The method of application and short term results of tympanostomy tubes for the treatment of primary secretory otitis media in three Cavalier King Charles Spaniel dogs

Prevalence and characterization of middle ear effusion in 55 brachycephalic dogs

OBJECTIVE

 Multiple, breeding-related malformations of the skull of brachycephalic dogs are well-known. Whereas the eye-catching deformities of the nose that lead to dramatic respiratory problems are obvious, changes of the middle ear are often an incidental finding on CT examinations and usually clinically inapparent. The objectives of this work were to investigate the prevalence and characteristics of middle ear effusion in brachycephalic dog breeds presented for multilevel surgery of upper airway obstructions.

MATERIAL AND METHODS

 Brachycephalic dogs with incidental middle ear effusion detected on CT scans obtained prior to surgical treatment of brachycephalic airway syndrome were prospectively enrolled. A perendoscopic tympanocentesis followed by macroscopic description, microscopic cytology and bacteriological analysis of the fluid was performed.

RESULTS

 Prevalence of middle ear effusion in all dogs presented to the department during the study period was 55/170 (32 %) in 86 middle ears. The only breeds suffering from MEE were French Bulldogs (FB) with a prevalence of 35/66 (53 %) and Pugs with a prevalence of 20/79 (25 %). Tympanocentesis was performed in 80 ears. In the majority of cases the effusion was either mucoid or serous, with a honey-like or ochre colour.Bacteriology was available for 76 ears and tested positive in 34 (45 %) cases. Cytology was performed in 73 ears and revealed all effusions to contain inflammatory cells with a high concentration in 23 (31.5 %) cases.

CONCLUSIONS AND CLINICAL RELEVANCE

 Brachycephalic dogs presented for surgical treatment of brachycephalic airway syndrome have a high prevalence of incidental middle ear effusions. Cytological findings differ from previously reported analyses of effusions in Cavalier King Charles spaniels with clinical symptoms of primary secretory otitis media, where usually cell-free effusions are found. A study comparing effusions of brachycephalic dogs with vestibular disease to those found as an incidental condition is warranted.

Normative wideband acoustic immittance patterns for middle ear evaluation in dogs

The objective of this study was to investigate the clinical use of wideband acoustic immittance (WAI) reflectance for middle ear assessment in dogs. Otoscopy and brainstem auditory evoked response testing was performed on all dogs prior to the WAI assessment. Following calibration, dogs were comfortably restrained while the probe was placed into the ear canal to obtain recordings. Testing was repeated for replicability. Repeatable WAI reflectance patterns were observed in 24 dogs, characterized by low-reflectance resonant peaks at approximately 1500-1800 Hz and 3000-4000 Hz. Observed patterns suggest WAI may be a practical means of assessing middle ear function in dogs.

Myringotomy in dogs: Contamination rate from the external ear canal - a pilot study

Myringotomy for sample collection from the middle ear cavity for cytology and bacterial culture is considered a routine method to diagnose otitis media in dogs. The objective of this study was to determine the rate of contamination of middle ear aspirates with material from the external ear canal obtained by video-otoscopic guided myringotomy. In canine cadavers (n = 17) free from otitis externa the external ear canals were flushed under video-otoscopic control and a fluorescent dye was instilled. After removal of residual fluid a myringotomy was performed. If air was aspirated, 1 mL of saline was instilled through the same myringotomy needle into the middle ear cavity and re-aspirated. Contamination from the external ear canal was demonstrated by positive fluorescence of the aspirate. Bacterial cultures and cytological examinations of the external ear canals and middle ear cavities were performed. Data from 28 ears under investigation were included. In 19 of 28 middle ear aspirates (67.9%), clear yellow fluorescent fluid was obtained, indicating a contamination from the external ear canal. Microorganisms were detected in 4 of 26 middle ear samples (15.4%) and in 15 of 26 external ear canals (57.7%). Sample collection by myringotomy in this study was associated with a high contamination rate, implying that the suitability of this method for detection of otitis media in patients with concurrent otitis externa is questionable. Furthermore, the potential for iatrogenic spread of pathogenic microorganisms into the middle ear cavity needs to be considered.

Cytological and microbiological characteristics of middle ear effusions in brachycephalic dogs

Background

Middle ear effusion is common in brachycephalic dogs with similarities to otitis media with effusion in children. Association with the cranial and eustachian tube morphology and bacterial infection is suspected in both species.

Hypothesis/objectives

To determine cytological and bacteriological features of middle ear effusions in dogs, provide information on histological features, and further assess the dog as a model of the human disease.

Animals

Sixteen live dogs, 3 postmortem cases of middle ear effusion, and 2 postmortem controls.

Methods

Prospective; clinical investigation using computed tomography, magnetic resonance imaging, video‐otoscopy, myringotomy; cytological assessment of 30 and bacteriology of 28 effusions; histology and immunohistochemistry (CD3 for T‐lymphocytes, Pax5 for B lymphocytes and MAC387 for macrophages) of 10 middle ear sections.

