Endoscopic balloon dilation of benign esophageal strictures in dogs and cats

A Comparative Assessment of the Diagnosis of Swallowing Impairment and Gastroesophageal Reflux in Canines and Humans

Swallowing impairment is a highly prevalent and clinically significant problem affecting people and dogs. There are myriad causes of swallowing impairment of which gastroesophageal reflux is the most common in both species. Similarities in anatomy and physiology between humans and canines results in analogous swallowing disorders including cricopharyngeus muscle achalasia, esophageal achalasia, hiatal herniation, and gastroesophageal reflux with secondary esophagitis and esophageal dysmotility. Accordingly, the diagnostic approach to human and canine patients with swallowing impairment is similar. Diagnostic procedures such as swallowing fluoroscopy, high-resolution manometry, pH/impedance monitoring, and endolumenal functional luminal imaging probe can be performed in both species; however, nasofacial conformation, increased esophageal length, and the difficulty of completing several of these procedures in awake dogs are inherent challenges that need to be considered. Human patients can convey their symptoms and respond to verbal cues, whereas veterinarians must rely on clinical histories narrated by pet owners followed by comprehensive physical examination and observation of the animal eating different food consistencies and drinking water. Dogs may also be unwilling to drink or eat in the hospital setting and may be resistant to physical restraint during diagnostic procedures. Despite the species differences and diagnostic challenges, dogs are a natural animal model for many oropharyngeal and esophageal disorders affecting people, which presents a tremendous opportunity for shared learnings. This manuscript reviews the comparative aspects of esophageal anatomy and physiology between humans and canines, summarizes the diagnostic assessment of swallowing impairment in both species, and discusses future considerations for collaborative medicine and translational research.

Successful treatment of a dog with phenobarbital-responsive sialadenosis and an oesophageal stricture

Background

Phenobarbital‐responsive sialadenosis (PRS) can cause nausea and vomiting, and is rarely reported in dogs.

Objectives

An 8‐year‐old neutered, male Pomeranian dog was presented to our teaching hospital with vomiting that began 2 years ago. The clinical signs repeatedly improved and deteriorated despite treatment.

Methods

The only abnormality found on physical examination was salivary gland enlargement, and no specific findings were observed on blood analysis and imaging tests. The results of the fine needle aspirate cytology from the salivary glands revealed possible sialadenosis. Phenobarbital was prescribed, and the patient's symptoms resolved. However, upon discontinuing drug, the patient's clinical signs recurred and did not improve even after re‐introduction of phenobarbital and the addition of other anticonvulsant drugs. An oesophageal stricture was observed on an oesophagram, and fibrosis was confirmed endoscopically. A balloon dilation was performed to expand the stenosis.

Results

After the first procedure, the patient's clinical signs initially improved, but relapsed 2 weeks later. A total of three oesophageal dilation procedures were performed using a sequentially larger diameter balloon. After the third procedure, the patient's clinical signs were managed without recurrence. The cause of recurrent gastrointestinal signs following the initial successful treatment of phenobarbital‐responsive sialadenosis was due to oesophageal stricture formation.

Conclusions

This case report demonstrates the successful management of PRS with subsequent oesophageal stricture formation in a dog.

Oesophageal obstruction due to trichobezoars in two cats

Case series summary

This case series describes two cats diagnosed with oesophageal obstruction due to trichobezoars. Both cases presented for acute dyspnoea, with thoracic radiographs revealing changes consistent with oesophageal foreign material causing ventral displacement of the trachea. Endoscopic removal was unsuccessful and both cases required surgical intervention. Case 1 died within 24 h of trichobezoar removal, likely from aspiration pneumonia. Case 2 developed laryngeal collapse 10 days after trichobezoar removal and required a permanent tracheostomy. Case 2 has been followed up for >1 year without any further complications.

Relevance and novel information

There is minimal published information on oesophageal trichobezoars in cats. These cases provide information on presentation, radiographic findings and complications associated with oesophageal trichobezoars. The intention of this case series is to increase the index of suspicion for this syndrome among clinicians treating feline patients.

Prospective evaluation of an indwelling esophageal balloon dilatation feeding tube for treatment of benign esophageal strictures in dogs and cats

Background

Despite multiple dilatation procedures, benign esophageal strictures (BES) remain a recurring cause of morbidity and mortality in dogs and cats.

