258 Vol. 23, No. 3 March Diagnosis and Treatment of Feline Uveitis *

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1 258 Vol. 23, No. 3 March 2001 CE Article #4 (1.5 contact hours) Refereed Peer Review FOCAL POINT Uveitis-associated vision loss can be avoided or minimized with appropriate therapy preceded by a thorough diagnostic workup that may include an ocular-fluid examination. Diagnosis and Treatment of Feline Uveitis * Colorado State University Cynthia C. Powell, DVM, MS Michael R. Lappin, DVM, PhD KEY FACTS Aqueous and vitreous humor can be used for cytologic, culture and sensitivity, and polymerase chain reaction testing as well as for determining antibody content, p The primary treatment goals for uveitis are to stop inflammation, prevent or control complications caused by inflammation, and relieve pain, p Antiinflammatory therapy can be critical for treating uveitis regardless of the cause, p Swift and aggressive treatment of uveitis is necessary to avoid such secondary complications as glaucoma, cataract formation, and retinal degeneration or detachment, p ABSTRACT: Uveitis can be a potentially sight-threatening ocular disease, and finding its cause is sometimes difficult. The primary treatment goals for uveitis are to stop inflammation, prevent or control complications caused by inflammation, and relieve pain. Eliminating the inciting antigen and controlling the inflammatory response are required to arrest inflammation. When possible, eliminate antigen by identifying and treating a specific cause. Steroids and NSAIDs can be used to control ocular inflammation. Such parasympatholytic agents as atropine can help prevent synechiae formation and development of secondary glaucoma and relax the ciliary-muscle spasm that contributes to ocular pain. The most common causes of feline uveitis include toxoplasmosis, feline immunodeficiency virus (FIV), lymphosarcoma (LSA) with or without feline leukemia virus (FeLV), feline infectious peritonitis (FIP), cryptococcosis, and idiopathic causes. Because many of these are serious systemic diseases, a thorough history, physical examination, and minimum database (including a complete blood cell count, serum biochemical panel, and urinalysis) are essential. Outdoor cats should be routinely tested for Toxoplasma gondii, FeLV, and FIV; cats reared in a cattery or cats younger than 2 years of age should be screened routinely for coronaviruses. Although the appearance of uveitis cannot be used to determine its cause, large keratic precipitates are more likely associated with diseases causing granulomatous inflammation (e.g., FIP, toxoplasmosis); pars planitis is more likely associated with FIV or toxoplasmosis. Examining aqueous or vitreous humor may be necessary to determine the cause of uveitis. Ocular fluids can be used for cytologic, culture and sensitivity, and polymerase chain reaction (PCR) testing and for determining antibody content. This article details the diagnostic techniques of aqueous and vitreous humor paracenteses and the treatment of uveitis in cats. DIAGNOSIS Anterior Chamber Paracentesis General anesthesia is recommended for anterior chamber paracentesis. To per- *A companion article entitled Causes of Feline Uveitis appeared in the February 2001 (Vol. 23, No. 2) issue of Compendium.

