This retrospective study found that although 14 percent of tubercular serpiginous-like choroiditis patients continued to progress a median of four weeks after initiating antituberculosis treatment, good outcomes were obtained with increased immunosuppression and continuation of treatment.
Tubercular serpiginous-like choroiditis is a relatively new disease entity in which serpiginous-like choroiditis is seen in patients with evidence of systemic or latent tuberculosis. It has two distinct presentations in the eye: 1) multifocal choroiditis that is discrete and noncontiguous at first and progresses relentlessly to a diffuse, contiguous variety, acquiring an active advancing edge resembling serpiginous choroiditis; or 2) diffuse plaque-like choroiditis showing amoeboid spread. Tubercular serpiginous-like choroiditis is believed to represent an immune-mediated hypersensitivity reaction to the acid-fast bacilli (Mycobacterium tuberculosis) sequestrated in the retinal pigment epithelium
The authors reviewed the charts of 110 serpiginous-like choroiditis patients with a tuberculin skin test, active lesions in at least one eye and at least 18 months' follow-up. Patients were grouped according to tuberculin skin test results. Of 84 patients who tested positive, 19 received systemic corticosteroids and 65 also received antituberculosis treatment. All patients who tested negative received corticosteroids. Patients with continued progression received an increased dose of corticosteroids with or without immunosuppressive agents.
Continued progression was observed in 14.3 percent of patients who tested positive and none who tested negative. Of the 12 patients showing progression, 11 were receiving antituberculosis treatment and corticosteroids and one was receiving corticosteroids only. The median time of progression was four weeks from the start of therapy, varying between 11 days and six weeks. When continued progression developed, the dose of oral prednisolone ranged between 10 and 80 mg per day.
Lesions started responding to revised therapy in all patients and showed healing over the next four to six weeks, with none of them demonstrating further progression. The lesions responded in all eyes, with final visual acuity of 20/40 or better achieved in 75 percent of eyes.
The authors write that the continued progression of choroiditis lesions after initiating antituberculosis treatment could be due to either paradoxical worsening or a delayed treatment effect. The exact reason for the development of paradoxical worsening is not clearly understood, but it could be caused by a higher bacillary load or the release of endotoxins following antibiotic treatment.
They conclude that it is important for ophthalmologists to be aware of the potential for a delayed treatment effect so as to avoid mislabeling a case as resistant or considering nontubercular etiologies.