Middle ear disease associated with congenital palatine defects in seven dogs and one cat

Medical records of eight dogs and one cat with congenital palatine defects were reviewed retrospectively. Five of the dogs had nasal discharge and seven had radiographic signs of middle ear disease, but no clinical signs of ear disease were identified in any of the dogs, nor were any reported by their owners during a one- to five-year follow-up period. One dog had an ipsilateral impairment of hearing detected by brainstem auditory evoked responses. The cat had clinical and radiographic signs of middle ear disease. These findings suggest that, as in humans, congenital palatine defects in dogs and cats may predispose to middle ear disease. Any associated deafness could cause problems for working dogs.

Auditory behavioral thresholds for Japanese macaques using insert earphones

The goal of this study was to measure behavioral auditory thresholds in four Japanese macaques. Animals were trained using food as a reward in an operant reinforcement paradigm. Stimuli were 1-s sinusoids with 10-ms rise/fall times delivered through insert earphones (Etymotic ER-1) having expandable foam eartips. The animals generally produced threshold contours similar in shape to those reported for other macaques species, except that the low-frequency thresholds may have been slightly higher in the present studies. At middle and high frequencies, thresholds fell at the lower extreme of the range previously reported in other macaque species. The possible difference in low-frequency thresholds may have been a result of either transducer and calibration differences between studies or true species variations, or both. Though somewhat limited at high frequencies, the insert earphones used in these studies offer more reliable calibrations, less susceptibility to changes in positioning with movement of the animal, and greater interaural attenuation.

Meningoencephalitis secondary to bacterial otitis media/interna in a dog

Central nervous system (CNS) complications of bacterial otitis media/interna are an infrequent occurrence in human patients and have rarely been reported in the veterinary literature. Early recognition of CNS involvement and the use of appropriate diagnostic tests to characterize the nature of the lesion(s) are crucial in determining the best course of treatment. In this paper, the authors describe a dog with bacterial meningoencephalitis secondary to otitis media/interna.

Peripheral vestibular disease associated with cryptococcosis in three cats

Peripheral vestibular disease referable to otitis media/interna was the main reason for presentation in three cats with cryptococcosis. In two cats, Cryptococcus neoformans var neoformans was isolated from the tympanic bulla. In the remaining cat, otitis media/interna was considered to be secondary to occlusion of the auditory tube by a nasopharyngeal granuloma associated with a C neoformans var gattii infection. This report emphasises the importance of maintaining an index of suspicion for a fungal aetiology in cats with signs of otitis media/interna, particularly in countries with a high prevalence of cryptococcosis. The presence of C neoformans may be overlooked with potentially fatal consequences where only standard methods for bacterial isolation are used to examine samples obtained from the middle ear.

Magnetic resonance imaging of otitis media in a dog

Otitis media/interna was diagnosed in a 20-month-old German shepherd with the assistance of magnetic resonance (MR) imaging. The MR images were acquired primarily to exclude a brain lesion responsible for vestibular signs. No brain lesion was detected, but obvious signs of chronic changes in the left bulla and external ear canal were confirmed. Thickening of the epithelium and soft tissue surrounding the external ear canal and a laminated appearance of high and low T2 intensities in the tympanic bulla's mucosa were present. The hypointense lines were suspected to be fibrous tissue, indicating chronic changes. This report suggests that MR imaging may serve as a useful imaging tool for otitis media and that it supplies information not obtained with radiography or computed tomography.

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.

Clinical and microbiological study of an otitis media outbreak in calves in a dairy herd

On a dairy farm, otitis media was diagnosed in 64 suckler calves (21.8%) during a study period of 2 years, and in 10 calves (3.4%) in the third year. The inflammation was unilateral in 63 and bilateral in 11 calves. The affected calves were dull, lacked appetite, were pyrexic and displayed drooping ear or ears and tilted heads with purulent discharge exuding from the external ear canal. Of the affected animals, 56 (87.5%) were aged between 3 and 8 weeks. Morbidity was higher during the calving season and during the autumn and winter months (October-December). Pasteurella haemolytica was isolated from 21 (32.8%), P. multocida from 20 (31.2%), Actinomyces pyogenes from 11 (17.2%) and Streptococcus pneumoniae from three (4.7%) of the clinically affected calves only during the first two study years. The exudate of the acute ear infections contained, in addition to Pasteurella spp., various bacteria and yeasts. Most of these bacteria were isolated from healthy ears as well, and are likely to be part of the normal ear flora. On the other hand most of the yeasts were isolated from otitic calves. After a short course of an appropriate treatment infections healed in all cases. Possible preventive measures are discussed.