Results

Effusions were associated with neurological deficits in 6/16 (38%) and concurrent atopic dermatitis and otitis externa in 9/16 (56%) of live cases. Neutrophils and macrophages predominated on cytology (median 60 [range 2%‐95.5%] and 27 [2%‐96.5%]) whether culture of effusions was positive or not. In histology sections, the mucosa was thickened in affected dogs but submucosal gland dilatation occurred in affected and unaffected dogs. There was no bacterial growth from 22/28 (79%) of effusions. Bacteria isolated from the other 6 (21%) were predominantly Staphylococcus pseudintermedius (4/6, 67%).

Conclusions and Clinical Importance

Clinical, morphological, and cytological findings in middle ear effusions of dogs and people suggest similar pathogeneses. Middle ear effusion of dogs could be a useful model of human otitis media with effusion. Such comparisons can improve understanding and management across species.

Bacteriology and cytology of otic exudates in 41 cavalier King Charles spaniels with primary secretory otitis media

BACKGROUND

Primary secretory otitis media (PSOM) in the cavalier King Charles spaniel (CKCS) is similar to otitis media with effusion (OME) in humans. A proposed aetiology of OME is inflammation of the middle ear mucosa, usually due to bacterial infection, leading to auditory tube dysfunction.

HYPOTHESIS/OBJECTIVES

Our objective was to characterize the microbiological and cytological findings of otic exudates from the external ear canal (EEC) (n = 68) and middle ear (ME) (n = 69) from 41 CKCSs with PSOM.

METHODS AND MATERIALS

Swab samples from the EEC and mucus aspirated from the ME after performing a myringotomy were obtained for bacterial culture and cytological analysis.

RESULTS

Fifty-five of 68 (81%) EEC and 46 of 69 (67%) ME yielded no bacterial growth. Thirty-eight of the 68 (56%) ears had no microbial growth from neither the EEC nor ME; seven (10%) had bacteria isolated from the EEC only; 17 (25%) had bacteria isolated from the ME only, and six (8%) had bacteria isolated from both EEC and ME. Thirty-four total bacterial isolates were cultured from ME. The most common bacterial species isolated were coagulase-negative staphylococci, followed by Staphylococcus pseudintermedius. Otic cytology identified coccoid organisms in only three of 68 EEC and four of 69 ME.

CONCLUSIONS

The role of bacteria in the pathogenesis of PSOM in CKCS is unclear. The majority of the EEC and ME of the CKCS with PSOM were negative by conventional bacterial culture and the cytological presence of bacteria was not correlated with culture positives. The potential role of noncultivable microbiota in PSOM requires exploration using molecular methods.

The Genetics of Deafness in Domestic Animals

Although deafness can be acquired throughout an animal's life from a variety of causes, hereditary deafness, especially congenital hereditary deafness, is a significant problem in several species. Extensive reviews exist of the genetics of deafness in humans and mice, but not for deafness in domestic animals. Hereditary deafness in many species and breeds is associated with loci for white pigmentation, where the cochlear pathology is cochleo-saccular. In other cases, there is no pigmentation association and the cochlear pathology is neuroepithelial. Late onset hereditary deafness has recently been identified in dogs and may be present but not yet recognized in other species. Few genes responsible for deafness have been identified in animals, but progress has been made for identifying genes responsible for the associated pigmentation phenotypes. Across species, the genes identified with deafness or white pigmentation patterns include MITF, PMEL, KIT, EDNRB, CDH23, TYR, and TRPM1 in dog, cat, horse, cow, pig, sheep, ferret, mink, camelid, and rabbit. Multiple causative genes are present in some species. Significant work remains in many cases to identify specific chromosomal deafness genes so that DNA testing can be used to identify carriers of the mutated genes and thereby reduce deafness prevalence.

Video-otoscopy-guided tympanostomy tube placement for treatment of middle ear effusion

OBJECTIVE

To describe video-otoscopy-guided tympanostomy tube placement in 12 cavalier King Charles spaniels with middle ear effusion and assess the clinical outcome.

METHODS

A retrospective review of medical records of cavalier King Charles spaniels diagnosed with middle ear effusion and treated with tympanostomy tubes placement between 2012 and 2014 was performed. Outcome was assessed based on a telephone questionnaire.

RESULTS

Twenty-two tympanostomy tubes were successfully placed in the tympanic membrane in 12 cavalier King Charles spaniels under video-otoscopic guidance using a rigid endoscope and grasping forceps. Follow-up based on an owner questionnaire was available for 11/12 dogs. Subjective improvement in hearing was observed in 9/11 dogs with three dogs achieving normal hearing, according to the owners, and six demonstrating partial improvements. Out of 11 dogs, 10 dogs were reported with improved quality of life. Pruritus of the ears resolved in 3/9 dogs. Clinical signs recurred in four dogs because of tube dislodgement.

