Cholesteatoma and meningoencephalitis in a dog with chronic otitis externa

Characteristics and diagnostic performance of nonechoplanar diffusion-weighted imaging in detecting canine tympanokeratoma (cholesteatoma)

Tympanokeratomas (cholesteatomas) are destructive keratinic masses of the middle ear that are often treated surgically. In humans, nonechoplanar (non-EP) diffusion-weighted (DW) MRI is efficient in diagnosing tympanokeratomas and differentiating recurrent tympanokeratomas from granulation or fibrous tissue after surgery. The objectives of this study were to (1) determine the characteristics of non-EP DWI of histologically or cytologically confirmed canine tympanokeratomas, (2) determine the performance of non-EP DW images, apparent diffusion coefficient (ADC) map and ADC values in discriminating between tympanokeratomas and other causes of otitis media in dogs, and (3) find an optimal ADC cut-off value. Medical records of dogs diagnosed on MRI with otitis media in two veterinary hospitals were retrospectively reviewed. Sixty-two ears with a cytological or pathological diagnosis of either tympanokeratoma (36/62) or nontympanokeratoma otitis media (26/62) were selected. Diffusion-weighted images had an accuracy of 77.4%, a sensitivity of 94.4%, and a specificity of 53.8% for the detection of tympanokeratoma. The ADC value of middle ear content ranged from 517 to 1355.10-6 mm2/s in tympanokeratoma and from 454 to 2447 × 10-6 mm2/s in nontympanokeratoma otitis media. An ADC value below 916 × 10-6 mm2/s interpreted as a tympanokeratoma yielded an accuracy of 78.7%, a sensitivity of 92.6%, and a specificity of 60%. In the study population, combined qualitative analysis of DW images and ADC maps was the most effective method for diagnosing tympanokeratomas with an accuracy of 80.9%, a sensitivity of 92.6%, and a specificity of 65%.

Middle ear cholesteatoma in two cats diagnosed with the aid of video-otoscopy

Case series summary

The present report describes middle ear cholesteatoma in two cats and also the use of video-otoscopy and flushing to assist with the diagnosis. CT and video-otoscopic examination and flushing were performed in two cats, a 13-year-old mixed breed spayed female cat and a 1-year-old mixed breed male cat, with middle ear cholesteatomas. During the procedure, keratinous material from the middle ears was collected for histopathological evaluation, demonstrating findings consistent with cholesteatoma, and the middle ears were flushed extensively.

Relevance and novel information

There is little information about middle ear cholesteatoma in cats, and to the authors' knowledge, there are no reports in cats investigating the use of video-otoscopy to aid in the diagnosis of aural cholesteatoma, and this report demonstrates that it can aid in the diagnosis of this condition in cats. In addition, one of the cats had a concurrent otic polyp, which has not been previously reported in cats with cholesteatoma. Additionally, this is the first report of cholesteatoma in a young cat. The access to the cholesteatoma material was via ventral bulla osteotomy in one cat and via external canal without video-otoscopy in the other. More information regarding cholesteatoma in cats will help identify potential similarities and differences of this condition in cats compared with humans and dogs.

Methicillin-resistant Staphylococcus schleiferi subspecies coagulans associated with otitis externa and pyoderma in dogs

Background:

Dermatological infections are the most common cases in the daily pet clinic. Since its discovery in 1990, Staphylococcus schleiferi subspecies coagulans have been reported more frequently in canine otitis externa and pyoderma and even in cases of zoonoses.

Aim:

Detect the presence of S. schleiferi subsp. coagulans of canine otitis externa and pyoderma, its antimicrobial resistance, and the presence of mecAgen.

Methods:

Three-hundred-thirty-one swabs from dogs with otitis externa and pyoderma were cultured on bacteriological agar for bacterial isolation and subsequent biochemical and molecular identification. The identified S. schleiferi subsp. coagulans were evaluated for their antimicrobial susceptibility using the Kirby–Bauer technique, including an oxacillin disk, and subsequently, a PCR was run to identify which ones had the mecA gene.

