Retrospective evaluation of ceruminous gland tumors confined to the external ear canal of dogs and cats treated with biopsy and CO2 laser ablation.

BACKGROUND: Treatments currently available for ceruminous gland tumors include surgery and radiation therapy, which come with high financial costs and frequent complication and recurrence rates. HYPOTHESIS: To evaluate the treatment, response, complication, and recurrence of ceruminous gland tumors confirmed with biopsy and ablated using CO2 laser. METHODS: Retrospective review of medical records from Iowa State University and the University of Illinois between January 1, 2016 and December 31, 2021. Electronic medical records were evaluated for a histopathologically confirmed ceruminous gland tumor via video-otoscopic aided biopsy and subsequent CO2 laser ablation. Signalment, tumor type, size, location within the ear canal, length of time tumor was present before presentation, advanced imaging, and follow-up including recurrence were assessed. RESULTS: Fourteen ceruminous gland adenomas (4 dogs, 10 cats) and 12 ceruminous gland adenocarcinomas (7 dogs, 5 cats) were identified. Bacterial otitis externa was present in 4/26 (15%) animals. Recurrence was identified in 1/14 (7%) ceruminous gland adenomas and 1/12 (8%) ceruminous gland adenocarcinomas. CONCLUSIONS AND CLINICAL IMPORTANCE: Video-otoscopic aided biopsy and CO2 laser ablation of ceruminous gland tumors in dogs and cats is a viable treatment option with low recurrence and complication rates with CO2 laser ablation.

Trichophyton mentagrophytes complex: A retrospective study of 64 dogs from the Central United States (1997-2020).

BACKGROUND: There are limited clinical studies evaluating the Trichophyton mentagrophytes complex, with most reports confined to small case studies. Additionally, the studies are dated and provide limited information on response to newer or currently available therapies. HYPOTHESIS/OBJECTIVES: The aim of the study was to determine if there is a breed prevalence, lesion distribution and seasonality associated with the T. mentagrophytes complex for dogs evaluated in the central United States. An additional aim of the study was to evaluate response to therapies because there are minimal data available on clinical response with newer systemic antifungal drugs. ANIMALS: A total of 64 canine medical records were evaluated that had a previous diagnosis of T. mentagrophytes complex infection. MATERIALS AND METHODS: A retrospective study of medical records to evaluate signalment, time of onset of clinical signs, clinical presentation and therapeutic management. RESULTS: A higher incidence of T. mentagrophytes complex infection was observed in the American Kennel Club (AKC) Sporting group (43%) and Terrier group (20%). A seasonal influence was noted, with the onset of clinical signs being highest in October. Lesions most often affected the muzzle (48%), followed by the head excluding the pinnae (21%). Ketoconazole, itraconazole and terbinafine appeared equivalent as systemic therapeutic options to treat T. mentagrophytes complex infections. CONCLUSIONS AND CLINICAL RELEVANCE: This study identified patterns in breeds, seasonality and lesion distribution for the T. mentagrophytes complex in dogs from the central United States. Additionally, the study found several reasonable and reliable treatment options for systemic therapy.

Chemical and microbiological stability of diluted ceftazidime in three different solutions under three storage temperatures over a 28 day period.

BACKGROUND: Ceftazidime (CAZ) solutions are being used based on anecdotal reports for otitis externa complicated by multidrug-resistant Pseudomonas aeruginosa (MDR PA). The chemical and microbiological stability of these proposed compounded solutions have not been evaluated, and likely are affected by the diluent and storage duration or temperature. HYPOTHESIS/OBJECTIVES: Compounded CAZ solutions would show variable degradation dependent on diluent, time and temperature. The antimicrobial activity of the solutions would reflect changes in concentration and not alterations to the chemical compound. METHODS AND MATERIALS: Ceftazidime was compounded with 100 mL 0.9% sodium chloride (NA+CAZ), 118 mL Triz-EDTA Aqueous flush (TE+CAZ) and 125 mL Douxo Micellar Solution (MI+CAZ). Aliquots of the solutions were stored at 25°C, 4°C and -20°C for 28 days. High-performance liquid chromatography was used to analyse CAZ recovery from compounded solutions at weekly intervals. A modified broth dilution technique was utilised to assess minimum inhibitory concentration (MIC) to monitor antimicrobial activity against a reference PA strain. RESULTS: Temperature, duration of storage and diluent each had independent effects on the chemical stability of CAZ. CAZ concentrations decreased over time as well as with increased temperature. NA+CAZ solutions exhibited the least degradation compared to the other solutions. The MIC for PA was most consistent for NA+CAZ solutions regardless of storage temperature and duration of storage. CONCLUSIONS AND CLINICAL IMPORTANCE: Chemical and microbiological stability of compounded CAZ solutions varied by diluent, storage temperature and duration of storage. Dilution in NA resulted in the lowest variation in stability over 28 days when stored at refrigerated or frozen temperatures compared to other diluents.

Diagnosis and clinical management of auricular chondritis in a dog presenting for evaluation of severe pain.

