Esophageal stenting for treatment of refractory benign esophageal strictures in dogs.

BACKGROUND: Benign esophageal strictures can recur despite multiple dilatation procedures and palliative management can be challenging. OBJECTIVE: To describe the technique and determine the outcome of esophageal stenting for treatment of refractory benign esophageal strictures (RBES) in dogs. ANIMALS: Nine dogs with RBES. METHODS: Retrospective review of records for dogs with RBES. Indwelling intraluminal esophageal stents were placed transorally with endoscopy, fluoroscopic guidance, or both. Follow-up information was obtained via medical record or telephone interview. RESULTS: Nine dogs had 10 stents placed including biodegradable stents (BDS) (6/10), self-expanding metallic stents (SEMS) (3/10), and a self-expanding plastic stent (SEPS) (1/10). All dogs had short-term improved dysphagia. Complications included ptyalism, apparent nausea, gagging, vomiting, or regurgitation (8/9), confirmed recurrence of stricture (6/9), stent migration (3/9), stent shortening (1/9), megaesophagus (1/9), incisional infection (1/9), and tracheal-esophageal fistula (1/9). Eight of 9 dogs required intervention because of the complications of which 4 of 8 dogs were eventually euthanized because of stent-related issues. One dog was lost to follow-up examination. CONCLUSIONS AND CLINICAL IMPORTANCE: Findings suggest that esophageal stent placement was safe and technically effective, but unpredictably tolerated in dogs with RBES. If a stent is placed, dogs should be monitored carefully for stent migration, dissolution of absorbable stents, and recurrence of strictures.

Gingival hyperplasia associated with the administration of amlodipine to dogs with degenerative valvular disease (2004-2008).

BACKGROUND: Calcium channel blocking drugs, usually nifedipine and less often amlodipine, have been reported to cause gingival hyperplasia (GH) in humans. HYPOTHESIS: Amlodipine, a dihydropyridine calcium channel blocking drug, can cause GH when administered chronically to older small dogs with degenerative valvular disease. ANIMALS STUDIED: From January 2004 to May 2008, 82 client-owned dogs with degenerative valvular disease and left atrial dilatation were treated with amlodipine in combination with spironolactone and enalapril and followed for >6 months. METHODS: Retrospective study. A chronological observation of GH in 2 dogs treated with amlodipine in 2004 and 2006 prompted the study. Patient histories and medical records of each dog treated with amlodipine for degenerative valvular disease from January 2004 to May 2008 were reviewed. RESULTS: GH was observed by clients and the authors in 7 of 82 (8.5%) dogs. Histologic confirmation of the diagnosis was made in 2 dogs. The minimum duration of treatment before diagnosis of GH was 5 months. GH began to resolve within 2 weeks of discontinuing amlodipine and resolution was complete within 6 months. Amlodipine administration was reinstituted in 1 dog in which GH had resolved, and GH reoccurred within 4 months. CONCLUSION AND CLINICAL IMPORTANCE: Long-term administration of amlodipine to dogs with degenerative valvular disease may cause GH in a small percentage of patients. GH resolves quickly after withdrawal of amlodipine treatment.

Multiple dose pharmacokinetics and acute safety of piroxicam and cimetidine in the cat.

The purpose of this study was to evaluate the multiple dose pharmacokinetics and acute safety of piroxicam and cimetidine alone and in combination in cats. Seven healthy cats were included in this randomized-crossover study. The cats were assigned to groups designated to receive cimetidine alone (15 mg/kg, p.o., q12 h), piroxicam alone (0.3 mg/kg, p.o., q24 h), and piroxicam combined with cimetidine (both at aforementioned doses). The cats were dosed for 10 days followed by at least a 2-week washout period between trials. Serial blood samples were collected following the first and last doses and analyzed utilizing a high-performance liquid chromatography with mass spectrometry detection (LC/MS) assay. Pharmacokinetic parameters were determined using noncompartmental analysis. Endoscopic evaluation of the gastric mucosa was performed and serum urea nitrogen (SUN), creatinine, alkaline phosphatase (ALP), and alanine transaminase (ALT) activities were evaluated. There were not a clinically relevant difference between the pharmacokinetic parameters of piroxicam administered alone or in combination with cimetidine after either the first or last dose. Gastric ulcers were not observed in any cats although gastric erosions were. The SUN, creatinine, ALP, and ALT activities remained within reference ranges for all cats. It appears that once daily, short-term use of piroxicam alone and in combination with cimetidine in cats is relatively safe based on the parameters evaluated in this study. However, further studies are necessary to determine the long-term gastrointestinal safety of piroxicam.

Radiographic and ultrasonographic findings of liver lobe torsion in a dog.

A twelve-year-old neutered male beagle presented for a cranial abdominal mass. The results of physical examination, laboratory tests, radiography, and ultrasonography are presented. A torsion of the quadrate lobe of the liver was diagnosed at surgery and confirmed by histopathology. A brief discussion of liver lobe torsion is presented.

Persistent right aortic arch and aberrant left subclavian artery in a white Bengal tiger (Panthera tigris).

