|Year : 2019 | Volume
| Issue : 8 | Page : 1366-1367
Commentary: Tubercular posterior scleritis - Nuances in practice!
Sivaraman Bala Murugan
Uveitis Services, Aravind Eye Hospital, Puducherry, India
|Date of Web Publication||22-Jul-2019|
Dr. Sivaraman Bala Murugan
Uveitis Services, Aravind Eye Hospital, Puducherry - 605 007
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Murugan SB. Commentary: Tubercular posterior scleritis - Nuances in practice!. Indian J Ophthalmol 2019;67:1366-7
Tuberculosis (TB) is an enigmatic disease which can manifest as a pathology affecting any structure of the eye. The diagnosis of TB becomes simple if the diagnostic results are positive and its treatment response is collaborated with the clinical findings. However, the clinical experience of the physician becomes highly significant when the laboratory findings are not straightforward.
The work-up of TB includes detailed anamnesis pertaining to systemic TB and basic investigations of TB like Mantoux test, interferon gamma release assays (IGRAs), and chest imaging. The basic art of correlating Mantoux test with the appropriate tuberculin units as per World Health Organization's recommendations of 5 Tuberculin Units with the systemic inflammatory parameters merits attention. However, as the kits for IGRA are not standardized and validated in the developing world, the recent index-TB guidelines do not mandatorily endorse performing it in all cases of ocular TB. But its utility has to be smartly used when the lesion is close to papillomacular area needing early institution of anti-inflammatory therapy or when the follow-up of the patient is doubtful. This is because IGRA is anin vitro equivalent ofin vivo PPD test (Mantoux test), and oral steroids and anti-inflammatory therapy cannot be immediately started pending the reports from PPD test. IGRA can also be usefully practised when the PPD results can be influenced by previous vaccination. It is highly useful in serpiginoid choroiditis and is not a panacea to the problems in TB diagnostics.
Chest imaging using high-resolution computerized tomogram is increasingly used by sound clinicians as chest X-ray can easily overlook findings in plenty of pulmonary TB by almost 40%. When it effectively rules out the pulmonary TB, it gives the liberty to the treating clinician to use fuller 1 mg/kg dosing of oral steroids. However, it has to be carefully used in borderline cases of both TB and sarcoidosis as a spectrum which is becoming popular in the recent years. Metastasis of systemic TB with parenteral steroids in military TB is a known fact that an astute clinician should remember in practice.
On the contrary, posterior scleritis with high-resolution computed tomography showing nil evidence of pulmonary TB can well be treated using parenteral steroids along with antitubercular drugs in the initial period. This can aid the clinician to aggressively control the inflammation induced by antitubercular drugs and paradoxical worsening. Opinion is divided among experts on the concept of priming with steroids before initiating antitubercular drugs in borderline cases. But what is very crystal clear is that cases which do not fit in the classical diagnostic features of TB or nontuberculous need close monitoring on the treatment response to steroids. If there is worsening of signs, one of the possible options to the treating clinician is to start a trial of antitubercular drugs, especially in the developing world. Truly, the priming of steroids before the actual initiation of antitubercular drugs acts as a blessing in disguise by aiding in a superior final visual outcome provided the treatment response is appropriately titrated and modulated as per needs. The objective parameters to monitor improvement need to be elegantly captured using B-scan, fundus autofluorescence, optical coherence tomogram, and fluorescein angiogram as appropriate. However, it is not a licence to treat all idiopathic cases with trial of antitubercular drugs and neglect the autoimmune and rare causes of posterior scleritis based on the subtle clues from the meticulous evaluation.
In the earlier era, in cases of high suspicion, topical Amikacin with antitubercular drugs along with anti-inflammatory therapy were administered. Few of the authors have excluded ethambutol owing to concerns of drug-induced optic neuropathy. Hence, monitoring of each of the clinical visits with relative afferent pupillary defect, color vision, and central fields testing could be done when the patients are on antitubercular drugs as per the recent guidelines along with liver/renal function tests.
Opinion is divided on the end point of antitubercular treatment in treating tubercular posterior scleritis. It is generally agreed that ocular TB is extrapulmonary and merits a duration more than pulmonary treatment with 6 months alone. Experts have suggested a variable period of more than 6 months to as high as 12 months in scleral TB with an average of 9 months. The take-home message for the clinician is that the straightforward answer of 9 months of antitubercular therapy in ocular TB is an average and needs to be adapted in our day-to-day practice. A rule of thumb is to ensure that inflammation is unequivocally quiescent in the preceding 3 months before stopping the antitubercular therapy. Although it practically sounds very lucid, it is not backed up by a scientific data.
What is elegantly clear in posterior scleritis caused by TB is that anti-inflammatory therapy can worsen the condition if caused by TB, This holds true for the polar form of TB in the recent concept of TB and sarcoid as the two distinct ends of the spectrum of a same disease. The clinician should be clear that shades of different colors of the spectrum do occur in the day-to-day practice similar to a rainbow!
| References|| |
Sharma SK, Ryan H, Khaparde S, Sachdeva KS, Singh AD, Mohan A, et al.
Index-TB Guidelines: Guidelines on extrapulmonary tuberculosis for India. Indian J Med Res 2017;145:448-63.
] [Full text]
Agarwal AM, Dutta Majumder P. Tubercular posterior scleritis: A case report and review of literature. Indian J Ophthalmol 2019;.67:1362-5.
Bansal R, Gupta A, Gupta V, Dogra MR, Bambery P, Arora SK. Role of anti-tubercular therapy in uveitis with latent/manifest tuberculosis. Am J Ophthalmol 2008;146:772-9.
Figueira L, Fonseca S, Ladeira I, Duarte R. Ocular tuberculosis: Position paper on diagnosis and treatment management. Rev Port Pneumol 2017;23:31-8.
Hemady R, Sainz de la Maza M, Raizman MB, Foster CS. Six cases of scleritis associated with systemic infection. Am J Ophthalmol 1992;114:55-62.
Jackson WB, Tabbara KF, Hyndiuk RA. Infections of the Eye. Boston, MA: Little, Brown; 1986. p. 481.
Gupta A, Gupta V, Pandav SS, Gupta A. Posterior scleritis associated with systemic tuberculosis. Indian J Ophthalmol 2003;51:347-9.
] [Full text]
Nanda M, Pflugfelder SC, Holland S. Mycobacterium tuberculosis scleritis. Am J Ophthalmol 1989;108:736-7.
Agrawal R, Gunasekeran DV, Raje D, Agarwal A, Nguyen QD, Kon OM, et al.
Global variations and challenges with tubercular uveitis in the collaborative ocular tuberculosis study. Invest Ophthalmol Vis Sci 2018;59:4162-71.