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.

Atypical manifestations of feline inflammatory polyps in three cats

Inflammatory polyps of the feline middle ear and nasopharynx are non-neoplastic masses that are presumed to originate from the epithelial lining of the tympanic bulla or Eustachian tube. The exact origin and cause are unknown, however, it is thought that inflammatory polyps arise as a result of a prolonged inflammatory process. It is unclear whether this inflammation initiates or potentiates the development and growth of inflammatory polyps. Cats with inflammatory polyps typically present with either signs of otitis externa and otitis media or with signs consistent with upper airway obstruction. Traditional diagnostics involve imaging of the tympanic bulla either with skull radiographs or computed topography (CT). Treatment consists of traction and avulsion of the polyp with or without ventral bulla osteotomy (VBO) to remove the epithelial lining of the tympanic bulla. The three cases described here are unusual manifestations or presentations of feline inflammatory polyps that address the following issues: (1) concurrent otic and nasopharyngeal polyps, (2) potential association with chronic viral infection, (3) polyp development in the contralateral middle ear, (4) CT appearance of the skull following VBO, and (5) development of secondary pulmonary hypertension.

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.

Nasopharyngeal stenosis secondary to soft palate dysgenesis in a cat

This report is the first description of soft palate dysgenesis inducing nasopharyngeal stenosis in a cat. The symptomatology included continuous stertorous respiration and changes in phonation. Open-mouth breathing, seromucous nasal discharge and sneezing were intermittently present. On physical examination the cat showed a respiratory pattern characteristic of upper airway disease, with stridor, increased inspiratory effort and severe bilateral obstruction of nasal passages to the airflow. Pharyngo-laryngoscopic evaluation showed an abnormal conformation of the soft palate that appeared attached to the caudal and lateral pharyngeal wall and stretched the whole length of the pharynx. A strip of soft tissue emanated from the caudal part of the hard palate to the right aspect of the base of the tongue. Caudal to this strip of tissue, the intrapharyngeal opening was stenosed, therefore preventing normal airflow. Surgical reconstruction was not recommended. The cat was clinically stable with mild respiratory symptoms 17 months after the diagnosis.

Prevalence and pathology of camel nasal myiasis in eastern areas of Iran

Camel botfly, Cephalopina titillator, causes severe economic losses to the camel industry in many camel-producing areas of the world. A total of 1328 camels, of different age groups and of both sexes, slaughtered at Mashhad Slaughterhouse, Khorasan Razavi Province, eastern Iran were inspected for infestation with larvae of C. titillator. After slaughtering, the head was dissected and grossly inspected for presence of C. titillator larvae and other gross abnormalities. Seven hundred and seventy one camels (58.1%) were infested with this larvae and the rate of infestation was significantly greater in the colder months (69.8%) compared to those of warmer ones (36.2%) and in males (65.0%) compared to those of the female camels (45.60%). The prevalence rate was lower in camels younger than 2 years old (39.8%) compared to those of 2-6 (61.5%) and over 6 years old (62.8%). Proper tissue sections from nasal cavity, pharynx, turbinates and frontal sinuses of 30 infested and 10 uninfested camels processed routinely for histopathological studies. The mucous membranes of the nasopharynx and frontal sinuses of the heavily infested camels were congested, swollen, edematous, occasionally haemorrhagic and infrequently occupied by copious amounts of muco-fibrinous exudates. Dark brown or black nodules were seen in the mucous membrane of these structures. The main histopathologic changes were desquamation, hydropic degeneration and hyperplasia of the mucosal epithelium with focal or diffused infiltration of lymphocytes, plasma cells, macrophages, eosinophils and fibroblasts in the mucosa and submucosal layers. Hyperemia of the blood vessels of the nasopharyngeal wall, goblet cell hyperplasia and cystic dilatation of submucosal secretory glands were also present in the heavily infested animals. This investigation was designed to record the prevalence together with gross and histopathological changes observed due to C. titillator in camels in eastern provinces of Iran.

