Periocular steroid

Periocular steroids can be administered by subconjimcti-val, sub-Tenon s capsule, or retrobulbar injection. A topical anesthetic often is instilled before the steroid is injected. This route of administration can be effective during surgical procedures, as a supplement to topical and systemic steroids in cases of severe inflammation, and in patients not compliant with the prescribed regimen. 

The use of periocular steroids has several limitations and complications. The injections are usually somewhat uncomfortable, and thus patients prefer to avoid them. Adverse ocular effects have included retinal detachment, optic nerve atrophy, and preretinal membrane formation. Intraocular pressure (lOP) can rise, particularly because the drug may remain in the eye for several days to weeks. Some of the observed effects may result from the vehicle rather than from the steroid itself. 

Topical or periocular steroids cause few systemic effects. When topical dexamethasone sodium phosphate was administered four times daily for 6 weeks, subjects showed reduced plasma levels of cortisol. However, elevation of 11-deoxycortisol with the oral metyrapone tartrate test indicated that the pituitary-adrenal axis was intact. 

Intralesional injection of steroid can lead to adrenal suppression. Infents and small children are especially susceptible, because a given amoimt of steroid is distributed in a smaller volume of fluid and tissue compartments. Infents injected with mixtiu es of triamcinolone acetonide and betamethasone or dexamethasone fiar periocular hemangiomas exhibited depressed serum cortisol and adrenocorticotropic hormone levels. The adrenal suppression can last up to 5 months and can result in weight loss and growth retardation. It is not known whether other corticosteroid preparations would produce similar effects or which other fectors might influence these results. In general, topical and periocular use of steroids produces minimal systemic effects. Withdrawal of topical or periocular steroids does not generally cause adrenal crisis. 

The use of periocular steroids circumvents many of the side effects associated with systemic steroids however, complications may still arise. lOP response is a particular concern, because depot medications cannot be removed easily, as compared with tapering or discontinuing an oral preparation. Cataractogenesis may occur with any steroid preparation with intravitreal corticosteroid implants, the incidence of cataract formation requiring surgery over 2 years is nearly 90%. 

Intermediate uveitis may not warrant any therapeutic intervention in mild cases where the visual acuity is 20/40 or better. However, medical therapy is required for most patients. Macular edema is a frequent complication and requires prompt management to prevent permanent vision loss. In general, topical steroids are minimally effective in intermediate uveitis, except in those patients who are aphakic. Periocular and systemic steroids are substantially more efficacious. Periocular steroid injections are preferable in unilateral presentations and in children, whereas oral or other systemic routes are required for bilateral cases. For steroid-resistant intermediate uveitis, immunosuppressive therapy or surgery (cryotherapy and vitrectomy) may be necessary. Complications associated with intermediate uveitis include persistent CME,... 

Ideally the effective dose should be used for the shortest time necessary to secure the desired clinical response. The dosage should be individualized as much as possible to the patient and the severity of the condition. The patient s general health must be considered and close supervision maintained to assess the effects of steroid therapy on the course of the disease and possible adverse effects. With ocular disease the route of steroid administration is an important determinant of the pharmacologic and therapeutic effects observed. Topical ocular therapy is usually satisfectory for inflammatory disorders of the eyelids, conjimctiva, cornea, iris, and ciliary body. In severe fiarms of anterior uveitis, topical therapy may require supplementation with systemic or periocular (local injection) steroids. Chorioretinitis and optic neuritis are most often treated with systemic steroids. 

Periocular injection of steroids should be reserved for those situations requiring an anti-inflammatory effect greater than that obtainable with topical or systemic administration. Concurrent administration of steroid by both topical and subconjunctival routes does appear to produce an additive therapeutic effect in severe inflammations, but periocular injection alone does not necessarily result in greater anti-inflammatory effects.These fects suggest that topical administration should be the primary route of steroid therapy for anterior segment inflammations. Table 12-3 compares the achmitages and disachmitages of the three routes of steroid administration. 

A stepwise approach to therapy was proposed for cases of ocular toxocariasis. For eye disease alone, local and periocular or systemic steroids should be used, with surgery (vitrectomy, membrane peel) when appropriate. For eye disease unresponsive to steroids, a specific anthelmintic agent is added and systemic steroids are continued (e.g., thiabendazole 50 mgAg per day for 7 days plus prednisolone 0.5 to 1.0 mg/kg per day). For eye disease with systemic symptoms (VLM) or high antibody levels, local steroids and mydriatics are used, in addition to oral thiabendazole and oral steroids from the outset. 

Locally administered steroids have been used with variable success. Although topically applied steroids are completely ineffective in alleviating the ocular signs or symptoms associated with class 2 disease, periocular... 

Corticosteroid administration by systemic (oral or intravenous), topical (ophthalmic and cutaneous), injected (periocular and subcutaneous), and inhalation and possibly nasal routes can elevate lOP In patients who are steroid responders, oral steroids produce approximately 60% the increase in lOP as compared with topical agents, most likely because of differences in achieved anterior chamber concentrations of the drug. Those with primary open-angle glaucoma respond to steroids at a rate of 46% to 92% compared with 18% to 36% of... 

Periocular injections, subconjunctival, subtenons, and retrobulbar injection of drugs have been frequently investigated as a means to increase ocular availability. Subtenon injections of steroids, such as triamcinolone acetonide, are frequently used to control inflammatory conditions of the posterior segment such as cystoid macular edema, although this delivery route carries a risk of inadvertent intraocular injection (45). 

As discussed previously, corticosteroids downregulate VEGF production in experimental models and possibly reduce breakdown of the blood retinal barrier (15,16). Similarly, corticosteroids have antiangiogenic properties possibly due to attenuation of the effects of VEGF (20,21). These properties of steroids are commonly used. Clinically, triamcinolone acetonide is used locally as a periocular injection to treat cystoid macular edema secondary to uveitis or as a result of intraocular surgery (22,23). In animal studies, intravitreal triamcinolone acetonide has been used to prevent proliferative vitreoretinopathy and retinal neovascularization (24—27). Intravitreal triamcinolone acetonide has been used clinically to treat proliferative vitreoretinopathy and choroidal neovascularization (28-31). 

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