Intranasally inoculated Mycoplasma hyorhinis causes eustachitis in pigs

Specific-pathogen-free pigs were experimentally inoculated with Mycoplasma hyorhinis, Pasteurella multocida, or both bacterial isolates to evaluate the role of these bacteria in the pathogenesis of otitis media. Six pigs were inoculated intranasally with 4.4 X 10(8) colony-forming units (CFU) of M. hyorhinis. Twenty-one days later, three of these six pigs were inoculated intranasally with 5.0 X 10(8) CFU of P. multocida. Three additional pigs were also inoculated intranasally at the time with P. multocida alone. Two pigs served as uninoculated controls. Seven days later, all pigs were euthanatized. Histologically, subacute inflammation was found in 10 auditory tubes of six pigs and two tympanic cavities of two pigs inoculated with M. hyorhinis. Immunohistochemically, M. hyorhinis antigens were detected on the luminal surface of eight of 10 inflamed auditory tubes, and ultrastructural examination confirmed mycoplasmal organisms in two pigs. M. hyorhinis was isolated from the inflamed tympanic cavities of two pigs. None of the pigs inoculated only with P. multocida had otitis, and P. multocida was not isolated from the tympanic cavity. These findings indicate that M. hyorhinis can cause eustachitis but rarely otitis media in specific-pathogen-free pigs.

Induction of temporary otitis media in specific-pathogen-free pigs by intratympanic inoculation of Mycoplasma hyorhinis

OBJECTIVE

To examine whether Mycoplasma hyorhinis inoculated into the tympanic cavity can cause otitis media in pigs.

ANIMALS

17- or 22-day-old specific-pathogen-free pigs.

PROCEDURE

Histologic and bacteriologic examinations were performed on specimens from the tympanic cavity and auditory tube at 0, 7, 14, and 25 days after intratympanic inoculation of M hyorhinis (auditory tube cloning strain 14).

RESULTS

In M hyorhinis-inoculated pigs, mild to moderate inflammation of the auditory tube and tympanic cavity first appeared at postinoculation day (PID) 7. In pigs euthanatized at PID 14, the degree of inflammation was aggravated. Immunohistochemical analysis revealed M hyorhinis antigens on the luminal surface of the auditory tube and tympanic cavity. By PID 25, lesions had lessened. By use of transmission and scanning electron microscopic examinations, mycoplasmal organisms were identified among the cilia in the auditory tubes at PID 14 but not at PID 25. Results of bacteriologic examination indicated that 10(4) to 10(6) color-changing units of M hyorhinis were isolated from the tympanic cavity at PID 0. Variable numbers of M hyorhinis were isolated at PID 7 and 14, and numbers were decreased at PID 25.

CONCLUSIONS

M hyorhinis inoculated into the tympanic cavity can cause a self-limiting otitis media in SPF pigs.

Evaluation of the canine tympanic membrane by positive contrast ear canalography

Positive contrast ear canalography was described briefly in 1973 as a method for detecting rupture of the tympanic membrane in dogs with otitis media. The purpose of this study was to evaluate the sensitivity and usefulness of the technique. The ears of 10 normal canine cadavers and 31 dogs with clinical signs of ear disease were examined using otoscopy, radiography and contrast radiography after infusing 2 to 5 ml of positive contrast medium into the ear canals. These examinations were repeated in the cadavers after the tympanic membrane had been punctured with a Spreull needle. In the cadavers 14 of 19 (74 per cent) of the tympanic membranes were visible otoscopically; contrast medium did not enter the tympanic bulla of any of the ears before the tympanic membrane was ruptured, but was visible in the bulla in every ear after rupture. In the clinical study, 40 of 61 (66 per cent) of the tympanic membranes were visible otoscopically, and 12 appeared to be ruptured. Radiographic signs of otitis media (increased opacity and/or thickening of the tympanic bulla) were identified in seven ears. Canalography was positive for rupture of the tympanic membrane in 13 ears, including four in which it appeared to be intact otoscopically. In normal canine ears, canalography was a more accurate method for detecting iatrogenic tympanic membrane rupture than otoscopy. In dogs with ear disease, canalography may be more sensitive for otitis media than either otoscopy or survey radiography.

