Retrobulbar cellulitis and abscessation: focus on short- and long-term concurrent ophthalmic diseases in 41 dogs

Patterns of bacterial culture and antimicrobial susceptibility test results for dogs with retrobulbar abscesses: 133 cases (2002-2019)

OBJECTIVE

To evaluate patterns of bacterial culture and antimicrobial susceptibility test results for dogs with retrobulbar abscesses and generate recommendations for empirical antimicrobial selection.

ANIMALS

133 dogs examined between 2002 and 2019.

PROCEDURES

Records were retrospectively reviewed to determine type of bacterial culture, number and type of bacterial isolates, antimicrobial susceptibility test results, concurrent and recent antimicrobial exposure, effect of culture results on antimicrobial regimen, and outcome.

RESULTS

Aerobic culture alone was performed in 37 dogs, and aerobic and anaerobic culture was performed in 96 dogs. Isolates were recovered from 96 dogs, with multiple isolates recovered from 54 (56%) of those dogs. Of the 69 dogs for which both aerobic and anaerobic culture was performed and at least 1 isolate was obtained, 34 (49%) had purely aerobic infections, 15 (22%) had mixed aerobic and anaerobic infections, and 20 (29%) had purely anaerobic infections. Pasteurella spp (n = 26), Streptococcus spp (20), and Escherichia coli (12) were the most common aerobic isolates. Bacteroides spp (n = 22), Actinomyces spp (10), and Fusobacterium (10) spp were the most common anaerobic isolates. Susceptibility test results led to changes in the antimicrobial regimen in 37 of 80 (46%) dogs. Of the 76 dogs for which outcome information was available, 78 (97%) recovered.

CLINICAL RELEVANCE

Multipathogen and anaerobic infections were common in dogs with retrobulbar abscesses. Susceptibility data supported the use of amoxicillin-clavulanate or a combination of clindamycin and enrofloxacin as first-line treatments. Additional study is needed to characterize anaerobic antimicrobial susceptibilities and to compare results of susceptibility testing with in vivo responses to antimicrobial administration.

Effect of oral antioxidants on the progression of canine senile cataracts: a retrospective study

Background

Cataracts are the leading cause of impaired vision or blindness in dogs. There are many antioxidants that can prevent cataract progression, but whether they are clinically effective in dogs has not been established.

Objectives

To analyze the delaying or preventing effect of oral antioxidants on canine senile cataracts through retrospective analysis.

Methods

Medical records of dogs from January 1, 2015 to July 10, 2020 were reviewed. Dogs that were 8 yr of age or older with senile cataracts were included in this study. The dogs were divided into two treatment groups (dogs administered with Ocu-GLO supplement and dogs administered with Meni-One Eye R/C supplement) and a control group (dogs that were not administered any supplement). Dogs with incipient and immature cataracts were included in this study. Altogether, 112 dogs (156 eyes) with incipient cataracts and 60 dogs (77 eyes) with immature cataracts were included. The period of time that cataracts progressed from incipient to immature, and from immature to mature was recorded for each dog.

Results

There was no significant delaying effect on the progression of incipient cataracts. However, both Ocu-GLO (hazard ratio = 0.265, p = 0.026) and Meni-One (hazard ratio = 0.246, p = 0.005) significantly delayed the progression of immature cataracts compared to the control group.

Conclusions

Although there was no significant delaying effect of oral antioxidants on incipient cataract progression, antioxidants could be used to delay the progression of senile immature cataract.

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.

Canine Retrobulbar Cellulitis and Abscessation in the Southeastern United States: A review of case management, diagnostic imaging, bacterial isolates, and susceptibility patterns

OBJECTIVE

To describe common bacterial organisms cultured from retrobulbar cellulitis and abscess lesions, in vitro susceptibility patterns, common diagnostic techniques utilized, etiologies encountered, and prevalence of blindness.

ANIMALS STUDIED

Thirty-eight dogs diagnosed with retrobulbar cellulitis or abscessation from 2007 to 2017.

PROCEDURE

For cases of orbital cellulitis or abscess, signalment, orbital imaging, cytology, histopathology, bacterial culture and susceptibility testing, presence of vision at the initial examination and resolution, and presumed cellulitis/abscess etiology were recorded.

RESULTS

Most cases were medically (78.9%) versus surgically managed (18.4%). Most common form of orbital imaging was computed tomography (48.5%) followed by ocular ultrasound (18.2%). Fifteen of eighteen cultures (83.3%) showed growth of aerobic bacterial organisms, anaerobic bacterial organisms, or both. Most common aerobic bacteria were gram-negative bacilli (40.0%) followed by Corynebacterium sp. (26.7%) and α-hemolytic Streptococci sp. (26.7%) but Micrococcus and Bacillus spp. were also identified. Most common anaerobic bacteria were gram-negative bacilli (40.0%). Antibiotics with highest susceptibility patterns included gentamicin, followed equally by amoxicillin/clavulanic acid, cephalothin, chloramphenicol, and imipenem. No bacteria were susceptible to cefovecin. Six cases presented with vision loss due to retrobulbar disease (15.8%). Idiopathic (50%) disease and tooth root abscessation (23.7%) were most commonly diagnosed cause of orbital disease.

