A review of techniques for the investigation of otitis externa and otitis media

Otitis externa, inflammation of the externa ear canal, is relatively easy to diagnose based on the history and physical examination findings. The diagnosis of otitis media, inflammation of the middle ear cavity, is more challenging, with the work-up being both costly and, at times, invasive. The pathogenesis of otitis externa has been classified into predisposing, primary, and perpetuating factors. It is critical to the management of ear disease that the clinician recognize and investigate which factors are contributing to each individual patient's ear disease. Failure to identify and address the primary and/or predisposing factors is the most common cause of chronic recurrent otitis externa. Chronic inflammation of the ear canal leads to the development of the perpetuating factors, which may be the major reason for treatment failure, regardless of the primary cause of the ear disease. In this article, the predisposing, primary, and perpetuating factors involved in ear disease will be presented, along with a review of the techniques used in the diagnosis of otitis externa and otitis media.     

Nd:YAG laser‐assisted transendoscopic procedure for treatment of otitis media in a horse

An 8‐year‐old Warmblood gelding was referred for evaluation of headshaking to the Clinic for Horses, University of Veterinary Medicine Hannover. Based on clinical signs and computed tomography – as well as magnetic resonance imaging – findings, otitis media was diagnosed. Medical treatment including trimethoprim potentiated sulfadimethoxine and meloxicam for 3 weeks did not result in cessation of clinical signs. Therefore, the tympanic cavity was opened transendoscopically using an Nd:YAG‐laser via the guttural pouch according to surgical procedures in human and small animal medicine, leading to a considerable improvement of clinical signs.     

Otitis media with effusion in the boxer: a report of seven cases

The aim of this study was to describe otitis media with effusion in seven boxers. All dogs presented with a range of clinical signs, which included head shaking, neurological dysfunction, pain on opening of the mouth and reduction in hearing ability. Otitis media was confirmed under general anaesthesia in each case by video‐otoscopic identification of a bulging pars tensa and subsequent myringotomy, which revealed a tenacious mucus plug within the middle ear. Brainstem auditory evoked response thresholds were elevated in all affected ears. In three cases, CT revealed soft tissue opacity in the affected bulla. All of the affected middle ears were flushed using warm sterile saline to remove the mucus. A combination of glucocorticoid and antibiotic in EDTA tris was instilled into the middle ears. After the initial middle ear flush under general anaesthesia, topical therapy was applied into the ear canals daily by the owners using the same combination of drugs. Dembrexine, a systemic mucolytic, was administered with food daily. Six out of seven dogs were also prescribed oral prednisolone. In each case, the middle ear effusion was sterile. All clinical signs resolved with treatment, with the exception of facial paralysis in two dogs. Otitis media with effusion should be considered a cause of otitis media in boxers.     

Experimental induction of secretory and purulent otitis media by the surgical obstruction of the eustachian tube in dogs

Secretory and purulent otitis media developed after the surgical obstruction of the eustachian tube in dogs. On 3 days after the obstruction, secretory otitis media alone was induced without regard of presence of aerobes in middle ear fluid. On 10 and 15–20 days, two types of otitis media were induced; in the secretory type aerobes were hardly detected, and in the purulent type a considerable number of various species of aerobes were detected. The present results suggest that the eustachian tube obstruction readily generates secretory otitis media and, when aerobes are present in the middle ear, the otitic condition may develop to purulent otitis media.     

The results of surgical treatment of otitis media and interna in the dog

The case histories, surgical treatment and post–operative progress of twelve dogs with otitis media and/or otitis interna and one dog with an adnexal carcinoma arising within the tympanic bulla are described. Résumé. On décrit les antécédents du cas, le traitement chirurgique et les progrès postopératoires chez douze chiens avec une otite moyenne et/ou une otite interne et chez un chien avec un carcinome des annexes se formant dans la bulle tympanique. Zusammenfassung. Die Krankengëschichte, chirurgische Behandlung und postoperativer Fortschritt von zwǒlf Hunden mit Mittelohrentzǔndung und/oder Innerohrentzùndung und von einem Hund mit Adnexkarzinom, das sich innerhalb der tympanalen Bulla bildete, wurde beschrieben.     