Squash-preparation cytology from nasopharyngeal masses in the cat: cytological results and histological correlations in 30 cases

Upper airway obstruction in cats can be a life-threatening condition. Early recognition of clinical signs and an appropriate diagnostic approach increases the possibility of appropriate therapeutic choices. The purpose of this study was to assess the efficacy and diagnostic value of squash-preparation cytology in providing an accurate diagnosis of masses growing in the nasopharynx of cats. Cytological specimens prepared by a squash technique from nasopharyngeal masses in 30 cats were collected under direct endoscopic guidance and classified into four groups: benign inflammatory/hyperplastic mass, lymphoma, carcinoma and sarcoma. The cytopathological diagnosis was compared with the final histopathological diagnosis and indices of diagnostic test accuracy were calculated. The results showed good agreement between the cytological and histological diagnosis with a sensitivity of 0.94, a specificity of 0.81, a positive likelihood ratio of 0.9, a negative likelihood ratio of 0.9 and an overall accuracy of 0.9. Squash-preparation cytology is considered an accurate diagnostic tool for distinguishing benign from malignant nasopharyngeal masses in cats. For differentiation of lymphoma and lymphoid reactions histopathological confirmation is recommended.

Stenotic nasopharyngeal dysgenesis in the dachshund: seven cases (2002-2004)

Medical records of seven dachshunds with congenital nasopharyngeal stenosis from abnormally thickened palatopharyngeal muscles were reviewed. The intrapharyngeal ostium in all cases consisted of only a narrow slit. Dogs were presented with various clinical signs--the most common being dyspnea, expiratory cheek puff, salivation, pharyngeal dysphagia, oral dysphagia (to a lesser extent), and macroglossia. Diagnostic procedures included direct pharyngeal inspection, pharyngeal and thoracic radiography, fluoroscopy, lingual ultrasonography, biopsies in two dogs, and a postmortem examination in one dog. Diagnoses were readily made with radiographs and visual examinations. Macroglossia was confirmed with transcutaneous ultrasonography or a transmandibular finger test.

Diagnosis and surgical treatment of a nasopharyngeal cyst in a dog

A 21-month-old boxer dog was presented with clinical signs caused by nasopharyngeal obstruction. A mineralised mass in the nasopharynx was identified by radiography. Computed tomography allowed accurate anatomical localisation of the cystic lesion and identification of an ossified wall. Surgical removal of the mass by a ventral approach resulted in complete resolution of clinical signs. Histopathological examination strongly suggested that the cyst was derived from remnants of Rathke's pouch.

Balloon dilatation of nasopharyngeal stenosis in a dog

CASE DESCRIPTION

A dog was examined because of a 6-month history of upper airway stridor that began after postoperative regurgitation of gastric contents.

CLINICAL FINDINGS

Constant stridor was evident during inspiration and expiration, although it was worse during inspiration. The stridor was no longer evident when the dog's mouth was manually held open. Computed tomography, rhinoscopy, and fluoroscopy were used to confirm a diagnosis of nasopharyngeal stenosis.

TREATMENT AND OUTCOME

The dog was anesthetized, and balloon dilatation of the stenosis was performed. Prednisone was prescribed for 4 weeks after the procedure to decrease fibrous tissue formation. Although the dog was initially improved, signs recurred 3.5 weeks later, and balloon dilatation was repeated. This time, however, triamcinolone was injected into the area of stenosis at the end of the dilatation procedure. Two months later, although the dog did not have clinical signs of stridor, a third dilatation procedure was performed because mild stenosis was seen on follow-up computed tomographic images; again, triamcinolone was injected into the area of stenosis at the end of the dilatation procedure. Three and 6 months after the third dilatation procedure, the dog reportedly was clinically normal.

CLINICAL RELEVANCE

Findings suggest that balloon dilatation may be an effective treatment for nasopharyngeal stenosis in dogs.

Long-term epidemiology, effect on body condition and interspecific interactions of concomitant infection by nasopharyngeal bot fly larvae (Cephenemyia auribarbisandPharyngomyia picta, Oestridae) in a population of Iberian red deer (Cervus elaphus hispanicus)

