Kathryn L. Wotman

Evaluation of duration of corneal anesthesia induced with ophthalmic 0.5% proparacaine hydrochloride by use of a Cochet-Bonnet aesthesiometer in clinically normal horses

OBJECTIVE To measure duration of corneal anesthesia and time and degree of maximal anesthetic effect of 0.5% proparacaine hydrochloride by use of a Cochet-Bonnet aesthesiometer in horses. ANIMALS 10 clinically normal adult horses. PROCEDURES Baseline corneal touch threshold (CTT) was measured in millimeters for 1 randomly selected eye of each horse by use of the aesthesiometer by applying the filament to the cornea at maximum length (60 mm) and decreasing in 5-mm increments until a consistent blink response was elicited. Following baseline CTT measurement, 0.2 mL of 0.5% proparacaine hydrochloride was instilled in the selected eye. The CTT was measured within 1 minute following proparacaine administration and every 5 minutes thereafter for 60 minutes. A mixed-model ANOVA with tested eye varying between subjects and measurement time varying within subject was used to test for main effects and any interaction between these factors. A contrast between means of baseline and each subsequent CTT identified the duration of corneal anesthesia as the time at which there was no difference from baseline. Maximal anesthetic effect occurred at the time with the lowest mean CTT. RESULTS Duration of corneal anesthesia achieved by use of proparacaine was 25 minutes, and maximal anesthetic effect occurred within 5 minutes, although CTT never went to 0 in any horse at any time. CONCLUSIONS AND CLINICAL RELEVANCE Duration of corneal anesthesia in horses was shorter than in dogs, and degree of maximal effect was less than in cats and dogs, most likely because of increased sensitivity of the equine cornea, compared with corneal sensitivity in those species.

Association of blood lactate concentration and outcome in foals.

BACKGROUND Lactate concentration in blood or plasma ([LAC]) and change in [LAC] are associated with survival in sick foals. HYPOTHESIS [LAC] and change in [LAC] over time are associated with survival at 96 hours and discharge in neonatal foals. Furthermore [LAC] and change in [LAC] over time correlate with blood culture results and blood pressure at admission. ANIMALS Two hundred and twenty-five foals consecutively admitted to a Neonatal Intensive Care Unit. METHODS Retrospective case review. Foals <or=30 days of age with [LAC] from arterial (190) or umbilical (35) blood gas analysis ([LAC](BG)) at admission, 24, and 48 hours. [LAC](BG), blood pressure, blood culture status, and outcome (survival versus nonsurvival at 96 hours and discharge) were recorded. Change in [LAC](BG) over time ([LAC](BG)DeltaT) was calculated. RESULTS [LAC](BG) was lower in survivors (96 hours and discharge) at all times. [LAC](BG)DeltaT was larger for survivors (96 hours). Odds of survival (96 hours and discharge) decreased 18, 39, 53 and 22, 38, and 47%, respectively, at each sample time for every 1 mmol/L increment in [LAC](BG) and increased 156% for each 1.0/day increment in [LAC](BG)DeltaT from admission to 24 hours at 96 hours. Blood pressure and [LAC](BG) were not correlated (P= .196) until removal of selected foals (mean arterial pressure <60 mmHg, admission [LAC](BG) <5.5 mmol/L) (P < .001). Bacteremia was not associated with [LAC](BG). Proposed admission [LAC](BG) cut-points for future studies were 6.5 mmol/L (96 hours) and 5.5 mmol/L (discharge). CONCLUSIONS AND CLINICAL IMPORTANCE Prospective studies evaluating [LAC], [LAC](BG)DeltaT, and cut-points in sick foals are warranted.

Effect of treatment with a topical ophthalmic preparation of 1% nalbuphine solution on corneal sensitivity in clinically normal horses

OBJECTIVE To assess the effect of treatment with a topical ophthalmic preparation of 1.2% nalbuphine solution on corneal sensitivity in clinically normal horses. ANIMALS 8 horses. PROCEDURES Baseline corneal touch threshold (CTT) was measured (defined as the mean filament length [mm] at which a consistent blink response was elicited) for both eyes of each horse by use of a Cochet-Bonnet aesthesiometer. Subsequently, 0.2 mL of 1.2% nalbuphine solution was instilled in 1 randomly selected eye of each horse, and 0.2 mL of artificial tears solution was instilled in the contralateral eye (control treatment). For all 8 horses, CTT of each eye was measured within 1 minute following nalbuphine or artificial tears administration and every 15 minutes thereafter for 60 minutes. For 5 of the 8 horses, CTT was also measured in both eyes at 120 minutes. Changes in CTT values from baseline over time were assessed, as were differences between treated and control eyes. RESULTS At any time point, corneal sensitivity following nalbuphine treatment did not differ significantly from control treatment findings. Mean CTTs for nalbuphine-treated and control eyes were 38.8 and 37.9 mm, respectively. In both groups, CTT was significantly lower than baseline value at 15, 45, 60, and 120 minutes. No tearing or redness developed in any eye treated with nalbuphine. CONCLUSIONS AND CLINICAL RELEVANCE Topical administration of ophthalmic 1% nalbuphine solution had no effect on corneal sensitivity in clinically normal horses. The topical ocular treatment was not associated with local irritation.