2 Compendium March 2001 Small Animal/Exotics 259 TABLE I Indications for Aqueous and Vitreous Humor Paracenteses in Cats Diagnosis Aqueous Humor Vitreous Humor Figure 1 Anterior chamber paracentesis. The needle is tunneled beneath the conjunctiva (a), and enters the eye at the limbus parallel to the iris plane with the bevel up (b). A subconjunctival bleb of aqueous humor sometimes forms after needle withdrawal (c). (Courtesy of Dr. Glen Severin, Colorado State University, Fort Collins) Vitreous Humor Paracentesis Vitreous humor paracentesis should be considered when other diagnostic methods have been unrewarding (Table I) and a vitreous or subretinal mass or exudation (Figure 2) can be found on ophthalmoscopy or ultrasonography. However, vitreous humor paracentesis is generally reserved for blind or nearly blind eyes because of the potential for causing severe ocular hemorrhage, retinal tear, and retinal detachment. Heavy sedation or general anesthesia is required. Because vitreous humor is viscous and can be difficult to aspirate, a 3-ml syringe is needed for adequate suction. Aspiration through a 25-gauge needle can be attempted first, but a 22-gauge needle is often necessary. Before aspiration, the bulbar conjunctiva is gently cleaned with 1:20 povidone iodine:sterile saline solution to remove all mucus and debris. The dorsolateral globe is grasped 6 to 7 mm beform paracentesis, a 25-, 27-, or 30-gauge needle on a 1- or 3-ml syringe; small rat-toothed forceps; adequate lighting; and magnification are needed. The bulbar conjunctiva and cornea should be gently flushed with a 1:20 povidone iodine:sterile saline solution (povidone iodine soap should not be used because it irritates the cornea and conjunctivae). The globe should be grasped with forceps at the limbus. The dorsolateral limbus is usually most accessible. The needle should enter the eye at the limbus and bevel up, parallel to the iris plane. The globe will be most stable if the needle enters the eye immediately adjacent to the hold of the forceps (Figure 1). Care should be taken to keep the needle bevel up and the tip away from the iris and lens. Up to 0.3 ml of aqueous humor can usually be slowly removed without collapsing the anterior chamber. After withdrawing the needle, gentle pressure should be applied to the centesis site using a moistened cotton swab. Samples of aqueous humor can be dropped directly onto a swab for culture and sensitivity testing or stored in a sterile container for determining antigen or antibody content. Cytology is best done on samples stored in a 1.5-ml blood collection tube containing ethylenediamine tetra-acetic acid (EDTA) concentrated by cen- Toxoplasma IgM, IgG NA gondii infection (ELISA); PCR Feline infectious PCR PCR peritonitis, feline immunodeficiency virus Feline leukemia Cytology Cytology virus/lymphosarcoma Bartonella Culture, NA henselae infection PCR Cryptococcus Cytology, Cytology, neoformans culture, culture, infection antigen antigen (latex (latex agglutination, agglutination, ELISA) ELISA) NA = not available; PCR = polymerase chain reaction. trifugation and stained with Diff-Quik (Baxter, Rome, Italy) or Wright s stain. PCR requires a special transport medium supplied by the laboratory conducting the test. Indications for aqueous humor paracentesis have been categorized by diagnosis in Table I. Mild hyphema can be the most common complication of aqueous humor paracentesis. Serious complications are rare if inadvertent contact with the iris or lens can be avoided. CYTOLOGY COMPLICATIONS OF PARACENTESIS ASPIRATION

3 260 Small Animal/Exotics Compendium March 2001 Figure 3 Vitreous humor paracentesis. The needle enters the globe 7 to 9 mm from the limbus (a) and is directed toward the center of the eye (b). (Courtesy of Dr. Glen Severin, Colorado State University, Fort Collins) Figure 2 Subretinal exudate caused by systemic mycosis. The tapetum is completely obscured (and likely destroyed), and the retina is elevated and folded by the exudate (arrows). hind the limbus with small, toothed forceps. The needle enters the globe 7 to 9 mm posterior to the limbus and adjacent to the forceps for maximal stabilization. The needle should be aimed toward the center of the globe (Figure 3). If a mass is present, ultrasonography can be used to guide the needle into the mass for aspiration. If the ocular media is clear, the needle can be visually guided, using indirect ophthalmoscopy. Care