BACKGROUND: The aetiology and appropriate treatment for auricular chondritis in the dog are currently unclear. This report describes a unique presentation and successful treatment of a dog with auricular chondritis. CLINICAL SUMMARY: A 12-year-old, female spayed, Labrador retriever dog was presented for severe pain thought to be neurological in origin. The pain was located to the right pinna and two punch biopsies were acquired and evaluated, revealing lymphoplasmacytic to pyogranulomatous inflammation involving the auricular cartilage with no infectious agents. Treatment with systemic oral prednisone resulted in resolution of clinical signs within four weeks of initiation of treatment. The dog remained free of clinical signs for six months following discontinuation of treatment before being euthanized for an unrelated reason. CONCLUSIONS: Further evaluation of canine auricular chondritis is needed, yet pain may be a prominent finding; monotherapy with systemic prednisone may provide quick and complete resolution of clinical sysmptoms.

Relative Oral Bioavailability of Two Amoxicillin-Clavulanic Acid Formulations in Healthy Dogs: A Pilot Study.

The use of human generic amoxicillin-clavulanic acid formulations in veterinary medicine is currently lacking supportive evidence. This pilot study was conducted to determine preliminary pharmacokinetic parameters and relative oral bioavailability of a human generic and veterinary proprietary 4:1 amoxicillin-clavulanic acid formulation in healthy dogs to evaluate whether drug exposure was similar and to determine if further comparative investigation is warranted. Each dog received a single oral dose of each formulation containing 500:125 mg of amoxicillin-clavulanic acid at two separate instances with a 2 wk washout period between product administration. Following drug administration, blood was collected at fixed times over 24 hr to measure plasma amoxicillin and clavulanic acid concentrations using liquid chromatography-mass spectrometry. There were no statistically significant differences between pharmacokinetic parameters of either formulation. Clavulanic acid showed greater between-dog variation in drug exposure between formulations compared with amoxicillin and was also observed to be more variable within the veterinary proprietary formulation. The average relative oral bioavailability was 98.2% (23.6% coefficient of variation) for amoxicillin and 152.6% (64.3% coefficient of variation) for clavulanic acid between formulations. This pilot investigation supports the need for further bioequivalence studies regarding these formulations before commenting on product interchangeability.

Nasal carriage of Staphylococcus schleiferi from healthy dogs and dogs with otitis, pyoderma or both.

In veterinary medicine, Staphylococcus schleiferi was previously assumed to be an inhabitant of carnivore skin, however, more recently, it has been repeatedly documented in the literature as both an inhabitant and as a pathogen. In order to determine the frequency of nasal carriage, and the methicillin susceptibility pattern of S. schleiferi from healthy dogs as well as dogs with otitis and/or pyoderma, a prospective study including 24 dogs with healthy ears and skin, 27 dogs with healthy ears and pyoderma, 15 dogs with otitis without pyoderma and 20 dogs with both otitis and pyoderma was performed. Specimens were obtained and cultured and isolates were identified as S. schleiferi based on growth and biochemical characteristics. S. schleiferi was isolated from the nares of 1 healthy dog, 3 dogs with recurrent pyoderma, 2 dogs with recurrent otitis, and 1 dog with both recurrent otitis and pyoderma. One of the S. schleiferi isolates was methicillin resistant. Nasal carriage of S. schleiferi does occur in healthy dogs as well as dogs with otitis and pyoderma. Methicillin resistant and sensitive S. schleiferi can be found in the nares of dogs with diseased ears and skin.

Terbinafine pharmacokinetics after single dose oral administration in the dog.

Terbinafine is an allylamine antifungal prescribed for the treatment of mycoses in humans. It is increasingly being used in veterinary patients. The purpose of this study was to evaluate the pharmacokinetic properties of terbinafine in dogs after a single oral dose. Ten healthy adult dogs were included in the study. A single dose of terbinafine (30-35 mg/kg) was administered orally, and blood samples were periodically collected over a 24 h period during which dogs were monitored for adverse effects. Two of 10 dogs developed transient ocular changes. A high-performance liquid chromatography assay was developed and used to determine plasma terbinafine concentrations. Pharmacokinetic analysis was performed using PK Solutions(®) computer software. Area under the curve (AUC) from time 0 to 24 h was 15.4 µg·h/mL (range 5-27), maximal plasma concentration (C(max) ) was 3.5 µg/mL (range 3-4.9 µg/mL) and time to C(max) (T(max) ) was 3.6 h (range 2-6 h). The time above minimal inhibitory concentration (T > MIC) as well as AUC/MIC was calculated for important invasive fungal pathogens and dermatophytes. The T > MIC was 17-18 h for Blastomyces dermatitidis, Histoplasma capsulatum and dermatophytes (Microsporum spp. and Trichophyton mentagrophytes), while the MIC for Sporothrix schenckii and Coccidioides immitis was exceeded for 9.5-11 h. The AUC/MIC values ranged from 9 to 13 µg h/mL for these fungi. Our results provide evidence supporting the use of terbinafine as an oral therapeutic agent for treating systemic and subcutaneous mycoses in dogs.

Teaching the didactic aspects of ophthalmology and dermatology using an off-site instructor.

A shortage of veterinary educators in various clinical disciplines is requiring faculty at veterinary schools to develop novel approaches to teaching professional students a core of information in each major clinical discipline. This article presents experiences at Washington State University (WSU) College of Veterinary Medicine in the teaching of the didactic components of ophthalmology and dermatology over four years using pre-prepared lectures developed by off-site instructors. The methodology of lecture preparation and presentation and various perspectives of student satisfaction with this teaching/learning method are presented.