Clinical, advanced imaging data and outcome of inflammatory and neoplastic orbital disease in 81 dogs and 16 cats in Australia (2010-2019).

OBJECTIVE: To characterize the clinical presentation, advanced imaging features, and outcome of orbital disease in a referral population of dogs and cats that underwent computed tomography (CT) or magnetic resonance imaging (MRI). ANIMALS STUDIED: Client-owned animals. PROCEDURES: Animals referred for orbital disease undergoing ophthalmic examination and either head MRI or CT were included. Demographic and imaging features were compared between animals diagnosed with inflammatory disease and neoplastic disease using Mann-Whitney U and Fischer's exact tests. RESULTS: Ninety-seven animals (81 dogs and 16 cats) were included. Eighty-four and 13 patients underwent CT and MRI scanning, respectively. Inflammatory orbital disease was more frequently detected than neoplasia in dogs (59% vs. 41%) and cats (62% vs. 39%). Orbital cellulitis was the most common diagnosis in dogs (36/81, 44.4%) and cats (8/16, 80%). A foreign body was suspected in 36.1% of dogs with orbital cellulitis but only 3 were retrieved during orbitotomy. Multi-drug resistant bacteria were identified in 3 samples and influenced treatment plans. The most common neoplasms were sarcoma (10/30) and carcinoma (7/30) in dogs and lymphoma in cats (3/6). Imaging findings of osteolysis (p = 0.0002) and intracranial extension (p = 0.0001) were significantly associated with neoplasia in dogs. In contrast, osteolysis extension was present in cats with both inflammatory (7/10) and neoplastic (6/6) orbital disease. CONCLUSIONS: Inflammatory disease, particularly orbital cellulitis, was more common than neoplasia in dogs and cats with orbital disease in our population. We recommend including bacterial culture and susceptibility as part of the diagnostic work up when orbital cellulitis is suspected.

Prospective evaluation of the prevalence of conjunctival and intraocular bacteria in dogs undergoing phacoemulsification following a standardized aseptic preparation with 0.5% povidone iodine.

PURPOSE: To evaluate bacterial contamination of conjunctiva and aqueous humor in dogs undergoing phacoemulsification following asepsis with 0.5% povidone iodine and determine the influence of intravenous antibiotics on outcome of contamination. METHODS: Client-owned dogs were prospectively enrolled and randomly assigned to a control group, receiving 22 mg/kg intravenous cefazolin at induction prior to sampling, or experimental group receiving no antibiotic prior to sampling, masked to the surgeon. Dogs receiving antimicrobials in the pre-operative period were excluded. Asepsis was performed on all operated eyes using 0.5% iodine with minimum 3 min contact time at induction of anesthesia and repeated before surgery. A conjunctival swab and aqueous humor sample were collected prior to incision and following incision closure, respectively. Samples were submitted for aerobic and anaerobic bacterial culture and susceptibility. RESULTS: Seventy-one eyes of 42 dogs were included. Median age was 9 years. Thirty-nine and 32/71 eyes received intravenous cefazolin and no antibiotic, respectively. Median procedure time was 40 min per eye. Conjunctival cultures were positive in 6 eyes (8.5%): Serratia marcescens (5 eyes) and Cutibacterium acnes (1 eye). Aqueous humor cultures were positive in 5 eyes (7.0%): S. marcescens (2 eyes), Pseudomonas aeruginosa (2 eyes), Staphylococcus pseudointermedius (1 eye). Prevalence of positive culture did not differ between groups (p = .74), order of eyes for bilateral procedures (p = .74) and diabetic status (p = 1). CONCLUSIONS: Bacterial contamination of the conjunctiva and aqueous humor was present in 8.5% and 7.0% of dogs undergoing phacoemulsification after asepsis. Lack of IV cefazolin was not significantly associated with positive culture.

Gabapentin reduces stress and does not affect ocular parameters in clinically normal cats.

OBJECTIVE: To describe the effects of gabapentin on ocular and behavioral parameters following oral administration in healthy cats. MATERIALS AND METHODS: Masked, placebo-controlled, randomized crossover-design study. Ten young, healthy cats were scheduled for two veterinary visits 7 days apart and randomly assigned to receive a compounded capsule containing 100 mg of gabapentin or placebo (100 mg lactose powder) at the first visit and the opposite treatment at the second visit. Respiratory rate, heart rate, stress score, sedation score, compliance score, horizontal pupil diameter, intraocular pressure, and Schirmer tear test-1 were measured prior to and 1.5, 3, and 6 h following capsule administration. Stress score, sedation score, and compliance score were assigned based on established behavioral scales. Results of the two treatments were statistically compared with a p-value <0.05 considered significant. RESULTS: Respiratory rate was significantly reduced at 1.5 (p = 0.049) and 3 (p = 0.03) hours following gabapentin administration. Stress score was significantly reduced at 1.5 (p = 0.01) hours following gabapentin administration. Sedation score was significantly increased at 1.5 (p = 0.015) and 3 (p = 0.03) hours following gabapentin administration. Gabapentin had no significant effect on heart rate, compliance score, or ocular values measured in this study. CONCLUSIONS: Gabapentin reduces stress and increases sedation at 1.5 h after treatment, with no significant effect on horizontal pupil diameter, intraocular pressure or Schirmer tear test-1 results.