1. In TB-endemic countries, think of TB as a probable/possible etiology of uveitis in
- Presence of one or a few large full-thickness choroidal granulomas that show enhanced vascularity/RAP on FFA
- Retinal periphlebitis with subvascular retinitis/choroiditis lesions/scars that show extensive peripheral retinal ischemia.
- Multifocal serpiginoid choroiditis/Serpiginous-like choroiditis lesions with vitreous cells.
2. In the presence of any of the above clinical phenotypes, collect evidence of MTB infection by way of tuberculin skin test/QuantiFERON-TB Gold; X-ray/CT chest. The 2-step testing (Bayesian probability) improves the likelihood of MTB as a probable/possible etiology of uveitis in TB-endemic regions.
3. Polymerase chain reaction to detect MTB DNA from ocular fluids has low sensitivity limiting its utility in clinical practice. If positive, it confirms the diagnosis of TBU but a negative test does not rule out MTB.
4. Start 4-drug anti-TB drug regimen in consultation with an internist. All four drugs INH (H); Rifampicin (R); Ethambutol (E) and Pyrazinamide (Z) for the first 2-3 months and H and R for the next 6-9 months.
5. Because of a predominantly paucibacillary immune response, TB uveitis frequently requires administration of corticosteroids by local/depot or systemic routes. In view of the enhanced VEGF expression by TB choroidal granulomas, adjunctive use of anti-VEGF agents accelerate response to treatment.
6. Look for clinical response in 4-6 weeks of initiating treatment.
7. Patients with multifocal serpiginoid choroiditis/ Serpiginous-like choroiditis phenotype need very close monitoring for paradoxical/adverse worsening. This may be seen in 40-50% of these patients on the initiation of anti-TB treatment. Widefield fundus imaging must be done to document regression/ worsening on each visit.
8. Complete remission is seen in nearly 80% of patients with TB uveitis.
9. Recurrence of uveitis may be seen if uveitis is caused by MDR (~10%), incomplete or non-compliance treatment or is due to an etiology other than TB.
10. Healed TB posterior uveitis may be complicated by the development of CNVM that becomes a diagnostic challenge due to extensive scarring. Do not ignore any fresh visual complaints.