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.     

COMPUTED TOMOGRAPHIC APPEARANCE OF INFLAMMATORY POLYPS IN THREE CATS

This report describes the use of computed tomography (CT) to evaluate the inner ear, tympanic bullae, nasopharyngeal area, and external ear canals of three cats. All cats presented for evaluation of upper respiratory signs or chronic ear infection. Nasopharyngeal masses were present in two cats, and a mass in the external ear canal was present in the third cat. In all three cats, CT was able to define the extent of osseous bulla involvement, which was confirmed at surgery. Computed tomography also defined the extent of the polyp in the nasopharyngeal area in two cats, and in the external ear canal in one cat. Surgical removal of the polyps was accomplished with a combined oral approach and ventral bulla osteotomy in cats 1 and 2. The polyp was removed from cat 3 using a combination of ventral bulla osteotomy and excision of the mass through the external ear canal. Microscopic examination confirmed all masses as nasopharyngeal (inflammatory) polyps.     

Feline inflammatory polyps: historical,clinical, and PCR findings for feline calici virus and feline herpes virus-1 in 28 cases

Inflammatory polyps are associated with significant aural or nasopharyngeal disease in cats. It has been proposed that chronic viral infection may induce the masses. Ventral bulla osteotomy (VBO) is usually recommended for definitive therapy but removal of masses from the nasopharynx or external ear canal by traction/avulsion is also used. A retrospective study of 28 cats with inflammatory polyps was conducted to correlate recurrence with mode of therapy. Tissues from 41 polyps were assayed for feline calicivirus and feline herpesvirus-1 by RT-PCR and PCR, respectively. Of the 14 cats initially treated by traction/avulsion, recurrence was detected in five of nine cats with radiographic evidence of bulla disease but none of the cats with normal bullae. Traction/avulsion is a reasonable treatment for inflammatory polyps if the bullae are radiographically normal. Failure to detect feline calicivirus and feline herpesvirus-1 suggests that tissue persistence of these viruses is not associated with the development of inflammatory polyps.     

BAER testing in a dog with bilateral external ear canal atresia

A 3 yr old male castrated Labrador retriever presented for evaluation and treatment of bilateral atresia of the external ear canals. The owners reported that the dog could hear only loud and high-pitched noises. Computed tomography of the head revealed intact vertical and horizontal ear canals filled with debris and a debris-filled right tympanic bulla. Air- and bone-conducted brainstem auditory evoked response (BAER) testing revealed an elevated response threshold to air-conducted stimuli and greater amplitude waveforms evoked by bone-conducted stimuli. The ear canals were surgically corrected via lateral ear canal resection. BAER testing postoperatively revealed a decrease in the air-conducted BAER threshold. This case is an example of the use of bone-conducted BAER testing to aid in the diagnosis of conductive deafness, and in determining prognosis for normal hearing after surgical treatment of external ear canal atresia.     

Nasopharyngeal and Middle Ear Polypoid Masses in Five Cats

Five cats with nasopharyngeal and middle ear polypoid masses are presented. The clinical signs included nasal discharge, sneezing, labored breathing, swallowing difficulty, and voice changes. Diagnosis was made by radiography and oropharyngeal examination. Surgical mangement consisted of local nasopharyngeal polyp resection in all cats, combined with ventral bulla osteotomy in three cats. Recurrence resulted in two of the five cats in which incomplete nasopharyngeal removal was performed initially, but not in the cats treated by bulla osteotomy. Four of the five cats were clinically normal 7 to 14 (median 13) months following surgery. The fifth cat had mild upper respiratory airway noise at 7 months. The histopathologic diagnosis of these growths was inflammatory tissue.     