The effects of four, commercial ceruminolytic agents on the middle ear

Four, commercially available ceruminolytic agents and physiological saline were screened for ototoxic and inflammatory reactions on the middle ear mucosae of guinea pigs (n = 38) and dogs (n = 24). Each solution was injected transtympanically in anesthetized animals. The effects were assessed by brain stem auditory evoked response (BAER) tests to evaluate hearing function and by histological examination of the middle ear structures. Varying degrees of hearing loss and inflammation were observed in some guinea pigs and dogs treated with solutions A, C, and D, whereas no abnormal finding was associated with solution B or saline.

Radiographic imaging of otitis media and interna in pigs

Middle and inner ear infections have been reported as a clinical entity in swine, other animal species and humans. In pigs, the anatomical-pathological and microbiological findings have been described. In this report, we describe radiographic findings in affected pigs. A total of 25 pigs with a head tilt and circling, as clinical signs of otitis media and interna, were examined. The majority were weaner-pigs with dyspnea or rhinitis. In radiographs, there was an increased opacity of the bulla tympanica, often accompanied by marginal destruction or thickening of the bulla wall. The radiographic findings confirmed the clinical diagnosis in each affected pig, but there were 5 false positive interpretations.

[Investigations on clinical diagnosis and pathogenesis of otitis media et interna in swine]

A total of 25 pigs with a head tilt as clinical sign of otitis media et interna were examined. The majority were weaner-pigs with respiratory tract disorders. In lateral and ventrodorsal radiographic views of the bulla tympanica, there was an increased opacity, often accompanied by marginal destruction or thickening of the bulla wall. The findings confirmed the clinical diagnosis in each affected pig. In the case of leptomeningitis an examination of the cerebrospinal fluid revealed a drastic increase in the cell count. In 20 of 23 microbiologically examined empyemic bullae a polyinfection was seen. The results indicate that the route of infection of the middle ear is by the auditory tube. Mange on the other hand plays only a minor role in the pathogenesis of otitis media.

Otitis media in preweaned Holstein dairy calves in Michigan due to Mycoplasma bovis

Mycoplasma bovis was isolated from the tympanic bullae of dairy calves with an exudative otitis media. The history, clinical signs, gross and histologic lesions, and bacteriologic findings are described for 5 preweaned Holstein calves with otitis media from a 600-cow dairy in Michigan. Clinical findings consisted of unilateral or bilateral ear droop, epiphora, head tilt, and recumbency in severely affected calves. Postmortem examination revealed unilateral or bilateral fibrinosuppurative to caseous exudate in the tympanic bullae. Histologically, a marked fibrinosuppurative to caseous exudate filled the tympanic air spaces. The partially ulcerated tympanic mucosa was markedly thickened with mononuclear cell infiltration and proliferation of fibrous connective tissue. Bone remodeling and periosteal hyperostosis were present in some osseous septa. Mycoplasma bovis was isolated from the tympanic bullae of all 5 calves and from the lungs of 2 calves and the frontal sinus of 1 calf. Mycoplasma bovis was isolated at > 100,000 colony forming units/ml from the bulk milk tank of the farm of origin. The isolation of M. bovis from the bulk milk tank, indicating subclinical mycoplasmal mastitis coupled with the feeding of waste milk from mastitic cows to calves is suggestive of a possible source of the infection resulting in otitis media in preweaned dairy calves.

Radiographic appearance of the middle ear after ventral bulla osteotomy in five dogs with otitis media

Radiographs of the middle ear were made in five dogs 60 to 78 months after ventral bulla osteotomy was performed to treat otitis media. The clinical results of surgery were considered satisfactory in four dogs and unsatisfactory in one. In 4 dogs with satisfactory results, radiographs demonstrated complete reformation of the bulla in 3 operated middle ears (3 dogs), with partial bulla reformation in the three middle ears (3 dogs). Radiographs in one dog with unsatisfactory results showed complete bulla reformation with no increase in lumen opacity. The proliferative bony response obliterating the middle ear previously reported in normal dogs after ventral bulla osteotomy was not seen in any of these patients.

