Rifabutin-associated uveitis
C. Review and adjust systemic medications and treat with topical corticosteroids
Pars plana vitrectomy with hyperemia of intravitreal antibiotics would not be the preferred answer because with the lack of surgery history, an infections etiology would be lower on the differential diagnosis (choice A). Treatment with topical and oral antibiotics would not be the preferred answer because of the insufficient intraocular penetration (choice B). Treat with systemic and topical corticosteroids would not be the preferred answer because of the importance of investigating underlying etiology prior to treatment (choice D).
Rifabutin is used for the treatment and prophylaxis of the M avium complex (MAC) infection.1 It is a semisynthetic derivative of rifamycin SV and has broad antimicrobial activity, including against MAC. It has been shown to have a dose-associated toxicity including polyarthralgia/arthritis, aphthous stomatitis, skin pigmentation, and uveitis.2 Signs and symptoms of anterior uveitis with or without hypopyon, intermediate uveitis, and posterior uveitis or panuveitis may occur between 2 weeks and 7 months following the start of therapy. Symptoms can present with dosage as low as 300 mg/d.3,4 Symptoms have been shown to worsen with increasing dose. Most cases resolve within 1 to 2 months of discontinuation of rifabutin and administration of topical corticosteroids. Published reports of rifabutin-associated uveitis have all been associated with concurrent medications like clarithromycin and fluconazole. These medications elevate serum rifabutin levels by inhibition of the hepatic microsomal cytochrome P-450 system that metabolizes rifabutin. This patient was taking concurrent clarithromycin as part of her MAC infection treatment.5,6 Patients with rifabutin-associated uveitis have excellent visual prognosis, and most return to 20/30 visual acuity 3 weeks after initiating topical corticosteroid treatment, in some cases without requiring medication cessation.7