CLINICAL SIGNIFICANCE

Video-otoscopic tympanostomy tube placement appeared to be indicated as a treatment for middle ear effusion in cavalier King Charles spaniels. It subjectively improved hearing, pruritus and quality of life in most dogs. The tympanostomy tubes dislodged in some cases, leading to recurrence of clinical signs, which were effectively eliminated by replacement of a fresh tube.

Panel 2

Objective

This report reviews the literature to identify the advances in our understanding of the middle ear (ME)–Eustachian tube (ET) system during the past 4 years and, on that basis, to determine whether the short-term goals elaborated in the last report were achieved and propose updated goals to guide future otitis media (OM) research.

Data Sources

Databases searched included PubMed, Web of Science (1945-present), Medline (1950 to present), Biosis Previews (1969-present), and the Zoological Record (1978 to present). The initial literature search covered the time interval from January 2007 to June 2011, with a supplementary search completed in February 2012.

Review Methods

The panel topic was subdivided; each contributor performed a literature search and provided a preliminary report. Those reports were consolidated and discussed when the panel met on June 9, 2011. At that meeting, the progress was evaluated and new short-term goals proposed.

Conclusions

Progress was made on 16 of the 19 short-term goals proposed in 2007. Significant advances were made in the characterization of ME gas exchange pathways, modeling ET function, and preliminary testing of treatments for ET dysfunction.

Implications for Practice

In the future, imaging technologies should be developed to noninvasively assess ME/ET structure and physiology with respect to their role in OM pathogenesis. The new data derived from form/function experiments should be integrated into the finite element models and used to develop specific hypotheses concerning OM pathogenesis and persistence. Finally, rigorous studies of treatments, medical or surgical, of ET dysfunction should be undertaken.

Primary secretory otitis media in Cavalier King Charles spaniels

Primary secretory otitis media (PSOM) is a disease that has been described in the Cavalier King Charles spaniel (CKCS). A large, bulging pars flaccida identified on otoscopic examination confirms the diagnosis. However, in many CKCS with PSOM the pars flaccida is flat, and radiographic imaging is needed to confirm the diagnosis. Current treatment for PSOM includes performing a myringotomy into the caudal-ventral quadrant of the pars tensa with subsequent flushing of the mucus out of the bulla using a video otoscope. Repeat myringotomies and flushing of the middle ear are necessary to keep the middle ear free of mucus.

Effect of middle ear effusion on the brain-stem auditory evoked response of Cavalier King Charles Spaniels

Brain-stem auditory evoked responses (BAER) were assessed in 23 Cavalier King Charles Spaniels with and without middle ear effusion at sound intensities ranging from 10 to 100 dB nHL. Significant differences were found between the median BAER threshold for ears where effusions were present (60 dB nHL), compared to those without (30 dB nHL) (P=0.001). The slopes of latency-intensity functions from both groups did not differ, but the y-axis intercept when the x value was zero was greater in dogs with effusions (P=0.009), consistent with conductive hearing loss. Analysis of latency-intensity functions suggested the degree of hearing loss due to middle ear effusion was 21 dB (95% confidence between 10 and 33 dB). Waves I-V inter-wave latency at 90 dB nHL was not significantly different between the two groups. These findings demonstrate that middle ear effusion is associated with a conductive hearing loss of 10-33 dB in affected dogs despite the fact that all animals studied were considered to have normal hearing by their owners.

Human evolutionary history: consequences for the pathogenesis of otitis media

The pathogenesis of otitis media is multifactorial, but the role of evolution on its development has not been addressed. We posit that the high prevalence of middle-ear disease is most likely restricted to humans, in contrast to other wild species, because the associated hearing loss would have reduced the fitness of affected individuals as a result of predation. We present here the possible consequences of two human adaptations that may have resulted in ubiquitous otitis media: the interaction of bipedalism and increased brain size, and the loss of facial prognathism resulting from speech or cooking. As a consequence of our adaptation for bipedalism, the female pelvic outlet is constricted, which, in the context of a rapidly enlarging brain, results in humans being born 12 months too soon. Significantly, immature eustachian tube structure and function, in conjunction with an immature immune system, helps to explain the high incidence of otitis media in the first year of life. But the persistence of middle-ear disease beyond this stage is not explained by "immaturity." The morphology of the palate changed with the adaptations that produced facial flattening, with concomitant effects on eustachian tube function. These changes resulted in relatively poor human physiologic tubal function in comparison to the nonhuman primate.

Relationship between pharyngeal conformation and otitis media with effusion in Cavalier King Charles spaniels

Otitis media with effusion (OME) is a common incidental finding in otherwise normal Cavalier King Charles spaniels (CKCS). In this study, measurements made on MRI were used to determine whether there was an association between OME and brachycephalic conformation. The results confirm that association and also demonstrate that, in CKCS, greater thickness of the soft palate and reduced nasopharyngeal aperture are significantly associated with OME. These results suggest that auditory tube dysfunction and OME may represent a previously overlooked consequence of brachycephalic conformation in dogs.