We studied the pattern of infection and the inter-annual variation and individual factors affecting the infection of 2 species of nasopharyngeal bot flies,Cephenemyia auribarbisandPharyngomyia picta(Diptera: Oestridae), in a population of Iberian red deer (Cervus elaphus hispanicus) from south central Spain (10 annual periods between 1990 and 2003). Mean prevalence±S.E.95%CIof infection was 35·19±4·24% (n=486). The frequency distribution of the parasites was markedly aggregated (K: 0·213, mean abundance±S.D.: 5·49±12·12). Parasite load of Oestridae peaked at calf and subadult age groups and declined thereafter, which suggests that acquired immunity may be acting. In common with other host–parasite relationships, male hosts were found to have higher prevalence and abundance levels than females. The prevalence ofP. pictawas positively affected by the presence ofC. auribarbiswhereas the intensity of infection ofP. pictawas negatively affected by the presence ofC. auribarbis. Intensity ofP. pictain concomitant infections withC. auribarbiswas lower than in pureP. pictainfections, whilst the intensity ofC. auribarbisinfections did not change. This provides good evidence of interspecific competence, which could be dealt with by parasites by means of asynchronous life-cycles and different maturation periods. Weather also affects the dynamics and transmission rates of these parasites. Previous annual rainfalls positively affected the level of infection with oestrids. Yearly autumn rainfalls affected positivelyP. picta, possibly due to an effect on the pupal stage survival. Infection of Oestridae affected body condition in calves and subadults, suggesting that oestrids could have sublethal effects on Iberian red deer. Future research is needed to investigate the effect of parasites on the dynamics of the Iberian red deer.

Use of positive contrast rhinography and intranasal sinography for diagnosis of a nasofacial sinus tract in a dog

Twelve days after a dog fight, a 2-year-old sexually intact female Bulldog was evaluated because of subcutaneous emphysema of increasing severity throughout the dogs body. Thoracic radiography revealed severe pneumomediastinum from which free air had extended into the retroperitoneal space, resulting in pneumoperitoneum. Tracheoscopic examination did not reveal a discontinuity of the trachea, pharynx, or larynx. A breach between the nasal cavity and subcutaneous tissues of the nasal region was suspected. Further diagnostic investigations included positive contrast rhinography and intranasal sinography. Via an angiographic catheter inserted into the left naris, positive contrast intranasal sinography revealed a sinus tract extending between the left nasal cavity and the subcutaneous tissue of the dorsal aspect of the nasal planum. Resolution of subcutaneous emphysema, pneumomediastinum, and pneumoretroperitoneum began 1 day after surgical closure of the intranasal opening of the sinus tract. To the authors' knowledge, this radiographic technique has not been reported.

Balloon dilatation of nasopharyngeal stenosis in a cat

A cat was diagnosed with nasopharyngeal stenosis on the basis of clinical signs, survey and contrast radiography, endoscopy and magnetic resonance imaging. The condition was successfully managed with repeated balloon dilatation.

Balloon dilation for the treatment of chronic recurrent nasopharyngeal stenosis in a cat

Balloon dilation was used for the treatment of a recurrent nasopharyngeal stenosis in a cat with chronic stertorous breathing. The procedure was performed on three occasions at intervals of three and four months using a 15 mm valvuloplasty balloon dilation catheter. After the first dilation, clinical signs reappeared within two weeks due to re-stenosis. After the second dilation, all signs of nasopharyngeal disease disappeared, and did not recur. Endoscopic re-evaluation after four months revealed a markedly enlarged nasopharyngeal opening with some degree of stenosis, and a third balloon dilation was performed. Five months later, the cat remained without clinical signs, although some recurrence of the stenosis was visible endoscopically. Complications occurred after the first dilation, and included mild conchal necrosis and transient mucopurulent discharge. Balloon dilation is a minimally invasive technique and can be a successful procedure for treating nasopharyngeal stenosis in cats.

Rhinoscopy, pharyngoscopy, and laryngoscopy

Rhinoscopy, pharyngoscopy, and laryngoscopy are important procedures to include in the workup of patients with upper airway disorders. They are simple to perform, yield important information, spare the patient from undergoing invasive rhinotomy, and improve client relations when a diagnosis is reached.

Management of inflammatory polyps in 37 cats

The case records of 37 cats treated for nasopharyngeal or aural inflammatory polyps were reviewed. Thirty of them were managed conservatively with the polyp being removed by traction alone. Long-term follow-up information was available for 22 cats, of which 13 (59 per cent) had no recurrence of clinical signs. The remaining nine cats required recurrent polyps to be removed surgically. Cats with only nasopharyngeal polyps were nearly four times more likely to be cured by traction alone than cats with aural polyps, and none of the cats that was treated with prednisolone after traction suffered a recurrence. Cats with more severe aural signs were more likely to require surgery.