[Results of bacteriologic and mycologic investigations of otitis media in dogs]

This study describes the bacteriological and mycological investigation of 212 ear swab samples of dogs with an otitis externa. 11 samples were sterile. Malassezia pachydermatis could be cultivated in 72.1% of all samples, in 21.9% of these cases in pure culture. In 27.9% of all samples only bacteria were found. Coagulase-positive haemolytic Staphylococcus and Malassezia pachydermatis were isolated together in 31.8% of all ear swab samples. Pseudomonas aeruginosa could be detected in 22.9%, haemolytic Streptococcus in 8.0%. The evaluation of antibiograms showed little resistance of staphylococcus to most common antibiotics or chemotherapeutics respectively, but the growth of Pseudomonas aeruginosa and especially Proteus spec. was only inhibited by a few substances.

Otitis media and interna and temporohyoid osteoarthropathy

Otitis media/interna in the equine most commonly is a chronic, insidious infection with the unique sequella of temporohyoid osteoarthropathy in some horses. Head shaking may be the only clinical sign of the early stages of this disease. The arthritic condition often leads to fusion of the temporohyoid joint with resultant stress fractures of the petrous temporal bone. When this occurs, the horse presents as an acute neurologic case with clinical signs of vestibular and facial nerve dysfunction. Diagnosis, treatment, and prognosis are discussed. Recognition of this syndrome is important because many of these horses can be treated successfully and can return to normal function.

Treatment of recurrent otitis media that developed after total ear canal ablation and lateral bulla osteotomy in dogs: nine cases (1986-1994)

OBJECTIVE

To assess clinical findings and long-term outcome of dogs treated for recurrent middle ear infection that developed after total ear canal ablation and lateral bulla osteotomy.

DESIGN

Retrospective case series.

ANIMALS

Of 94 dogs (142 ears) treated by means of total ear canal ablation and lateral bulla osteotomy for end-stage otitis, 9 developed recurrent middle ear infection.

PROCEDURE

Information regarding treatment and outcome were retrieved from the medical records.

RESULTS

Antibiotic treatment was attempted in 8 dogs, but failed to cure recurrent otitis media in 7 of 8 dogs. Seven dogs were treated by means of exploratory surgery, which consisted of ventral bulla osteotomy and tympanic curettage. One dog was cured, 1 developed another infection and was euthanatized, and the 5 remaining dogs developed another middle ear infection after the first exploratory surgery. Infection resolved after retained epithelium was removed from the tympanic cavity during a second exploratory surgery of the bulla in these 5 dogs.

CLINICAL IMPLICATIONS

Antibiotic treatment rarely is effective for resolving recurrent middle ear infection that develops after total ear canal ablation and lateral bulla osteotomy. Ventral bulla osteotomy and curettage can be a successful method of treatment, provided retained epithelium and debris are completely removed from the ear canal and tympanic cavity.

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.

Endoscopy of the auditory tube diverticula in four horses with otitis media/interna

Endoscopic examination of the auditory tube diverticula was a diagnostic aid in the evaluation of 4 horses with otitis media/interna and associated osseous changes of the stylohyoid and petrous temporal. One of the horses was examined because of persistent head shaking; the other 3 were examined because of an acute onset of facial and vestibulocochlear nerve dysfunction. Proliferative lesions involving the petrous temporal bone and proximal portion of the stylohyoid bone were identified endoscopically in all 4 horses. Endoscopy is a noninvasive procedure that provides an alternative to skull radiography and tympanocentesis in the diagnosis of otitis media/interna in horses. In addition, risks associated with general anesthesia are avoided.

