Nonspecific therapy for uveitis

Nonspecific therapy for feline anterior uveitis includes topical mydriatics, corticosteroids, and nonsteroidal anti-inflammatory drugs (NSAIDs) (Table A). The primary goals of such therapy are to stop inflammation, stabilize the blood-aqueous barrier, decrease pain, and prevent blindness.1 Failure to address these processes can result in complications such as posterior synechiae, secondary glaucoma, cataracts, retinal detachment, and retinal degeneration.2

Table A: Therapeutic Agents for Nonspecific Treatment of Uveitis

Corticosteroids are the classic medications for minimizing the inflammatory process.1-3 Anterior uveitis, unless severe, can often be managed topically.2 Both 1% prednisolone acetate and 0.1% dexamethasone have excellent potency and corneal penetration. Although contraindicated in cases of corneal ulceration, topical corticosteroids have a low potential for causing systemic effects with short-term use, so they are considered safe in patients in which you suspect a systemic infectious or neoplastic cause. Topical NSAIDs, such as 0.03% flurbiprofen, are less potent than corticosteroids but can be used in patients in which topical corticosteroids are contraindicated2 or in combination with corticosteroids in patients with severe uveitis.1

To reduce pain, the mydriatic of choice is 1% atropine ointment since it is less likely to cause increased salivation than the analogous solution formulation in cats.3 Atropine is a direct-acting anticholinergic that causes pupillary dilation and cycloplegia (paralysis of the muscles of the ciliary body). Pupillary dilation reduces the risk for posterior synechia formation and subsequent pupillary occlusion.1-3 Cycloplegics are contraindicated in patients with secondary glaucoma. Cycloplegia increases the resistance to aqueous outflow, so careful intraocular pressure monitoring is recommended. Alternatively, tropicamide may be used when a patient is at risk for developing secondary glaucoma since it has a shorter duration of action. Glaucoma may develop when intraocular pressures are normal in the face of marked ocular inflammation or when a marked difference in intraocular pressure exists between eyes. In patients with secondary glaucoma, discontinue cycloplegics, and initiate therapy with topical carbonic anhydrase inhibitors. These agents are considered safe in patients with secondary glaucoma since they do not contribute to the inflammatory process.

In patients with any degree of posterior uveitis, systemic anti-inflammatory therapy is required because topical medications do not reach therapeutic concentrations in the retina or choroid.2,3 Glucocorticoids, such as prednisolone and dexamethasone, are the systemic medication of choice in cats because of their decreased capacity to cause hepatic glucuronidation, which results in the severe adverse effects seen with systemic NSAIDs. Initiate systemic corticosteroid therapy with caution, however, and avoid it in animals in which an infectious agent or neoplasia is suspected.1,2 Short-term NSAID administration is considered safe and can be used in patients in which an infectious agent is suspected and the diagnosis is pending.4 In patients in which an underlying cause cannot be identified (idiopathic or immune-mediated uveitis), aggressive nonspecific therapy is indicated, and recurrence is not uncommon despite therapy.5

REFERENCES

1. Townsend WM. Canine and feline uveitis. Vet Clin North Am Small Anim Pract 2008;38(2):323-346.

2. Powell CC, Lappin MR. Diagnosis and treatment of feline uveitis. Compend Contin Educ Pract Vet 2001;23(3):258-269.

3. Stiles J, Townsend WM. Feline ophthalmology. In: Gelatt KN, ed. Veterinary ophthalmology. 4th ed. Ames, Iowa: Blackwell Publishing, 2007;1123-1124.

4. Lascelles BDX, Court MH, Hardie EM, et al. Nonsteroidal anti-inflammatory drugs in cats: a review. Vet Anaesth Analg 2007;34(4):228-250.

5. Maggs DJ. Feline uveitis: an intraocular lymphadenopathy. J Feline Med Surg 2009;11(3):167-182.