Etiologies of intermediate uveitis in a tertiary center: an age-oriented medical assessment?

To analyze the distribution of intermediate uveitis (IU) etiologies by age in order to guide the diagnostic approach. We conducted a monocentric retrospective study of 126 adult patients referred to an internal medicine department at a tertiary center with a diagnosis of intermediate uveitis of unknown cause between July 2002 and April 2023. Among the 126 patients, most were women (n = 77; 61%), with a median age of 49 [33;62] years; 113 (90%) were Caucasian. Idiopathic IU was the most common etiology across all age groups. In patients under 30 years old (n = 20), idiopathic IU was observed in 10 cases (50%), followed by pars planitis in 7 cases (35%) and multiple sclerosis in 2 cases (10%). In the 30–60-year group (n = 71), idiopathic IU remained the most frequent (n = 34, 48%), followed by sarcoidosis (n = 15, 21%) and lymphoma (n = 5, 7%). Other etiologies included pars planitis (n = 3), multiple sclerosis (n = 3), and infections (n = 2). After 60 years (n = 35), idiopathic IU was again the most prevalent (n = 22, 63%), followed by lymphoma (n = 6, 17%) and sarcoidosis (n = 5, 14%). Infectious diseases were observed in 2 cases. The etiologic distribution of IU varies with age. Before 30, idiopathic IU, pars planitis, and multiple sclerosis are the most common etiologies. After 30, idiopathic IU, sarcoidosis, and lymphoma become more prevalent, with lymphoma appearing after 45. After 60, lymphoma is more common than sarcoidosis. These findings support the use of an age-stratified diagnostic approach in the evaluation of IU.