Chronic otitis externa/media with total ear canal ablation and bulla curettage in a North American bison (Bison bison).

An adult female North American bison (Bison bison) with a chronic otitis externa/media of the right ear was examined because of a 4-mo history of intermittent anorexia, apparent painful behavior, and auricular discharge from the right ear. Computerized tomography (CT) demonstrated osteolysis of the tympanic, petrous, and squamous aspects of the temporal bone with soft tissue replacement and sclerosis of the right bulla. A total ear canal ablation with bulla curettage was performed, and cefazolin-impregnated polymethacrylate beads were left within the right bulla and the remnant temporal bone. Six months after the surgery, the bison had no clinical signs of otitis media.     

Otitis media in a llama

A 7-month-old female llama was examined because of chronic otitis media and externa of 7 months' duration. Radiographically, the tympanic bullae appeared thicker than normal, and the ventral borders were poorly defined; the left external acoustic meatus (ear canal) appeared to be narrower than the right. The llama was treated with penicillin, and the ear canals were lavaged daily. Contrast radiography was performed on day 15 to determine the shape and size of the ear canals and evaluate the integrity of the tympanic membranes. Contrast medium was visible radiographically in the left tympanic bulla, indicating that the left tympanic membrane was ruptured, but the right tympanic membrane appeared to be intact. The left ear canal was narrower than the right, and the bony ear canals had a well-defined sigmoid shape. The right ear improved with medial treatment alone, but the left ear did not. Therefore, lateral ear canal resection was performed. After surgery, however, exudate was still evident in the left ear canal, and the llama became more lethargic and more reluctant to eat. Lateral bulla osteotomy was attempted, but no purulent material was obtained, and curettage of the bulla resulted in hemorrhage. Because of this and because of the llama's poor physical condition, a decision was made to euthanatize the llama. The sigmoid shape of the bony ear canal and the multicompartmental nature of the tympanic bulla make surgical treatment of otitis media and externa in llamas difficult. Further study of surgical treatments for otitis media in llamas is needed.     

Development and validation of an endoscopic myringotomy technique to treat otitis media and interna in a case series of three guinea pigs (Cavia porcellus)

Background: Medical treatment of clinical otitis media and interna in guinea pigs is often unsatisfactory. Total ear canal ablation and lateral bulla osteotomy are used successfully in dogs, cats, and rabbits to treat chronic, medically nonresponsive ear disease. However, in guinea pigs this surgery can cause death. This study aimed to evaluate and describe a standardized myringotomy technique to treat guinea pigs with otitis media and interna. Methods: Ear dissections and endoscopically assisted myringotomy were evaluated on guinea pig carcasses to choose the most suitable endoscope and optics. Three client-owned guinea pigs with chronic otitis media and interna had a myringotomy with bacteriological sampling and therapeutic irrigation of the tympanic cavity performed. Anesthesia for the procedures was 25 minutes, the patients were recovered and eating within 2–6 hours, and discharged on targeted antibiotic therapy within 24 hours. Videotoscopy was performed at 7- and 14-days follow-up to assess the ear canal, healing of the tympanic membrane, and to evaluate the tympanic cavity. Repeat lavaging of the tympanic cavity was performed until the tympanic membrane incision was healed. Further follow-up occurred at 21- and 154-days postmyringotomy. Results: Two out of three guinea pigs had complete resolution of clinical signs, and the other showed clinical improvement from a 90° head tilt to a 30° head tilt. Conclusions and case series relevance: Videotoscopy assisted myringotomy under general anesthesia was a quick and straightforward endosurgical technique in three guinea pigs with chronic otitis media and interna. It allowed the collection of fluid for bacteriological culture and provided symptomatic relief.     