Traumatic ear canal separations and para-aural abscessation in three dogs

Three dogs were presented for para-aural abscessation. Ear canal separations were suspected preoperatively, based on histories of trauma, physical examination findings of minimally inflamed external ear canals with abrupt endings, and radiographic evidence of discontinuity of the ear canals. Concurrent otitis media, based on radiographic findings, was diagnosed in all three dogs. Disruptions of the external ear canals were confirmed at surgery, and the dogs each responded to total ear canal ablation and lateral bulla osteotomy.

Demonstration of Mycoplasma hyorhinis as a possible primary pathogen for porcine otitis media

A study of the pathology of the ear was performed on 479 pigs ranging in age from 1 day to 1 year. Histologically, 364 (76.0%) of 479 pigs were affected with otitis. Eustachitis was the most common and preceded an inflammation of other sites of the ear, and an acute eustachitis occurred from as early as 1 week of life. Immunohistochemical examination of frozen cryostat sections revealed Mycoplasma hyorhinis (Mhr) antigens on the luminal surface of the eustachian epithelia in 14 (50.0%) of 28 piglets examined. All the pigs positive for Mhr had an acute eustachitis. Ultrastructural examination on the auditory tubes with positive immunostaining disclosed many mycoplasmas among the cilia. Mhr was isolated from the auditory tubes and tympanic cavities of 19 (67.9%) and 16 (57.1%) of 28 piglets examined, respectively. Porcine otitis media may be caused primarily by Mhr infection in the auditory tube.

Isolation of Mycoplasma hyorhinis and Mycoplasma arginini from the ears of pigs with otitis media

Mycoplasmas were isolated from the middle ears and nasal cavities of clinically ill, young pigs that were slaughtered due to an unfavourable prognosis. The isolation rates of Mycoplasma hyorhinis were 27 of 43 (62.8 per cent) from the auditory tube, 22 of 43 (51.2 per cent) from the tympanic cavity, and 15 of 25 (60.0 per cent) from the nasal cavity. M arginini was also recovered at rates of 11 of 43 (25.6 per cent) from the auditory tube, 7 of 43 (16.3 per cent) from the tympanic cavity, and 9 of 25 (36.0 per cent) from the nasal cavity. Dual infections with M hyorhinis and M arginini occurred in these sites in some cases. M hyorhinis was isolated from 16 (80.0 per cent) of 20 pigs with otitis media diagnosed histologically, and from two (25.0 per cent) of eight pigs without this condition. The isolation rate was significantly different (P < 0.05) between the groups, suggesting either that the organism triggers development of the disease of the ear or that the agent(s) or factors responsible for otitis media in the pigs created favourable conditions at this site for colonisation by M hyorhinis.

Detection of Mycoplasma hyorhinis in porcine eustachitis

Pathologic study of the ear was performed on 179 young swine, ranging in age from 1 day to 18.6 weeks. Histologically, eustachitis was the most common and its inflammatory reaction appeared to precede otitis. Immunohistochemically, Mycoplasma hyorhinis (Mhr) antigens were detected on the luminal surface of the auditory epithelia in 19 of 179 cases (10.6%). All the cases, positive for Mhr antigens, were associated with an acute eustachitis. Ultrastructural examination of two piglets confirmed these immunohistochemical data. The present results indicate that Mhr may be a primary cause of acute eustachitis in young swine.

Tympanic bulla osteotomy for treatment of middle-ear disease in cats: 19 cases (1984-1991)

Twenty-two tympanic bulla osteotomies were performed in 19 cats for the treatment of bacterial otitis media (n = 11), inflammatory polyps (n = 7), or middle-ear neoplasia (n = 4). Inflammatory polyps mostly affected young adult cats (mean age, 1.5 years), whereas otitis media affected middle-aged cats (mean age, 5.5 years) and neoplasia affected older cats (mean age, 10.25 years). Although not specific for the underlying disease process, fluid density within the tympanic bulla or thickening of the bulla was observed radiographically in 100% of cats with middle-ear disease. In cats for which results were available, bacterial culturing revealed pathogens in 6 cats diagnosed with otitis media and in 7 cats with benign or malignant tumors within the bulla. The ventral approach to the bulla was the most common surgical procedure (18 osteotomies), followed by the lateral approach combined with ablation of the vertical and horizontal parts of the external acoustic meatus (4 osteotomies). Immediate postoperative complications were common but short-term, and included Horner's syndrome (11 cats), facial nerve paralysis (5 cats), and otitis interna (2 cats). Bulla osteotomy resulted in resolution of clinical signs without recurrence in cats with middle-ear polyps. Drainage of the infected tympanic cavity aided in resolution of the clinical signs of bacterial otitis media, but the long-term clinical course was characterized by persistent neurologic deficits (5 cats) and recurrence of disease (2 cats). Neoplastic infiltration of the tympanic bulla was associated with a poor prognosis, and although surgery helped to establish a diagnosis, it did not alter the clinical course of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Inflammatory middle ear disease of the dog: the clinical and pathological features of cholesteatoma, a complication of otitis media

