How is unclassified uveitis diagnosed
What diagnostic workup is of value for a patient with unclassified uveitis?
History and physical examination should be used to guide further workup in all cases of uveitis. Anterior uveitis is commonly idiopathic; therefore extensive evaluation is often unnecessary in a patient presenting with a single episode of uveitis without signs or symptoms of a systemic disease . Patients with recurrent or chronic anterior uveitis, uveitis affecting the intermediate or posterior segments, panuveitis, or with an abnormal history or physical exam warrant additional testing. Routine labs including CBC, comprehensive metabolic panel, UA, ESR, and CRP should be considered in this setting. The need for further workup (e.g., infectious disease studies, imaging, autoantibodies) will depend on the results of initial testing as well as the history and exam.
Medication history (all patients): certain medications like bisphosphonates, moxifloxacin, sulfonamides, MEK and BRAF inhibitors, anti-CTLA4 antibodies and PD-1 inhibitors can cause uveitis.
Chest x-ray (all patients): sarcoidosis is part of the differential diagnosis of all patterns of uveitis. A chest x-ray is also a useful screen for TB.
Syphilis testing (all patients): like sarcoidosis, syphilis can cause any type of uveitis in the absence of characteristic systemic manifestations.
Purified protein derivative (PPD)/Quantiferon (select patients): positive results do not indicate active disease and can be misleading; therefore TB testing should be reserved for cases where there is suspicion for infection (exposure history, chest x-ray findings, and specific findings on ocular exam such as serpiginous choroiditis or focal choroidal nodules).
ANA (select patients): indicated only in the evaluation of pediatric patients with pauciarticular onset JIA and uveitis, as it has prognostic implications in these patients. It is not indicated for routine screening of adult patients with unclassified uveitis because it has an extremely low diagnostic and prognostic value unless other features of SLE, SS, anti-C1q disease, or another ANA-associated disease are present. Note that many patients with SLE who develop uveitis frequently have anti-C1q antibodies.
HLA-B27 (select patients): appropriate for patients presenting with AAU, even in the absence of a demonstrable SpA given its prognostic implications.
The following are not recommended as part of the initial evaluation:
Angiotensin-converting enzyme level: elevations are nonspecific and may be seen in sarcoidosis, liver disease, granulomatous infections (TB, leprosy), Gaucher’s disease, hyperthyroidism, Hodgkin’s disease, and various causes of lung disease.
ANCA: ANCA-associated vasculitis is an extremely rare cause of uveitis. Routine testing is not recommended in the absence of retinal vasculitis.
