Introduction
Tuberculosis (TB) is caused by gram positive organism Mycobacterium tuberculosis (Mtb), which is a highly infectious disease. According to WHO 2018, it is ranked above HIV AIDS as a leading cause of death from single infectious agent.1 India is also endemic for tuberculosis and shares largest global burden. Tuberculosis most commonly affects lungs in 80% of the patients and in remaining 20% patients other organs are involved that may even include eye.2 So amongst extrapulmonary tuberculosis – Ocular tuberculosis is one of its type. There is a broad spectrum of varied clinical manifestations in Ocular tuberculosis affecting various structures of eye-any part of adnexa, different layers and globe structure, contents of orbit, optic nerve to orbital apex posteriorly.3 Conjunctiva, cornea and sclera is involved in primary disease, while manifestation of secondary disease is tuberculous uveitis.3 Granulomatous uveitis is one of the most common manifestations of ocular tuberculosis, which results from secondary dissemination of bacteria via extensive uveal and choroidal vasculature.2 Findings include- solitary or multiple choroidal nodules, choroiditis, and retinal vasculitis.3 If not treated well and not timely recognised can lead to unfavourable outcomes.4 Even though in tuberculosis uveitis is concurrently seen, it is difficult to prove its direct association. Ocular TB is usually not associated with pulmonary tuberculosis, as up to 60% of extrapulmonary tuberculosis patients may not have pulmonary disease and chest X ray is normal in latent TB.4 There is a significant reduction in recurrences of uveitis, following addition of corticosteroids to anti- tubercular therapy in uveitis patients with; latent/ manifest TB.4
Table 1
Clinical features at the time of presentation
Table 2
Investigations
Table 3
Patients after 3 months
|
|
Patient 1 |
Patient 2 |
Patient 3 |
|
Visual acuity |
CFCF |
After start of ATT- 6/12(B) |
After start of ATT- 6/9- 6/6 |
|
Duration of therapy |
3 months |
3 months |
3 months |
Table 4
At 6 months- improved clinical picture
Materials and Methods
A prospective observational study done on 3 patients presenting to ophthalmology outpatient of Sapthagiri Institute of Medical Sciences, Bangalore.
Study period
6 months (March 2022- October 2022). Three patients who presented to the ophthalmology outpatient with diminision of vision were thoroughly examined. Clinical features of the patient suggested of anterior uveitis. BCVA (Best corrected visual acuity), Color vision, Slit lamp examination, dilated fundus examination was done. Systemic investigations in pertaining to Uveitis was done (CBC, Mantoux, CXR, CRP, ESR, serology- HIV, HbsAg, HCV, VDRL, ACE). Both ophthalmological as well as systemic findings were correlated. Patients who turned out to be strongly mantoux positive, were referred to chest physician for further systemic evaluation, and they were started on anti-tubercular medication (ATT). ATT was administered following which systemic steroids were started. Manifestations of any concurrent extrapulmonary as well as pulmonary involvement was evaluated. These patients were then followed up to closely monitor their response to treatment as well as side effects of ATT.
Results
All patients systemically had all investigations negative (including Chest X-ray) except and strong Mantoux reaction with signs of active anterior Uveitis and Vitritis. In collaboration with the department of chest medicine, Anti tubercular treatment was commenced. Patients have recovered from the Uveitis and have improved symptomatically and clinically.
Discussion
India is endemic for tuberculosis-contributes to share largest global burden. Its really difficult to diagnose tuberculosis infection. Only when M tuberculosis is cultured and its DNA is amplified from the involved tissue- a definitive diagnosis is possible. In the cases, when the above condition is not possible, a diagnosis of presumed ocular tuberculosis is made when the indirect evidence can suggest strongly for tuberculosis which is responsible for patient’s clinical condition.5 Mantoux test is feasible to patient in terms of availability and affordability. Strongly positive mantoux signifies tuberculosis that helps in commencing ATT which can be further sight saving. Intraocular TB is a great mimicker of various uveitis entities and it can be considered in differential diagnosis of any type of intraocular inflammation.3 QuantiFERON®-TB Gold test- is an diagnostic test, not done seeing patients affordability of our patients in the study. All the patients treated with ATT and concomitant oral steroids showed improvement clinically.
A retrospective study done by Shahidatul-Adha et al. on patients showed patients to have positive Mantoux test (94.1%) and raised erythrocyte sedimentation rate (ESR) value (58.8%).4
Conclusions
Uveitis can be a presenting feature of Extra pulmonary TB. Easily available and affordable Mantoux test can help in detecting TB and commencing treatment which can be sight saving. Our study shows strongly positive Mantoux test > 20 mm, is suggestive of ocular tuberculosis, which is a required considerate for starting patients on Antitubercular medication(ATT). A close follow up for these patients is needed, as they have been started on ATT after testing mantoux strongly positive and should be closely monitored for any ocular toxicity due to ATT.
Our study shows the role of strongly positive Mantoux test in diagnosing and treating ocular tuberculosis.