Eosinophilic keratitis in 46 eyes of 27 horses in the Mid-Atlantic United States (2008-2012).

OBJECTIVE To review the signalment, clinical characteristics, treatment, and outcome of equine EK cases in the Mid-Atlantic United States; to evaluate the effects of topical or systemic corticosteroid treatment, oral cetirizine treatment and secondary corneal infection on disease duration; and to evaluate the association between corticosteroid and cetirizine treatment and likelihood of recurrence. ANIMALS Twenty-seven horses (47 eyes) diagnosed with EK from 2008 to 2012. PROCEDURE Retrospective medical record review followed by phone interview to obtain recurrence data. RESULTS Average age of affected horses was 8.2 years, SD 5.8 years. Eleven of 27 horses (41%) were diagnosed with EK in July. Twelve horses (44%) had been affected in previous years. Time to resolution averaged 3.7 months, SD 2.3 months. Ten horses (18 eyes) were treated with systemic dexamethasone, with a significantly shorter time to resolution, P = 0.03, averaging 2.23 months, SD 1.13 months, relative to horses not so treated, averaging 4.20 months, SD 1.47 months. Secondary infection led to a significant increase in time to resolution, P = 0.03, average 4.1 months, SD 1.7 months, relative to horses without secondary infection, average 3.0 months, SD 1.5 months. All eyes were visual at resolution. Horses treated with cetirizine were less likely to have recurrence during the follow-up period (1/13, or 8%) relative to horses not so treated (8/14, or 57%). CONCLUSIONS Eosinophilic keratitis has a seasonal occurrence in summer in the Mid-Atlantic United States. Systemic but not topical corticosteroid treatment may decrease therapy duration. Treatment with cetirizine may be associated with a decreased risk of recurrence.

Return to work following unilateral enucleation in 34 horses (2000–2008)

UNLABELLED REASONS FOR STUDY: The effect of unilateral enucleation on vision and potential loss of performance in horses has received little study. OBJECTIVE To evaluate the likelihood of return to prior discipline following unilateral enucleation in horses, assessing the role of age at enucleation, equine discipline, reason for enucleation, time to vision loss and eye enucleated. HYPOTHESIS Unilateral enucleation has no significant effect on likelihood of return to work in horses, for both right and left eyes, across age and discipline. METHOD A retrospective review of medical records identified 92 horses that underwent unilateral enucleation at the University of Pennsylvania New Bolton Center from April 2000-April 2008. Case variables determined from the medical record included breed and sex of horse, age at enucleation, which eye was enucleated, reason for enucleation and onset of vision loss. Pre- and post operative occupations were determined by telephone interview with the owner or trainer of each horse. RESULTS Based on hospital surgery logs, 92 enucleations were performed over the 8 year period and 77 records were available for review, with follow-up information available for 34 horses. Of these, 29/34 (85%) horses returned to work in pleasure or trail riding (11/13), flat racing (7/10), hunter/jumpers (4/4), dressage (3/3), group lessons (1/1), eventing (1/1), steeplechase (1/1) and as a broodmare (1/1). Four of 5 horses (4/34, or 12% sample) that did not return to work (2 pleasure and 2 racing) were retired due to anticipated or perceived decrease in performance or behaviour change following unilateral enucleation, with the remaining horse retired from racing for lameness issues unrelated to enucleation. Twenty-two of 25 horses (88%) with acute vision loss and 7/9 horses (78%) with gradual vision loss returned to their previous discipline. CONCLUSIONS Horses are able to return to a variety of occupations after unilateral enucleation.

Presumed immune-mediated hemolytic anemia in two foals with Rhodococcus equi infection.

OBJECTIVE To describe the clinical presentation, case management, and outcome in 2 foals with Rhodococcus equi infection associated with presumptive severe immune-mediated hemolytic anemia. SERIES SUMMARY Two foals diagnosed with R. equi pneumonia on the basis of tracheal wash cultures, thoracic radiographs, and thoracic ultrasonography were concurrently diagnosed with hemolytic anemia. Both foals required whole blood transfusions, and were treated with the antimicrobial combination of rifampin and a macrolide (eg, clarithromycin, erythromycin, or azithromycin). Dexamethasone was used to prevent further hemolysis in both foals, and to treat acute lung injury/acute respiratory distress syndrome in 1 of the foals. Both foals survived, and required prolonged antimicrobial therapy. NEW OR UNIQUE INFORMATION PROVIDED Although extra-pulmonary disorders are commonly diagnosed in foals infected with R. equi, hemolytic anemia is rarely described. Dexamethasone is considered the treatment of choice for immune-mediated hemolytic anemia, but may be contra-indicated in foals with severe bacterial infections. In these foals, a relatively low dose and short duration of dexamethasone was utilized in an attempt to minimize immune suppression, although early discontinuation in 1 foal precipitated a second hemolytic crisis.

