INFLUENCE OF INHALED SMOKE FROM UPPER RESPIRATORY LASER SURGERY

Endoscopic tracheal lavage cytology was evaluated before and 24 hours after standing transendoscopic laser surgery of the upper airway in 18 horses (9 patients undergoing Neodymium:yttrium aluminum garnet [Nd:YAG] surgery and 9 non-patient horses undergoing argon surgery). Paired endoscopic tracheal lavages taken 24 hours apart were evaluated in six control horses to determine if the lavage technique influenced the cytology. After 24 hours, no inflammation was noted in three, mild inflammation was noted in six and suppurative inflammation in four surgically treated horses. Five of the surgically treated horses underwent general anesthesia prior to baseline tracheal lavage and had evidence of inflammation in pre-laser lavage samples; this made it difficult to assess the true incidence of laser-induced inflammation in horses in this report. Five of six control horses had a normal tracheal lavage at 24 hours. Six normal adult horses had baseline tracheal mucous clearance rates determined using scintigraphy followed one week later by tracheal mucous clearance rates two hours after either standing transendoscopic Nd:YAG ventriculectomy or standing transendoscopic argon cauterization of a 2 × 2 cm area of dorsal pharynx. The horses were left in pasture for three weeks, followed by a second baseline and post-laser tracheal mucous clearance rate using the opposite laser technique. There was no significant difference between the first and second baseline measurements. The order of laser treatments had no effect on the results obtained. There was no significant difference between the baseline tracheal mucous clearance rates (mean 1.65 ± 0.65 cm/min) and tracheal mucous clearance rates post-laser surgery (mean 1.62 ± 1.21 cm/min). Neither laser technique altered tracheal mucous clearance rates significantly (argon mean 1.57 ± 0.59 cm/min and Nd:YAG mean 1.67 ± .68 cm/min.     

Comparison of the caudal lung borders determined by percussion and ultrasonography in horses with recurrent airway obstruction

The aim of the study was to evaluate the diagnostic value of thoracic percussion and ultrasonography with the help of distance measurements and statistical methods in the determination of the caudal lung border in horses with recurrent airway obstruction (RAO). Examinations were performed on 11 healthy, warm-blooded horses of different breeds, age and grade of disease. First, the caudal lung border was determined by the traditional indirect percussion method in the 10th, 12th, 14th and 16th intercostal spaces at the end of inspiration and expiration on both sides of the thorax. To apply standardised measurements, a fix point was chosen as described earlier by the same authors for healthy horses. The distance between this point and the caudal lung border was measured with a tape-measure. Percussion was followed by ultrasonographic determination of the caudal lung border. Measurements were performed in the same way as described for the percussion technique. Mean values and standard errors of absolute values of differences between percussion and ultrasonographic measurements were the following, in centimetres (10th, 12th, 14th and 16th intercostal spaces). Left side expiration: 1.4, 0.4; 0.8, 0.2; 0.9, 0.2; 0.8, 0.4; left side inspiration: 0.8, 0.3; 1.5, 0.3; 1.4, 0.3; 1.1, 0.3; right side expiration: 2.1, 1.0; 2.1, 0.5; 1.6, 0.5; 0.8, 0.1; right side inspiration: 1.5, 0.7; 1.2, 0.6; 0.8, 0.2; 0.8, 0.3, respectively. Ultrasonography proved to be reliable in determining the caudal lung borders in horses with RAO. Results of the percussion examination did not differ significantly from those of the ultrasound method which was used as a reference technique. The differences between inspiration and expiration were greater in horses with RAO than in healthy horses in a previous study. Based on these results, percussion can be used as an integrated part of the physical examination in diagnosing caudal shift of the caudal lung border of horses suffering from RAO.     

Permanent Tracheostomy in Standing Horses: Technique and Results

Permanent tracheal stomas were created in seven sedated, standing horses with severe upper airway obstruction. After local anesthesia, a 3-cm by 6-cm rectangle of skin was removed from the ventral surface of the neck, 3 cm distal to the cricoid cartilage. The sternothyrohyoideus muscles were clamped proximally and distally, then transected to expose the tracheal rings. The ventral third of four tracheal rings was dissected from the tracheal mucosa that was then incised in a double "Y." Two layers of suture were used to achieve mucocutaneous closure. Stomas healed without serious complications; two mares subsequently foaled, and three horses were used for riding.     