Objective

Investigate the use of an indwelling Balloon Dilatation esophagostomy tube (B‐Tube) for treatment of BES in dogs and cats.

Animals

Nine dogs and 3 cats.

Methods

Animals with BES were recruited for our prospective study. Endoscopic and fluoroscopic evaluation of the esophagus and balloon dilatation were performed under general anesthesia, followed by placement of an indwelling B‐Tube. The animals' owners performed twice daily at‐home inflations for approximately 6 weeks. Repeat endoscopy was performed before B‐Tube removal. Animals were reevaluated for changes in modified dysphagia score (MDS) after B‐Tube removal.

Results

The B‐Tube management was relatively well tolerated and effective in maintaining dilatation of a BES while in place. These animals underwent a median of 2 anesthetic episodes and were monitored for a median of 472 days (range, 358‐1736 days). The mean MDS before treatment was 3.1 ± 0.5/4.0 and final follow‐up MDS were significantly (P < .0001) improved at 0.36 ± 0.65/4.0. Eleven of 12 animals (91.7%) had improved MDS at the end of the follow‐up period, with 8/12 (66.7%) having an MDS of 0/4, 2/12 (16.7%) an MDS of 1/4, and 1/12 (8.3%) an MDS of 2/4. One dog died.

Conclusions and Clinical Importance

The B‐Tube offers an effective, and more economical method, and often decreased anesthetic time to repeated balloon dilatation procedures for the treatment of BES in dogs and cats.

Membrane-like structure in the urinary bladder neck of a young cat: diagnosis and treatment using balloon dilatation and a balloon-expandable metallic stent

Case summary

A 33-month-old, spayed female domestic shorthair cat was referred to the Animal Health Trust for the investigation of urinary incontinence and straining to urinate. A membrane-like structure was detected in the bladder neck, which caused partial obstruction of the urinary bladder. A combination of different imaging techniques, including ultrasonography, radiography, CT and fluoroscopy, was essential in the diagnosis, surgical planning and treatment of this intravesicular stricture. During retrograde vaginourethrocystogram, unexpected subcapsular accumulation of contrast medium was seen around both kidneys on radiographs and confirmed with CT. Three different treatments were performed, including surgical debridement, balloon dilatation and placement of a self-expanding metallic stent across the stricture. Histopathology of the membrane was unable to differentiate whether the lesion was congenital or acquired. No urinary incontinence was observed 5 months after placement of the metallic stent.

Relevance and novel information

This is the first reported case using fluoroscopic-guided balloon dilatation of the bladder neck for the treatment of a bladder neck stricture. Presence of renal subcapsular contrast medium secondary to a retrograde vaginourethrocystogram due to partial obstruction at the bladder neck in a cat has not been previously described.

Balloon dilation for the treatment of nasopharyngeal stenosis in seven cats

Objectives

The objective of this study was to evaluate the effectiveness of balloon dilation for the treatment of nasopharyngeal stenosis in cats.

Methods

The medical records of seven cats with nasopharyngeal stenosis treated with balloon dilation were reviewed. The most common presenting clinical signs included upper airway noise, sneezing, nasal and/or ocular discharge. All seven cats were confirmed to have nasopharyngeal stenosis via nasopharyngeal endoscopy and were treated with balloon dilation under endoscopic guidance.

Results

All seven cats had acceptable short-term control (median 14 days) of clinical signs after the procedure. Two of six cats had successful long-term control (median 34 days) of clinical signs after one balloon dilation and an additional 2/6 cats had acceptable long-term control of clinical signs after a second balloon dilation procedure. The most significant complication of balloon dilation was the recurrence of stenosis.

Conclusions and relevance

The findings of this study indicate that balloon dilation is a safe and effective treatment option for the relief of clinical signs associated with nasopharyngeal stenosis in cats. Multiple procedures may be necessary for the best chance of long-term success.

Prevalence of Gastroesophageal Reflux in Cats During Anesthesia and Effect of Omeprazole on Gastric pH

Background

Gastroesophageal reflux (GER) is poorly characterized in anesthetized cats, but can cause aspiration pneumonia, esophagitis, and esophageal stricture formation.