should be taken not to advance the needle into the opposite retina and choroid. Slightly altering the needle position may help if aspirating the fluid is difficult. If bacterial endophthalmitis is suspected and a vitreous injection of antibiotic planned, the syringe should be removed, leaving the needle in place for injection. Vitreous humor samples should be handled in the same manner as are aqueous humor samples for culture, cytology, or PCR. TREATMENT The primary treatment goals for uveitis are to stop inflammation, prevent or control complications caused by inflammation, and relieve pain. Specific and nonspecific therapies are used to treat uveitis. Specific therapies address etiologic agents (e.g., bacteria, fungi) or other contributors to inflammation (e.g., foreign body, corneal ulcer, luxated lens) identified through the examination and diagnostic workup. Nonspecific therapy includes decreasing the ocular-inflammatory response with antiinflammatory drugs, mydriasis to prevent synechia formation, and cycloplegia to decrease pain. Glaucoma therapy should be instituted when there is evidence of decreased aqueous-humor outflow. Nonspecific Therapy Antiinflammatory therapy is critical for treating uveitis regardless of the cause. Failure to control inflammation can lead to posterior synechiae, glaucoma, cataracts, retinal detachment, and retinal degeneration. Corticosteroids and NSAIDs are often used (Table II). Corticosteroids can be used topically, subconjunctivally, or systemically to treat ocular inflammation. The route of administration depends primarily on the severity of inflammation and its location in the eye. Anterior uveitis is usually treated topically 1 ; however, if inflammation is not well controlled, subconjunctival or systemic medication may be necessary. Topical preparations with the best potency and corneal penetration are prednisolone acetate suspension (1%) and dexamethasone solution (0.1%) or ointment (0.05%). 2 Topical corticosteroids are contraindicated for corneal ulceration because they inhibit wound healing and augment collagenase activity in the cornea. 3 Systemic administration has minimal corneal effects and can be used with concurrent corneal ulceration and anterior uveitis. 4 Ocular release of prostaglandins can cause disruption of the blood ocular barrier and uveitis. NSAIDs decrease inflammation by inhibiting cyclooxygenase and prostaglandin production. Because NSAIDs, unlike corticosteroids, do not inhibit the lipoxygenase inflammatory pathway and little information is available on their use in treating feline uveitis, they should be considered for use when corticosteroids are contraindicated. Available topical ophthalmic NSAIDs include suprofen (1%), diclofenac (0.1%), flurbiprofen (0.03%), and ketorolac (0.5%). Ocular hemorrhage caused by platelet aggregation inhibition can be a potential complication of their use. 3,5 Because topical NSAIDs may complicate bacterial corneal infections, they have not been recommended for use in the presence of corneal infection. 3,6 Systemic drug therapy is necessary to treat posterior uveitis because therapeutic concentrations cannot be attained in the retina and choroid with topical drugs. Be- TESTING OF HUMOR SAMPLES STOPPING INFLAMMATION RELIEVING PAIN

4 Compendium March 2001 Small Animal/Exotics 261 TABLE II Drugs Used to Treat Uveitis in Cats Topical Drugs Corticosteroids Prednisolone acetate (1% suspension) or dexamethasone sodium phosphate (0.1% solution, 0.05% ointment) NSAIDs Diclofenac (0.1% solution), flurbiprofen (0.03% solution), suprofen (1% solution), or ketorolac (0.5% solution) Mydriatic/cycloplegic drugs (parasympatholytics) Atropine sulfate (0.5% and 1% solution and ointment) Tropicamide (0.5% and 1% solution) Dose Every 1 12 hr Every 6 12 hr Every 8 24 hr Every 6 12 hr Mydriatic drugs (sympathomimetics) Phenylephrine hydrochloride In conjunction with (2.5% and 10% solution) parasympatholytic Oral Drugs Dose Corticosteroids Prednisolone mg/kg (5-mg tablet; prednisone every hr [5- and 20-mg tablet]) (higher doses for initial therapy of severe inflammation) NSAIDs Acetylsalicylic acid (80-mg tablet) Ketoprofen (12.5-mg tablet) Phenylbutazone (100-mg tablet) Subconjunctival Drugs Long-acting corticosteroids Methylprednisolone acetate Betamethasone Triamcinolone 80 mg every hr 2 mg/kg initially, 1 mg/kg/day maintenance 5 7 mg/kg every hr (recommended not to exceed 5 days) Dose 4 mg/eye 0.75 mg/eye 4 mg/eye cause corticosteroids suppress the immune response, however, they should be used with caution (if at all) when infection is suspected, especially if given systemically. If used during infection, concurrent treatment with an effective antimicrobial is essential. Use of systemic NSAIDs in cats has been associated with potentially serious side effects, including bone marrow suppression, gastrointestinal ulceration, hemorrhage, vomiting, and diarrhea. 