CONCLUSION

Retrobulbar cellulitis/abscess is a serious and vision-threatening process, which can be effectively managed by broad-spectrum antibiotics such as gentamicin or amoxicillin/clavulanic acid, but not cefovecin. This study identified three organisms that have not been previously reported to be associated with orbital cellulitis (Corynebacterium sp., Bacillus sp. and Micrococcus sp.).

Clinical features and MRI characteristics of retinal detachment in dogs and cats

The aim of this retrospective observational study was to characterize the MRI appearance of retinal detachment (RD) in a sample of dogs and cats. Study inclusion was based on the following medical record criteria: (a) had a diagnosis of RD in at least one eye by either funduscopic examination or ocular ultrasound and had an MRI evaluation including the eyes, or (b) had a diagnosis of RD documented in an MRI report for at least one eye and also had a clinical eye examination. Eighteen patients (12 dogs, 6 cats) and 35 eyes met the inclusion criteria, although four eyes that were clinically examined could not be visualized funduscopically and did not have ocular ultrasound performed (criterion 2). The MRI and clinical diagnosis (via either funduscopy or ultrasound) of RD/no RD was concordant in 27 of 31 eyes (87%). Qualitatively, RD appeared as a variable intensity curvilinear structure located internal and adjacent to the sclera on all sequences and was best delineated on T2W sequences. RDs inconsistently contrast enhanced and, although there was no statistical difference, subjectively appeared more clearly delineated on dorsal and parasagittal images. In conclusion, findings from the current study support using MRI as an ancillary diagnostic test for confirmation or further characterization of RD in dogs and cats.

Diagnosis and surgical management of a retrobulbar abscess causing unilateral exophthalmos in a Boer goat

A 10-year-old Boer goat wether presented for unilateral exophthalmos of 2- to 3-week duration. Ocular ultrasonography and computed tomography (CT) were utilized in the diagnosis of the patient's orbital disease and surgical planning. Exenteration was performed under the same general anesthetic event as CT. Cytology, culture, and histopathology were performed after exenteration. Cytology was consistent with a mixed bacterial infection. Culture confirmed the presence of Streptococcus ovis. Histopathology on the enucleated globe and mass revealed no evidence of tumor and confirmed intraocular extension of retrobulbar inflammation. Histopathologic diagnosis was consistent with severe chronic orbital pyogranuloma and fibrinosuppurative endophthalmitis confined to the subretinal space. The abscess recurred in the orbital space 2 weeks postoperatively; the orbit was explored. Repeat culture was consistent with S. ovis, Staphylococcus schleigeri subspecies coagulans, and Fusobacterium necrophorum. Complete resolution was obtained after drainage and lavage of the orbit. Abscess is cited as a cause of exophthalmos in small ruminants, but no individual case reports exist. Advanced imaging allowed presumptive diagnosis and surgical planning. Histopathology confirmed intraocular extension of retrobulbar disease.

Causes, outcomes, and owner satisfaction of dogs undergoing enucleation with orbital implant placement

OBJECTIVE

To describe clinical and histopathologic pre-operative diagnoses as well as associated post-operative complications following orbital silicone implantation in dogs undergoing enucleation and evaluate owner satisfaction.

ANIMALS STUDIED

One hundred and eighty-six dogs who underwent enucleation with orbital implant.

PROCEDURES

Medical records from dogs that underwent enucleation with orbital implant performed at Virginia-Maryland Veterinary Teaching Hospital between 2007 and 2019 were reviewed. Owners were surveyed via telephone regarding client satisfaction.

RESULTS

Enucleation followed by orbital implant placement occurred in 215 eyes of 186 dogs. The most common pre-operative diagnoses were glaucoma (68.8%), uveitis (17.7%), cataracts (15.8%), intraocular neoplasia (13.0%), and lens luxation (10.7%). The most common histopathologic diagnoses were retinal degeneration (46.5%), uveitis (39.5%), cataract (29.8%), retinal detachment (27.4%), and secondary glaucoma (26.5%). Fourteen eyes (6.5%) from ten dogs had post-operative complications reported including orbit cellulitis (n = 11), implant migration (n = 1), and implant extrusion (n = 1). Five of these dogs (50%) had concurrent diabetes mellitus. Median complication time from surgery was 41 days (range: 11-541 days). Ninety-five owner survey responses were completed with a median time of 6.3 years following surgery. Most owners, 85.3% (n = 81), were satisfied with the post-operative outcome.

CONCLUSION

Enucleation with implantation of an orbital implant is a viable and safe method for irreversibly blind eyes. Diabetes mellitus may be a risk factor for the development of post-operative complications. Intraocular neoplasia was not associated with development of post-operative complications. Results of this study indicated high owner satisfaction rates for improving cosmetic appearance after enucleation in dogs.

Orbital compartment syndrome resulting in unilateral blindness in two dogs

Orbital compartment syndrome (OCS) is described in humans as an acute rise in intraorbital pressure following a severe and rapidly evolving orbital affection. It includes orbital oedema, haemorrhage or infection causing a marked reduction in local blood perfusion, and severely affecting the orbital neurovascular structures. If not promptly recognised and treated, it results in irreversible blindness. It is one of the rare ophthalmic surgical emergencies, requiring lateral canthotomy and cantholysis. This case report describes two canine cases of complex orbital, periorbital and facial abscesses resulting in OCS and permanent unilateral blindness diagnosed by ultrasonography, computed tomography and electroretinography.