10/8/17. Feline Conjunctivitis. Feline Ophthalmology. Feline Herpes Virus Type-1. Feline Herpes Virus Type-1. Feline Herpes Virus Type-1 Treatment

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1 10/8/17 Feline Ophthalmology Feline Conjunctivitis Herpes virus type-1 Chlamydophila felis Robert Swinger, DVM, DACVO Animal Eye Guys of South Florida Mycoplasma felis Calicivirus Bartonella Non-infectious: eosinophilic, allergic, tear film abnormalities Feline Herpes Virus Type-1 Most common cause of extraocular disease is cats Nearly 80% of cats are thought to carry the virus, most remaining latent in the trigeminal nerve ganglia; 30-45% will shed virus throughout life; 88% of relapses are unilateral Causes conjunctivitis, keratitis, corneal ulceration, symblepharon, epiphora, sequestrum, and anterior uveitis Dendritic corneal lesions are pathognomonic Feline Herpes Virus Type-1 - Treatment Famciclovir, a prodrug for penciclovir, has been widely accepted for the treatment of FHV-1 In a study, cats were treated with 90mg/kg TID for 21 days; no hematologic or biochemical abnormalities were noted; patients showed lower clinical scores and shed less virus My general dose: 125mg PO BID for an adult cat and 62.5mg PO BID for a kitten; comes in 125, 250, and 500mg tablets (largest being the most economical) Feline Herpes Virus Type-1 Confirmation of Disease Dendritic lesions are pathognomonic PCR is most common method commonly part of feline upper respiratory panels offered by most laboratories In my practice, testing is not commonly performed unless patients fails to respond to treatment as expected; refractive cases Trifluridine this is the only commercially available topical anti-viral; expensive, irritating, and requires frequent application to be effective (every 4 hours) Cidovovir % (compounded) shown in two studies to be more effective (0.5%) than trifluridine and is dosed every 12 hours 1

2 L-lysine is an essential amino-acid thought to reduce viral shedding and decrease the severity of clinical signs Competes with arginine for incorporation into the viral genome It is better used as a chronic preventative supplement that a treatment once clinical signs are present Adult cat dose 500mg every hours If a corneal ulcer is present: Corneal debridement with a cotton tipped applicator is recommended and thought to lower the viral particle load Broad-spectrum topical antibiotics should be added to the treatment plan (such as tobramycin) Depending on the level of discomfort, topical atropine ointment and systemic analgesics (NSAID or opiod) may be utilized E-collar Open diagnosis conjunctivitis treatment Eosinophilic keratitis Many cats will present for conjunctivitis without an obvious cause and many clients will not pursue diagnostic testing.so, below is my broad treatment for these cases. Topical NSAID (flurbiprofen BID) Systemic famciclovir (125mg PO BID for adult cat) for 2-3 weeks Systemic doxycycline (5mg/kg PO BID) for 2-3 weeks This protocol should treat the treatable Eosinophilic keratitis is an immune-mediated inflammatory disease of the cornea that is characterized by progressive vascularization and cellular infiltration of the cornea Commonly does not cause discomfort unless ulceration or secondary infection ensues Pathognomonic white plaques are present Cytology discovering #1 eosinophil is confirmatory Eosinophilic keratitis treatment The condition responds to topical corticosteroids (prednisolone phosphate or dexamethasone) used 3 times daily until resolved; may require long-term use to maintain remission Often, concurrent FHV-1 may be present, so concurrent oral famciclovir may be warranted Topical tacrolimus 0.03% has been beneficial and successful but may take longer to obtain remission If corneal ulceration is present, oral megestrol acetate may be beneficial (5mg daily and tapered) caution with potential side affects (compounded topically as well) Non-healing corneal ulcers Cats also develop indolent non-healing corneal ulcers often superficial, loose epithelial edges, non-infected Corneal debridement may be beneficial; DO NOT perform grid keratotomy (often leads to sequestrum) In addition to topical antibiotics, may add oral famciclovir even if FHV-1 is not highly suspected 2

3 Corneal sequestrum Upper Eyelid Agenesis Common sequelae to chronic corneal ulceration Persians and Himalayans are predisposed Dark brown/black necrotic corneal lesion Keratectomy is ideal; some do slough but corneal perforation is common Treatment is similar to that of a routine ulceration Frequently seen in more than one kitten in affect litters Degree of agenesis is variable; most can blink but have discomfort from associated trichiasis Mild cases can be treated with cryoepilation of the offending hairs Severe cases require eyelid reconstruction and skin grafting Eyelid Agenesis Treatment Eyelid tumors in cats Unlike dogs, most eyelid tumors in cats are malignant or at least locally invasive Most common: mast cell, squamous cell carcinoma, fibrosarcoma, adenocarcinoma, and basal cell carcinoma Apocrine hidrocystomas Uveitis These are cystic structures occasionally seen in the eyelids of Persian and Himalayan Benign and filled will translucent to brown colored fluid If problematic, these can be surgical excised or treated with with either cryotherapy or CO2 laser Anterior uveitis: blepharospasm, corneal edema, conjunctival hyperemia, aqueous flare, keratic precipitates, miosis, and a decreased intraocular pressure Chorioretinitis: hyporeflective lesions in the fundus, vitreal infiltrates, and retinal detachment Chronic uveitis: neovascularization of the iris, posterior synechia, cataract, lens luxation, and glaucoma. 3