Computed tomographic features of feline nasopharyngeal polyps

The computed tomographic (CT) findings of histopathologically confirmed nasopharyngeal polyps are described in 13 cats. Most polyps were mildly hypoattenuating to adjacent muscles and isoattenuating to soft-tissue (n= 13), homogeneous (n = 12) and with ill-defined borders (n = 10) on precontrast images. After contrast medium administration, the polyps were homogeneous (n = 11), with well-defined borders (n = 13), oval (n = 13), and had rim enhancement (n = 13). Nasopharyngeal polyps were pedunculated in 11 cats with a stalk-like structure connecting the polyp through the auditory tube to an affected tympanic bulla. All cats had at least one tympanic bulla severely affected, with CT images identifying: (1) complete (n = 12) or partial (n = 1) obliteration of either the dorsal or ventral compartments with soft-tissue attenuating material; (2) pathologic expansion (n = 13) with wall thickening (n = 10) that was asymmetric in nine cats; and (3) identification of a polyp-associated stalk-like structure (n = 11). Nine cats had unilateral tympanic bulla disease ipsilateral to the polyp, and four cats had bilateral tympanic bulla disease, most severe ipsilateral to the polyp with milder contralateral pathologic changes. Two cats had minimal osteolysis of the tympanic bulla. Enlargement of the medial retropharyngeal lymph node was seen commonly (n = 8), and in all cats it was ipsilateral to the most affected tympanic bulla. One cat had bilateral lymphadenopathy. CT is an excellent imaging tool for the supportive diagnosis of nasopharyngeal polyps in cats. CT findings of a well-defined mass with strong rim enhancement, mass-associated stalk-like structure, and asymmetric tympanic bulla wall thickening with pathologic expansion of the tympanic bullae are highly indicative of an inflammatory polyp.     

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.     

Inflammatory polyps of the middle ear in 5 dogs

OBJECTIVE: To describe inflammatory polyps of the middle ear in 5 dogs. STUDY DESIGN: Case series. ANIMALS: Five dogs with ear disease. METHODS: Medical records (1995-2001) were reviewed to identify dogs with inflammatory polyps of the middle ear. Signalment, clinical signs, ancillary diagnostic procedures, treatment, postoperative complications, and outcome were recorded. Owners and referring veterinarians were contacted to document outcome. RESULTS: Dogs with inflammatory polyps of the middle ear were male and aged 4 to 13 years. Two dogs had bilateral polyps, whereas 3 had unilateral polyps. The most common clinical presentation was otitis externa and media, with radiographic evidence of otitis media. Polyps were treated by ventral bulla osteotomy (VBO) in 1 dog and total ear canal ablation with lateral bulla osteotomy (TECA-LBO) in 4 dogs. Polyps consisted of a fibrovascular stroma infiltrated with neutrophils, macrophages, lymphocytes, and plasma cells. The overlying epithelium was frequently ulcerated. Immediate postoperative complications included a seroma after VBO (1 dog) and transient unilateral facial nerve paralysis after bilateral TECA-LBO (1 dog). No recurrence occurred within 9 to 69 months. CONCLUSIONS: Unilateral or bilateral, inflammatory polyps can occur in the middle ear of dogs in association with otitis externa and media. No recurrence occurred after surgical removal of the polyps. CLINICAL RELEVANCE: Inflammatory polyps of the middle ear in dogs can be a cause of otitis externa/media. Surgical removal of aural polyps has a good prognosis.     

Evaluation of auditory function in a population of clinically healthy cats using evoked otoacoustic emissions

Cats may demonstrate deafness due to a variety of aetiologies and the current preferred method for assessing auditory function is the brainstem auditory evoked response (BAER). The BAER has largely been replaced by otoacoustic emission (OAE) testing in human neonatal deafness screening as the equipment is more readily available, is cheaper and the test is less invasive and simpler. This is the first study to demonstrate that transient evoked OAEs (TEOAE) and distortion product OAEs (DPOAE) can be recorded in cats using commercially available equipment. Protocols for recording the emissions and analysing the results are given. DPOAE testing is suggested to be quicker in this population of healthy cats and shows promise in rapidly providing detailed information about auditory function at a variety of different frequencies.     

Use of BAER to identify loss of auditory function in older horses

Objective To use the brainstem auditory evoked response (BAER) to test the hypothesis that auditory function could be worse in older horses than in younger horses. Procedure BAER waveforms in response to click stimuli were measured in five younger horses (5–8 years) and four older horses (17–22 years). Results Compared with the younger horses, the older horses showed significantly (P < 0.02) worse BAER thresholds and significantly (P < 0.02) worse BAER wave V amplitudes to the 90 decibels above normal hearing level stimulus. These results were consistent with partial deafness in the older horse group. Conclusion BAER assessment can be used to identify partial deafness in older horses. Such horses should be managed appropriately, with particular care taken in noisy environments where hearing loss could put the horse and/or its owner at risk of harm.     