Medical therapy of otitis externa and otitis media.

Medical regimens for the successful treatment of infectious otitis may vary widely depending on the degree of pathologic changes of the external ear canals, the status of the tympanic membranes, and the specific microorganisms involved. Chronic otitis media is especially problematic, because impaction of the bullae can be difficult to resolve and these cases often involve antibiotic-resistant bacterial organisms. In fact, the continuing emergence of resistant Pseudomonas spp and Staphylococcus spp will ensure that the medical therapy of otitis remains a dynamic art for the foreseeable future. This article considers the specific antimicrobial agents available for otic use, their potential toxicities, and guidelines for their use.     

Diagnosis and treatment of otitis media in dogs and cats.

Otitis externa/media is commonly found in dogs with chronic ear diseases and in cats with upper respiratory disease and polyps. Diagnosis of otitis media requires attention to history and clinical signs, but it also requires other methods of determining disease within the bulla. If the integrity of the eardrum cannot be determined, assume that there is middle ear disease and proceed accordingly. It is prudent to take necessary precautions to avoid the use of potentially ototoxic ear cleaners or topical medications in suspected otitis media cases. Therapeutic success is possible using systemic and topical treatment within the cleaned bulla. Referral to a dermatology specialist or a radiologist for a CT scan may be indicated in some refractory cases. Surgical intervention may be required to cure these difficult cases.     

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.     

Computed tomographic characteristics of pneumolabyrinth in a French bulldog with otitis media and externa

A four‐year‐old female French bulldog was presented for evaluation of acute, left‐sided peripheral vestibular syndrome. Computed tomographic (CT) examination of the head revealed the presence of air within the left cochlea and vestibule, consistent with pneumolabyrinth. This was concurrent with ipsilateral otitis media and externa. Pneumolabyrinth is an uncommon finding in humans and is most frequently due to head trauma and temporal bone fracture. This is the first report describing pneumolabyrinth in a dog, apparently of nontraumatic origin in this case.     

Pseudomonas aeruginosa otitis media and interna in a chinchilla ranch

Pseudomonas aeruginosa has been associated with conjunctivitis, enteritis, pneumonia, septicemia, sudden death, and abortion in chinchillas. This case report describes an unusual clinical presentation and diagnosis of P. aeruginosa otitis media and interna with neurologic manifestations. To our knowledge, this clinical presentation has not been reported previously in chinchillas.     

Microbial flora and antimicrobial susceptibility patterns from dogs with otitis media

This study evaluated the middle ear microbial flora and antimicrobial susceptibility patterns from dogs with otitis media. Antimicrobial susceptibility patterns were obtained on 164 micro-organisms from 107 ears of 82 dogs with otitis media that presented to Louisiana State University over a 12-year period. The most common micro-organisms isolated were Staphylococcus intermedius (26.8%), Pseudomonas aeruginosa (23.2%), β-haemolytic streptococcus (12.8%), Proteus spp. (11.0%) and Staphylococcus epidermidis (8.5%). Antimicrobial susceptibility testing was performed on all isolates employing the disk diffusion method (Kirby-Bauer). Minimum inhibitory concentration (MIC) testing for enrofloxacin and ciprofloxacin was performed on 10 of the 18 P. aeruginosa isolates found to be resistant to enrofloxacin on Kirby-Bauer. Of these isolates, 6 (60%) were susceptible, 1 (10%) was intermediate and 3 (30%) were resistant to enrofloxacin. Eight of these isolates (80%) were susceptible to ciprofloxacin, 1 (10%) showed intermediate susceptibility and 1 (10%) was resistant.     

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.     

Bulla curettage for chronic otitis media and interna in dogs.

In a series of 10 clinically affected and 6 clinically normal dogs, the technique of bulla curettage via the external ear canal, after lateral ear resection, was evaluated. In 5 of the 10 dogs with chronic otitis media and interna, the head carriage became normal 2 to 8 weeks after surgery and remained so for at least 18 months; 4 other dogs improved, but the improvement was either temporary or incomplete. In the clinically normal dogs, postsurgical complications were minimal; the tympanic membrane healed completely in 4 of the 6 dogs.