Ultrasonographic evaluation of tracheal collapse in dogs

Tracheal ultrasonography was performed to measure the width of the tracheal ring shadow and to assess the clinical relevance of these measurements for identifying tracheal collapse. The first tracheal ring width (FTRW) and thoracic inlet tracheal ring width (TITRW) were measured on both expiration and inspiration. The mean of the FTRW width (129 dogs) was greater in expiration (10.97 ± 1.02 mm, p = 0.001) than that in inspiration (9.86 ± 1.03 mm). For 51 normal dogs, the mean of the TITRW width was greater in expiration (9.05 ± 1.52 mm, p = 0.001) than in inspiration (8.02 ± 1.43 mm). For 78 tracheal collapse dogs, the mean of the TITRW width was greater in expiration (15.89 ± 1.01 mm, p = 0.001) than in inspiration (14.85 ± 1.17 mm). The TITRW/FTRW ratio of the normal dogs was higher (p = 0.001) in expiration (0.81 ± 0.09) than that in inspiration (0.79 ± 0.10). When compared between the normal and tracheal collapse dogs, the TITRW/FTRW ratio was also increased (p = 0.001) both in expiration (1.54 ± 0.09) and inspiration (1.47 ± 0.08), respectively. Based on these results, the cutoff level of the TITRW/FTRW ratio was statistically analyzed according to the receiver operating characteristic curve and it could be set at 1.16 in expiration and at 1.13 in inspiration. We have demonstrated that tracheal ultrasonography is a useful technique for the evaluation of tracheal collapse and it can be a supportive tool together with the radiographic findings for making the correct diagnosis.     

Use of scintigraphy for the determination of mucociliary clearance rates in normal, sedated, diseased and exercised horses.

Mucociliary clearance rates from the trachea were determined in normal, sedated, diseased and exercised horses from scintigraphs obtained after an injection of technetium-99m sulphide colloid into the tracheal lumen. The group mean tracheal clearance rate of eight clinically normal horses during 42 trials was 2.06 +/- 0.38 cm/min. Significant between horse differences were found (p less than 0.05). When six and seven of these horses were given xylazine and detomidine hydrochloride, respectively, mean group tracheal clearance rates dropped significantly (p less than 0.05). The decreases from each normal horse's mean tracheal clearance rate ranged from 18 to 54%. There did not appear to be a difference between the tracheal clearance rates (TCRs) of the normal horses and those with chronic respiratory disease. Postexercise evaluations were not significantly different from the pre-exercise TCRs in three clinically normal horses and three horses with chronic obstructive pulmonary disease (p greater than 0.05). This minimally invasive scintigraphic technique for determining TCRs has proved to be useful and reliable.     

Thoracic percussion to determine the caudal lung border in healthy horses

BACKGROUND: The application of equine thoracic percussion has been ignored because of the availability of modern imaging techniques. Ultrasonography is a reliable tool in determining the caudal lung border of horses. The aim of the study was to compare percussion with ultrasonography to determine lung borders in horses. HYPOTHESIS: That thoracic percussion can detect the caudal lung border and that its accuracy is comparable with thoracic ultrasonography. ANIMALS: Fifteen randomly chosen, healthy, Warmblood horses. METHODS: The caudal lung border was detected by percussion and ultrasonography at the end of inspiration and expiration on both sides of the thorax. A reference point close to the withers was determined, allowing standardized measurements. The distance between this point and the caudal lung border in different intercostal spaces (ICS) was measured by a tape measure. RESULTS: No significant difference was found between percussional and ultrasonographic results. Greater differences were found between inspiration and expiration by ultrasonography compared with percussion in all intercostal spaces on both sides of the thorax. It was significant (P = .028) in the 12th ICS in the right hemithorax. CONCLUSIONS AND CLINICAL IMPORTANCE: Percussion is a reliable tool to determine the caudal lung border in healthy horses. Differences caused by the displacement of the lung during respiration should be taken into consideration when applying either method.     