Nasopharyngeal polyps arising in the middle ear of the cat

The clinical presentation, diagnosis and surgical treatment of four cats with nasopharyngeal polyps are described. In three cats the microscopic appearance of the polyps together with the finding of radiographic densities in the tympanic bullae point to the middle ear as the origin of these polyps. These are inflammatory lesions and it is suggested that they occur as the result of ascending infection from the nasopharynx. Experience has shown that, in spite of recurrence in some cases, simple traction rather than bulla osteotomy is the preferred method of treatment.     

Nasopharyngeal polyps in cats

Nasopharyngeal polyps are non-neoplastic, inflammatory growths that arise from the middle ear or the eustachian tube and extend into the pharynx. The exact etiology of nasopharyngeal polyps is unclear; proposed etiologies include a response to chronic upper respiratory tract infection, chronic otitis media, ascending infection from the nasopharynx, or a congenital origin. Clinical signs usually relate to obstruction of the nasopharynx, with Horner's syndrome and head tilt being consistent with otitis media and otitis interna, respectively. Diagnostic tools include digital or visual examination above the soft palate, flexible fiberoptic caudal rhinoscopy, radiography, computed tomography, and magnetic resonance imaging. Ventral bulla osteotomy combined with traction removal of the polyp is the recommended treatment, although traction only followed by prednisolone therapy can be considered in some cases, especially when there is no evidence of otitis media.     

Wound Healing and Brain Stem Auditory Evoked Potentials After Experimental Ventral Tympanic Bulla Osteotomy in Dogs

Ventral tympanic bulla osteotomy was performed in 13 normal dogs to evaluate healing and retention of brain stem auditory evoked potentials (BSAEP). Healing was evaluated by gross and microscopic examination of the middle ears after 1 (n = 2), 4 (n = 8), 5 (n = 1), and 6 (n = 1) weeks. One dog was eliminated from the study. Brain stem auditory evoked potentials were measured using an air-conducted sound stimulus before and after surgery and before killing. Nine of 12 dogs re-formed the tympanic bulla by formation of fibrous connective tissue lined with cuboidal epithelium in the osteotomy site. Four of the nine dogs had a reduced tympanic bulla volume (estimated 20% to 40% volume reduction) caused by soft tissue ingrowth through the osteotomy. Nine of 12 dogs had proliferation of subperiosteal new bone from the inner surface of the tympanic bulla that varied in severity. Three of these nine dogs had nearly complete obliteration of the tympanic cavity by proliferating subperiosteal new bone. Eight dogs had nodules of granulation tissue containing new bone and mineralization diffusely distributed on the surfaces of the middle ear. The measured BSAEP sensitivity before killing was equivalent to preoperative levels in 11 dogs. The remaining dog had no change in auditory sensitivity after surgery but had a markedly reduced BSAEP detection threshold before killing. This appeared to be attributable to mechanical impingement on the ossicles and tympanic membrane by proliferating bone within the tympanic cavity. This study showed that after ventral tympanic bulla osteotomy the tympanic bulla rapidly re-forms with no deleterious effect on hearing in most dogs treated. However, the internal surfaces of the middle ear appear to be sensitive to surgical trauma, and extensive new bone proliferation is easily induced. This response may be extreme, resulting in middle ear obliteration and reduced auditory sensitivity.     

Computed tomographic evidence of bulla effusion in cats with sinonasal disease: 2001-2004