4 Causes of Uveitis Treatment for uveitis Uveitis/chorioretinitis Infectious causes include FIV, FeLV, FIP, toxoplasmosis, bartonellosis, and FHV-1 Fungal disease (cryptococcus, histoplasma, coccidioides, and blastomyces) is common but variable based on geographic location Neoplasia, both primary and metastatic Systemic hypertension Immune-mediated Ideopathic (nearly 50-70% of causes) Treat the underlying infectious cause if found Toxoplasmosis: clindamycin (20-50mg/kg/day for 21 days) Bartonella: azithromycin (10mg/kg/day for 21 days) or doxycycline (10mg/kg/day for 21 days) Systemic anti-inflammatories, often prednisolone 0.5mg/kg/day tapered Topical anti-inflammatories, often a steroid, such as prednisolone acetate 1% in combination with a NSAID, such as flurbiprofen; both are used every 8-12 hours Cataracts in Cats Glaucoma in Cats Rare; occasionally seen as primary lesion but often secondary to chronic uveitis Anterior lens luxations are common due to zonular degradation resulting from chronic uveitis Surgery, either phacoemulsification with implantation of an artificial lens or intracapsular lensectomy, are both quite successful Like cataracts, primary glaucoma is rare; almost always secondary to uveitis Treatment is often challenging The combination drug (dorzolamide 2%/timolol 0.5%; brand name Cosopt) is well tolerated and seems to be the best option for feline glaucoma (used every 8-12 hours) Prostaglandin analogs, such as latanoprost, do not work well in cats Blind eyes should be removed risk of post-traumatic sarcomas Ciliary body ablations (intraocular gentamicin) are not recommended in cats risk of post-traumatic sarcomas Hypertensive Retinopathy Hypertensive Treatment Relatively common disease in aged cats and most consistently associated with chronic renal insufficiency and hyperthyroidism Acute blindness is the most common presentation; Presenting systolic blood pressure >200mmHg is likely Ocular manifestations include retinal arterial tortuosity, retinal hemorrhage, retinal edema and bulla, retinal detachment, retinal degeneration, hyphema, and retinal degeneration The calcium channel blocker, amlodipine, is the drug of choice (often 0.625mg once daily; increased based on patient response) Patients should be reevaluated every 5-7 days and medication adjusted until systolic blood pressure is between mmHg Serum chemistry (primarily renal) should be monitored In most cases, the retina will re-attach once the blood pressure normalizes and in acute cases, functional vision returns 4

5 Retinal Degeneration Retinal Degeneration Progressive retinal atrophy in the Abyssinian Taurine Deficiency Essential amino acid needed for retinal health (primarily cones) cats do not synthesize enough naturally and require ingestion Uncommon in cats fed commercial food however does occur in homemade diets, dog food diets, and those with GI disease leading to malabsorption Drug-associated retinal toxicity The most significant is enrofloxacin-associated retinal degeneration Experimentally, 50mg/kg/day caused significant retinal changes after 1-2 doses; vision loss is permanent Recommended dose: 2.5mg/kg PO every 12 hours Diffuse Iris Melanoma Post-traumatic ocular sarcoma Rare but likely fatal disease in cats Most common intraocular tumor in cats Rate of metastasis: 25-64% - often very late in the course Often begins as benign iris melanosis and may be monitored for years Signs of malignancy: degree of pigmentation, elevation above the iris, involvement of the iridocorneal angle, elevated intraocular pressure, and presence of pigmented cells in the anterior chamber Removal of the globe is often curative if performed early Generally associated with a traumatic event several years prior to sarcoma development (average 3-4 years) Controversy if tumor arises from lens epithelial or undifferentiated uveal cells Metastases are often already present when intraocular tumor is identified Other feline tidbits Questions When enucleating, remember the optic nerves and chiasm are short; DO NOT pull or elevate the globe excessively this can blind the fellow globe Avoid neomycin when possible; while it is the most commonly used topical drug in veterinary medicine, it is believed to be responsible for several anaphylactic deaths Atropine solution is bitter; use ointment in cats Compounded buprenorphine slow release (0.12mg/kg SQ once) works well for pain management (72 hours) 5