Electromyographic activity of the stylopharyngeus muscle in exercising horses

REASONS FOR PERFORMING STUDY: There is a need to understand the process which leads to failure of recruitment of the stylopharyngeus muscle in clinical cases of nasopharygeal collapse. We therefore studied the timing and intensity of stylopharyngeus muscle activity during exercise in horses. OBJECTIVE: To measure the electromyographic (EMG) activity of the stylopharyngeus muscle in exercising horses and correlate it with the breathing pattern. METHODS: Five horses were equipped with a bipolar fine wire electrode placed on the stylopharyngeus muscle and a pharyngeal catheter. The horses exercised on a treadmill at speeds corresponding to 50 (HRmax50), 75 and 100% of maximum heart rate, and EMG activity of the stylopharyngeus muscle and upper airway pressures were recorded. The EMG activity of the stylopharyngeus muscle was then correlated to the breathing pattern and the activity quantified and reported as a percentage of the baseline activity measured at HRmax50. RESULTS: There was ongoing activity of the stylopharyngeus muscle throughout the breathing cycle; however, activity increased towards the end of expiration and peaked early during inspiration. Tonic activity was present during expiration. Peak, mean electrical and tonic EMG activity increased significantly (P<0.05) with exercise intensity. CONCLUSION: The stylopharyngeus muscle has inspiratory-related activity and tonic activity that increases with speed. POTENTIAL RELEVANCE: The stylopharyngeus muscle is one of a group of upper airway muscles that function to support and maintain the patency of the nasopharynx during inspiration. Failure of recruitment of the stylopharyngeus muscle during exercise is a potential explanation for clinical cases of dorsal pharyngeal collapse, but further work investigating the activity of the stylopharyngeus muscle in horses affected by this disease is needed.     

Effect of tracheal mucus and tracheal cytology on racing performance in Thoroughbred racehorses

REASON FOR PERFORMING STUDY: Accumulations of mucus within the trachea are often found during endoscopic examinations of the airways of poorly performing racehorses, but the clinical importance of this finding is unknown. OBJECTIVES: To determine the effect of tracheal mucus, pharyngeal lymphoid hyperplasia (PLH) and cytological indices of tracheal aspirate on racing performance in Thoroughbred horses assessed by race place and whether the horse was raced. METHODS: Endoscopic examination of the nasopharynx, larynx and trachea was performed, and a tracheal aspirate obtained monthly at Thistledown racetrack from April to December, 2002 and 2003. Horses received a score of 0-4 for the degree of PLH and 0-4 for the amount of mucus visible in the trachea. The tracheal aspirate was assessed for turbidity, and total and differential cell counts. Generalised estimating equations models were used as repeated measures models for each risk factor and the level of association assessed through the risk factor's P value in the model. RESULTS: Moderate to severe tracheal mucus (2-4) was a risk factor for poor racing performance. There was no association between degree of PLH, cell counts or turbidity of tracheal wash fluid and racing performance. However, horses that raced had higher total neutrophil counts in tracheal wash aspirates than horses that did not race. CONCLUSIONS: Grades 2-4 tracheal mucus should be considered a potential cause of poor racing performance in Thoroughbred horses. CLINICAL RELEVANCE: Because moderate to severe tracheal mucus accumulation, and not increased tracheal neutrophils, was a risk factor for poor racing performance, functionally significant airway inflammation may best be confirmed by the presence of mucus rather than increased number of neutrophils in the trachea.     

Comparison of the antioxidant status in tracheal and bronchoalveolar epithelial lining fluids in recurrent airway obstruction