7 Aspirin, phenylbutazone, and ketoprofen can be used systemically with careful attention to dosage and possible side effects. 8 The course of phenylbutazone should be as short as possible, preferably not exceeding 5 days at higher dosages, and the drug should be withheld if inappetence or depression develops. 7 Because duodenal perforation in a cat after treatment with oral carprofen was recently reported, use of that drug in cats cannot be recommended until further study. 9 Subconjunctival corticosteroids have been used to supplement topical or systemic ones in cases of severe ocular inflammation or in patients in which frequent topical treatment is not possible. 1 Most subconjunctival preparations are long acting and provide a constant source of drug release for 2 to 4 weeks. A disadvantage to their use is the inability to withdraw medication if complications arise. Drugs injected subconjunctivally enter the eye through the cornea, by leakage through the injection site, and through the sclera. 6 Topical and subconjunctival corticosteroid use is contraindicated in cats with active corneal ulceration and may cause reexcretion of feline herpesvirus-1 in carrier cats with previous episodes of viral keratitis. 10 Cats with a history of ulcerative keratitis should be monitored closely for development of corneal ulcers. Cycloplegics relieve pain associated with anterior uveitis by relaxing ciliary-body and iris-muscle spasms. Mydriatics prevent or break down posterior synechiae by dilating the pupil and decreasing iris-lens contact. Cycloplegia and mydriasis can be accomplished using a parasympatholytic agent. Topical atropine sulfate ointment (1%) has been used most often (the solution form is more likely to reach the mouth via the nasolacrimal duct and cause profuse salivation attributable to its bitterness). The duration and frequency of application depend on the severity of inflammation. Very mild inflammation can usually be treated only once daily; severe inflammation may require treatment up to three to four times daily. Administering a sympathomimetic may help achieve mydriasis when synechiae have already formed. 11 Therapy for Specific Causes Toxoplasmosis Many cats with uveitis can be seropositive for T. NSAIDs CORTICOSTEROIDS CYCLOPLEGICS

5 264 Small Animal/Exotics Compendium March 2001 gondii but otherwise clinically healthy. Because most present with anterior uveitis, topical treatment with 1% atropine every 12 to 24 hours to effect, and prednisolone (1%), or dexamethasone (0.1%) is usually indicated. The frequency of corticosteroid treatment varies depending on the severity of clinical signs, but every 6 hours is generally minimal. If response has been poor, uveitis severe, or more frequent administration of topical corticosteroids is needed but not possible, oral prednisolone can usually be safely given in antiinflammatory dosages without risk of potentiating systemic toxoplasmosis. After inflammation subsides, treatment can be slowly tapered. If corticosteroids have been tapered too quickly or discontinued too soon, inflammation will recur. We recommend aggressive treatment until uveitis has resolved. Oral corticosteroids can usually be tapered first, followed by topical ones. Systemically ill cats seropositive for T. gondii should always be treated with an anti-toxoplasma drug. In cats with uveitis only, treatment with an anti-toxoplasma drug can be justified in cats seropositive for T. gondii when other causes of uveitis have been ruled out, particularly if glucocorticoid therapy has been ineffective. Clindamycin has been the drug of choice for treating clinical toxoplasmosis in cats. 12 Although several dose ranges have been reported, we recommend oral clindamycin (10 to 12.5 mg/kg every 12 hours for 4 weeks). Most cats will tolerate liquid clindamycin administered at 4 C. Oral trimethoprim sulfonamide combination therapy (15 mg/kg every 12 hours for 2 to 4 weeks) can also be used to treat toxoplasmosis but is less suitable because of potential side effects caused by folic-acid deficiency in cats. 12 Frequent monitoring for mental depression, anemia, leukopenia, and thrombocytopenia should be done, especially if treatment is longer than 2 weeks. 