During a study of inflammatory middle ear disease in the dog cholesteatoma was found to accompany otitis media in seven of the 62 ears examined (11 per cent). The clinical, radiological and pathological findings in these animals imply that cholesteatoma in the dog is an aggressive lesion which must be differentiated from uncomplicated otitis media.

Inflammatory middle ear disease of the dog: the pathology of otitis media

Inflammation within the middle ear cavity was recognised in 62 of the ears of 42 dogs with chronic otitis externa and otitis media, after biopsy or necropsy of the middle ear. The pathological changes in the middle ear resembled those reported in other species or after the experimental induction of otitis media in dogs. Perforations in the tympanic membrane were rarely found; on the contrary, the membrane was often thickened. However, the question of whether a perforation in the tympanic membrane must occur before otitis externa can extend to otitis media was not resolved.

Staphylococcus schleiferi subsp. coagulans subsp. nov., isolated from the external auditory meatus of dogs with external ear otitis

A new subspecies, Staphylococcus schleiferi subsp. coagulans, was isolated from the external auditory meatus of dogs suffering from external ear otitis and is described on the basis of studies of 21 strains. Phenotypic studies showed that these strains are more closely related to Staphylococcus intermedius than to other staphylococci, but DNA hybridization studies indicated that they are closely related to Staphylococcus schleiferi N850274T. On the basis of biochemical distinctiveness (positive test tube coagulase test and different carbohydrate reactions) and the etiological importance (frequent isolation from otitis specimens from dogs) of these strains, we propose to classify them as a subspecies of S. schleiferi. The strains of this new subspecies are coagulase tube test, beta-hemolysin, and heat-stable nuclease positive but clumping factor negative. A simple scheme for the differentiation of S. schleiferi subsp. coagulans from the other coagulase-positive staphylococci is presented. The type strain is GA211 (= JCM 7470).

Chronic otitis externa and otitis media treated by total ear canal ablation and ventral bulla osteotomy in thirteen dogs

Ventral bulla osteotomy was combined with total ear canal ablation for the treatment of chronic otitis externa and otitis media in 13 dogs (14 ears) that had been refractory to medical and surgical treatments. Resolution of disease occurred in 11 dogs (12 ears). One dog with unilateral disease underwent a second operation before achieving a good result. One dog was euthanatized for persistent unilateral disease after three surgical procedures. The recurrence of disease in these two dogs (15%) was associated with remnants of ear canal integument within the osseous horizontal canal or tympanic bulla. Facial paralysis occurred in four dogs (31%) and there were no complications in eight dogs (62%). This technique shows no advantage over lateral bulla osteotomy combined with total ear canal ablation for the treatment of chronic otitis externa and otitis media.

Total ear canal ablation combining bulla osteotomy and curettage in dogs with chronic otitis externa and media

Ear canal ablation combining bulla osteotomy and curettage was performed on 44 dogs (n = 72 ears). Indications for the procedure included one or more of the following: chronic nonresponsive otitis externa and/or media (n = 71), tumor in the horizontal portion of the ear canal (n = 1), failed lateral ear resection (n = 11), ossified auricular cartilages secondary to chronic otitis externa (n = 22), failed previous total ear canal ablation (n = 1), and otitis interna (n = 1). In 40 dogs, the surgery was successful in alleviating all clinical signs of otitis externa and media. During the immediate postoperative period, 2 dogs died of causes unrelated to otitis. Complications related to the surgery developed in 9 of the surviving 42 dogs. Ultimately, 95% (40 of the surviving 42) of the dogs were cured by use of this procedure. Surgery successfully resolved the original problems in 97% (66 of 68) of the surgically treated ears of these dogs.