Results:

Thirty-four (22.97%) and twelve (6.56%) isolates were identified as S. schleiferi subspecies coagulans from otitis externa and pyoderma, respectively. Fluoroquinolones, the most widely used group of antibiotics in Peru, showed a susceptibility of 58.82% (20/34) in cases of otitis externa and 50% (6/12) in cases of canine pyoderma. Meanwhile, nitrofurantoin was the antibiotic with the best efficacy in both cases, with 97% (33/34) in otitis externa and 83% (10/12) in pyoderma. Furthermore, 40% (13/34) of S. schleiferi subsp. coagulans isolated from otitis externa were resistant to methicillin, and 85.29% (29/34) had the mecA gene. On the other hand, the only methicillin-resistant isolate from pyoderma was also the only one with a mecA gene.

Conclusion:

This study is the first report of S. schleiferi subsp. coagulans in Peru, finding a higher percentage than reported in other South American countries.

Clinical analysis and nonsurgical management of 11 dogs with aural cholesteatoma

BACKGROUND

Aural cholesteatomas, also called tympanokeratomas, are destructive and expansile growths of keratinizing epithelium that develop in the middle ear. They have been reported sporadically in dogs, and surgery is usually the recommended treatment.

OBJECTIVES

To describe the common clinical, radiological and histological findings of cholesteatoma; to report on the outcome of conservative management.

ANIMALS

Eleven dogs (13 ears) with cholesteatomas.

METHODS AND MATERIALS

Medical records were reviewed for dogs diagnosed with cholesteatoma between 2012 and 2018. All dogs had computed tomography (CT) and/or magnetic resonance imaging (MRI) followed by trans-canal endoscopic procedure (TEP) for removal and biopsy of middle ear lesions. Dogs were then treated with in-clinic flushing initially weekly tapered to monthly, as well as at-home ear cleaning and application of topical otic steroid medication, initially daily then tapered to once or twice weekly.

RESULTS

Nine dogs had a history of chronic otitis externa; head tilt or facial paralysis was present in seven and four cases, respectively. Otic examination identified a protruding nodule in seven ears. CT demonstrated soft tissue-like material in 12 bullae and expansion in seven bullae. MRI revealed minimally contrast-enhancing bulla contents in 12 ears. Post-TEP and with maintenance medical treatment, nine ears had no further signs of middle ear disease during a mean follow-up of 27.9 months.

CONCLUSIONS AND CLINICAL IMPORTANCE

The results suggest that otitis externa may not necessarily precede cholesteatoma in all dogs. MRI appears to be more sensitive than CT for identifying cholesteatomas. Conservative treatment of cholesteatomas could be useful before or as an alternative to surgery.

Bilateral tympanokeratomas (cholesteatomas) with bilateral otitis media, unilateral otitis interna and acoustic neuritis in a dog

Background

An aural cholesteatoma, more appropriately named tympanokeratoma, is an epidermoid cyst of the middle ear described in several species, including dogs, humans and Mongolian gerbils. The cyst lining consists of stratified, keratinizing squamous epithelium with central accumulation of a keratin debris. This case report describes vestibular ganglioneuritis and perineuritis in a dog with chronic otitis, bilateral tympanokeratomas and presumed extension of otic infection to the central nervous system.

Case presentation

An 11-year-old intact male Dalmatian dog with chronic bilateral otitis externa and sudden development of symptoms of vestibular disease was examined. Due to the dog’s old age the owner opted for euthanasia without any further examination or treatment and the dog was submitted for necropsy. Transection of the ears revealed grey soft material in the external ear canals and pearly white, dry material consistent with keratin in the tympanic bullae bilaterally. The brain and meninges were grossly unremarkable. Microscopical findings included bilateral otitis externa and media, unilateral otitis interna, ganglioneuritis and perineuritis of the spiral ganglion of the vestibulocochlear nerve and multifocal to coalescing, purulent meningitis. A keratinizing squamous epithelial layer continuous with the external acoustic meatus lined the middle ear compartments, consistent with bilateral tympanokeratomas. Focal bony erosion of the petrous portion of the temporal bone and squamous epithelium and Gram-positive bacterial cocci were evident in the left cochlea. The findings suggest that meningitis developed secondary to erosion of the temporal bone and ganglioneuritis and/or perineuritis of the vestibulocochlear nerve.

Conclusions

Middle ear tympanokeratoma is an important and potentially life-threatening otic condition in the dog. Once a tympanokeratoma has developed expansion of the cyst can lead to erosion of bone and extension of otic infection to the inner ear, vestibulocochlear ganglion and nerve potentially leading to bacterial infection of the central nervous system.

Electronic supplementary material

The online version of this article (10.1186/s13028-018-0386-4) contains supplementary material, which is available to authorized users.