By J. Fernando Arevalo, MD, FACS
This article describes an approach to diagnosing uveitides by viewing them as a collection of approximately 30 separate diseases characterized by intraocular inflammation, not as a manifestation of underlying "etiologies."
Traditionally these diseases have been grouped by the primary anatomic location of the inflammation as anterior uveitis, intermediate uveitis, posterior uveitis and panuveitis. In the past, standardized ''review of system'' questionnaires often have been used to identify symptoms of a systemic disease and a laboratory evaluation conducted to identify the ''cause,'' an approach often termed ''the etiologic diagnosis of uveitis.''
A refinement on this is the ''naming-meshing'' approach. If no underlying disease is found and a specific syndromic name cannot be given to the uveitis, it is termed ''idiopathic.'' This has led to tactics, such as shotgun ''uveitis survey'' laboratory testing (a practice deplored by uveitis experts), the idea that one should only ''work up'' the second attack of uveitis (because of the low yield of shotgun laboratory testing) and conduct exhaustive searches for laboratory evidence of sarcoidosis or other systemic diseases (often using tests with a low positive predictive value), even when there is no other evident organ involvement.
Underlying these approaches is the flawed notion that uveitis typically is a manifestation of ''something else'' that must be identified regardless of cost, and the flawed concept that discovering an idiopathic systemic disease renders the uveitis nonidiopathic.
A more modern approach is to recognize that the clinician's goal is to diagnose a specific uveitic disease. The likely diagnosis can be derived from the history, examination, and, for posterior uveitides, sometimes imaging studies. Laboratory testing then is used to identify infectious diseases not identified by the morphologic picture and systemic diseases with an impact on the patient's health. Making the correct diagnosis of a specific uveitic entity is critical to management, as each disease has its own course, treatment and prognosis.
The authors say that a patient's uveitis is characterized along several dimensions: course, laterality, anatomic location of the inflammation, morphology, presence of active infection and host (age, presence of a systemic disease). Posterior uveitis can be characterized further by whether it is primarily a retinitis, choroiditis, or retinal vasculitis; whether it is paucifocal or multifocal; and the morphology of the lesions. This characterization narrows the differential diagnosis to one or, at most, a few diseases.
Laboratory screening (i.e., testing all patients) should be reserved for those diseases that can present as any type of uveitis, whereas targeted testing (i.e., testing a subset with specific features) should be used selectively. Laboratory testing should be used to identify a therapy-altering infection or a systemic disease that will affect the patient's health.
Uveitis that is not one of the established diagnoses is designated as "undifferentiated" with the course, laterality and anatomic location (e.g., undifferentiated bilateral chronic anterior uveitis).
They conclude that this approach should lead to the correct diagnosis of the specific uveitic disease in the large majority of cases without overuse of laboratory testing.