A 3-mo-old male white Bengal tiger (Panthera tigris) presented with the chief complaint of regurgitation of solid food since weaning at 2 mo of age. Compared with its littermates, the tiger was in poor body condition and weighed only 10.3 kg when its littermates were estimated at 20-25 kg. Thoracic radiographs showed a megaesophagus cranial to the heart base. A contrast esophagram more clearly outlined the megaesophagus, and fluoroscopy demonstrated normal motility of the caudal esophagus. Endoscopic examination revealed a structure coursing dorsally from right to left over the esophagus and a constrictive band on the left of the esophagus at the heart base. Nonselective angiography confirmed the presence of a persistent right aortic arch, as well as an aberrant left subclavian artery. A left fourth intercostal thoracotomy was performed, and the ligamentum arteriosum was double ligated and divided. The left subclavian artery did not cause significant compromise of the esophagus and was not manipulated at surgery. The tiger recovered well from anesthesia and surgery. Solid food was slowly introduced over a 2-mo period without any regurgitation. The cub gained weight rapidly after surgery.

Ancillary diagnostic techniques for the lame patient.

The cause of lameness is usually identified through evaluation of signalment, history, and physical examination. Radiographic evaluation provides a definitive diagnosis in many cases; however, laboratory evaluation may prove useful in the characterization of certain conditions or in the prognostication of the condition. In some instances where the definitive diagnosis remains elusive, arthroscopic examination is a minimally invasive diagnostic tool that may be more affordable and available than computed tomography. This article reviews laboratory evaluation of the lame patient and arthroscopic evaluation of joint abnormalities.

Tracheal collapse in a young boxer.

A four-month-old, female boxer developed severe inspiratory dyspnea three days after elective ear crop surgery. Radiographs confirmed the diagnosis of collapse of the distal cervical trachea. The puppy was treated with oxygen, aminophylline, and ampicillin, but required emergency tracheostomy to stent the collapsed region. Clinical signs resolved following application of five polypropylene total-ring prostheses, and the puppy continued to do well despite significant growth to maturity.

Endoscopic examination of the choanae in dogs and cats: 118 cases (1988-1998).

OBJECTIVE: To determine whether endoscopic examination of the choanae resulted in diagnosis of various diseases in dogs and cats with signs of respiratory tract disease. DESIGN: Retrospective study. ANIMALS: 91 dogs and 27 cats that had endoscopic examination of the choanae. PROCEDURE: Medical records were reviewed for endoscopy findings and results of examination of biopsy or cytologic specimens. RESULTS: 34 animals had neoplasia in the choanal region; in 26 animals, diagnosis was confirmed by evaluation of specimens obtained by endoscopy. Five dogs with neoplasia had an erroneous diagnosis of rhinitis made on the basis of evaluation of specimens obtained by endoscopy. Six dogs and 2 cats had foreign objects in the choanae; 7 foreign objects were removed endoscopically, whereas 1 required nasal flushing. Results of endoscopy and biopsy of the choanae provided diagnosis of cryptococcosis and aspergillosis, but did not aid in the diagnosis of pythiosis or nasal mites. CONCLUSIONS AND CLINICAL RELEVANCE: Endoscopic examination of the choanae may assist in rapid diagnosis of nasal neoplasms, foreign objects, and certain infectious organisms.

Evaluation of the Palmaz stent in the trachea and mainstem bronchi of normal dogs.

OBJECTIVE: This study evaluates the efficacy of the Palmaz balloon expandable intraluminal stent in the trachea and mainstem bronchi of normal dogs. STUDY DESIGN: Effects of the stent were evaluated by physical examination, thoracic radiography, respiratory tract fluoroscopy and endoscopy, tracheal diameter measurement, postmortem examination, and airway histomorphometry. ANIMALS OR SAMPLE POPULATION: Ten normal beagle dogs. METHODS: Stent size was estimated from thoracic radiographs in awake dogs. Group I dogs (n = 4) had two stents placed: one in the thoracic trachea (TT) plus a randomly chosen mainstem bronchus (MB). Group II dogs (n = 3) had stents placed in the MB (one stent), TT (one stent), and mid- or proximal cervical trachea (CT) (one or two stents). Three dogs were used as sham-operated controls (group III). Temperature, pulse, respiration, and cough were measured twice daily. Dogs were evaluated at 21 and 49 to 56 days after stent placement, euthanatized, and tissues were collected for histomorphometric analysis of stent integration and epithelial pathology. RESULTS: Mean tracheal diameters of awake (10.5 +/- 1.7 mm) and anesthetized dogs before stent implantation (13.9 +/- 2.0 mm) were significantly different (P < .01). Complications associated with stent placement included acute pulmonary edema (n = 2), stent migration (n = 7), stent collapse (n = 4 CT, 2 TT, and 1 MB), and positive tracheal culture (n = 10). Group II dogs coughed more at rest, exercise, and with tracheal palpation than dogs in other groups (P < .01). Group I dogs coughed more at rest than group III dogs (P < .01). Stent integration ranged from 0 to 91.3%. Squamous metaplasia and epithelial ulceration associated with stents ranged from 0 to 57.5% and 0 to 32.7%, respectively. CONCLUSIONS: Determination of stent size should be based on measurements taken on anesthetized dogs because use of inappropriately sized stents may promote stent migration, squamous metaplasia, and/or ulceration. Epithelialization over stent struts may occur if the stent is closely associated with tracheal epithelium. CLINICAL RELEVANCE: Palmaz stents do not appear to be appropriate for placement in the CT of dogs; however, with technical modifications, application in the TT and MB may be feasible.