2020–2021 BCSC Basic and Clinical Science Course™
9 Uveitis and Ocular Inflammation
Chapter 10: Infectious Uveitis: Bacterial Causes
Nocardia asteroides is a gram-positive rod with partially acid-fast beaded branching filaments—a bacterium that acts like a fungus. Although ocular involvement in patients with N asteroides infection is rare, ocular disease may be the presenting problem in this potentially lethal but treatable systemic disease characterized by pneumonia and disseminated abscesses. The responsible organism is commonly found in soil, and initial infection occurs by ingestion or inhalation, causing an insidious inflammation. Immunocompromised individuals are more likely to be affected.
Ocular involvement occurs by hematogenous spread of the bacteria, and symptoms may vary from the mild pain and redness of anterior uveitis to the severe pain and decreased vision of panophthalmitis. Nocardia infection can affect essentially any ocular structure, including periorbital tissue and the adnexae. Findings range from keratitis, necrotizing scleritis, or an isolated, unilateral choroidal or subretinal mass (abscess) with minimal vitritis to panuveitis with anterior chamber cell and flare, vitritis, and multiple choroidal abscesses with overlying retinal detachment mimicking fungal endophthalmitis.
Excerpted from BCSC 2020-2021 series: Section 9 - Uveitis and Ocular Inflammation. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.