. Colonic volume increased in irrigated dogs in response to daily irrigation over the 8 week period of the study. CONCLUSIONS: Colonic irrigation resulted in significantly decreased fecal production over a 24-hour period. Therefore management of dogs with colostomies would be more practical and cost effective. It did not result in complete fecal continence in this study. Further clinical studies are indicated to determine if longer periods of irrigation would result in complete continence.     

THORACIC RADIOGRAPHIC FEATURES OF ANTICOAGULANT RODENTICIDE TOXICITY IN FOURTEEN DOGS

Thoracic radiographs and clinical records from 14 dogs with confirmed anticoagulant rodenticide toxicity were reviewed. Twelve of the 14 dogs were presented with a chief complaint of respiratory distress, and 12 had elevated prothrombin and activated partial thromboplastin times consistent with a coagulopathy secondary to a clotting factor deficiency. Thoracic radiographs of the 14 dogs were reviewed and abnomalities included increased mediastinal soft tissue opacity with extra and intrathoracic tracheal narrowing (4/14), increased mediastinal soft tissue opacity without tracheal narrowing (8/14), variable degrees of pleural effusion (13/14) and generalized, patchy interstitial/alveolar pulmonary infiltrates (8/14). Radiographic evidence of cardiomegaly and pulmonary artery abnormalities consistent with concurrent heartworm infestation were detected in one dog. In four dogs, dramatic tracheal narrowing was identified on the lateral thoracic radiograph caused by either mediastinal hemorrhage compressing the trachea or submucosal hemorrhage within the tracheal lumen. The trachea was displaced in a ventral direction in two dogs, and extra and intrathoracic luminal diameter narrowing was evident cranially in all four dogs. Two of these four dogs had soft tissue opacity within the dorsal trachea that extended from the larynx to the intrathoracic trachea. Twelve of the 14 dogs survived with standard treatment protocols utilizing injectable and oral vitamin K₁. One dog died from pancreatitis and disseminated intravascular coagulopathy. The other dog died soon after presentation due to severe, disseminated hemorrhage. Follow-up thoracic radiographs were made in four dogs that survived and showed resolution of the mediastinal, pleural and pulmonary changes within one to five days after the initiation of vitamin K₁ therapy.     

Megacolon with myenteric hypoganglionosis in a foal

A 6-month-old Clydesdale filly had chronic abdominal distention and intermittent febrile episodes. Abdominal surgery revealed impaction of the right dorsal colon, which was relieved by evacuation of contents through an enterotomy. Four days after surgery, abdominal distention recurred and progressed. The filly was euthanatized. Necropsy revealed the right dorsal colon to be markedly distended with digesta. Microscopically, there was a marked reduction in myenteric ganglion cells in the right dorsal colon and cecum and mild to moderate reduction of myenteric ganglion cells in the left ventral and transverse colon.