Factors influencing polymerase chain reaction outcomes in patients with clinically suspected ocular tuberculosis

Orbital tuberculosis: a case report and update on the role of imaging in treatment

Orbital tuberculosis is a manifestation of extra-pulmonary tuberculosis that is challenging to diagnose and treat. Here, we describe the pivotal role of serial imaging in the diagnosis and treatment of orbital tuberculosis. A 28-year-old male presented with recurrent right upper eyelid swelling and a supraduction deficit associated with a firm painless orbital mass, seen on initial computed tomography to be an extensive superomedial lesion producing mass effect. Biopsy revealed a tuberculosis-like granulomatous inflammation, which, coupled with a positive QuantiFERON gold test, led to empiric anti-tuberculin treatment. Serial radiologic imaging following initiation of treatment showed progressive reduction in mass size, supporting the diagnosis and determining the length of treatment. This rare case demonstrates the utility of serial radiologic exams in the diagnosis and treatment of orbital tuberculosis.

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.

BTS clinical statement for the diagnosis and management of ocular tuberculosis

The BTS clinical statement for the diagnosis and management of ocular tuberculosis (TB) draws on the expertise of both TB and and ophthalmic specialists to outline the current understanding of disease pathogenesis, diagnosis and management in adults. Published literature lacks high-quality evidence to inform clinical practice and there is also a paucity of data from animal models to elucidate mechanisms of disease. However, in order to improve and standardise patient care, this statement provides consensus points with the currently available data and agreed best practice.

The Utility of Nonroutine Intraocular Fluid Polymerase Chain Reaction for Uveitis in Indonesia

Purpose

To investigate the utility of nonroutine polymerase chain reaction analysis of intraocular fluid to guide the diagnosis of infectious uveitis.

Patients and Methods

A retrospective cohort study was conducted by reviewing medical record data from intraocular fluid samples of uveitis patients who underwent single-plex real-time polymerase chain reaction analysis at the Department of Ophthalmology, Faculty of Medicine, Universitas Indonesia - Cipto Mangunkusumo Kirana Eye Hospital between January 2014 and December 2018.

Results

The positivity rate of nonroutine polymerase chain reaction analysis was 17.2%. The vitreous sample tended to show a higher positive outcome (28.6%) than the aqueous sample (16.2%), even though the outcome was not statistically significant. Mycobacterium tuberculosis and Toxoplasma gondii were the most frequently observed microorganisms in the polymerase chain reaction analysis among uveitis patients in our setting. The duration of symptoms, type of sample fluid (aqueous/vitreous), or presence of anterior chamber cells ≥2 were not significantly associated with polymerase chain reaction positivity (p > 0.05).

Conclusion

Nonroutine polymerase chain reaction analysis of intraocular fluid among a cohort of Indonesian patients demonstrated low positivity. The sensitivity and specificity of nonroutine single-plex polymerase chain reaction could not be estimated due to limitations such as lost to follow-up patients and incomplete monitoring data. The use of multiplex polymerase chain reaction in the future may be beneficial in our setting.

Treatment Outcome of Tubercular Uveitis in a High TB and HIV Setting: A Prospective Cohort Study

Purpose

To determine the time to resolution of inflammation in tubercular uveitis (TBU) cases on standard anti-tubercular treatment. Sub-analysis of time to resolution according to HIV status was also performed.

Patients and Methods

A prospective cohort study of presumed idiopathic uveitis cases >18 years underwent the tuberculin skin test, QuantiFERON-TB Gold test, and ocular tuberculosis (TB) polymerase chain reaction test. Adult TBU cases were treated with standard anti-tubercular therapy (and corticosteroids) for 9 months. Cases were followed-up for resolution of inflammation at 1.5, 3, 6, 9, 12 and 15 months post-diagnosis. Outcome measure was resolution of inflammation on ≤10 mg oral prednisone per day.

Results

Seventy-nine presumed idiopathic uveitis cases were enrolled in the study, 49 (62%) were diagnosed with TBU. The mean (SD) age of TBU cases at diagnosis was 41.8 (13.4) years. Using a multilevel mixed effects model, resolution was achieved at 6 months in the TBU cases (OR = 1.21; 95% CI, 1.03-1.41; P = 0.017). Using generalized estimating equations, resolution was also achieved at 6 months in the TBU cases (OR = 1.21; 95% CI, 1.05-1.39; P = 0.008). The HIV-positive cases (OR = 1.62; 95% CI, 1.13-2.31; P = 0.008) and the HIV-negative cases (OR = 1.25; 95% CI, 1.06-1.48; P = 0.009) achieved resolution at 9 months.

