Ultra-Wide Field Imaging in Paradoxical Worsening of Tubercular Multifocal Serpiginoid Choroiditis after the Initiation of Anti-Tubercular Therapy

Paradoxical Reaction in Intraocular Tuberculosis: Report of Three Cases

PURPOSE

To present paradoxical reaction (PR) in three cases with ocular tuberculosis (OTB) treated with antitubercular therapy (ATT), highlighting diagnostic challenges and treatment strategies.

METHODS

We retrospectively reviewed clinical records of three OTB patients presenting with paradoxical worsening after ATT initiation at two Brazilian university hospitals.

RESULTS

The patients (2 males, 1 female) experienced worsening clinical presentation (increased inflammation, vision loss) within two to three weeks after initiating ATT. One patient who was HIV-positive with unilateral multifocal choroiditis developed PR soon after starting antiretroviral therapy. The second patient presented with a choroidal tuberculoma in both eyes. The third patient also had multifocal choroiditis and developed a localized choroidal elevation with a double-layer sign as a manifestation of PR. All patients were maintained on ATT therapy in association with corticosteroids and experienced improvement of inflammatory signs.

CONCLUSION

This case series highlights the potential for PR in OTB patients. Close monitoring and prompt therapeutic adjustments are crucial for management success.

The immune response in tubercular uveitis and its implications for treatment: From anti-tubercular treatment to host-directed therapies

Tubercular uveitis (TB-uveitis) remains a conundrum in the uveitis field, which is mainly related to the diverse clinical phenotypes of TB-uveitis. Moreover, it remains difficult to differentiate whether Mycobacterium tuberculosis (Mtb) is present in the ocular tissues, elicits a heightened immune response without Mtb invasion in ocular tissues, or even induces an anti-retinal autoimmune response. Gaps in the immuno-pathological knowledge of TB-uveitis likely delay timely diagnosis and appropriate management. In the last decade, the immunopathophysiology of TB-uveitis and its clinical management, including experts' consensus to treat or not to treat certain conditions with anti-tubercular treatment (ATT), have been extensively investigated. In the meantime, research on TB treatment, in general, is shifting more toward host-directed therapies (HDT). Given the complexities of the host-Mtb interaction, enhancement of the host immune response is expected to boost the effectiveness of ATT and help overcome the rising burden of drug-resistant Mtb strains in the population. This review will summarize the current knowledge on the immunopathophysiology of TB-uveitis and recent advances in treatment modalities and outcomes of TB-uveitis, capturing results gathered from high- and low-burden TB countries with ATT as the mainstay of treatment. Moreover, we outline the recent progress of HDT development in the pulmonary TB field and discuss the possibility of its applicability to TB-uveitis. The concept of HDT might help direct future development of efficacious therapy for TB-uveitis, although more in-depth research on the immunoregulation of this disease is still necessary.

Stepwise approach for fundus imaging in the diagnosis and management of posterior uveitis

An array of retinochoroid imaging modalities aid in comprehensive evaluation of the immunopathological changes in the retina and choroid, forming the core component for the diagnosis and management of inflammatory disorders such as uveitis. The recent technological breakthroughs have led to the development of imaging platforms that can evaluate the layers of retina and choroid and the structural and functional alteration in these tissues. Ophthalmologists heavily rely on imaging modalities such as dye-based angiographies (fluorescein angiography and indocyanine green angiography), optical coherence tomography, fundus autofluorescence, as well as dye-less angiography such as optical coherence tomography angiograph,y for establishing a precise diagnosis and understanding the pathophysiology of the diseases. Furthermore, these tools are now being deployed with a 'multimodal' approach for swift and accurate diagnosis. In this comprehensive review, we outline the imaging platforms used for evaluation of posterior uveitis and discuss the organized, algorithmic approach for the assessment of the disorders. Additionally, we provide an insight into disease-specific characteristic pathological changes and the established strategies to rule out disorders with overlapping features on imaging.

Tubercular serpiginous choroiditis

Tubercular association with serpiginous choroiditis, also called ‘serpiginous-like choroiditis’ or ‘multifocal serpiginoid choroiditis’ (MSC) is reported from world over, especially from endemic countries. Though the exact mechanism is not yet clear, a direct or indirect infectious trigger by Mycobacterium tuberculosis (MTB) is believed to cause choroiditis.

The link of immune mechanisms with ocular inflammation caused by MTB is emerging, and has been supported by both experimental and human data. The molecular and histopathological findings of tubercular serpiginous-like choroiditis have been demonstrated in clinicopathological reports, as well as in animal models. Young to middle-aged healthy males are more frequently affected. The choroiditis lesions of tubercular serpiginous-like choroiditis evolve as multifocal lesions, affecting the retinal periphery as well as posterior pole. They begin as discrete lesions, and spread in a serpiginoid pattern to become confluent. Fundus imaging including autofluorescence is extremely helpful in monitoring patients for response to therapy. Its diagnosis is essentially clinical. Corroborative evidence is obtained by a positive tuberculin skin test, or a positive QuantiFERON-TB Gold (Cellestis, Carnegie, Victoria, Australia) test, and/or radiological (chest X-ray or chest CT scan) evidence of TB elsewhere in the body. Systemic corticosteroids are the mainstay of therapy to control active inflammation, while ATT helps to reduce recurrence of inflammatory attacks. Immunosuppressive agents are indicated in cases with relentless progression, paradoxical worsening, or recurrent choroiditis.