12 Azithromycin can be used for cats that are intolerant to clindamycin or sulfa drugs; however, the most appropriate dose has not been determined. Nonspecific treatment for uveitis should be administered concurrently. No evidence has suggested that topical glucocorticoid use potentiates systemic toxoplasmosis. Feline Infectious Peritonitis The long-term prognosis of FIP can be poor, even with treatment. However, some cases may be reasonably managed for several months with medical therapy. Because the development of FIP is immune mediated, the primary treatment goal is suppressing the immune response. Several protocols have been described, but there is no consensus on optimal treatment of systemic disease. 13 The treatment goals for ocular FIP are to control inflammation and prevent sequelae. For FIP-induced uveitis, systemic and topical corticosteroids may be required (see Nonspecific Therapy section). Feline Leukemia Virus/Lymphosarcoma Ocular disease does not occur with FeLV infection, except by its association with the development of LSA or potentially by predisposing cats to secondary causes of uveitis from immunosuppression. Because LSA is unlikely to be isolated to the eye, other organ involvement should be investigated. Cats with LSA should be categorized by stage (I through V), and FeLV status should be determined because both affect treatment response and prognosis. Many chemotherapeutic drugs have been used to treat LSA in cats. An excellent review of these drugs and administration protocols can be found in the literature. 14 Ancillary therapy with topical corticosteroids and atropine can help control ocular inflammation and prevent sequelae (see Nonspecific Therapy section). Systemic corticosteroids should be used with caution because their effect on viral replication has not been determined. Blind, painful eyes may require enucleation. If virus-induced immunosuppression is part of the clinical syndrome, immunomodulator or antiviral therapy should be considered. Using oral interferon-α (30 U every 24 hours) seems to improve quality of life in some cats but does not affect viremia. This protocol has not been assessed in controlled studies of ocular disease associated with FeLV. Antiviral therapy (azidothymidine [AZT] administered as described for FIV) may lessen risk for secondary infections but has not been assessed in controlled studies on treating the ocular manifestations of FeLV. Feline Immunodeficiency Virus Treatment of FIV should be primarily aimed at management of secondary infections when they are identified. T. gondii and Cryptococcus neoformans infections seem to be the most common. However, ocular inflammation (anterior uveitis, pars planitis) can also be a direct result of the virus. Using AZT may improve quality of life and prolong life expectancy in cats with FIV infection. 15,16 A regimen of oral AZT (5 mg/kg every 8 to 12 hours) can be tolerated by most cats and has minimal toxicity. However, the efficacy of AZT for the treatment of FIV-induced ocular disease has not been determined. Topical corticosteroids and atropine therapy can be used to control pain and inflammation. Systemic corticosteroids should be used with caution because their effect on viral replication has not been determined. Cryptococcosis Ketoconazole, itraconazole, and fluconazole are the AGGRESSIVE TREATMENT TREATMENT GOALS SYSTEMIC INFECTION

6 Compendium March 2001 Small Animal/Exotics 265 Figure 4 Cataract (black arrow), posterior synechia (white arrow), and iris pigmentation secondary to chronic anterior uveitis. drugs most often used for treating cryptococcal infections in cats. Fluconazole has the fewest side effects 17,18 and penetrates the central nervous system, unlike ketoconazole and itraconazole. Oral fluconazole and itraconazole can be tolerated by most cats at the empiric dose of 50 to 100 mg every 24 hours. Treatment with antifungal agents should be continued for 1 month after clinical signs resolve and the cryptococcal titer has dropped by at least two orders of magnitude. 