BACKGROUND: Sinonasal disease is common in cats; chronic inflammatory disease and neoplasia are diagnosed most frequently. Radiographic and computed tomographic (CT) findings in nasal disease have been reported, although involvement of other cranial structures has not been fully described to our knowledge. HYPOTHESIS: We hypothesized that neoplastic or inflammatory obstruction of the auditory tube associated with sinonasal disease could result in CT evidence of effusive bulla disease in affected cats. ANIMALS: 46 cats with sinonasal disease, 18 control cats. METHODS: CT images acquired in cats with (n = 46) and without (n = 18) sinonasal disease were reviewed for evidence of concurrent bulla effusion. CT findings of soft tissue or fluid opacity within the tympanic bulla or thickening of the bone of the bullae were considered evidence of effusive bulla disease. RESULTS: The prevalence of bulla effusion in cats with sinonasal disease was 28% (13/46) and was significantly higher than that observed in cats without sinonasal disease (1/18, P = .043). CT findings that were found in association with effusive bulla disease included imaging features of sinusitis and nasopharyngeal disease. The most common neoplasm associated with bulla effusion was nasopharyngeal lymphoma. Bulla effusion was not observed in any cat with nasal carcinoma. CONCLUSIONS AND CLINICAL IMPORTANCE: Findings of this study suggest that auditory canal dysfunction may play a larger role in feline sinonasal disease than was previously recognized. The implications of these findings for management of cats with chronic inflammatory or neoplastic sinonasal disease require further investigation.     

PATHOLOGIC BASIS FOR RIM ENHANCEMENT OBSERVED IN COMPUTED TOMOGRAPHIC IMAGES OF FELINE NASOPHARYNGEAL POLYPS

In postcontrast computed tomographic (CT) images, feline nasopharyngeal polyps typically demonstrate enhancement of the peripheral rim. Computed tomographic images and histologic specimens of a case series of 22 cats with surgically removed nasopharyngeal polyps were reviewed retrospectively in an attempt to elucidate the origin of rim enhancement. Polyps were present in the tympanic cavity in 15 (68%) cats (three with extension into the nasopharynx), only in the nasopharynx in four (18%) cats, and only in the external ear canal in the remaining three (14%) cats. All polyps had variable degrees of epithelial injury. Hemorrhage and inflammatory infiltration were significantly more marked in the superficial stroma whereas edema was significantly more marked in the core stroma. In noncontrast CT images (n = 22), the tympanic bulla was thickened in all 15 cats with a polyp in the tympanic cavity and enlarged in eight (53%) of these cats. In postcontrast CT images (n = 15), an outer zone of relatively increased attenuation compatible with a rim was observed in 11 (73%) polyps. The magnitude and extent of rim enhancement in CT images was positively correlated with the histologic grade of inflammation in the superficial stroma and negatively correlated with the grade of edema in the superficial stroma. It appears that inflammation is the major determinant of contrast medium accumulation in feline nasopharyngeal polyps, and the tendency for inflammation to affect predominantly the superficial layers explains the frequent observation of a rim in postcontrast CT images.     

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.     

Feline nasopharyngeal polyps.

In summary, an ideal diagnostic plan for cats with suspected FNPs should include a thorough anesthetized oropharyngeal examination, otoscopic examination, and imaging studies, which may consist of a bulla radiographic series or specialized imaging studies such as CT or MR scans. In general, if signs indicative of otitis media are present, ventral bulla osteotomy should be advised. As a result of the distinct appearance of FNPs, a preoperative biopsy is not indicated in all instances but should be considered if there are atypical features to the history or presentation. Traction-avulsion of polyps through the external ear canal or auditory tube from the oropharynx may have a lower success rate than traction-avulsion combined with ventral bulla osteotomy. If the veterinarian opts to treat FNPs by traction-avulsion alone as a result of financial constraints imposed by the client, the client should be strongly cautioned regarding potential recurrence. Postoperative complications are possible with any treatment option, but neurologic impairment, including Horner's syndrome, facial neuropathy, and hypoglossal neuropathy, is significantly more likely after surgical intervention by ventral bulla osteotomy than after traction-avulsion alone. A high percentage of these complications are self-limiting. In all instances, appropriate culture and sensitivity and biopsy specimens should be collected so as to enable provision of appropriate postoperative care. Antibiotic therapy should be provided based on culture and sensitivity test results. The use of postoperative steroids to prevent recurrence is controversial.     