An evaluation of tympanometry, otoscopy and palpation for assessment of the canine tympanic membrane

Three techniques for the assessment of the integrity of the canine tympanic membrane were evaluated experimentally. Tympanometry, an objective technique, was shown to be very accurate for the evaluation of the integrity of the ear drum. Otoscopic examination by experienced personnel was shown to be moderately accurate under controlled conditions when the external ear canal was not inflammed. However, under field conditions when otitis externa was present, visual inspection of the tympanic membrane was seldom possible even after lavage of the ear. Palpation of the tympanic membrane with a blunt probe was shown to be very inaccurate and led to rupture of the tympanic membrane in a high proportion of cases. These results imply that two widely used techniques for the examination of the canine tympanic membrane are unsatisfactory. Furthermore, they suggest that previous reports of the prevalence of ear drum perforations in dogs may need reappraisal. Tympanometry is a non-invasive, objective and practical technique for the assessment of ear drum integrity which is worthy of further evaluation.

Total ear canal ablation combined with lateral bulla osteotomy for end-stage otitis in dogs. Results in thirty dogs

Thirty dogs with end-stage otitis were treated by either unilateral or bilateral total ear canal ablation and lateral bulla osteotomy. Otitis was considered end stage when the horizontal ear canal was collapsed, stenotic, or occluded in conjunction with chronic infection of the external and middle ear. The dogs were evaluated clinically and radiographically for 4 to 63 months. The frequency of scratching, head shaking, aural drainage, and para-aural fistulation was significantly decreased. Abnormal ear carriage and head tilt were not changed. The results in 23 dogs were graded as excellent or improved. One dog died of intraoperative hemorrhage. Complications during the period from suture removal to follow-up included para-aural fistulation (3 dogs), facial nerve paralysis (5 dogs), and head tilt (3 dogs).

Surgical management of otitis media and otitis interna

Surgical management of otitis media and otitis interna includes the following options: lateral bulla osteotomy, ventral bulla osteotomy, or curettage of the tympanic cavity. Because otitis media frequently accompanies chronic nonresponsive otitis externa, one of the above procedures may be combined with operative procedures of the external ear canal. Also, gentle selective curettage of the tympanic cavity may be combined with either lateral or ventral bulla osteotomy in the treatment of otitis media and interna. The choice of surgical procedure(s) should be based on the condition of the external ear canal (vertical and horizontal parts), the duration of clinical signs, response to previous surgery, and the familiarity of the surgeon with the different approaches and techniques. With the increased reporting of long-term results following surgical management of otitis externa, media, and interna, more meaningful conclusions concerning selection of surgical procedure may be made in the future.

Otitis media and otitis interna. Etiology, diagnosis, and medical management

In this article, the etiologies, clinical signs, diagnostic aids, and treatments for otitis media and interna are discussed. A review of the anatomy and physiology of the middle and inner ear structures precedes each discussion.

Otitis media in guinea pigs: pathology and bacteriology

In the course of post-mortem examination of conventional random-bred and inbred (immunosuppressed) strain 2/N guineapigs kept in separate quarters, otitis media was diagnosed in 62 of 462 animals (13.4%) and 18 of 66 animals (27.3%) respectively. Clinical signs of otitis media were seen in only two random-bred animals but in nearly 50% of affected inbred animals. In random-bred guineapigs, purulent, often bilateral, otitis media was associated mainly with the isolation of Streptococcus zooepidemicus, Bordetella bronchiseptica, Pasteurella and Actinobacillus spp. and micrococci. In strain 2/N guineapigs serous or purulent often bilateral otitis media was associated mainly with the isolation of B. bronchiseptica and Pseudomonas aeruginosa serotypes 10 and 11. The simultaneous occurrence of similar pathogenic bacteria in both ears of bilaterally affected animals and in pneumonic lung tissue (in random-bred animals) suggested ascending and descending infection originating from the upper respiratory tract. It is concluded that otitis media, associated with the isolation of a variety of respiratory bacterial species, must be considered a major disease problem in guineapigs.