Radiographic anatomy of the cribriform plate (Lamina cribrosa)

The radiographic appearance of the cribriform plate was investigated in 16 canine cadaver heads. The cribriform plate appeared as a "V"-shaped multilinear bone-opaque stripe in the caudal nasal region in projections perpendicular to the hard palate in 6 dogs with a skull index between 50.00 and 54.00. In 9 dogs with a skull index between 55.40 and 74.40, the cribriform plate had a more "C"-shaped and sharp appearance. In vertically oblique projections with an obliquity greater than 20 degrees, the cribriform plate lost its sharp outline and finally (40 degrees) disappeared. In lateral projections the cribriform plate appeared as a "C"-shaped interrupted bone-opaque stripe in all 16 dogs. In more brachycephalic dogs frontal bone structures superimposed on the cribriform plate on ventrodorsal and dorsoventral views and accentuated the radiographic appearance of the plate. Vertically oblique views separated both structures to produce two lines.

Use of a mucosal advancement flap for the treatment of nasopharyngeal stenosis in a cat

A three-and-a-half-year-old male neutered domestic short-haired cat was presented with a three-year history of stertor and intermittent open-mouth breathing. No airflow was detected from either nostril when checked using a cold slide test. Oropharyngeal swabs were positive for calicivirus, while skull radiographs were suggestive of a dorsal deviation of the soft palate. The diagnosis of nasopharyngeal stenosis was confirmed via cannulation of the nasal passages and direct examination of the oropharynx under general anaesthesia. A midline approach through the soft palate was used to excise the adhesions. The resulting defect was reconstructed by advancement of a mucosal flap elevated from the dorsal nasopharynx and laryngopharynx. The cat was free of clinical signs 28 months later.

Nasopharyngeal diseases in cats: a retrospective study of 53 cases (1991-1998)

The records of 53 cats with nasopharyngeal disease were examined. Of the cats with nasopharyngeal disease, 49% had lymphosarcoma and 28% had polyps. Clinical signs in these cats were compared to 24 cats with nasal disease alone. Cats with only nasal disease more commonly had historical nasal discharge and sneeze, whereas cats with nasopharyngeal disease more often had stertorous respiration, phonation change, and typically reported less nasal discharge or sneeze. It is important to include nasopharyngeal disease in the differential diagnosis for cats with nasal discharge, sneeze, stertor, or phonation change.

Surgical repair of nasopharyngeal stenosis in a cat using a stent

An intraluminal stent was used to maintain patency of a recurrent nasopharyngeal stenosis (NPS) in a cat. The stenotic membrane within the nasopharynx was resected, and a 2-cm long, braided-wire endoprosthesis was placed as a stent. The patient was evaluated at one day, six weeks, 19 weeks, and 49 weeks following surgery. The cat tolerated the stent well. The 19-week recheck revealed granulation tissue partially obstructing the pharyngeal aspect of the stent which was subsequently surgically resected. Complications after excision of the granulation tissue included intermittent upper respiratory congestion and nasal discharge. The 49-week recheck showed no increased granulation tissue; however, upper respiratory congestion was still present. This particular stent, and its use as described in this paper, is recommended in cases of chronic recurrent NPS.

Localization and migration route of Cephalopina titillator (Diptera: Oestridae) larvae in the head of infested camels (Camelus dromedarius)

The localization and migration routes of Cephalopina titillator larvae were studied in the heads of 45 naturally infested camels. Larvae were located in the pharyngeal cavity (95.6%), the labyrinth of the ethmoid bone (71.1%), the turbinates (28.9%) and the lower nasal meatus (6.7%). Out of 261 first-instar larvae, 73.7% were found in the labyrinth of the ethmoid bone and 26.3% in the turbinates, while 88.9% of second-instar larvae were observed in the pharyngeal cavity and 11.1% in the labyrinth of the ethmoid bone. Most third-instar larvae (91.9%) were found in the pharyngeal cavity, with a few larvae in the labyrinth of the ethmoid bone (6.5%) and lower nasal meatus (1.6%). The first moult occurred in the labyrinth of the ethmoid bone. The second moult was observed in both the labyrinth of ethmoid bone and the pharyngeal cavity. The migration route of these larvae in the infested head was discussed.

