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Clinical features and outcomes of horses presenting with equine immune mediated keratitis (IMMK) to two veterinary hospitals in the United Kingdom and Finland: 96 cases (2009-2021).
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  • Juliette F. Preston,
  • Minna P. Mustikka,
  • Maria-Christine Fischer,
  • Bettina Dunkel
Juliette F. Preston
The Royal Veterinary College Department of Clinical Science and Services

Corresponding Author:[email protected]

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Minna P. Mustikka
Helsingin yliopisto Elainlaaketieteellinen tiedekunta Kliinisen hevos- ja pienelainlaaketieteen osasto
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Maria-Christine Fischer
The Royal Veterinary College Department of Clinical Science and Services
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Bettina Dunkel
The Royal Veterinary College Department of Clinical Science and Services
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Abstract

Background: Limited literature exists regarding equine Immune Mediated Keratitis (IMMK) in Europe. North America-based publications describe minimal blepharospasm, rare corneal ulceration and no uveitis; clinical impression suggests that these signs are common in Europe. Objectives. Assess the prevalence of blepharospasm, corneal ulceration and uveitis and their impact on outcome in horses diagnosed with IMMK in European countries. Study design: Retrospective case series of 95 horses with IMMK in the UK and Finland. Methods. Clinical records of horses with IMMK were retrospectively evaluated. The UK and Finland populations were comparable; therefore, descriptive statistics were performed on combined data on subtypes of IMMK and clinical features. Odds ratios (OR) and confidence intervals (CI) were calculated for impact of blepharospasm, ulceration or presence of uveitis on the outcome of enucleation and treatment duration. Results. IMMK subtype was classified as 10/95 (10.5%) epithelial, 50/95 (52.6%) anterior stromal, 15/95 (15.8%) mid-stromal, 4/95 (4.2%) endothelial cases and 16/19 (16.8%) unrecorded. Blepharospasm was documented in 35/95 (36.8%), corneal ulceration in 28/95 (29.5%), and signs of uveitis in 24/95 (25.4%) of horses. Increased odds of enucleation were associated with the presence of blepharospasm (OR 5.9, 95% CI 1.7-20.8), corneal ulceration (OR 3.3, 95% CI 1.0-10.5) and signs of uveitis (OR 8.6, 95% CI 2.5-29.6). The presence of blepharospasm, corneal ulceration or uveitis did not significantly alter the odds of ongoing medication. Main limitations: Data were collected over a wide timeframe and the diagnosis was mainly made without histopathology. A broad definition of uveitis was used and there was a bias towards complicated cases being retained for follow up. Conclusions. The clinical features of IMMK were similar between two geographically distinct European countries but different to findings described in the USA. Blepharospasm, corneal ulceration and signs of uveitis can occur with IMMK and increase the odds of enucleation.