Prevalence of middle ear effusion in French bulldogs without clinical signs of otic disease: A retrospective study of magnetic resonance imaging (2017-2022).

BACKGROUND: Canine middle ear effusion (MEE) is usually asymptomatic, being an incidental finding when computed tomography or magnetic resonance imaging (MRI) of the head is performed for other reasons unrelated to otic disease. The clinical relevance of the presence of material in the tympanic bulla (TB) remains uncertain, and more detail about its prevalence and appearance in MRI are required. OBJECTIVE: To assess the prevalence of presence of material within the TB of French bulldogs (FB) with no clinical signs suggestive of otitis (externa, media or interna) that underwent high-field MRI for other medical reasons. ANIMALS: Two hundred fifty-two TB of 126 FB were included in this study. MATERIALS AND METHODS: Nonexperimental retrospective study in which MRI images were evaluated by a board-certified veterinary radiologist. RESULTS: Fifty-eight per cent of the dogs had material in the TB lumen (46% of the TB) and 59% were bilaterally affected. The signal intensity of this material related to the grey matter was variable on T1w and mainly hyperintense on T2w sequences. CONCLUSION AND CLINICAL RELEVANCE: FB are predisposed to MEE. This is important when assessing imaging studies of TB of FB with chronic otitis externa, as high percentage of cases may have concurrent MEE. MRI findings in FB with MEE are characterised by a hyperintense signal to the grey matter on T2w in most cases and variable on T1w sequences.

Otitis media with effusion in two Boston terrier dogs.

Otitis media (OM) in dogs can occur as a primary condition instead of as an extension of an otitis externa (OE), characterized by the presence of fluid in the middle ear (ME) referred to as OM with effusion (OME). OME has been reported in a brachycephalic breed (boxer), and the same condition is described as primary secretory OM in Cavalier King Charles Spaniels. These dogs can be asymptomatic or present with pain, facial nerve paralysis and reduced hearing. This report describes two cases of OME with associated neurologic signs in Boston terriers with no previous history of OE, normal external ear canals and tympanic membranes. Neurologic evaluation revealed right head tilt along with vestibular ataxia and frequent walking tight circles to the right in case 1, and a dull mentation with a right-sided head tilt and torticollis, vestibular tetra-ataxia, ambulatory tetraparesis and circling to the right in case 2. MRI imaging of the brain was performed. Results showed bilateral OM with right-sided otitis interna and equivocal associated otogenic meningitis in case 1 and right-sided OM in case 2. Myringotomy was performed, and both dogs' ME sampled for cytology that only revealed inflammatory cells; and bacterial cultures which revealed a light growth of Pseudomonas aeruginosa in case 1. ME were flushed with sterile saline. Oral glucocorticoids and antibiotics based on the susceptibility results, and a compound antibiotic and glucocorticoid ear solution were prescribed to case 1. Neurologic improvement was observed a few days after the appointment, but a mild right-sided head tilt remained evident. Owner of case two elected humane euthanasia due to patient respiratory difficulties upon anaesthetic recovery and other concurrent healthy concerns. Current findings reinforce that brachycephalic dogs may be prone to develop OME, and advanced imaging tests are key to the diagnosis.

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.

Influence of computed tomographic dimensions of the nasopharynx on middle ear effusion and inflammation in pugs and French bulldogs with brachycephalic airway syndrome.

OBJECTIVE: To compare the prevalence of middle ear abnormalities in pugs and in French bulldogs and evaluate the influence of nasopharyngeal dimensions on middle ear effusion. STUDY DESIGN: Retrospective study. ANIMALS: Thirty pugs and 30 French bulldogs with brachycephalic airway syndrome and no known history of ear disease. METHODS: Computed tomographic (CT) studies were reviewed for middle ear effusion, mucosal contrast enhancement, signs of osteitis, and tympanic wall thickness. Soft palate thickness and cross-sectional areas of the nasopharynx at the opening of the auditory tube were measured and normalized to each individual's skull index before statistical comparison between breeds. Statistical dependence of middle ear abnormalities and nasopharyngeal dimensions was assessed by using Spearman's rank correlation tests. RESULTS: Middle ear effusion was observed in 17 of 30 (56.7%) French bulldogs and five of 30 (16.7%) pugs. Contrast enhancement of the tympanic bulla was noted in 25 of 60 (41.6%) French bulldog ears and three of 60 (5.0%) pug ears. The cross-sectional airway dimensions (difference [Δ] = 0.31 cm2 , P < .0001) and soft palate thickness (Δ = 0.44 cm, P < .0001) were reduced in pugs compared with in French bulldogs. Weak correlations were detected between soft palate thickness and nasopharyngeal dimensions and presence of tympanic bulla effusion (r = 0.324 and r = 0.198, respectively) or contrast enhancement (r = 0.270 and r = 0.199, respectively). CONCLUSION: Middle ear effusion and inflammation were more common in French bulldogs than in pugs and did not seem related to nasopharyngeal dimensions. CLINICAL SIGNIFICANCE: French bulldogs with brachycephalic airway syndrome seem predisposed to middle ear effusion and inflammation.