Choanal atresia and secondary nasopharyngeal stenosis in a dog

A 20-month-old, intact male shih tzu was evaluated for chronic upper airway disease. Endoscopic examination established a diagnosis of choanal atresia, a developmental anomaly of the posterior nasal cavity. Although surgical intervention provided temporary relief, stenosis of the nasopharynx by obstructive scar tissue was confirmed within four weeks. A permanent tracheostomy provided long-term relief of the respiratory difficulty. This is the first report of choanal atresia or nasopharyngeal stenosis in a dog.

Oestrosis in red deer from Spain

A survey of naso-pharyngeal myiasis affecting red deer (Cervus elaphus) in southern Spain was conducted. The parasites involved were the larvae of Pharyngomyia picta and Cephenemyia auribarbis (Diptera:Oestridae), which coexist sympatrically within this host. Males and older animals had higher prevalences and intensities of fly larvae. Differences in behaviour and habitat use by male and female deer, and the increase of head size in older males are possibly responsible for this. There were low densities of C. auribarbis while P. picta was the species most frequently observed, although both oestrids were located in the same host cavities. The earlier larviposition by C. auribarbis, and its faster larval development may reflect asynchronous life-cycles of both oestrids; this may decrease inter-specific competition between these sympatric species.

Spontaneous proliferative lesions in the nasopharyngeal meatus of F344 rats

Spontaneous proliferative lesions in the nasopharyngeal meatus were identified as the cause of death in 12 of 1,600 male and 5 of 1,600 female Fisher 344 (F344) rats used in 2-yr carcinogenicity studies; none of the lesions were considered treatment related. All the rats showed dyspnea, abdominal distension, and clinical deterioration. Gross features were characterized by simultaneous occurrence of conspicuous gaseous distension of the intestinal tract, especially in the ileum and cecum, and focal nodular lesions in the nasopharyngeal meatus. Histopathologically, the nasopharyngeal meatus was partially obstructed by the following proliferative lesions: 3 areas of hyperplasia of the ectopic sebaceous glands in the soft and hard palate, 4 areas of squamous metaplasia (SM) with massive hyperkeratosis, 5 squamous cell papillomas (SCPs), and 5 squamous cell carcinomas (SCCs). No pathological changes were found in the distended portion of the intestinal tract. Formalin-fixed, paraffin-embedded samples of the proliferative lesions from the nasopharyngeal meatus were examined for the presence of mutations in the c-H-ras and c-K-ras genes. In vitro amplification of DNA using a polymerase chain reaction was combined with a nonisotopic method for selective oligonucleotide hybridization. Two of the 4 SM lesions, 3 of the 5 SCPs, and 5 of the 5 SCCs contained 1-3 point mutations in the c-H-ras and/or c-K-ras gene. Immunohistochemically, overexpression of p53 protein was found in 1 area of SM with a dysplastic lesion and 2 SCCs. These findings indicate that detailed examination of the upper respiratory system, including the nasopharyngeal meatus, may be particularly helpful for identifying primary occult lesions in F344 rats that show only gut distension at necropsy in long-term toxicity studies. In addition, mutations of the ras genes may be an important step in the early stages of carcinogenesis in the rat nasopharyngeal meatus, whereas p53 mutations could occur relatively late.

Field examination of the equine patient with nasal discharge

This article describes the field investigation of horses with nasal discharge (serous, purulent, blood and feed). Flow charts on how to evaluate affected horses, and photographs of the examination procedures and of horses affected with nasal discharge are included.

Nasopharyngeal cryptococcosis

Naturally occurring cryptococcosis in five cats, a dog and a koala is described. Involvement of the nasopharynx was documented in all patients, and nasopharyngeal mass lesions accounted for the major presenting complaints in four. Signs referable to nasopharyngeal disease included snoring, stertor, inspiratory dyspnoea and aerophagia. Diagnoses were made by caudal rhinoscopy using a retroverted flexible endoscope, vigorous orthograde flushing with saline, or at necropsy. Concurrent cryptococcal rhinitis was present in all cases, although involvement appeared limited to the caudal nasal cavity in most cases. Typical signs of nasal cavity disease, such as sneezing and nasal discharge, were often absent. Treatment of nasopharyngeal cryptococcosis should include physical dislodgement or debulking of lesion(s) to provide immediate alleviation of upper airway obstruction, followed by systemic antifungal therapy to eliminate residual infection from the nasal cavity. Infections caused by Cryptococcus neoformans var gattii accounted for a disproportionately large number of these cases.