Objective

To determine whether pre‐anesthetic orally administered omeprazole increases gastric and esophageal pH and increases serum gastrin concentrations in anesthetized cats, and to determine the prevalence of GER using combined multichannel impedance and pH monitoring.

Animals

Twenty‐seven healthy cats undergoing elective dental procedures.

Methods

Prospective, double‐masked, placebo‐controlled, randomized clinical trial. Cats were randomized to receive 2 PO doses of omeprazole (1.45–2.20 mg/kg) or an empty gelatin capsule placebo 18–24 hours and 4 hours before anesthetic induction. Blood for measurement of serum gastrin concentration was collected during anesthetic induction. An esophageal pH/impedance catheter was utilized to continuously measure esophageal pH and detect GER throughout anesthesia.

Results

Mean gastric pH in the cats that received omeprazole was 7.2 ± 0.4 (range, 6.6–7.8) and was significantly higher than the pH in cats that received the placebo 2.8 ± 1.0 (range, 1.3–4.1; P < .001). Omeprazole administration was not associated with a significant increase in serum gastrin concentration (P = .616). Nine of 27 cats (33.3%) had ≥1 episode of GER during anesthesia.

Conclusions and Clinical Relevance

Pre‐anesthetic administration of 2 PO doses of omeprazole at a dosage of 1.45–2.20 mg/kg in cats was associated with a significant increase in gastric and esophageal pH within 24 hours, but was not associated with a significant increase in serum gastrin concentration. Prevalence of reflux events in cats during anesthesia was similar to that of dogs during anesthesia.

Pharmacokinetics of esomeprazole following intravenous and oral administration in healthy dogs

Investigation into the pharmacokinetic profile of esomeprazole was conducted using eight healthy dogs after intravenous (IV) and oral (po) administration in a two-part randomized crossover study. The dogs were fasted for a minimum of 12 hours and then received esomeprazole either intravenously (dose range 0.93–1.48 mg/kg) or orally using an enteric-coated formulation (dose range 0.95–1.50 mg/kg). After a 1-week washout period, the dogs received an alternative treatment. Serial blood samples were collected at predetermined time points, and plasma esomeprazole concentrations were determined by using ultra-high-performance liquid chromatography–mass spectrometry. Noncompartmental pharmacokinetic analyses were performed. Then, the area under the plasma concentration/time curve (AUC) and maximal plasma concentration (C_max) values were normalized to a 1.0 mg/kg dose of esomeprazole, that is, AUC/dose. Median (range) dose-normalized peak plasma concentration (C_max) values for the IV and po formulations were 4.06 µg/mL (2.47–4.57 µg/mL) and 1.04 µg/mL (0.31–1.91 µg/mL), respectively. The median (range) time-to-peak concentration (T_max) for the po formulation was 105 minutes (45–360 minutes). Median (range) plasma terminal half-life (t_½) was 45.56 minutes (39.43–64.20 minutes) for the IV formulation and 63.97 minutes (44.02–109.94 minutes) for the enteric-coated po formulation. The median (range) po bioavailability was 63.33% (32.26%–79.77%). Clinically, both po and IV formulations were well tolerated with minimal side effects observed.

Endoscopic Balloon Dilation of Esophageal Strictures in 9 Horses

Background

Medical treatment of esophageal strictures in horses is limited and the use of balloon dilatation is described in few cases. Long‐term follow up after balloon dilatation and the use of intralesional corticosteroids has not been evaluated.

Objectives

To describe the use of endoscopic guided, esophageal balloon dilatation in horses for cervical and thoracic esophageal strictures and administration of intralesional corticosteroids at the time of dilatation.

Animals

Nine horses from the hospital population with benign esophageal strictures.

Methods

Retrospective study: Medical records were reviewed from horses presented to the William R. Pritchard, Veterinary Medical Teaching Hospital at UC Davis from 2002 to 2013. Records were searched using the key words: equine, horse, balloon dilatation, bougienage, and esophageal stricture.