Traumatic tympanic bulla fracture

A Pekingese dog was presented for evaluation of head trauma with ventral head and neck swelling, puncture wounds, palpable mandibular fractures, and loss of menace, severe miosis, and loss of palpebral reflex of the right eye. Computed tomography confirmed multiple mandibular and zygomatic fractures, a right ear canal avulsion, and a complete right tympanic bulla fracture with ventral displacement. The tympanic bulla fracture was managed conservatively. Topical lubrication and antibiotic ointment was prescribed for the right eye. A subtotal hemimandibulectomy was performed to address the mandibular fractures. A temporary oesophagostomy feeding tube was placed. No short‐term complications developed as a result of the fractured bulla and avulsed ear canal being left in situ, and no complications were reported 18 months after the injury. To the authors’ knowledge this is the first report of a traumatic tympanic bulla fracture in the dog.     

Virtual otoscopy for evaluating the inner ear with a fluid-filled tympanic cavity in dogs

The feasibility of virtual otoscopy (VO) imaging was evaluated in five dogs with experimentally induced otitis media, two control dogs, and two canine patients with otitis media. VO images of the tympanic cavity and ossicles were generated with commercially available software using raw computed tomography (CT) data. Eight out of 10 ears inoculated with pathogen exhibited obvious clinical signs associated with otitis externa. CT images revealed soft tissue density material occupying the tympanic bulla compatible with otitis media in three dogs with experimentally induced otitis media and two patients. No remarkable features were observed on the radiographs. Four different VO views (ear canal, tympanic bulla, eustachian tube, and ossicular chain) were created. Promontory, cochlea window, tympanic, and septum bulla as well as ossicles were easily and clearly distinguished except for the incus and stapes of the clinical patients. VO images were not more suitable than images created with conventional CT for accurately diagnosing otitis media in this study. However, it appears that VO could be more feasible for assessing the complex structure of the inner ear in dogs with fluid-filled tympanic cavities since fluid accumulation within the tympanic bulla did not affect the evaluation of bony tissue in the middle ear on VO images.     

Atresia of the external acoustic meatus in a dog

Summary: A 3 year old, female great Dane with atresia of the right external ear canal had recurrent episodes of ear pain. Radiography revealed absence of air in the right external acoustic meatus, thickened bone of the right tympanic bulla and increased radiodensity of the chamber of the bulla. Total ear canal ablation and lateral bulla osteotomy were performed. The superficial portion of the external ear canal was absent and the deeper segment of the vertical ear canal began as a blunt ended cartilage tube. A patent lumen in the existent portion of the external ear canal and the tympanic bulla contained wax, hair and exfoliated squames. The tympanic membrane was not intact. No bacteria were cultured from the contents of the external and middle ear. The dog responded well to surgery and was free of pain 11 months later. Failure to surgically correct atresia of the ear canal in young dogs may allow the accumulation of cellular and sebaceous debris with subsequent involvement of the middle ear in an inflammatory response.     

Surgical treatment of middle ear cholesteatoma using an oral approach in 2 dogs

Middle ear cholesteatoma is caused by the formation of epidermoid cysts that result in distention and enlargement of the tympanic bulla with subsequent destruction of surrounding tissues. We report treatment of middle ear cholesteatoma in 2 dogs, via an oral surgical approach. Abnormal tympanic bulla contents and the wall compressing the pharynx were successfully removed in both cases. Computed tomography imaging, surgical findings, and histopathology results were consistent with middle ear cholesteatoma in both cases. The outcomes in both cases suggest that an oral surgical approach may be an alternative treatment for middle ear cholesteatoma in dogs.Key clinical message:Despite the limited number of cases described herein, our report indicates that the direct oral approach for canine cholesteatoma may be and alternative approach.     

Oral and peripheral vestibular signs in a cat with squamous cell carcinoma

A 13-year-old female, spayed cat had oral and vestibular signs resulting from a 3-cm mass extending from the tympanic membrane to the nasopharynx. Radiography revealed a soft-tissue density in the tympanic bulla. Cytologic examination and biopsy confirmed the presence of a squamous cell carcinoma. Squamous cell carcinoma causes vestibular signs in the cat. In this cat, squamous cell carcinoma, involving the middle and inner ear, resulted in oral and vestibular signs.     