Nasopharyngeal conidiobolomycosis in a horse

Nasopharyngeal conidiobolomycosis caused by Conidiobolus coronatus was diagnosed in a horse after endoscopic and histopathologic examinations of a biopsy specimen. The fungal lesions in the nasopharynx were substantially reduced in size after intralesional injection of amphotericin B through the biopsy channel of a videoendoscope in combination with i.v. administration of sodium iodide and oral administration of potassium iodide during a 2-month period. Endoscopy performed 15 months after initial examination revealed regression of the granulomatous masses in the nasopharynx and complete disappearance of the nasal masses. Two months later, clinical signs recurred, and the owner elected euthanasia without evaluation and treatment. Nasopharyngeal conidiobolomycosis may be treated successfully with intralesional injection of amphotericin B in combination with administration of sodium iodide and potassium iodide, but there is a possibility of recrudescence of infection.

Nasopharyngeal epidermal cyst in a dog

Plain film radiography, magnetic resonance imaging, and histologic evaluation were used to diagnose nasopharyngeal epidermal cyst in a 12-year-old male Miniature Poodle with inspiratory stridor. The cyst was lined with stratified squamous epithelium, with variable keratinization. Most of the epithelium was well-differentiated and supported by a fibrovascular tissue separating it from underlying woven bone. One margin of the mass had a transition from stratified squamous to columnar respiratory epithelium. Other reported epidermal cysts in dogs have been confined to the middle ear or intracranial area. This case was unique, because the mass was located in the nasopharyngeal area, causing airway obstruction. This lesion was most likely acquired rather than congenital, because the dog had a history of middle ear inflammation, as well as bite wound trauma to the throat region. The mass was successfully removed by use of a transpalatal approach, and signs attributable to respiratory obstruction were alleviated. The dog had no abnormal clinical signs several months after the procedure.

Transnasal incision of restrictive nasopharyngeal cicatrix in three horses

Three horses were found to have an extensive nasopharyngeal cicatrix that was responsible for respiratory impairment. The cicatrization was diagnosed by use of endoscopy during evaluations of the horses for inspiratory stridor. All 3 horses were treated by endoscope-guided transnasal incision of the cicatrix and were able to resume their previous activities.

[Imported infestations of nasopharyngeal parasites in dogs]

In this paper infestations of the nasal cavity with Myxobdella annandalei in a dog after a sojourn in Nepal and with Linguatula serrata in 2 stray dogs from Turkey, which were imported to Germany, are described.

Nasal and retrobulbar mass in a cat caused by Pythium insidiosum

Nasal and retrobulbar infection caused by the Oomycete Pythium insidiosum is described in a cat. The diagnosis was established on three criteria. The staining of broad, sparsely septate hyphal elements in biopsy tissue using a fluorescein-labelled antiglobulin specific for P. insidiosum, detection of antibodies to P. insidiosum by an immunodiffusion test, and isolation of the aetiological agent in pure culture from the biopsy tissue. Treatment with ketoconazole for 6 weeks resulted in clinical improvement, but proptosis of the left eye slowly appeared after the discontinuation of treatment. This case represents a new host for P. insidiosum, namely, a domestic, shorthaired cat, from North Carolina, U.S.A.

Cryptococcosis of the nasopharynx in mice and rats

An attempt to infect the upper respiratory tract of mice and rats with various bacteria and fungi by intranasally instillation was performed. Cryptococcus neoformans was the only agent to invade the tissue. The infection was limited to the nasopharynx, a phenomenon which probably indicates the presence of a specific chemotaxis or receptor.