Results

Nine horses with esophageal strictures were treated with esophageal balloon dilatation. Five horses survived (survival at writing ranged from 2 to 11 years after discharge) and all nonsurvivors were <1 year of age and presented with concurrent problems or developed complications including megaesophagus, unresolved esophageal obstruction requiring esophagostomy, or severe aspiration pneumonia. Four horses were treated with intralesional corticosteroids with no adverse effects noted in the survivors (n = 3). Four horses available for long‐term follow up were alive at 2, 5, 6, and 11 years after presentation and 3 of these horses were being fed a hay‐based diet.

Conclusions

Resolution of esophageal strictures in the horse can be performed successfully, safely, and under standing sedation using balloon dilatation. Intralesional corticosteroids might reduce the incidence of recurrent strictures.

Treatment of traumatic penile urethral stricture in a dog with a self-expanding, covered nitinol stent

CASE DESCRIPTION

An 8-month-old castrated male mixed-breed dog was evaluated because of hematuria, stranguria, and dysuria of approximately 2 weeks' duration that developed immediately following elective castration.

CLINICAL FINDINGS

Results of physical examination, ultrasonography, retrograde double-contrast cystourethrography, and urethroscopy were consistent with a traumatic urethral stricture immediately proximal to the os penis resulting in a partial obstruction of urine outflow. Results of ultrasonographic examination of abdominal organs were considered normal. Digital radiography revealed no evidence of calculi.

TREATMENT AND OUTCOME

Balloon dilation of the urethral stricture was performed and was followed by 2 bougienage procedures during the subsequent 2 weeks when clinical signs returned. The owners declined scrotal urethrostomy, and a self-expanding, covered nitinol stent was placed approximately 3 weeks after the initial evaluation, resulting in amelioration of clinical signs. Results of follow-up urethroscopy and contrast cystourethrography 1 year after stent placement revealed a statically positioned, patent urethral stent, although a small number of polypoid mucosal structures were identified distal to the stent and 1 small structure consistent with tissue ingrowth into the stent was identified.

CLINICAL RELEVANCE

Placement of a covered nitinol stent resulted in long-term resolution of clinical signs associated with traumatic stricture of the penile urethra in this young dog. Because the os penis in dogs limits radial expansion of the urethra, its presence may limit the use of stents in this location.

Imaging evaluation of dogs and cats with Dysphagia

The current literature is reviewed in this paper regarding the application of diagnostic imaging in the evaluation of swallowing disorders of the dog. The applications of radiography, contrast radiography, and contrast videofluoroscopy are discussed with pertinent case examples provided for emphasis. The indications for image-guided interventions are also described.

Esophageal stricture in a cougar (Puma concolor)

A 7-mo-old female cougar (Puma concolor) was presented with a 2-wk history of anorexia and a 1-wk history of regurgitation. Barium contrast esophagogram and gastroesophagoscopy revealed the presence of a segmental intraluminal esophageal stricture in the middle third of the esophagus. The stricture was potentially secondary to a previous anesthetic episode. Three endoscopic balloon dilations allowed increasing the luminal diameter to a size that enabled the cougar to eat food softened with water without any signs of discomfort or regurgitation. Two months after being discharged, the cougar was doing well, had gained weight and was eating horsemeat softened with water.

Antemortem diagnosis and treatment of toxoplasmosis in two cats on cyclosporin therapy

Clinical toxoplasmosis was diagnosed antemortem in two cats being treated with therapeutic doses of cyclosporin. The diagnosis was made by detecting tachyzoites on cytological examination of bronchoalveolar lavage fluid from one case and pleural effusion from the other. Despite early diagnosis and aggressive treatment in both cases, only one cat survived. Reactivation of latent Toxoplasma gondii infection secondary to cyclosporin-induced immunosuppression was considered likely in both cases. The presence of respiratory signs in cats treated with cyclosporin should alert clinicians to the possibility of clinical toxoplasmosis. Consideration should be given to determining the serostatus of cats to T gondii prior to use of drugs which are potent inhibitors of cell mediated immunity, such as cyclosporin. Two cases of feline toxoplasmosis are presented.

Balloon dilation of a urethral stricture in a dog

A 2-year-old male neutered Scottish Terrier presented with dysuria caused by complete urethral obstruction due to a stricture secondary to catheter-induced trauma. The urethral obstruction was resolved by balloon dilation of the stricture under fluoroscopic guidance.