BILATERAL MULTIFOCAL SCLERAL PYOGRANULOMATOSIS IN A DOG

ESVO Prague 2011G. Cazalot1, S. Lavergne2

1 Clinique vétérinaire La Borde Rouge, Toulouse, France, 2 University of Illinois-Urbana, College of Veterinary Medicine, Urbana, IL, USA

Material & Methods

A 1.5 year-old female Scottish Terrier (Cerise) was referred for severe, acute and painful bilateral kérato-uveitis with multifocal scleromalacia (photos 1-2-3).Prior to referral, oral and topical corticosteroids and antibiotics were administrated unsuccessfully. Numerous serologies were performed (leishmania infantum, toxoplasma gondii, ehrlichia canis, leptospira spp, borrelia burgdorferi) but all were negative.At presentation,  slit-lamp and ophthalmoscopic examination revealed a deep multifocal sleromalacia  of both eyes (black arrows) with prominent extension of inflammation to cornea, uvea and retrobulbar tissues, with perilimbal corneal oedema and neovascularization, hypotony, and slight exophthalmos.

Because of multiple very painful multifocal scleral perforations with vitreous haemorrhage, the left eye underwent enucleation. One week later, in spite of the preservation of oral and topical antibiotics and corticosteroids, the right eye perforated and underwent enucleation as well.

Results

The histopathology of the left eye revealed a severe pyogranulomatous infiltration of the sclera, slightly extended to the cornea, the choroid, the ciliary body and the orbital fat. No organisms were identified with PAS (Periodic Acid Schiff) and Fite Faraco reactions.

No abnormalities were detected in the complete blood cell count, serum biochemical profile, urinalysis, and ophthalmic and abdominal echography. Serum samples from this dog as well as samples from 13 dogs that were healthy at the time of collection, were analyzed using an Anti-Myeloperoxidase Detection Kit (Diamedix Inc.) based on an ELISA technique.

Based on the values established in the control dog (AVE + 3 SD), the patient’s serum was negative anti-MPO antibodies (graph 1). Interestingly some of the “control” dogs displayed some anti-MPO antibodies. This relates to the fact that ANCAs are encountered in multiple immune-mediated diseases. Conclusion

To the authors knowledge, necrotic scleritis is very uncommon in dogs. It’s a serious idiopathic disease of the sclera presumed to have an immune-mediated etiology. Even if azathioprine or corticosteroids at immunosuppressive dosages could be used temporary, the prognosis seems to be poor in dogs and complications often lead to blindness or scleral staphylomas. Enucleation then remains the treatment of choice.

Wegener’s disease is associated with anti-PR3 antibodies rather than anti-MPO antibodies in humans. PR3, however, does not exist in dogs. Further lab experiments would be required to look for other types of ANCAs in this dog.

Purpose

Necrotizing scleritis is very uncommon in dogs and presumed to have an immune-mediated etiology as in human patients suffering from the Wegener’s syndrome. Anti-neutrophil cytoplasmic antibodies (ANCA) have been reported in autoimmune syndromes such as Crohn’s disease, Wegener’s syndrome, and rheumatoid arthritis in human beings. This clinical case describes a bilateral and multifocal necrotizing scleritis in a dog.

La Borde Rouge

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Graph 1