Intermediate uveitis refers to inflammation localized primarily in the vitreous cavity, whereas posterior uveitis refers to inflammation involving the retina, choroid or optic nerve. Although both intermediate and posterior uveitis are less common than anterior uveitis, their potential to cause permanent vision loss is far greater. Prompt and appropriate treatment of these forms of uveitis is essential to minimizing the risk of long-term ocular complications and vision loss. The first consideration in evaluating patients with uveitis, therefore, should be to rule out infections and neoplastic masquerades. Infections and malignancies tend to respond poorly to our standard treatment with corticosteroids and non-corticosteroid immunosuppressive agents, and untreated ocular infections and malignancies can produce significant systemic morbidity, and even death.
Toxoplasmosis is the most common infectious cause of posterior uveitis.
The diagnosis is typically straightforward, since most patients have a focal retinochoroiditis, often in the setting of moderate to severe vitreous inflammation and adjacent or nearby retinochoroidal scars. Large, yellow, subretinal infiltrates in an elderly white woman with intraocular lymphoma. Consider systemic infections, such as syphilis and tuberculosis, in patients with intermediate and otherwise non-diagnostic forms of posterior uveitis. We tend to test for syphilis in virtually all patients with these forms of uveitis, because the test is risk-free and inexpensive, and because missing a diagnosis of syphilis can have such serious implications for the overall health of the patient. Remember, however, that less specific tests for syphilis, such as the RPR and VDRL, may be negative in up to 30 percent of patients with syphilitic uveitis.