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.

Behavioral and clinical signs of Chiari-like malformation-associated pain and syringomyelia in Cavalier King Charles spaniels.

BACKGROUND: Diagnosis of Chiari-like malformation-associated pain (CM-P) or clinically relevant syringomyelia (SM) is challenging. We sought to determine common signs. ANIMALS: One hundred thirty client-owned Cavalier King Charles spaniels with neuroaxis magnetic resonance imaging (MRI) and diagnosis of CM-P/SM. Dogs with comorbidities causing similar signs were excluded with exception of otitis media with effusion (OME). METHODS: Retrospective study of medical records relating signalment, signs, and MRI findings. Dogs were grouped by SM maximum transverse diameter (1 = no SM; 2 = 0.5-1.99 mm; 3 = 2-3.9 mm: 4 = ≥4 mm). Differences between all groups-groups 1 versus 2-4 and groups 1-3 versus 4-were investigated. Continuous variables were analyzed using 2-sample t-tests and analysis of variance. Associations between categorical variables were analyzed using Fisher's exact or chi-square tests. RESULTS: Common signs were vocalization (65.4%), spinal pain (54.6%), reduced activity (37.7%), reduced stairs/jumping ability (35.4%), touch aversion (30.0%), altered emotional state (28.5%), and sleep disturbance (22%). Head scratching/rubbing (28.5%) was inversely associated with syrinx size (P = .005), less common in group 4 (P = .003), and not associated with OME (P = .977). Phantom scratching, scoliosis, weakness, and postural deficits were only seen in group 4 (SM ≥4 mm; P = .004). CONCLUSIONS AND CLINICAL IMPORTANCE: Signs of pain are common in CM/SM but are not SM-dependent, suggesting (not proving) CM-P causality. Wide (≥4 mm) SM is associated with signs of myelopathy and, if the dorsal horn is involved, phantom scratching (ipsilateral) and torticollis (shoulder deviated ipsilateral; head tilt contralateral).

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.

Twelve years of chiari-like malformation and syringomyelia scanning in Cavalier King Charles Spaniels in the Netherlands: Towards a more precise phenotype.

Chiari-like malformation (CM), syringomyelia (SM) and middle ear effusion (also called PSOM) are three conditions that frequently occur in Cavalier King Charles Spaniels (CKCS). Both CM and SM are currently screened in the Netherlands prior to breeding and are graded according to the British Veterinary Association's Kennel Club (BVA/KC) scheme. This study evaluated the prevalence and estimated genetic parameter of CM, SM and middle ear effusion from 12 years of screening results. For SM, the classical method using the BVA/KC scheme, was compared with exact measuring of the central canal dilation. For CM, the BVA/KC scheme was compared with a more detailed scheme. Next to this the presence of microchip artifacts was assessed. 1249 screening of 1020 dogs were re-evaluated. Results indicated the presence of CM in all dogs, suggesting it has become a breed-specific characteristic. And although different grades of CM were observed, the condition did not deteriorate over time. SM was present in 39% of the dogs and a clear age effect was demonstrated, with SM increasing with age. This emphasizes the importance of screening at appropriate age, since SM can worsen with increasing age. One alternative is to promote repeated measures. The presence of middle ear effusion in this study was 19%-21% for dogs younger than 3 years, and 32%-38% for dogs older than 3 years. In as much as 60%, microchip artifacts were noticed, leading to the recommendation to place microchips in another location in breeds that are susceptible to developing SM. Finally, this study estimated the heritability of CM in this population, due to the lack of phenotypic variance, to be very low at 0.02-0.03. The heritability for SM central canal dilatation to be 0.30, compared to 0.13 for the classical BVA/KC method, using a model including the age effect and the combined effect of veterinary clinic and year of the evaluation. Genetic correlations were rather small, ranging from 0.16-0.33. As a conclusion, screening for SM and CM in the entire population should be maintained, and a selection scheme against SM should be based on estimated breeding values for the exact measurement of the central canal dilatation.

Denervation of the Tensor Veli Palatini Muscle and Effusion in the Tympanic Cavity.

An English springer spaniel was presented for right-sided atrophy of the muscles of mastication, analgesia and paralysis of the face, and vestibular dysfunction. Neurological signs were consistent with a lesion involving the pons and rostral medulla resulting in deficits in the function of the trigeminal, facial, and vestibular nerves. MRI disclosed a right-sided extraparenchymal mass consistent with a trigeminal nerve sheath neoplasm that was compressing and invading the pons and medulla. Atrophy of the muscles of mastication, innervated by the trigeminal nerve, was also observed on MRI. Additionally, effusion was present in the ipsilateral tympanic cavity. Gross and microscopic evaluation of the right tensor veli palatini muscle (TVPM) was consistent with neurogenic atrophy. Effusion in the tympanic cavity was likely the result of an inability to open the auditory tube as a consequence of paralysis of the TVPM. Without the ability to open the auditory tube, gases present within the auditory tube and tympanic cavity may be absorbed, creating a negative pressure environment that leads to fluid transudation and effusion build up. To the authors' knowledge, this is the first report to document neurogenic atrophy of the TVPM with concurrent effusion in the ipsilateral tympanic cavity.

