Comparison of uveitis manifestations in patients with active systemic tuberculosis and those with positive interferon-gamma release assay without active disease

Objective: To evaluate the clinical manifestations of uveitis in patients with active systemic tuberculosis (TB) and compare them to those with uveitis of undetermined cause who were positive for the interferon-gamma release assay (IGRA) but did not have active systemic TB. Methods: This retrospective study included 118 patients: 51 with uveitis and active systemic TB, 52 with undetermined cause of uveitis and positive IGRA but no active systemic TB, and 15 with positive Mycobacterium tuberculosis (Mtb) polymerase chain reaction (PCR) results from ocular fluids but no active systemic TB. Demographic data, ocular findings, and systemic TB investigations were analysed and compared. Results: Patients with evidence of active TB were predominantly younger. Typical manifestations of ocular TB (OTB) were more frequently observed in patients with active systemic TB (p < 0.001) and were significantly associated with younger age (p = 0.002). In patients without active systemic TB but positive Mtb PCR from ocular fluid, ocular manifestations closely resembled those of patients with active systemic TB, particularly with respect to the presence of choroidal granulomas. In contrast, patients with an undetermined cause of uveitis who tested positive for IGRA were older, and their clinical features were more often atypical. Conclusions: Uveitis associated with active systemic TB was characterised by typical OTB manifestations and occurred more frequently in younger patients. These findings highlight the importance of considering TB in the differential diagnosis of uveitis, especially in younger individuals, and suggest that atypical manifestations may be more common in older patients and in patients without active TB.