Automated lesion segmentation and quantification for prediction of paradoxical worsening in patients with tubercular serpiginous-like choroiditis

To develop and evaluate a fully automated pipeline that analyzes color fundus images in patients with tubercular serpiginous-like choroiditis (TB SLC) for prediction of paradoxical worsening (PW). In this retrospective study, patients with TB SLC with a follow-up of 9 months after initiation of anti-tubercular therapy were included. A fully automated custom-designed pipeline was developed which was initially tested using 12 baseline color fundus photographs for assessment of repeatability. After confirming reliability using Bland–Altman plots and intraclass correlation coefficient (ICC), the pipeline was deployed for all patients. The images were preprocessed to exclude the optic nerve from the fundus photo using a single-shot trainable WEKA segmentation algorithm. Two automatic thresholding algorithms were applied, and quantitative metrics were generated. These metrics were compared between PW + and PW- groups using non-parametric tests. A logistic regression model was used to predict probability of PW for assessing binary classification performance and receiver operator curves were generated to choose a sensitivity-optimized threshold. The study included 139 patients (139 eyes; 92 males and 47 females; mean age: 44.8 ± 11.3 years) with TB SLC. Pilot analysis of 12 images showed an excellent ICC for measuring the mean area, intensity, and integrated pixel intensity (all ICC > 0.89). The PW + group had significantly higher mean lesion area (p = 0.0152), mean pixel intensity (p = 0.0181), and integrated pixel intensity (p < 0.0001) compared to the PW- group. Using a sensitivity optimized threshold cut-off for mean pixel intensity, an area under the curve of 0.87 was achieved (sensitivity: 96.80% and specificity: 72.09%). Automated calculation of lesion metrics such as mean pixel intensity and segmented area in TB SLC is a novel approach with good repeatability in predicting PW during the follow-up.

Clinical and Imaging Factors Associated With the Outcomes of Tubercular Serpiginous-like Choroiditis

PURPOSE

To analyze baseline clinical and imaging risk factors associated with poor outcome in patients with tubercular serpiginous-like choroiditis (TB SLC).

DESIGN

Retrospective clinical study.

METHODS

Charts and fundus photographs of consecutive patients with active TB SLC seen at a single tertiary referral center with 6 months follow-up after initiation of treatment were reviewed. Logistic mixed models were performed to determine the clinical and imaging factors associated with the response to therapy, including the opacity of choroiditis graded according to a 3-point scale.

RESULTS

This study included 203 eyes of 183 patients with active TB SLC. Poor initial best-corrected visual acuity (BCVA) and foveal and optic disc involvement were associated with poor response to therapy at 6 months (odds ratio [OR] 4.489, 95% confidence interval [CI]: 1.92-10.47; P = .001; OR 2.892, 95% CI: 1.23-6.81; P = .015; OR 11.633, 95% CI: 3.17-42.71; P < .001, respectively). The high opacity grades (2 and 3) were also associated with poor outcomes OR 9.541; 95% CI: 2.94-30.91; P = .001). Poor baseline BCVA and high grade of opacity of the lesions were the composite risk factors for paradoxical worsening of TB SLC (OR 7.555, 95% CI: 1.78-32.02; P = 0.006; OR 7.434, 95% CI: 1.34-41.18; P =0.021, respectively).

CONCLUSIONS

TB SLC with higher grades of lesion opacity at baseline may be associated with greater risk of poor therapeutic response and paradoxical worsening. Grading of baseline lesion opacity may be used in future prospective studies to predict the biological behavior of the lesions and may serve as a guide to therapeutic interventions.

Ocular tuberculosis: Where are we today?

Diagnosis and management of ocular tuberculosis (OTB) poses a significant challenge. Mixed ocular tissue involvement and lack of agreement on best practice diagnostic tests together with the global variations in therapeutic management contributed to the existing uncertainties regarding the outcome of the disease. The current review aims to update recent progress on OTB. In particular, the Collaborative Ocular Tuberculosis Study (COTS) group recently standardized a nomenclature system for defining clinical phenotypes, and also proposed consensus guidelines and an algorithmic approach for management of different clinical phenotypes of OTB. Recent developments in experimental research and innovations in molecular diagnostics and imaging technology have provided a new understanding in the pathogenesis and natural history of the disease.