Cholesterol granuloma associated with otitis media and destruction of the tympanic bulla in a dog

An 8-year-old, male neutered Irish Setter was presented with a 2-week history of pain upon opening the mouth and chronic otitis externa. Computed tomography examination revealed destruction of the left tympanic bulla with a soft-tissue density within the remains of the tympanic cavity. Cytology of aspirates collected from tissue adjacent to the tympanic bulla revealed suppurative inflammation and bacteria. A ventral bulla osteotomy was performed. Histopathology of granulation tissue within the remains of the tympanic cavity was diagnostic of cholesterol granuloma.     

ASSESSMENT OF THREE RADIOGRAPHIC PROJECTIONS FOR DETECTION OF FLUID IN THE RABBIT TYMPANIC BULLA

Otitis media in the rabbit commonly results in fluid accumulation in the tympanic bulla. Radiographic detection of fluid in the tympanic bulla is only moderately sensitive in the dog and cat. The purpose of this study was to investigate the accuracy of radiographic detection of fluid in the rabbit tympanic bulla for three different radiographic projections. Forty rabbit cadavers were used. Half of the tympanic bullae were randomly allocated to be filled with soft tissue material. Following this procedure, each specimen was radiographed in three projections: dorsoventral (DV), rostro 40° ventral-caudodorsal (R40°V-CdDO), and left and right latero 40° ventral-laterodorsal (Lat40°V-LatDO). After imaging, each specimen was frozen and sectioned to determine the content of the tympanic bullae. Images were interpreted and scored independently by two board-certified radiologists. There was no significant difference in sensitivity or specificity between the three projections when compared with the gross findings following sectioning, but observer confidence was highest for the DV projection. Accuracy of radiographic fluid detection was similar to that reported in the dog and cat. The DV and R40°V-CdDO allow comparison of both tympanic bullae on a single radiograph, but the DV was subjectively easier to position, while the Lat40°V-LatDO requires two radiographs for comparison.     

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.     

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 TOMOGRAPHY FEATURES OF MIDDLE EAR CHOLESTEATOMA IN DOGS

We describe the computed tomography (CT) findings in 11 dogs with middle ear cholesteatoma. The cholesteatoma appeared as an expansile tympanic cavity mass with a mean attenuation value of 55.8±4.2 Hounsfield units. There was no appreciable contrast enhancement of the tympanic bulla contense but ring enhancement was seen in four dogs. Due to the slow progressive growth, the lesion causes severe bone changes at the contour of the tympanic bulla, including osteolysis, osteoproliferation and osteosclerosis, expansion of the tympanic cavity, and sclerosis or osteoproliferation of the ipsilateral temporomandibular joint and paracondylar process. Cholesteatoma can cause lysis of the petrosal part of the temporal bone, leading to intracranial complications. Although not definitive, CT provides useful information for distinguishing a middle ear cholesteatoma from otitis media and neoplasia. In otitis media, enlargement of the tympanic cavity is not routinely observed. In tumors that primarily affect the middle or inner ear, the predominant signs are lysis of the contour of the tympanic bulla or the petrosal part of the temporal bone, soft tissue swelling around the middle ear and marked contrast enhancement. In tumors that arise from the external ear, a soft tissue mass is visible within the external acusticus meatus, and the middle ear is only involved secondarily.     

APPARENT WALL THICKENING IN FLUID FILLED VERSUS AIR FILLED TYMPANIC BULLA IN COMPUTED TOMOGRAPHY

A series of CT imaging experiments was performed to test the hypothesis that when the tympanic bulla is filled with fluid there would be a false impression of bulla wall thickening. CT images were obtained before and after introduction of water in the tympanic bulla of a fresh canine cadaver. Images were acquired using different mA settings, slice thicknesses, reconstruction algorithms, and displayed at different window widths. The wall of the fluid filled bulla appeared thicker than that of the air filled bulla. This artifact was also demonstrated on a phantom composed of a thin (0.5 mm) and a thick (5 mm) piece of aluminum imaged in air and water. The effect was more apparent when images were acquired as thick slices (>5 mm), reconstructed with a soft tissue algorithm, or displayed with a narrow window (<250 CT numbers). The radiologist must be aware of this artifact when interpreting CT images of the tympanic bullae.     