REASONS FOR PERFORMING STUDY: Following a period of airway inflammation the clearance of inflammatory cells along the mucociliary escalator may impose a considerable oxidant load on the trachea. OBJECTIVES: To determine the degree of oxidative stress in tracheal epithelial lining fluid (ELF) in comparison to that present in peripheral airways after an acute exposure to organic dust. METHODS: Tracheal wash fluid and bronchoalveolar lavage fluid (BALF) were collected for cytology and antioxidant analyses from 6 recurrent airway obstruction (RAO)-affected horses and 6 healthy control horses before and after stabling on straw bedding for 24 h. RESULTS: In RAO-affected horses, organic dust exposure resulted in a significant decrease in ascorbic acid concentration in tracheal ELF (P<0.0001), which was greater than the decrease in bronchoalveolar ELF (P = 0.0003). The percentage decrease in tracheal ELF ascorbic acid correlated with the percentage decrease in bronchoalveolar ELF ascorbic acid (r = 0.76; P = 0.004) following exposure. CONCLUSIONS: Acute organic dust exposure results in significant antioxidant depletion in the trachea, which may reflect inflammation and oxidative processes in peripheral airways. POTENTIAL RELEVANCE: Further work is required to evaluate the role of ascorbic acid depletion in the pathogenesis of RAO.     

Effects of posture and accumulated airway secretions on tracheal mucociliary transport in the horse

Tracheal mucociliary clearance was determined in horses by measuring the rostrad transport of the radiopharmaceutical ^99mtechnetium-sulphur colloid following deposition on the tracheal epithelium by intratracheal injection. The effects of head position (head elevated to normal standing position vs head lowered) and of accumulated purulent secretions on tracheal mucociliary clearance were evaluated for the first time in the horse. In normal horses tracheal mucociliary clearance was greatly accelerated by lowering the head so that the cranial trachea was lower than the caudal trachea. Horses confined with their heads elevated for 24 hours developed an accumulation of purulent airway secretions (and associated increased numbers of bacteria) in the lower respiratory tract and showed a decrease in tracheal mucociliary clearance when compared with their previously measured rate when the lower airway contained only normal secretions. These findings have implications for management practices where horses are prevented from lowering their heads, such as transportation and cross-tying, which may therefore contribute to lower respiratory tract disease in horses.     

THORACIC RADIOGRAPHIC APPEARANCE IN THE NORMAL LLAMA

The goal of this study was to collect quantitative and qualitative radiographic information of the normal adult llama thorax. Standing right-left lateral radiographs of the thorax of 16 normal llamas were made. Normal ratios of cardiac height, width, and height plus width to thoracic vertebrae 3-5 and thoracic height were calculated. Normal values determined for tracheal angle of divergence from the thoracic spine, cardiophrenic and cardiosternal contact are additional potential indicators of cardiac enlargement. Ratios of normal pulmonary artery and vein, caudal vena cava and trachea to the height of the fourth thoracic vertebra should allow identification of pathology of these structures. Observations regarding pulmonary vessels and airways, thoracic spine, sternebrae and portions of the gastrointestinal tract observed on thoracic radiographs are also included. It is proposed that these normal values and observations can be used to better evaluate diseases of the cardiovascular and respiratory systems of adult llamas.     

Effect of commercially available nasal strips on airway resistance in exercising horses

OBJECTIVE: To determine the effect of a commercially available nasal strip on airway mechanics in exercising horses. ANIMALS: 6 horses (5 Standardbreds and 1 Thoroughbred). PROCEDURE: Horses exercised on a treadmill at speeds corresponding to 100 and 120% of maximal heart rate with and without application of a commercially available nasal strip. Concurrently, tracheal pressures, airflow, and heart rate were measured. Peak inspiratory and expiratory tracheal pressures, airflow, respiratory frequency, and tidal volume were recorded. Inspiratory and expiratory airway resistances were calculated by dividing peak pressures by peak flows. Endoscopic examination of the narrowest point of the nasal cavity (ie, nasal valve) was performed in 1 resting horse before, during, and after application of a nasal strip. RESULTS: During exercise on a treadmill, peak tracheal inspiratory pressure and inspiratory airway resistance were significantly less when nasal strips were applied to horses exercising at speeds corresponding to 100 and 120% of maximal heart rate. Application of the nasal strip pulled the dorsal conchal fold laterally, expanding the dorsal meatus. CONCLUSIONS AND CLINICAL RELEVANCE: The commercially available nasal strip tented the skin over the nasal valve and dilated that section of the nasal passage, resulting in decreased airway resistance during inspiration. The nasal strip probably decreases the amount of work required for respiratory muscles in horses during intense exercise and may reduce the energy required for breathing in these horses.     