Ocular Toxocariasis: Beyond Typical Patterns through the New Imaging Technologies

PURPOSE

To report five cases of ocular Toxocariasis (OT) in which ultrawide-field (UWF) imaging was helpful in diagnosis and assessment. OT is an underdiagnosed condition triggered by the ocular invasion of Toxocara larvae. Typical features are peripheral granuloma or endophthalmitis.Methods: A retrospective case series of 10 outpatients were studied by complete ophthalmologic examination and complementary tests. UWF retinal imaging, fundus autofluorescence (FAF) and spectral-domain optical coherence tomography (SDOCT) were retrospectively analyzed. Five patients with suspected OT were included.Results: UWF imaging and FAF was able to detect all retinal lesions in a single rapid capture. Two patients showed positive serology for Toxocara. An image suggesting the larva in the vitreous cavity was shown in one patient. Antihelmintic 15 treatment along with steroids was prescribed in two patients.Conclusion: UWF imaging and SDOCT provide a more efficient approach and follow-up in OT, raising final standards of care.

Yellow Subretinal Lesions following Initiation of Antituberculosis Therapy in A Tubercular Choroidal Granuloma: A Sign of Paradoxical Worsening?

PURPOSE

To describe the presentation and management of atypical subretinal lesions following initiation of antitubercular therapy for a tubercular choroidal granuloma.

CASE REPORT

An 18-year-old female was diagnosed with choroidal granuloma and shallow exudative retinal detachment in the left eye. Biopsy from a cervical lymph node was positive for tuberculosis. She was treated with antitubercular therapy (ATT) and oral steroids. After one week of therapy exudative detachment increased markedly and discrete yellowish-white subretinal lesions appeared first in the inferior periphery, then temporally and later involved the macula leading to a drop in visual acuity. A diagnosis of paradoxical worsening was considered and she was managed with a higher dose of oral corticosteroids, intravitreal methotrexate and intravitreal ranibizumab. The granuloma healed and the subretinal lesions as well as exudative detachment gradually resolved with improvement in visual acuity.

CONCLUSION

Subretinal yellow-white lesions may develop as a paradoxical response to ATT.

Advances in imaging of uveitis

Advances in multimodal imaging have significantly contributed to the management of many uveitis diseases in recent years. The most significant developments include the use of optical coherence tomography to obtain a more accurate and reproducible assessment of ocular inflammation, the application of optical coherence tomography angiography in choroiditis and retinal vasculitis, new possibilities for studying vitritis with ultrawide field imaging, and the most recent applications of fundus autofluorescence in uveitis. In this review, we provide an overview of the most significant advances in multimodal imaging of uveitis achieved in recent years.

Paradoxical reactions in ocular tuberculosis

Paradoxical reactions following initiation of anti-tubercular therapy have been documented most often in extrapulmonary tuberculosis. A combination of factors such as delayed hypersensitivity, decreased suppressor mechanisms, and an increased response to mycobacterial antigens mediated by the host’s immune system have been implicated in the development of these reactions. Similar worsening in patients with ocular tuberculosis while on treatment has been described. It is therefore important for the clinician to be aware of this occurrence, as prompt recognition and timely institution of corticosteroids and immunosuppressants can lead to restoration of vision. In these patients, an alteration or discontinuation of anti-tubercular therapy may not be indicated.

Enigma of serpiginous choroiditis

Serpiginous choroiditis (SC) is an asymmetrically bilateral inflammation of the choroid that leads to loss of choriocapillaris atrophy or loss of overlying retinal pigment epithelium. Over the last few decades, SC has passed through a long evolution of nomenclature, etiologies and morphological variations. Initially diagnosed in patients with tuberculosis and syphilis, SC was predominantly considered as autoimmune process. With the advancement of molecular diagnosis, a new aspect of infectious subtypes of SC has emerged out. The terminologies such as serpiginous-like choroiditis (SLC) and multifocal serpiginoid choroiditis are now used to denote the subtypes of SC which are associated with infectious etiologies especially tuberculosis. In a country endemic for tuberculosis such as India, it is very important to differentiate between classic SC and SLC before initiating aggressive immunomodulatory therapy. Also, management of paradoxical worsening of the clinical condition with antitubercular treatment is another challenge in SLC and ophthalmologists should be aware of such situations. With advent of newer imaging modalities, monitoring the patient with choroiditis and identification of complications such as choroidal neovascular membrane have become much easier. This article aims to review the existing literature on SC with a special emphasis on management of SC and SLC.

Infectious uveitis: an Asian perspective

Several intraocular infections can present with protean manifestations posing major diagnostic and management challenges. Infections such as tuberculosis, dengue and chikungunya fever have continued to remain major endemic diseases that are associated with uveitis in the Asia Pacific region. These entities often require a high index of clinical suspicion and laboratory analysis including assays of ocular fluids and/or tissues for confirmation of the diagnosis. Infectious uveitis caused by tuberculosis, dengue and chikungunya can present with characteristic clinical features and imaging findings on ancillary investigations; that may provide clue to the early diagnosis. Use of modern imaging modalities such as enhanced-depth imaging optical coherence tomography, optical coherence tomography angiography and ultra-wide field fundus photography greatly aid in the evaluation of these conditions. In the current review, we have discussed the epidemiology, clinical phenotypes, imaging characteristics, diagnosis and management of uveitis caused by tuberculosis, dengue and chikungunya.