Clinical and computed tomography findings in cats with nasopharyngeal stenosis

OBJECTIVES

Concurrent anomalies are often found in nasopharyngeal stenosis and choanal atresia; some seem to be of primary nature, whereas others may be coincidental. This study aimed to report the computed tomography features and related comorbidities of these diseases.

MATERIALS AND METHODS

A cross-sectional retrospective study was performed using case and control groups defined according to the presence of signs of upper airway disease and the presence/absence of nasopharyngeal stenosis, respectively. The inclusion criteria were full-head tomography scans and access to clinical records. The exclusion criteria were brachycephalic breed, head trauma and neoplasm. Clinical and computed tomographic findings and relevant comorbidities were recorded.

RESULTS

Forty-three cats were included, 23 cases and 20 controls. The case group was significantly younger, had more paranasal sinus anomalies and never had turbinate lysis, also, had significantly more soft palate anomalies, which was significantly shorter. Nasopharyngeal stenosis varied from membrane appearance to partial or complete adhesion of the soft palate to the nasopharynx, was mainly located in the caudal region of the nasopharynx and was imperforated in approximately half of the cases. Imperforated membranes were significantly thicker in the sagittal plane and were significantly associated with nasal obstruction and soft tissue attenuation of the tympanic bulla. Hiatal hernia and ventricular asymmetry were only encountered in three and two cases, respectively, with nasopharyngeal stenosis.

CLINICAL SIGNIFICANCE

Computed tomography in cats with nasopharyngeal stenosis can identify concurrent anomalies, can help to differentiate a possible choanal atresia and evaluate the magnitude of its significance.

Investigation of a retroesophagoscopic approach to nasopharyngoscopy as an alternative to the conventional retroflexed endoscopic approach for selected indications in feline cadavers and client-owned cats

OBJECTIVE

To describe a retroesophagoscopic approach (ROSA) to nasopharyngoscopy and compare it with the conventional retroflexed endoscopic approach (REA).

ANIMALS

36 feline cadavers and 2 client-owned cats with nasopharyngeal disorders.

PROCEDURES

36 veterinarians participated in the experimental portion of the study involving feline cadavers. Each veterinarian performed the ROSA and REA to nasopharyngoscopy on a feline cadaver once, attempting to identify and biopsy 2 landmarks (soft palate and choanae) with each approach while time was recorded. Numeric scales were used to measure perceived ease of use and image quality for both techniques. Data were compared between approaches by an independent statistician. The ROSA approach was also used as part of the diagnostic workup for the 2 client-owned cats.

RESULTS

35 of the 36 (97%) veterinarians were able to identify and biopsy both landmarks using the ROSA, whereas 21 (58%) veterinarians were able to visualize both landmarks using the REA and 19 (53%) successfully biopsied the landmarks. Image quality for the soft palate was scored higher with the ROSA (median score, 7.5/10) than with the REA (4.5/10). The ROSA was fast and easy to perform. This approach was also successfully performed in the 2 client-owned cats with nasopharyngeal disorders, with no complications reported.

CONCLUSIONS AND CLINICAL RELEVANCE

The ROSA was found to be a fast, effective, and easy alternative endoscopic technique for assessment of the nasopharynx in cats. This approach may allow use of various instruments that could be relevant for interventional procedures. However, the ROSA was also invasive and should be considered for diagnostic and therapeutic purposes for selected indications only when REA is unsuccessful.

Transpalatal reconstruction and stenting for treatment of choanal atresia and nasopharyngeal stenosis in a dog

CASE DESCRIPTION

A 3-year-old 17.5-kg (38.5-lb) mixed-breed dog was referred for evaluation because of nasal discharge, sneezing, and signs of nasal congestion of approximately 9 months' duration. A diagnosis of nasopharyngeal stenosis (NPS) was made prior to referral.