19 When present, anterior uveitis should be treated with a topical corticosteroid (e.g., 1% prednisolone acetate) and atropine. Treatment of chorioretinitis requires systemic drug therapy. Judicious use of oral corticosteroids along with antifungal therapy may be necessary to control inflammation associated with posterior segment infection. 20 Eyes with severe posterior segment infection not responding to antifungal medication may require enucleation. Figure 5 Area of hyperreflective tapetum in the ocular fundus of a cat (arrow), indicating a focal area of retinal degeneration. Bartonellosis Bartonella infection can be transmitted by the flea Ctenocephalides felis. Bartonella infection is common in cats, although clinical disease has rarely been reported. However, in one study, cats with uveitis had a higher Bartonella-infection rate than did healthy cats, 21 suggesting that Bartonella infection could be associated with the development of uveitis in some cats. Bartonella should be considered a diagnostic differential for cats with uveitis without other known causes, particularly if glucocorticoid therapy has been ineffective and there has been a history of flea infestation. Cats that meet these criteria and are positive for Bartonella should be treated for bartonellosis. In one cat, doxycycline was effective at a dose of 5 mg/kg every 12 hours. 22 However, a dosage of 10 to 22 mg/kg orally every 12 hours for 2 to 4 weeks was recently recommended because lower dosages have been shown to be ineffective for treating bacteremia. 23 Oral enrofloxacin (22.7 mg every 12 hours) can be alternatively given to unresponsive cats or those with tetracycline intolerance. Topical, nonspecific therapy should be used concurrently to treat uveitis. COMPLICATIONS Uveitis should be aggressively treated to avoid secondary, sight-threatening complications. Synechiae formation can lead to glaucoma by obstructing the flow of aqueous humor through the pupil and/or out of the iridocorneal angle. The intraocular pressure (IOP) of eyes with glaucoma secondary to anterior uveitis may be in the normal range because of the simultaneous decrease in aqueous humor production and outflow. Tonometry to measure IOP should be performed in all cases of anterior uveitis. The Schiøtz indentation tonometer and the Tono-Pen applanation tonometer (Medtronic Xomed Surgical Products, Inc., Jacksonville, FL) are used most often in private practice for measuring IOP. The development of secondary glaucoma should be suspected when IOP is greater than 10 mm Hg in eyes with anterior uveitis, and these eyes should be closely monitored for increasing IOP. Glaucoma can be best treated with carbonic anhydrase inhibitors and β-blockers to decrease aqueous humor production. Carbonic anhydrase inhibitors should be administered orally (dichlorphenamide [0.5 to 1.5 mg/kg two to three times daily], methazolamide [3 to 4 mg/kg twice daily]) or topically (dorzolamide, brinzolamide; one drop three FIGHTING INFECTION MEASURING INTRAOCULAR PRESSURE SYNECHIAE FORMATION

7 266 Small Animal/Exotics Compendium March 2001 times daily). Systemic side effects (e.g., vomiting, diarrhea, panting, depression, potassium depletion) are less likely with topical treatment. β-blockers (topical β-adrenergic blocking agents; e.g., timolol, betaxolol, carteolol, levobunolol, metipranolol) should be administered twice daily. Because of potential systemic absorption, β-blockers should be used with caution in animals showing signs of heart failure or bronchial asthma. Uveitis may cause cataracts, especially in chronic cases (Figure 4). The extent of cataract formation depends on the severity and duration of inflammation and may be minimal or affect the entire lens. Lens subluxation or complete luxation can also be caused by chronic uveitis and is especially common when eyes have become buphthalmic from glaucoma. Removal of a cataract or a luxated lens caused by chronic or recurrent anterior uveitis is usually unrewarding because uveitis can be severely exacerbated by surgery. Inflammation of the retina and posterior uvea (choroid) usually occurs simultaneously and is called chorioretinitis. Chorioretinitis can cause partial or complete retinal detachment and often results in degeneration of the affected retina. Irregularly shaped areas of tapetal hyperreflectivity (Figure 5) are usually the result of retinal degeneration secondary to previous inflammation. Extensive chorioretinitis can result in visual impairment or complete blindness. REFERENCES 1. Collins BK, Moore CP: Diseases and surgery of