Clinical findings and outcomes of ulcerative keratomycosis in 30 horses in the mid-Atlantic United States (2006–2007)

Summary The purpose of this study was to determine the clinical course and outcome associated with keratomycosis in horses in the mid-Atlantic USA. Records of horses diagnosed with keratomycosis at New Bolton Center from November 2006 to November 2007 with positive fungal culture were retrospectively studied. Neither horses with ulcerative keratitis and a negative fungal culture nor those with stromal abscesses were included. Subject details, history, clinical findings, therapy and outcome were recorded. Thirty horses fitted both inclusion criteria (diagnosis of keratomycosis and positive corneal fungal culture). Fourteen of 30 cases occurred during summer. Aspergillus was the most commonly cultured fungal genus (17/30, or 57%) followed by Alternaria (4/30). Seventeen horses had positive bacterial and fungal cultures. Fifteen of 30 horses were treated surgically by a keratectomy and amnion (8) or conjunctival (7) graft. Itraconazole was the most common topical anti-fungal therapy and was utilised in 25/30 horses. Globe survival was 97% (29/30). All surviving globes had a positive menace response and were visual at the last examination. It was concluded that in the mid-Atlantic USA, fungal keratitis is common, has the highest incidence in summer, and is usually associated with a positive outcome. Aspergillus may be a relatively more common corneal pathogen in this region than elsewhere in the USA. Surgical cases were more likely to have fungal hyphae identified on cytology and tended to be hospitalised longer than medical cases. There was no apparent association between surgical disease and all other patient, organism and treatment variables.

Clinical features and outcomes of severe ulcerative keratitis with medical and surgical management in 41 horses (2000-2006).

Summary The clinical features and outcomes of equine ulcerative keratitis with and without conjunctival graft surgery were assessed using a retrospective study. Medical records of horses hospitalised from July 2000-January 2006 for ulcerative keratitis were included if a diagnosis of melting ulcer, descemetocele or iris prolapse was made, or if surgery was recommended due to severity of corneal disease, and aggressive medical therapy using a subpalpebral catheter was instituted. Treatment and outcome variables were evaluated with and without conjunctival graft surgery. Forty-one horses, 21 that had surgery and 20 for whom surgery was recommended but not performed, were included. Horses were hospitalised for an average of 24 days, with 37/41 melting ulcers, 17/41 descemetoceles and 3/41 iris prolapses, with no statistical difference in frequencies between groups. Bacterial or fungal organisms were cultured from 22/39 cases, with 10 Aspergillus spp. and 8 Pseudomonas spp. Infectious organisms were seen on corneal cytology in 23/30 cases. Surgical cases were hospitalised for an average of 4.9 days prior to surgery. Abdominal discomfort was observed in 8/41 hospitalised horses, with 5/8 operated horses developing caecal impactions. Thirty-five horses retained an intact globe, including 18/20 treated medically and 17/21 that had surgery. Hospitalisation cost was 24% more for cases that had surgery than for medical cases. It was concluded that there was no statistical difference in length or cost of hospitalisation between surgical and nonsurgical groups. Outcomes from both groups were similar, with a high frequency of globe retention.

Combined excision and intralesional bevacizumab for sebaceous carcinoma of the eyelid in an Amur tiger (Panthera tigris altaica)

An 18-year-old zoo-kept female Amur tiger presented with an approximately 5 mm diameter lateral canthal eyelid mass in the left eye which grossly appeared red and irregular. The mass was completely excised via lateral canthoplasty. Histopathologic evaluation was consistent with a diagnosis of sebaceous cell carcinoma, which is a potentially aggressive cutaneous neoplasm. The sebaceous carcinoma recurred within 3 months and slowly increased in size until a second surgical excision was performed 9 months following the first surgery. The second surgical excision was combined with intralesional injection of 10 mg of the antiangiogenic drug bevacizumab. Histology confirmed the diagnosis. The tiger was euthanized 16 months postoperatively for reasons unrelated to, and without recurrence of, the eyelid neoplasm. At postmortem, no gross periocular or metastatic lesions were noted, and histopathology of the lateral canthus provided no evidence of recurrence. Surgical excision combined with intralesional bevacizumab treatment induced life-long resolution of the sebaceous carcinoma. Bevacizumab treatment may be associated with the regression of periocular angiogenic proliferative conditions, including neoplasia, by inhibiting angiogenesis.