CLINICAL FINDINGS

Sneezing, bilateral mucopurulent nasal discharge, reduced nasal airflow, stertor, and increased inspiratory effort were noted on physical examination. Results of serum biochemical analysis were within respective reference ranges. Review of CT images of the skull revealed findings consistent with severe bilateral partial osseous choanal atresia and NPS. Retrograde rhinoscopy confirmed membranous NPS.

TREATMENT AND OUTCOME

A ventral rhinotomy was performed; communication between the pharynx and nasal passageway was reestablished by surgical debridement of the caudal border of the palatine bone and vomerine crest and groove, followed by dissection of the membranous NPS and reconstruction of the caudal part of the nasopharynx. A covered nasopharyngeal stent was placed in the newly established nasopharynx. The dog recovered uneventfully but was presented 3 weeks later with recurrent signs; diagnostic findings were consistent with stenosis rostral to the stent. The stenosis was treated with balloon dilation, and a second covered stent was placed rostral to and overlapping the first stent, spanning the stenotic region. Eleven months after this procedure, the dog was doing well.

CLINICAL RELEVANCE

Results for this patient suggested that ventral rhinotomy and covered nasopharyngeal stent placement can be used successfully for the management of osseous choanal atresia in dogs; however, careful attention to preoperative planning and potential complications is necessary.

Extended palatoplasty as surgical treatment for nasopharyngeal stenosis in six cats

OBJECTIVE

To describe the use of extended palatoplasty as treatment of caudal nasopharyngeal stenosis in cats.

MATERIALS AND METHODS

CT was used to confirm the diagnosis in cats with clinical signs consistent with nasopharyngeal stenosis. Extended palatoplasty rostral to the tonsils using monopolar electrocautery allowed simultaneous removal of the caudal soft palate together with the stenotic area. Cats were re-evaluated 2 weeks postoperatively. Telephone interview was used to obtain long-term follow-up.

RESULTS

Six domestic shorthair cats were diagnosed with nasopharyngeal stenosis, with clinical signs of snoring (n=4), stertor (n=4), nasal discharge (n=3) and sneezing (n=1). CT scan identified a soft-tissue stricture at the level of the caudal nasopharynx in all cats. Other abnormalities included bilateral rhinitis (n=3), retropharyngeal adenomegaly (n=2), unilateral sinusitis (n=1) and bilateral otitis externa with unilateral otitis media (n=1). Excision of the caudal soft palate and the entire stenotic soft-tissue membrane was successful in all six cats. No pre-, intra- or postoperative complications were observed. Short-term outcome revealed clinical improvement in all cases. Long-term outcome revealed no recurrence of clinical signs in four cats. In one cat, occasional sneezing was reported. One cat died 1 month postoperatively for reasons unrelated to the respiratory condition.

CLINICAL SIGNIFICANCE

Extended palatoplasty was an effective technique to treat caudal nasopharyngeal stenosis and provide improvement of clinical signs without postoperative complications in all cases.

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.

Use of a novel surgical approach for treatment of complete bilateral membranous choanal atresia in an alpaca cria

CASE DESCRIPTION A 4-hour-old 6.3-kg (13.9-lb) female alpaca cria was evaluated because of severe respiratory distress and difficulty nursing since birth. CLINICAL FINDINGS The cria had open-mouth breathing and cyanotic membranes, with no airflow evident from either nostril. Supplemental oxygen was delivered, and the patient was anesthetized and intubated orotracheally; a CT evaluation of the head confirmed bilateral membranous obstruction of the nasal cavities, consistent with complete bilateral choanal atresia. TREATMENT AND OUTCOME Choanal atresia was treated with an endoscopically assisted balloon-dilation technique, and temporary tracheostomy was performed. Stenosis recurred, requiring revision of the repair and intranasal stent placement 3 days after the first surgery. The tracheostomy tube was removed the next day. Complications during hospitalization included mucoid obstruction of the tracheostomy tube, granulation tissue development in the trachea near the tracheostomy site, mucoid stent obstruction, aspiration pneumonia, and presumed partial failure of passive transfer of immunity. The stents were removed 2 weeks after admission, and the cria was discharged 3 days later. The owner was advised that the animal should not be bred. At last follow-up 3 years later, the alpaca was doing well. CLINICAL RELEVANCE Surgical treatment with a balloon-dilation technique and placement of nasal stents with endoscopic guidance were curative in this neonatal alpaca with bilateral membranous choanal atresia. Computed tomography was useful to determine the nature of the atresia and aid surgical planning. Because a genetic component is likely, owners should be advised to prevent affected animals from breeding.