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.

Prevalence of ear disease in dogs undergoing multidetector thin-slice computed tomography of the head.

Previous reports describing the prevalence of ear diseases in dogs have primarily been based on dogs presenting with clinical signs of disease. The prevalence of subclinical ear disease remains unknown. The purpose of this cross-sectional retrospective study was to describe the prevalence of lesions consistent with middle and external ear disease in dogs presented for multidetector computed tomography (CT) of the head and/or cranial cervical spine at our hospital during the period of July 2011 and August 2013. For each included dog, data recorded were signalment, CT findings, diagnosis, and treatment. A total of 199 dogs met inclusion criteria. Nineteen dogs (9.5%) were referred for evaluation of suspected ear disease and 27 dogs (13.5%) had histories or physical examination findings consistent with otitis externa. A total of 163 dogs (81.9%) had CT lesions consistent with external ear disease (i.e. ear canal mineralization, external canal thickening, and/or narrowing of the external canal). Thirty-nine dogs (19.5%) had CT lesions consistent with middle ear disease (i.e. soft tissue attenuating/fluid material in the tympanic bullae, bulla wall thickening or lysis, and/or periosteal proliferation of the temporal bone). Findings from this study indicated that the prevalence of external and middle ear disease in dogs could be higher than that previously reported.

The association of middle ear effusion with trigeminal nerve mass lesions in dogs.

The trigeminal nerve is involved in the opening of the pharyngeal orifice of the Eustachian tube by operating the tensor veli palatini muscle. The hypothesis was investigated that middle ear effusion occurs in a more severe disease phenotype of canine trigeminal nerve mass lesions compared with dogs without middle ear effusion. Three observers reviewed canine MRIs with an MRI-diagnosis of trigeminal nerve mass lesion from three institutions. Various parameters describing the musculature innervated by the trigeminal nerve were scored and compared between dogs with and without middle ear effusion. Nineteen dogs met the inclusion criteria. Ipsilateral middle ear effusion was observed in 63 per cent (95% CI 48.4 per cent to 77.6 per cent) of the dogs. The size of the trigeminal nerve mass lesions was positively correlated with the severity of masticatory muscle mass loss (Spearman r=0.5, P=0.03). Dogs with middle ear effusion had a significantly increased generalised masticatory muscle mass loss (P=0.02) or tensor veli palatini muscle loss score (P=0.03) compared with those without. Larger trigeminal nerve mass lesions were associated with a greater degree of masticatory muscle mass loss. Masticatory muscle mass and, importantly, tensor veli palatini muscle mass was more severely affected in dogs with middle ear effusion suggesting an associated Eustachian tube dysfunction.

Prevalence of effusion in the tympanic cavity in dogs with dysfunction of the trigeminal nerve: 18 cases (2004-2013).

BACKGROUND: Animals with disorders involving the trigeminal nerve or its nuclei in the brainstem can have effusion in the tympanic cavity ipsilateral to the side of the neurological deficits. The tensor veli palatini muscle (TVP), innervated by the mandibular branch of the trigeminal nerve, opens the pharyngeal orifice of the auditory tube. With denervation of the TVP, dysfunction of the auditory tube may occur, which could lead to effusion. HYPOTHESIS/OBJECTIVES: To determine the prevalence of effusion in the tympanic cavity in dogs with disorders involving the trigeminal nerve. ANIMALS: Eighteen client-owned dogs were evaluated retrospectively. METHODS: Retrospective study. RESULTS: Diagnostic imaging databases were searched for dogs having undergone magnetic resonance imaging (MRI) evaluation for signs referable to dysfunction of the trigeminal nerve. Signalment and neurological examination findings were recorded. The MRI study was evaluated for the presence or absence of effusion. MRI characteristics of the affected trigeminal nerve and the muscles of mastication were recorded. Based on the location of the trigeminal nerve lesion, dogs were divided into three categories: brainstem, trigeminal canal, or extracranial. Eighteen dogs met the inclusion criteria. Six of 18 dogs (33%) had effusion in the tympanic cavity ipsilateral to the affected trigeminal nerve. CONCLUSION AND CLINICAL IMPORTANCE: A substantial proportion of dogs with a lesion affecting the trigeminal nerve had effusion in the tympanic cavity. This finding likely represents denervation of the TVP muscle, which may have led to dysfunction of the auditory tube.

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.

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.