ULTRASONOGRAPHIC EVALUATION OF THE EXTERNAL EAR CANAL AND TYMPANIC MEMBRANE IN DOGS

Ultrasonographic imaging of the canine external ear canal, tympanic membrane, and tympanic bulla was described in five healthy beagle dogs before and after infusion of saline into the ear canal. Saline served as an acoustic window. With this method, the external ear canal, and tympanic bulla were visible in the same imaging plane and the integrity of the tympanic membrane could be evaluated indirectly by confirming an intact tympanic membrane, which appeared at the end of the ear canal as a hyperechoic line with reverberation. Experimentally, perforated tympanic membrane could be evaluated by identifying anechoic saline in the tympanic bulla lumen. The air and fluid-filled tympanic bulla were also visualized. Ultrasonography with saline as an acoustic window appears to be helpful for the evaluation of the external ear canal, tympanic membrane, and tympanic bulla and it may have the potential to be a useful clinical tool in evaluation of integrity of the tympanic membrane.     

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.     

Clinical and pathological evaluation of sulbactam/ampicillin for treatment of experimental bovine pneumonic pasteurellosis

An experiment was conducted to evaluate the efficacy of sulbactam/ampicillin for treatment of bovine pneumonic pasteurellosis. Twenty-one Hereford calves were experimentally infected with bovine herpesvirus-1 and an ampicillin-resistant strain of Pasteurella haemolytica, then treated for three days with either sulbactam/ampicillin, chloramphenicol, or a placebo. The treatments were evaluated by comparing clinical illness scores, total sick days, weight changes, mortality rates, and postmortem lung scores between treatment groups. Both antibiotics were highly effective in reducing respiratory disease in the experimentally infected calves. The clinical response to sulbactam/ampicillin treatment was comparable with that of chloramphenicol and was significantly improved compared with the response to the placebo treatment. These findings suggest that the efficacy of sulbactam/ampicillin may be comparable to that of chloramphenicol for treatment of pneumonic pasteurellosis involving ampicillin-resistant strains of P. haemolytica.     

A pathologic and bacteriologic study on otitis media in swine.

A pathologic and bacteriologic study on otitis media in swine was performed on 237 swine, ranging in age from 1 day to 1 year. These 237 swine from eight selected farms were slaughtered due to unfavorable prognosis associated with clinical signs of illness. One hundred sixty-three (68.8%) of the 237 swine were found to be affected with otitis, though only a few swine showed clinical signs characteristic of the disease. One hundred fifty-one (63.7%), 53 (22.4%), and 39 (16.5%) had lesions in the middle, external, and internal ear, respectively. Of the 151 cases with otitis media, bilateral and unilateral infection accounted for 114 (75.5%) and 37 (24.5%), respectively. Only 5/53 swine with otitis externa and 6/39 swine with otitis interna failed to show otitis media. All swine with infection in the tympanic cavity had inflammatory lesions in the auditory tube. Examination of the swine grouped by age revealed that, regardless of age, incidence of otitis media was 50-70%. In swine younger than 1 month old, otitis media tended to center on the auditory tube, where a mild infiltration of neutrophils into the mucous membrane was frequent. Thereafter, otitis media increased in degree and extent with age. Forty (26.5%) of the 151 swine affected with otitis media were accompanied by a substantial amount of inflammatory exudate in the tympanic cavity and bulla. Purulent exudate was found in 20/40 (50%) swine. Severe otitis media prevailed in swine between 1 and 4 months of age, showing inspissation of a suppurative exudate in the tympanic cavity and lysis of the underlying osseous wall of the tympanic bulla with subsequent fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)