eMedicine Specialties > Ophthalmology > Retina

Retinopathy, Birdshot: Treatment & Medication

Author: C Michael Samson, MD, Associate Professor, Department of Ophthalmology, New York Medical College; Consulting Staff, Co-director of Uveitis Service, Faculty in Residency Training Program, Director of Uveitis Fellowship Training Program, Department of Ophthalmology, New York Eye and Ear Infirmary; Private Practice, Vitreous Retina Macula Consultants of New York
Coauthor(s): Amro Mohamed Mohamoud Ali, MB, ChB, Consulting Staff, New York Eye and Ear Infirmary; C Stephen Foster, MD, FACS, FACR, FAAO, Clinical Professor of Ophthalmology, Harvard Medical School; Consulting Staff, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary; Founder and President, Ocular Immunology and Uveitis Foundation, Massachusetts Eye Research and Surgery Institution
Contributor Information and Disclosures

Updated: Sep 25, 2008

Treatment

Medical Care

The appropriate level of treatment is determined by the severity of the inflammation. Conflicting reports exist regarding the efficacy of steroids. Some patients with mild inflammation may respond well to regional injection of steroids. Other patients require the use of systemic prednisone for control of the inflammation. Some patients may be controlled on less than 10 mg/d, while other patients require higher doses. Long-term treatment, even 10 mg/d of steroids, is undesirable, considering the high risk of significant morbidity and mortality of such treatment. Many patients show no significant response to steroid therapy.

Cyclosporine has been shown to have a beneficial effect on birdshot retinochoroidopathy inflammation in retrospective case series. Initial reports demonstrated improved visual acuity, decreased vitritis, and stabilization of eyes with cyclosporine dosages of 10 mg/kg/d. However, this dose also was associated with a high incidence of nephrotoxicity and hypertension. Vitale and colleagues reported a series of 19 cases of birdshot retinochoroidopathy, which demonstrated that cyclosporine treatment with lower dosages, from 2.5-5 mg/kg, can be effective.⁷ This series showed control of vitreal inflammation in 88.5% of eyes and improved or stable visual acuity in 83.3% of eyes. However, the low incidence of drug toxicity was most striking; there were only 2 cases of hypertension and no cases of nephrotoxicity.

One suggestion is to initially start cyclosporine dosages at 2.5 mg/kg and then to increase to the level necessary to control the inflammation, while ensuring avoidance of drug adverse effects. The maximum dosage is 5 mg/kg according to this author. Monitoring for blood counts and renal function is performed every 4-6 weeks, along with blood pressure monitoring. Cyclosporine serum levels are not followed at these dosing regimens. Other potential adverse effects, such as hirsutism, paresthesias, tremor, and gingival hyperplasia, are not risks for morbidity, but are mentioned, since lowering of drug dosage or discontinuation of the medication may be indicated if such adverse effects occur to a point of affecting the quality of the patient's life.

One study reports the use of ketoconazole as adjunct therapy to cyclosporine. Ketoconazole delays metabolism of cyclosporine; hence, it may lower the dose of cyclosporine required to maintain control of inflammation. Silverstein and Wong demonstrated that cyclosporine trough levels could be maintained in a patient when the cyclosporine dosage was dropped from 200 mg/d (3 mg/kg) to 50 mg/d (0.75 mg/kg) with the addition of ketoconazole at 200 mg/d. This amounts to an 80% reduction of cyclosporine consumption. While this may be cost-saving, one cannot necessarily equate stabilization of cyclosporine serum levels with adequate control of inflammation nor with reduced potential toxicity. After all, the serum cyclosporine levels are still in the therapeutic range, and one might expect cyclosporine toxicity prevalence to be unchanged. Additionally, ketoconazole is not without potential adverse effects, especially the risk of hepatitis.

Other immunomodulatory therapies have been described. Kiss and colleagues reported the use of mycophenolate mofetil, azathioprine, methotrexate, and daclizumab in a series of 28 patients with birdshot retinochoroidopathy; however, the small size of the study precludes any comment on the efficacy of any single drug.⁸ LeHoang and colleagues reported the use of intravenous immunoglobulin in a series of 18 patients as initial therapy for active birdshot retinochoroidopathy, and they noted stable vision in 33 of 36 eyes over a mean follow-up period of 39 months.⁹

Medication

The goals of pharmacotherapy are to reduce morbidity and to prevent complications.

Immunosuppressive agents

May have a beneficial effect on birdshot retinochoroidopathy inflammation.

Cyclosporine (Sandimmune, Neoral)

Cyclic polypeptide that suppresses some humoral immunity and, to a greater extent, cell-mediated immune reactions, such as delayed hypersensitivity, allograft rejection, experimental allergic encephalomyelitis, and graft-versus-host disease for a variety of organs. For children and adults, base dosing on ideal body weight. The dose of 10 mg/kg/d is associated with a high incidence of nephrotoxicity and hypertension.

Corticosteroids

Have both anti-inflammatory (glucocorticoid) and salt-retaining (mineralocorticoid) properties. Glucocorticoids have profound and varied metabolic effects. In addition, these agents modify the body's immune response to diverse stimuli.

Prednisone (Deltasone, Sterapred, Orasone, Meticorten)

Immunosuppressant for treatment of autoimmune disorders; may decrease inflammation by reversing increased capillary permeability and suppressing PMN activity. Stabilizes lysosomal membranes and suppresses lymphocytes and antibody production.

Antifungal agents

Their mechanism of action may involve an alteration of RNA and DNA metabolism or an intracellular accumulation of peroxide that is toxic to the fungal cell. They also may inhibit P450 enzymes involved in drug metabolism.

Ketoconazole (Nizoral)

For use concomitantly with cyclosporine. Imidazole broad-spectrum antifungal agent that acts on several of the P450 enzymes, including the first step in cortisol synthesis, cholesterol side-chain cleavage, and conversion of 11-deoxycortisol to cortisol. Also increases levels of drugs metabolized by P450 enzymes, such as cyclosporine.

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