Wound Healing and Brain Stem Auditory Evoked Potentials After Experimental Total Ear Canal Ablation With Lateral Tympanic Bulla Osteotomy in Dogs

Experimental total ear canal ablation with lateral tympanic bulla osteotomy (TECA-LBO) was performed in 13 normal dogs to evaluate healing and retention of brain stem auditory evoked potentials (BSAEP) after surgery. Healing was evaluated by gross and microscopic examination of the surgery sites after 1 (n = 2), 4 (n = 8), 5 (n = 1), and 6 (n = 1) weeks. One dog was eliminated from the study. Brain stem auditory evoked potentials were measured using an air-conducted sound stimulus before and after surgery and before killing. Two dogs had nearly complete obliteration of the tympanic cavity by immature fibrous connective tissue. Eight dogs responded to surgery by either complete or partial re-formation of the tympanic cavity. Retention of the tympanic membrane in three dogs promoted re-formation of the tympanic cavity and blind epithelialized pockets in the surgery site with accumulation of keratinized debris. Granulation tissue formation and extensive proliferation of new bone on the internal surface of the tympanic bulla was seen in 10 dogs. Proliferative bone completely obliterated the tympanic cavity in two of these dogs. Eleven of 13 dogs had no detectable air-conducted BSAEP after surgery. There was no change in BSAEP measurements before killing compared with postoperative measurements in any dog. Two dogs with retained tympanic membranes had measurable BSAEP after surgery. This study shows that healing after TECA-LBO may be highly variable. Retention of the tympanic membrane and small osteotomies appeared to promote reformation of tympanic cavities and prevent ingrowth of granulation tissue. New bone proliferation was frequently observed in response to curettage of the epithelium lining the tympanic bulla. Hearing, as determined by BSAEP measurements, was lost except when the tympanic membrane and ossicles were retained. Retained tympanic membranes promoted accumulation of keratinized cellular debris that could become a nidus for infection or late abscessation in some dogs. These results indicate that resection of as much of the lateral and ventral tympanic bulla as possible and removal of the tympanic membrane may provide consistently improved results after TECA-LBO.     

Unilateral and Bilateral Congenital Sensorineural Deafness in Client-Owned Pure-Breed White Cats

Background: Congenital sensorineural deafness has been reported frequently in experimental mixed-breed white cats but there is a paucity of data on occurrence of deafness in client-owned pure-breed white cats.
Objective: To describe hearing status in client-owned pure-breed white cats.
Animals: Eighty-four pure-breed client-owned cats with white coat color of 10 registered breeds presented for routine hearing evaluation before breeding (1995–2008).
Methods: Hearing was assessed by click-evoked brainstem auditory evoked response.
Results: Overall deafness prevalence was 20.2%; 9 cats (10.7%) were bilaterally deaf and 8 cats (9.5%) were unilaterally deaf. There was no association between sex and deafness status ( P = .85). Deafness status was associated with iris color ( P = .04).
Conclusions and Clinical Importance: Congenital sensorineural deafness frequently occurs in pure-breed cats with white coat color. Unilateral sensorineural deafness was as common as bilateral deafness.     

Wound contamination and antimicrobial susceptibility of bacteria cultured during total ear canal ablation and lateral bulla osteotomy in dogs.

OBJECTIVE: To detect contamination of wound sites from surgical handling of excised tissues during total ear canal ablation and lateral bulla osteotomy in dogs, and to compare susceptibility of bacterial isolates to cefazolin with susceptibility to other antimicrobial agents. DESIGN: Prospective clinical study. ANIMALS: 13 dogs. PROCEDURE: Dogs were treated surgically for otitis externa and media via total ear canal ablation and lateral bulla osteotomy. Specimens for aerobic bacterial culture were obtained from SC tissue immediately following skin incision, tissues excised from the osseous bulla (after transection of the horizontal ear canal and lateral bulla osteotomy), and from SC tissue prior to skin closure. Antimicrobial susceptibility of bacterial isolates to various antibiotics was determined by use of a broth dilution assay. RESULTS: There was a significant association between isolation of Streptococcus canis and Escherichia coli from specimens from the osseous bulla and specimens from the SC tissues prior to skin closure, indicating contamination of the SC tissues during surgery. Seventy percent of bacterial isolates were susceptible to cefazolin. CLINICAL IMPLICATIONS: Measures to limit bacterial contamination resulting from tissue handling during total ear canal ablation and lateral bulla osteotomy are necessary. Bacteriologic culture of tissue of the osseous bulla and determination of antimicrobial susceptibility are recommended. Administration of cefazolin alone may not be efficacious for antimicrobial prophylaxis.