A multicenter retrospective study into endogenous causes of uveitis in cats in the United Kingdom: Ninety two cases

Abstract

Purpose The purpose of this study was to investigate the most common causes of endogenous feline uveitis in a UK referral population and to investigate associations based on signalment. Methods Retrospective multicenter cross‐sectional study from 2010 to 2019 including cats presented to the Animal Health Trust and the Royal Veterinary College with clinical signs consistent with uveitis. Cats were included in analyzes if they had a full physical examination including an ophthalmic examination, complete blood count, serum biochemistry, and infectious disease testing for at least two diseases unless the diagnosis was found on clinical examination (eg, neoplasia). Results A total of 92 cats were included in the study. The majority of cats presenting with uveitis were male (66.3%). The most common causes of endogenous uveitis were idiopathic uveitis (42/92 45.7%), feline infectious peritonitis (FIP) 15/92 16.3%), and lymphoma (10/92 10.9%). Fisher's exact test showed differences in breed across diagnosis groups (p = .002) with purebred cats being overrepresented in the lymphoma and FIP groups. Kruskal‐Wallis test showed differences in median age across diagnosis groups (p < .001) with cats in the FIP group having the youngest age (median 1.4 years, interquartile range (IQR) 0.4–1.8 years) and cats in the neoplasia (primary or paraneoplastic) group having the oldest age (median 12.8 IQR 10.8–13.8). Idiopathic uveitis was unilateral in 56.1% of cases, and infectious causes were unilateral in 47.8% of cases. Conclusions The most common cause of endogenous uveitis in a population of cats in the UK was idiopathic uveitis, followed by FIP and lymphoma.

Ophthalmic and immunopathological characterization of systemic infectious diseases in cats

“…FIP is one of the most important infectious diseases of cats, with high prevalence and lethality. 9 In addition, FIP is an important cause of endogenous uveitis, 25 and it was equally relevant in this study. Of all the organs, the kidneys, brain, and eyes are the most commonly affected by the FIP virus.…”

“…8,26 In the cases described in the present study, the main ocular manifestations varied from inflammatory/neoplastic cells infiltrating the anterior uvea, to the formation of neoplastic nodules expanding the iris, as described in the literature. 25,26 Furthermore, lymphocytic aggregates around the scleral venous plexus, and occasionally surrounding vessels from the meninges of the optic nerve, were frequently observed, which has not been described in the literature.…”

“…16 Histologically, ocular FIP in the current study was characterized by anterior and/or posterior uveitis; vasculitis in the scleral venous plexus; inflammatory infiltrates associated with free fibrin in the anterior, posterior, and vitreous chamber; and meningitis, which sometimes extended to the nervous tunic, agreeing with what is described in the literature. 9,10,16,21,25,27 In half of the cases with ocular FIP, the systemic disease was characterized as noneffusive. This information differs from what is described in the literature, which suggests that inflammatory ocular manifestations are more frequently associated with noneffusive cases.…”

“…10 Of the infectious agents that involve the eye and can cause systemic diseases, viruses, bacteria, fungi, and protozoa have been reported, and the importance of each agent varies according to the study. 10,20,25…”

2022 AAFP/EveryCat Feline Infectious Peritonitis Diagnosis Guidelines

“…88,109,110 In two studies of uveitis, FIP was a common cause, diagnosed in 16% of cats. 111,112 Aqueous flare, hyphema, hypopyon, fibrinous exudate and keratic precipitates within the anterior chamber may be detected during ophthalmic examination (Figures 10 and 11). 75,85 Chorio-retinitis can present as retinal perivascular cuffing due to inflammatory cell infiltrates or as focal to diffuse subretinal detach-ment.…”