the canine anterior uvea, in Gelatt KN (ed): Veterinary Ophthalmology. Philadelphia, Lippincott Williams & Wilkins, 1999, pp Jaanus SD: Anti-inflammatory drugs, in Bartlett JD, Jaanus SD (eds): Clinical Ocular Pharmacology. Boston, Butterworths, 1989, pp Opremcak EM: Antiinflammatory agents, in Mauger TF, Craig EL (eds): Havener s Ocular Pharmacology. St. Louis, Mosby, 1994, pp Wilkie DA: Control of ocular inflammation. Vet Clin North Am: Small Anim Pract 20(3): , Regnier A: Antimicrobials, anti-inflammatory agents, and antiglaucoma drugs, in Gelatt KN (ed): Veterinary Ophthalmology. Philadelphia, Lippincott Williams & Wilkins, 1998, pp Bartlett JD, Cullen AP: Clinical administration of ocular drugs, in Bartlett JD, Jaanus SD (eds): Clinical Ocular Pharmacology. Boston, Butterworths, 1989, pp Evans RJ: Clinical pharmacology and therapeutics, in Chandler EA, Gaskell CJ, Gaskell RM (eds): Feline Medicine and Therapeutics. Oxford, UK, Blackwell Scientific Publications, 1994, pp Mathews KA: Nonsteroidal antiinflammatory analgesics to manage acute pain in dogs and cats. Compend Contin Educ Pract Vet 18(10): , Runk A, Kyles AE, Downs MO: Duodenal perforation in a cat following the administration of nonsteroidal anti-inflammatory medication. JAAHA 35(1):52 55, Reubel GH, Ramos RA, Hickman MA, et al: Detection of active and latent feline herpesvirus 1 infections using the polymerase chain reaction. Arch Virol 132: , McGregor MLK: Anticholinergic agents (parasympatholytics), in Mauger TF, Craig EL (eds): Havener s Ocular Pharmacology. St. Louis, Mosby, 1994, pp Dubey JP, Lappin MR: Toxoplasmosis and neosporosis, in Greene CE (ed): Infectious Diseases of the Dog and Cat. Philadelphia, WB Saunders Co, 1998, pp Addie DD, Jarrett O: Feline coronavirus infection, in Greene CE (ed): Infectious Diseases of the Dog and Cat. Philadelphia, WB Saunders Co, 1998, pp Vondeharr MA, Morrison WB: Lymphosarcoma, in Morrison WB (ed): Cancer in Dogs and Cats Medical and Surgical Management. Philadelphia, Lippincott Williams & Wilkins, 1998, pp Hartman K: AZT in the treatment of feline immunodeficiency virus infection: Part 1. Feline Pract 23(5):16 21, Hartman K: AZT in the treatment of feline immunodeficiency virus infection: Part 2. Feline Pract 23(6):13 20, Malik R, Wigney DI, Muir BD, et al: Cryptococcosis in cats: Clinical and mycological assessment of 29 cases and evaluation of treatment using orally administered fluconazole. J Med Vet Mycol 30(2): , Medleau L, Greene CE, Rakich PM: Evaluation of ketoconazole and itraconazole for treatment of disseminated cryptococcosis in cats. Am J Vet Res 51(9): , Jacobs GJ, Medleau L, Calvert CC, et al: Cryptococcal infection in cats: Factors influencing treatment outcome, and results of sequential serum antigen titers in 35 cats. J Vet Intern Med 11(1):1 4, Martin CL, Stiles J: Ocular infections, in Greene CE (ed): Infectious Diseases of the Dog and Cat. Philadelphia, WB Saunders Co, 1998, pp Lappin MR, Jensen W, Kordica DL, et al: Bartonella spp. antibodies and DNA in aqueous humor of cats. Feline Med Surg 2:61 68, Lappin MR, Black JC: Bartonella spp infection as a possible cause of uveitis in a cat. JAVMA 214(8): , Breitschwerdt EB, Green CE: Bartonellosis, in Greene CE (ed): Infectious Diseases of the Dog and Cat. Philadelphia, WB Saunders Co, 1998, pp About the Authors Drs. Powell and Lappin are affiliated with the College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins. Dr. Powell is a Diplomate of the American College of Veterinary Ophthalmology, and Dr. Lappin is a Diplomate of the American College of Veterinary Internal Medicine. SYSTEMIC SIDE EFFECTS OF DRUGS CATARACTS CHORIORETINITIS

8 268 Small Animal/Exotics Compendium March 2001 ARTICLE #4 CE TEST The article you have read qualifies for 1.5 contact hours of Continuing Education Credit from the Auburn University College of Veterinary Medicine. Choose the one best answer to each of the following questions; then mark your answers on the test form inserted in Compendium. 1. Which of the following statements regarding diagnosis of feline uveitis is false? a. FIV, FIP, LSA, and toxoplasmosis are often associated with feline uveitis. b. Large keratic precipitates are often associated with diseases that cause granulomatous inflammation (e.g., toxoplasmosis, FIP). c. The clinical appearance of anterior uveitis can often be used to distinguish one cause from another. d. The diagnostic workup for uveitis should include a complete blood cell count, urinalysis, serum chemistry profile, thorough history, and physical examination. 