Signalment, clinical presentation, concurrent diseases, and diagnostic findings in 28 dogs with dynamic pharyngeal collapse (2008-2013)

Background

Most information about pharyngeal collapse in dogs is anecdotal and extrapolated from human medicine. A single case report describing dynamic pharyngeal collapse in a cat has been published, but there is no literature describing this disease process in dogs.

Objective

To describe the signalment, clinical presentation, concurrent disease processes, and imaging findings of a population of client‐owned dogs with pharyngeal collapse.

Animals

Twenty‐eight client‐owned dogs with pharyngeal collapse.

Methods

Radiology reports of dogs for which fluoroscopy of the respiratory system was performed were reviewed retrospectively. Patients with a fluoroscopic diagnosis of pharyngeal collapse were included in the study population. Data regarding clinical signs, diagnostic, and pathologic findings were evaluated.

Results

Twenty‐eight dogs met the inclusion criteria. The median age of affected patients was 6.6 years, whereas median body condition score was 7/9. The most common clinical signs were coughing (n = 20) and stertor (n = 5). In 27 of 28 cases, a concurrent or previously diagnosed cardiopulmonary disorder was detected. The most common concurrent disease processes were mainstem bronchi collapse (n = 18), tracheal collapse (n = 17), and brachycephalic airway syndrome (n = 8). Fluoroscopy identified complete pharyngeal collapse in 20 of 28 dogs.

Conclusions

Pharyngeal collapse is a complex disease process that likely is secondary to long‐term negative pressure gradients and anatomic and functional abnormalities. Based on the findings of this study, pharyngeal fluoroscopy may be useful diagnostic test in patients with suspected tracheal and mainstem bronchial collapse to identify concurrent pharyngeal collapse.

Upper respiratory tract endoscopy in the cat: a minimally invasive approach to diagnostics and therapeutics

CLINICAL CHALLENGES

Endoscopy of the feline upper respiratory tract has always taken a bit of a back seat to exploration of the canine nose and paranasal sinuses, pharynx and trachea, due to some anatomic limitations and lack of availability of appropriate-sized equipment.

PRACTICAL RELEVANCE

With proper training, however, even the inexperienced endoscopist can find that endoscopy and endoscopic surgery can be of tremendous utility in feline practice. What had previously been largely off-limits sites, in terms of direct visualization and surgical intervention, the feline rhinarium, paranasal sinuses, pharynx and trachea are now anatomic areas that can be effectively visualized in most clinical scenarios. Moreover, endoscopic surgery is now an area gaining significant appreciation for its diagnostic and therapeutic benefits.

AUDIENCE

This article will not serve as a complete treatise on disease processes of the upper respiratory tract in cats, but rather is intended as a technical and instructional reference point on upper airway endoscopy for veterinary surgeons, both in first opinion as well as referral small animal practice.