Incomplete tracheal intussusception in a dog

An 18-year-old male miniature poodle had a chronic nonproductive cough. On radiographic examination, an opacification resembling a foreign body was noticed within the trachea at the level of the sixth cervical vertebra. When the trachea was examined endoscopically, a circumferential flap-like lesion was found. To differentiate the invagination from an annular mass, thoracic computed tomography (CT) of the trachea was performed. There was cranial displacement and invagination of a tracheal segment creating the flap-like lesion. Tracheal intussusception should be considered as a cause of an annular tracheal mass.     

Tracheal morphometrics in the Thoroughbred horse

Equine tracheal lesions have been associated with the orotracheal intubation procedure. These lesions may occur because of differences in the dimensions of the endotracheal tube and the trachea. The importance of the dimensions of the trachea for studies on respiratory mechanics and the lesions produced by the endotracheal tubes encouraged us to determine the size of trachea of the Thoroughbred horse. This study determined and compared the length and internal diameters of the tracheas from 59 Thoroughbred horses, 35 males and 34 females, weighing between 400 kg and 500 kg, and free of signs of respiratory or cardiopulmonary diseases. The tracheas were removed from the horses between 2 and 12 hours after death. The internal diameters were measured in tracheal rings one, twenty, forty and the last before the carina. The length of each trachea was measured in both the normal and extended state. The number of tracheal rings was also determined. In the unstretched trachea, the width of the last tracheal ring and the number of tracheal rings were significantly greater in males than females. The results of this study provide information for better design and manufacturing of endotracheal tubes and as basic information for further studies on equine respiratory mechanics.     

Dynamic tracheal collapse as a cause of exercise intolerance in a thoroughbred

A 2-year-old Thoroughbred filly was admitted to the hospital for evaluation of exercise intolerance. Resting videoendoscopic evaluation (i.e., while the horse was standing) of the nasopharynx and trachea revealed right arytenoid paresis and a tracheal defect that was 100 cm distal to the external nares. Surgery, consisting of a right prosthetic laryngoplasty, was performed. However, postoperative videoendoscopic evaluation revealed minimal abduction of the affected arytenoid cartilage. Dynamic videoendoscopic evaluation (i.e., while the horse was exercising) revealed the right arytenoid to be fixed in a submaximal position with no evidence of collapse into the airway. When the endoscope was positioned in the midcervical tracheal region, marked tracheal collapse was identified during exercise. Tracheal collapse can critically limit athletic function. Treatment of tracheal collapse depends on causative factors, the length of the trachea involved, and accessibility of the affected tracheal segment. The use of dynamic tracheal videoendoscopy should be considered in athletic horses with exercise intolerance in which the cause cannot be determined from resting or dynamic videoendoscopic evaluations of the nasopharynx.     

COMPUTED TOMOGRAPHIC,RADIOGRAPHIC, AND ENDOSCOPIC TRACHEAL DIMENSIONS IN ENGLISH BULLDOGS WITH GRADE 1 CLINICAL SIGNS OF BRACHYCEPHALIC AIRWAY SYNDROME

Tracheal hypoplasia is commonly seen in English Bulldogs affected with brachycephalic airway syndrome. Previously published diagnostic criteria for tracheal hypoplasia in this breed have been a radiographic tracheal diameter:tracheal inlet ratio (TD:TI) < 0.12 or a tracheal diameter:third rib diameter ratio (TD:3R) < 2.0. Computed tomography has become increasingly used for airway evaluation, however published information is lacking regarding CT tracheal dimensions in English Bulldogs. Objectives of this prospective cross‐sectional study were to describe radiographic and CT tracheal dimensions in a sample of clinically normal English Bulldogs and compare these values with tracheoscopy scores. Computed tomography (n = 40), radiography (n = 38), and tracheoscopy (n = 40) studies were performed during a single general anesthesia session for each included dog. Tracheal measurements were recorded at three locations: cervical, thoracic inlet, and thorax. Tracheal diameters were narrowest at the thoracic inlet with all techniques. Computed tomographic measurements averaged 19% greater than radiographic measurements. All included dogs had radiographic tracheal measurements greater than the previously published criteria for tracheal hypoplasia. Mean CT TD:TI was 0.26 (± 0.03, 0.20–0.33), and mean CT TT:3R was 2.27 (± 0.24, 1.71–2.74). Radiographic TD:TI and CT TD:TI were significantly correlated (P = 0.00); however radiographic TT:3R and CT TT:3R were not significantly correlated (P = 0.25). Tracheoscopy identified hypoplastic changes in all dogs and tracheoscopy scores were not correlated with CT or radiography diameter measurements. In conclusion, findings indicated that some CT and radiographic tracheal diameter measurements were comparable in English Bulldogs however diameters for both imaging techniques were not comparable with tracheoscopy scores.     

