Pathology in Practice.

In collaboration with the American College of Veterinary Pathologists.

Ocular findings in cats with blastomycosis: 19 cases (1978-2019).

OBJECTIVE: To document ocular findings in cats with blastomycosis. ANIMALS: 35 cats with blastomycosis. PROCEDURES: Medical records from 1978 through 2019 were reviewed to identify cats with confirmed Blastomyces infection. Cats were grouped as having or not having ocular involvement. Clinical signs, histopathologic findings, and response to treatment were evaluated. RESULTS: 21 of the 35 (60%) cats with confirmed blastomycosis had ocular abnormalities. Two of 21 cats with ocular abnormalities also had systemic hypertension and were excluded. Of the remaining 19 cats, 15 (79%) had bilateral ocular signs. Ten (53%) cats had inflammatory ocular lesions, and 9 (47%) had neuro-ophthalmic abnormalities. Six of the 19 (32%) cats appeared to be completely blind, and 5 (26%) appeared to be unilaterally blind. For the 10 cats with inflammatory ocular lesions, the most common lesions were anterior uveitis (9/20 eyes), active chorioretinitis (6/20 eyes), and retinal detachment (4/20 eyes). For the 9 cats with neuro-ophthalmic abnormalities, the most common abnormalities were a negative menace or tracking response (10/18 eyes) and negative pupillary light response (4/18 eyes). CLINICAL RELEVANCE: Results suggested that ocular involvement is common in cats with blastomycosis and that both inflammatory lesions and neuro-ophthalmic abnormalities can be seen. Blastomycosis should be considered in the differential diagnosis for cats with anterior uveitis, posterior segment inflammation, or neuro-ophthalmic abnormalities, and a complete ophthalmic examination should be performed in all cats with confirmed or suspected blastomycosis.

Retrobulbar and Tongue Base Pyogranulomatous Myositis Resulting in Strabismus in a Dog: Case Report.

A seven-year-old female spayed Australian Shepherd was presented for a 3-day history of left eye ventromedial strabismus, episcleral injection, protrusion of the third eyelid, miosis, and enophthalmia. Magnetic Resonance Imaging (MRI) identified lesions in the left medial pterygoid muscle and left tongue base. Cytology and histopathology revealed pyogranulomatous inflammation with rod-shaped bacteria and pyogranulomatous myositis, respectively. One month of oral antibiotics resolved both lesions. Repeat MRI showed a mild decrease in size of the left medial pterygoid muscle consistent with fibrosis. Clinically, residual, positional ventral strabismus remained upon dorsal neck extension, but all other ophthalmic abnormalities resolved. To the authors' knowledge, this is the first report of pyogranulomatous myositis causing this constellation of clinical signs and of repeat imaging depicting resolution of these lesions with therapy.

Tear film concentrations of topically applied 0.5% oxytetracycline ointment in normal canine eyes.

OBJECTIVE: To determine the tear film levels of oxytetracycline in normal canine eyes after application of the ophthalmic ointment, Terramycin™ (0.5% oxytetracycline, polymyxin B sulfate), to guide appropriate treatment frequency. ANIMALS STUDIED: Ten research beagles. PROCEDURES: Ten research beagles with confirmed normal eyes were administered 0.02 mL of Terramycin™ ophthalmic ointment onto the dorsal bulbar conjunctival surface of the right eye. Tear samples were collected via dye-less Schirmer tear strips at 2, 4, 6, 8, and 12 hours post-administration. The sample for each timepoint was collected on a separate day, and concentrations of oxytetracycline were determined using high-performance liquid chromatography (HPLC). RESULTS: There was a semi-logarithmic decline in the median tear concentration of oxytetracycline. The median (2.5th and 97.5th percentiles) tear concentrations of oxytetracycline at 2, 4, 6, 8, and 12 hours were 43.5 µg/mL (11.1-302.2 µg/mL), 28.7 µg/mL (8.04-113.7 µg/mL), 16.1 µg/mL (4.96-37.7 µg/mL), 9.2 µg/mL (4.52-28.1 µg/mL), and 6.11 µg/mL (4.36-26.7 µg/mL), respectively. Mean (±SD) drug recovery via HPLC was 88% (±7.5%). CONCLUSIONS: Ophthalmic Terramycin™ achieves a substantially higher tear level than the MIC for common bacterial corneal pathogens up to 12 hours post-administration in normal eyes. Anti-collagenolytic tear levels were not achieved at the timepoints evaluated or with the manufacturer-prescribed dosing frequency. HPLC can be used to analyze tear concentrations of ophthalmic ointment formulations.

Ophthalmic findings in 10 captive, anesthetized chimpanzees (Pan troglodytes).

OBJECTIVES: To document ophthalmic findings, Schirmer's tear test I (STT), and intraocular pressure (IOP) values for anesthetized chimpanzees (Pan troglodytes). ANIMALS STUDIED: Ten captive chimpanzees from Zoo Knoxville and Chattanooga Zoo. PROCEDURES: Ten chimpanzees were anesthetized for annual physical examinations, blood collection, and ophthalmic examination. Each was anesthetized with intramuscular (IM) injections of dexmedetomidine, midazolam, and ketamine. Ophthalmic findings and STT and IOP values in addition to general health information were recorded for each chimpanzee. Pupillary diameter was measured after topical tropicamide administration. A Shapiro-Wilk test of normality was done for age, weight, STT values, IOP values, and pupil size. RESULTS: Ages ranged from 11 to 42 years. Weight range was 40.9-83.6 kg. The mean STT was 13.4 ± 5.3 mm/min. The mean IOP was 14 ± 4.2 mm Hg. Seven of the 10 chimpanzees were considered geriatric, and each had perilimbal lipid deposits. Sedative-associated miosis was successfully counteracted with a regimen of repeated applications of tropicamide, enabling complete fundic examination. CONCLUSIONS: A complete ophthalmic examination can be done on anesthetized chimpanzees with the protocol used in this study.

Long-term outcome of phacoemulsification in raptors-A retrospective study (1999-2014).

OBJECTIVE: To determine long-term outcome of phacoemulsification in raptors at the University of Tennessee Veterinary Medical Center. ANIMALS STUDIED: Seven nonreleasable diurnal raptors including, four bald eagles (Haliaeetus leucocephalus), two red-tailed hawks (Buteo jamaicensis), and one peregrine falcon (Falco peregrinus) that had undergone phacoemulsification. All birds showed behavioral changes attributable to visual deficits prior to surgery. PROCEDURES: All birds underwent phacoemulsification for cataracts. Four underwent bilateral phacoemulsification, and three had unilateral surgery. Due to a low sample size, statistics were not done. RESULTS: Six raptors (nine eyes) had long-term follow-up (median 75 months, range 28 to 105 months). Seven of these eyes (78%) were visual at last examination. Of those visual eyes, two developed mild to moderate posterior synechiae, four had mild to moderate capsular opacities, and one developed a lipid keratopathy. The remaining two eyes with long-term follow-up were from the same red-tailed hawk. Both eyes developed fibropupillary membranes that were blinding. One eye was pseudophakic, and the other was aphakic and also developed a rhegmatogenous retinal detachment. Another bald eagle was euthanized two months after surgery due to refractory glaucoma; one eye was pseudophakic. CONCLUSIONS: Phacoemulsification is a viable treatment for captive raptors with cataracts. The most severe complications occurred relatively soon after surgery. Captive raptors appear to adapt well to aphakia.