Head tilt in rabbits caused by pasteurellosis and encephalitozoonosis

Rabbits (Oryctolagus cuniculus) of non-dwarf (Group A) and dwarf (Group B) strains showing a common clinical sign of head tilt (torticollis) were examined. With 1 exception, all rabbits of group A had otitis and empyema of either one or both middle ears. Pasteurella multocida was isolated from pus and from the nose of all but 1 of these rabbits, and on occasion was also isolated from the brain. By contrast in all dwarf rabbits the presence of the protozoan Encephalitozoon cuniculi was confirmed both histologically and serologically. This parasite did not affect the ears of the animals but rather the central nervous system. We assume that the different exposure to both agents, rather than the degree of susceptibility, was responsible for the differences found between the 2 types of rabbits.

Bacterial and mycoplasmal flora of the middle ear of laboratory rats with otitis media

Purulent otitis media was confirmed at necropsy in 35 laboratory rats, 14 of which had shown clinical signs of middle ear infection. The bacterial flora of both the affected and grossly normal middle ears was similar, often mixed, and comprised mainly of Staphylococcus haemolyticus, Pasteurella pneumotropica and Corynebacterium spp. Twenty-one isolates of Mycoplasma spp. were recovered from the middle ears of 11 rats with purulent otitis media and one normal rat. Fourteen of the isolates were further identified as either Mycoplasma arthriditis (eight isolates) or Mycoplasma pulmonis (six isolates). In ears affected with otitis media, mycoplasmas were isolated significantly more often from subclinical than from clinical cases, while Pasteurella pneumotropica was isolated significantly more often from clinical than subclinical cases.

Natural history of infection with Pasteurella multocida in rabbits

Monitoring of rabbits at a commercial rabbitry for Pasteurella multocida infection revealed that the nares of 10 litters of New Zealand White rabbits were not colonized before weaning at 8 weeks of age, regardless of whether or not the does were infected. The earliest nasal infection was detected at 12 weeks of age, and by 22 weeks of age, 23% had P multocida infection. Rhinitis developed 2 or more weeks after infection was detected in most rabbits. A survey of 76 adult rabbits in the breeding colony revealed that 72% had P multocida infection. In 31 rabbits with rhinitis, 90% were infected, whereas in 55 rabbits with P multocida infection, only 50% had rhinitis. During the period of surveillance, there was an epizootic of rhinitis caused by P multocida. All age groups except preweanlings were affected. Serotyping of 29 isolates of P multocida revealed that 93% were somatic type 12. Surveillance of rabbits for pasteurellosis at a laboratory animal facility revealed that the following clinical syndromes developed in decreasing order of magnitude: rhinitis, conjunctivitis, abscesses, and otitis media.

Peripheral vestibular syndrome in the dog: a review of 83 cases

Clinical data and follow-up evaluations of 83 cases of peripheral vestibular syndrome in the dog were reviewed. The absence of physical abnormalities of the tympanic membrane and absence of radiographic changes within the tympanic bulla or petrous temporal bone were the criteria used to make the diagnosis of idiopathic benign vestibular disease. When grouped according to the cause of the syndrome, most of the dogs had been diagnosed as having either otitis media/interna (49%) or idiopathic benign vestibular disease (39%). Clinical evidence suggested that most of the cases of otitis media/interna were secondary to otitis externa.

Cause and pathogenesis of middle ear infection in young feedlot cattle

Two populations of feedlot cattle--weaned calves and yearlings--suffered otitis media. In calves the disease was acute and epizootic and had a prevalence of about 400 cases per 2000 cattle, whereas in yearlings, it was chronic and sporadic and had a prevalence of 1 case per 2000 cattle. Clinical signs were facial paralysis, otorrhea, and head tilt. The middle ears from 64 dead calves and 22 dead yearlings were examined. Calf ears had acute infection, with exudate in air cells and rupture of tympanic membranes. Yearling ears had chronic infection, with exudate in air cells, rupture or destruction of tympanic membranes, and necrosis of air cell partitions. Mixtures of Pasteurella multocida and Corynebacterium pseudotuberculosis were isolated from diseased ears, but Pasteurella multocida predominated in acute infections and Corynebacterium pseudotuberculosis predominated in chronic infections.