CT-soft tissue window of the cranial abdomen in clinically normal dogs: an anatomical description using macroscopic cross-sections with vascular injection

The aim of this study was to provide a detailed anatomic atlas of the cranial abdomen by means of computed tomography (CT). Three mature dogs, all mixed breed males, were used. The dogs were sedated, anaesthetized and positioned in sternal recumbency. CT scans from the eighth thoracic vertebra to the fourth lumbar vertebra were performed using a third-generation equipment (TOSHIBA 600HQ scanner) with 1 cm slice thickness. CT-images of the cranial abdomen were taken with soft-tissue window (WL: −14, WW: 658) settings. Dogs were killed and vascular-injection technique was performed: red and blue latex filled the vascular system. Injected dogs were frozen in the same position as used for CT examination and sectioned with an electric bandsaw at 1-cm-thick intervals. The cuts matched as closely as possible to the CT-images. The anatomic sections were compared and studied with the corresponding CT-images, and clinically relevant abdominal anatomic structures were identified and labelled on the corresponding CT-images. The results of our study could be used as a reference for evaluating CT-images of the canine cranial abdomen with abdominal diseases.     

Effect of exercise on the partitioning of equine respiratory resistance

Pleural, tracheal, pharyngeal and mask pressures as well as airflow and tidal volume of five ponies on a treadmill (incline 8.3 degrees) were recorded simultaneously while resting, walking, trotting slowly, trotting fast, after standing for 30 secs and 5 mins after the end of the exercise. The curves obtained were used to calculate total pulmonary resistance (RL), lower airway resistance (RLA) and upper airway resistance (RUA). The latter was also divided into nasal resistance (Rnas) and laryngeal plus extrathoracic tracheal resistance (Retr + lar). Furthermore, the inspiratory and expiratory components of each of these R values were estimated. Levels of RL, RLA and RUA were increased significantly during exercise but, during the recovery period, the values were significantly lower than those pre-exercise. RUA represented 82 per cent of RL at rest and this percentage did not change significantly during and after exercise. The nasal resistance to RUA ratio was always higher than 0.5. The fact that RL increased with exercise intensity was due to the increase of RUA during inspiration, and mainly a result of the increase of RLA during expiration. At fast trot, RLA represented 5 and 50 per cent of RL during inspiration and expiration respectively. It was concluded that heavy exercise induces in ponies an increase of RL, one reason for which could be the partial collapse of the extrathoracic and intrathoracic airways during inspiration and expiration respectively.     

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.     

Adenosquamous Carcinoma of the Trachea in a Domestic Ferret (Mustela putorius furo)

A 4-year-old, castrated, male domestic ferret (Mustela putorius furo) was evaluated for a possible upper respiratory tract infection and wheezing for approximately 3 weeks. Supportive care for a suspected upper respiratory tract infection was initiated; however, the patient became progressively more dyspneic over the next 48 hours. A possible tracheal mass was identified upon thoracic radiographic imaging of the ferret. Tracheoscopy and a computed tomography scan of the neck and thorax confirmed the presence of a tracheal mass approximately 3 cm from the larynx obstructing 80% of the tracheal lumen. Rather than pursuing surgical resection, the owners elected humane euthanasia. An adenosquamous carcinoma of the trachea was diagnosed after histologic analysis. This tumor type has been diagnosed in the lungs of ferrets that were experimentally exposed to carcinogens found in cigarette smoke; however, there are no previous reports of this or any other tumor type associated with the ferret trachea. A tracheal mass causing a partial upper airway obstruction should be considered within the differential disease diagnosis list when a ferret is presented with dyspnea.