Effects of Cephenemyia spp. (Diptera: Oestridae) on the nasopharynx of black-tailed deer (Odocoileus hemionus columbianus)

A study was conducted to determine gross and microscopic tissue changes in the nasopharynx of black-tailed deer (Odocoileus hemionus columbianus) infected with nasal bot fly larvae (Cephenemyia spp.). Paired retropharyngeal recesses were the preferred sites for the growing second and third stage larvae of two species of Cephenemyia (C. apicata and C. jellisoni). Retropharyngeal recesses distended into "pouches" that harbored up to 30 larvae. Pouches were oriented caudal-laterally toward the basisphenoid bone of the cranium. Lateral support of the pouch mass was provided by the stylohyoid bone. The laryngeal orifice was never occluded by the enlarged recesses. The distal pouch wall was relatively thin and remained uniform in thickness as expansion progressed. Occasionally, aberrant larvae were found protruding through the distal wall of the pouch. Disruption of the epithelium and submucosa by larval mouth hooks and integumentary spines were examined by scanning electron microscopy. Histological examination of infected recesses revealed substantial loss of epithelium and mucous glands. Enlargement of recesses into pouches resulted from fibrosis. Healing occurred after larvae egressed from the pouches. Degenerating mucous glands, epithelial metaplasia, epithelial desquamation, and intense inflammation were found near larvae. An eosinophilic exudate with a mixture of macrophages and erythrocytes was present in the lumen of the pouch. The presence of larvae within the pouch inhibited secondary bacterial infection and suppuration. Infection by larvae caused severe local trauma and intense tissue response.

Nasopharyngeal cicatrices in horses: 47 cases (1972-1985)

Nasopharyngeal cicatrices were observed endoscopically in 47 horses examined because of abnormal respiratory noises and/or exercise intolerance. A review of these cases revealed a correlation between cicatrization and age, sex, and the presence of other upper airway abnormalities. The age of affected horses ranged from 6 to 21 years, with a mean age of 12.7 +/- 7.8 (+/- 2 SD) years. Females were affected 2.7 times more frequently than males. Abnormalities commonly observed with a nasopharyngeal cicatrix included chondritis of the arytenoid cartilage, epiglottic deformity, and deformity of the guttural pouch openings. The nasopharyngeal cicatrix was responsible for respiratory obstruction in only 3 horses. Treatment for the cicatrix was not performed on any horse in this series. Generalized nasopharyngeal and laryngeal inflammation were postulated as causes of the cicatrices and associated abnormalities.

Surgical and medical management of rhinophycomycosis (conidiobolomycosis) in a horse

A horse had severe granulomatous lesions of the upper airways that were attributable to Conidiobolus coronatus. Therapeutic success was documented by clinical examination of the horse 4 years after treatment by surgical extirpation and intralesional and topical use of amphotericin B.

The pathology of nasopharyngeal myiasis in Saudi Arabian camels (Camelus dromedarius)

Thirty-two out of thirty-five camels examined at Jeddah and Riyadh slaughter houses were infected with the camel nasal bot Cephalopina titillator. The larvae occurred mainly in the nasopharynx and, occasionally, degenerated larvae were found embedded between the turbinated bones. In the pharynx, the pathological changes included the formation of lymphoid nodules, with central abscesses, at the sites of larval attachment, and a combination of inflammatory, degenerative and reparative processes in other parts of the pharyngeal wall. The nasal cavity was congested and filled with mucus in which some larvae were entangled.

A survey for Anatrichosoma (Nematoda: Trichinellida) in wild-caught Macaca mulatta

One hundred rhesus monkeys which were captured from two geographical sites were tested for Anatrichosoma, a nematode that lives in the nasal passages. The monkeys were tested using both fecal examinations and nasal swabs. Three percent of the monkeys from one site were positive, and 68% from the other site were positive. Twenty-one percent of the animals tested by fecal examination were positive and 48% were positive using nasal swab examination.

Observations on the mechanism of functional obstruction of the nasopharyngeal airway in the horse

Fibreoptic endoscopy was used to study the movements of the larynx and pharynx during nasal occlusion in 10 horses, which showed signs consistent with functional pharyngeal obstruction (FPO) on exercise. Cine-endoscopic films were made on 3 such horses. Consideration of the anatomy of the region indicates that FPO may best be regarded as a subluxation of the nasopharyngeal and larygneal airways and it was found that a constant component of the movements which brought about this subluxation was a marked caudal retraction of the larynx. It is suggested that this caudal retraction of the larynx occurred as a result of the action of th sternothyrohyoid and omohyoid muscles and that removal of a portion of these muscles might prevent subsequent airway subluxation in horses prone to FPO on exercise.