2. Which of the following statements regarding ocular paracentesis is true? a. Aqueous and vitreous humor paracenteses should be routinely performed to determine the cause of uveitis. b. Vitreous humor paracentesis is a relatively safe procedure with a low risk of complications. c. Vitreous humor paracentesis should be performed with the patient under general anesthesia, but anterior chamber paracentesis only requires topical anesthesia. d. Ocular fluids can be used for cytology, determining antibody content, culture, and PCR. 3. In treating uveitis, a. nonspecific therapy is only used when a specific cause cannot be identified. b. the primary goals are to stop inflammation, relieve pain, and prevent or control complications. c. topical hydrocortisone (1%) is the corticosteroid of choice for treatment of anterior uveitis. d. chorioretinitis can be treated by topically administering corticosteroids if treatments are given at least every 4 hours. 4. Which of the following statements regarding topical drugs for treating feline uveitis is false? a. Prednisolone acetate suspension (1%) and dexamethasone solution (0.1%) or ointment (0.05%) are the topical preparations with the best potency and corneal penetration. b. Topical corticosteroids are contraindicated in the presence of corneal ulceration because they inhibit wound healing and augment collagenase activity in the cornea. c. Topical NSAIDs have been shown to be as effective in treating ocular inflammation as are topical corticosteroids. d. Topical NSAIDs are not recommended when corneal infection is present. 5. Which of the following statements regarding pain associated with feline uveitis is false? a. Ciliary-body and iris-muscle spasms are a major source of pain associated with anterior uveitis. b. Phenylephrine (10%) dilates the pupil, helping relieve ocular pain associated with anterior uveitis. c. Atropine, a cycloplegic and mydriatic drug, relieves ocular pain by relaxing uveal muscle spasms. d. Atropine, a parasympatholytic drug, can decrease tear production but should be used judiciously. 6. Which statement regarding subconjunctival corticosteroids is false? a. They should not be used with corneal ulceration because the drugs are partially absorbed through the cornea. b. Many forms are long acting and provide continuous drug release for 2 to 4 weeks. c. Because subconjunctival forms are long lasting, oral and topical corticosteroid therapy is usually not necessary. d. A disadvantage to their use is the inability to withdraw the drug if complications arise. 7. Treatment with an anti-toxoplasma drug is indicated in cats with a. uveitis (suspected to be caused by Toxoplasma) that are not seropositive. b. idiopathic uveitis, especially when glucocorticoid therapy has been ineffective. c. uveitis that are seropositive for T. gondii when other causes of uveitis have been ruled out, especially when glucocorticoid therapy has been ineffective. c. none of the above 8. Which of the following statements regarding posterior uveitis is true? a. It can be adequately treated by frequently administering topical medications. b. If an infectious cause is suspected, systemic corticosteroids should not be used or should be used with caution and with concurrent appropriate antimicrobial therapy. c. It is usually isolated to the choroid, sparing the retina. d. Systemic use of corticosteroids is always contraindicated when an infectious cause is suspected. 9. Glaucoma secondary to uveitis a. is not a concern unless the intraocular pressure is greater than 25 mm Hg.

9 Compendium March 2001 Small Animal/Exotics 269 b. is caused by an increase in aqueous humor production characteristic of anterior uveitis. c. only occurs in purebred dogs predisposed to primary glaucoma. d. should be suspected if the intraocular pressure is not below normal because aqueous humor production decreases with anterior uveitis. 10. Which of the following statements regarding complications of uveitis is false? a. When a cataract is caused by recurrent uveitis, surgery is usually unrewarding. b. Irregularly shaped areas of tapetal hyperreflectivity often indicate retinal degeneration secondary to inflammation. c. Glaucoma can result from anterior and posterior synechiae. d. A cataract caused by uveitis will invariably progress to maturity.