Treatment of acquired nasopharyngeal stenosis using a removable silicone stent

The aim of this prospective study was to characterise patient characteristics and the histories of cats with acquired nasopharyngeal stenosis (ANS), and to describe the use of a removable silicone stent for treatment. ANS was diagnosed in 15 cats with clinical signs present for a median of 4 months. Clinical signs included stertor and inspiratory difficulty, nasal discharge, sneezing, dysphagia, regurgitation, vomiting and anorexia. Radiographs revealed a dorsal deviation or deformation of the caudal part of the soft palate in 10 of the cats, a soft tissue density across the cranial nasopharynx in four and no abnormality in one. The stenosis was initially dilated with a Kelly forceps in 10 of the cats and by balloon dilatation in five. A segment of a 24 Fr silicone thoracic catheter was used for the stent in five cats; in the other 10 cats a segment of a 28 Fr catheter was used. The stent was removed after 3 weeks in 12 cats and after 4 weeks in the other three. Endoscopy revealed an adequate nasopharyngeal diameter in all of the cats. At both 3 and 10 months after surgery the response was considered to be satisfactory, with complete resolution of clinical signs in 14 cats and improvement in the remaining cat. The treatment of ANS by stenosis dilatation followed by temporary stenting with a silicone stent is a rapid, safe, economical and effective procedure.

Palatal erosion and oronasal fistulation following covered nasopharyngeal stent placement in two dogs

Treatment options for dogs with nasopharyngeal stenosis include fluoroscopic placement of metallic stents. Reported complications include entrapment of hair and food, obstruction and persistent nasal discharge. Two toy breed dogs were examined for persistent nasal discharge and halitosis at 4 and 20 months after placement of permanent metallic stents for acquired nasopharyngeal stenosis. Full thickness defects were found in the palate of both dogs, with extensive communication between the mouth and the nasal passages. Portions of the metal stent were observed within the lesion in both patients. Additional treatment was declined by the owner of one dog; the stent was removed through the fistula in the other dog. Palatal erosion with secondary oronasal fistulation is a potential complication of nasopharyngeal stent placement in dogs.

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.

Nasopharyngeal disease in cats: 2. Specific conditions and their management

PRACTICAL RELEVANCE

Nasopharyngeal disease is a common presenting problem in feline medicine.

CLINICAL CHALLENGES

The management of feline nasopharyngeal disease can be challenging at a number of levels. In many cases, a specific diagnosis may remain elusive. Some conditions may not be curable so owners need to understand the requirement for long-term management. In addition, treatment may be compromised by poor patient compliance.

AUDIENCE

This review, which is directed at any clinicians involved in the management of cats with nasopharyngeal disease, discusses acute rhinitis (cat 'flu) and a variety of conditions causing chronic rhinosinusitis/chronic nasopharyngeal disease. The intention is to assist treatment decision making by reviewing the most appropriate therapies from the options available for these patients.

EVIDENCE BASE

The information presented in this article is based on peer-reviewed publications and the clinical experience of the authors.

Recurrent pulmonary edema secondary to elongated soft palate in a cat

A 9-month-old intact female Persian cat presented with recurrent pulmonary edema secondary to an elongated soft palate. Endoscopic evaluation of the pharynx and larynx showed that the elongated soft palate was overlying the epiglottis. Partial resection of the soft palate was performed and the cat showed no further respiratory signs. This report is the first description of elongated soft palate causing airway obstruction in a brachycephalic cat.

Nasopharyngeal stenosis with concurrent hiatal hernia and megaesophagus in an 8-year-old cat

A case of nasopharyngeal stenosis with secondary hiatal hernia is described. An 8-year-old castrated male domestic shorthair cat was referred for a chronic upper respiratory problem and presumptive vomiting. Despite conservative management by the primary care veterinarian, the cat's condition progressed. The cat was presented to an emergency facility prior to referral to a specialty hospital. On presentation, inspiratory stridor was evident. Thoracic radiography revealed a hiatal hernia. Computed tomography indicated pharyngeal edema and probable nasopharyngeal stenosis. Endoscopy confirmed the presence of nasopharyngeal stenosis consistent with either stricture or choanal atresia. Balloon dilation of the choana was performed. The hiatal hernia regressed spontaneously post-resolution of the nasopharyngeal stenosis. The cat remained asymptomatic at recheck 3 months later.