Conclusion

Resolution of inflammation in TBU cases on anti-tubercular treatment with corticosteroids was achieved at 6 months and maintained throughout the study. Our study suggests a minimum of 6 months treatment is required for significant resolution. Resolution of inflammation in HIV-positive and HIV-negative TBU cases needs to be further explored.

Tubercular DNA PCR of ocular fluids and blood in cases of presumed ocular tuberculosis: a pilot study

Background:

The definitive diagnosing of ocular tuberculosis (TB) is difficult; therefore, there is a need of better understanding of investigating TB DNA in presumed ocular TB patients.

Objectives:

The aim of this study is to correlate tubercular DNA PCR of aqueous/vitreous and blood in cases of presumed ocular TB.

Design:

A prospective study.

Methods:

DNA was extracted from aqueous of cases of choroidal tuberculoma (group 1) and serpiginous choroiditis (group 2) and from vitreous of cases of vasculitis (group 3) and macular hole/retinal detachment (group 4). Gel-based PCR and real-time PCR amplification were performed using IS6110 primer on ocular fluids. The same was also performed on the blood samples of cases in which tubercular DNA was detected in the ocular fluids.

Results:

Overall, 31 cases were analysed in our study. Tubercular DNA was detected in ocular fluids of seven cases: group 1, two cases (67%); group 2, one case (17%); group 3, four cases (27%); and no case of group 4. Blood samples of six of these seven patients were positive for tubercular DNA. Of these six patients, four had evidence of systemic TB and were on ATT. Two cases had no evidence of active systemic TB, yet PCR was positive from blood and ocular fluids.

Conclusion:

Tubercular DNA detected from ocular fluids may possibly be due to bystander DNA and may not indicate primary ocular tubercular infection. Thus, caution must be exercised prior to labelling a case of uveitis as being tubercular based on the results of molecular assays on ocular fluids alone. The results of PCR on ocular fluids should be correlated with PCR on blood and systemic findings.

Global prevalence and clinical outcomes of tubercular uveitis: a systematic review and meta-analysis

Tubercular uveitis (TBU) is an inflammation/infection of the eye secondary to Mycobacterium tuberculosis infection. The difficulty in making the diagnosis has resulted in variable prevalence and clinical response rates. We aimed to determine the global prevalence of TBU in uveitis patients stratified by TB high-burden countries (HBCs) and non-HBCs and by geographic regions and the clinical response of TBU to antitubercular treatment We performed a systematic review and meta-analysis of TBU studies published in PubMed, Scopus and EMBASE, up to June 30, 2020. A random effects model was used for all meta-analyses. Of 5,018 articles identified, 70 prevalence studies (65,607 uveitis and 3,166 TBU cases) and 18 clinical outcome studies (1,570 TBU cases; 1,304 responded to anti-tubercular therapy [ATT]) were analyzed. The overall weighted prevalence of TBU was 4.0% (95% CI, 3-5); in TB HBCs it was 7.0% (95% CI, 5-11), non-HBCs 3.0% (95% CI, 2-4), and sub-Saharan Africa 11.0% (95% CI, 8-15). The overall weighted clinical response was 82.0% (95% CI, 75-89). Despite the difficulty in diagnosing TBU, the prevalence is expectantly higher in HBCs, and sub-Saharan Africa and the clinical outcome is poor. Standardization of diagnostic criteria and ATT is warranted in future cohort studies.

Diagnosis of osteoarticular tuberculosis: multi-targeted loop-mediated isothermal amplification assay versus multiplex PCR

Aim: Diagnosis of osteoarticular tuberculosis (OATB) is quite challenging and there is an urgent need to design a prompt and precise diagnostic test. Methods: We developed a multi-targeted loop-mediated isothermal amplification (LAMP) assay using mpt64 (Rv1980c) and pstS1 (Rv0934) targets for the detection of Mycobacterium tuberculosis in OATB patients. Results: The sensitivities of 100 and 82.4% were obtained in confirmed (n = 10) and suspected (n = 57) OATB cases, respectively by multi-targeted LAMP with a specificity of 96.9% (n = 33). Moreover, the sensitivities attained by multi-targeted LAMP in total OATB cases were significantly higher (p < 0.05-0.01) than multiplex PCR (mpt64 + pstS1) and GeneXpert assay. Conclusion: Our LAMP is simple, reliable and cost-effective method, which may develop into an attractive diagnostic kit for early detection of OATB cases.

The diagnostic value of polymerase chain reaction for ocular tuberculosis diagnosis in relation to antitubercular therapy response: a meta-analysis

BACKGROUND

Polymerase chain reaction (PCR) is currently considered the method of choice for diagnosing ocular tuberculosis. However, the sensitivity and specificity of PCR using ocular samples remain uncertain. Our meta-analysis aimed to review the diagnostic accuracy of PCR testing in confirming ocular tuberculosis, with responses to antitubercular therapy (ATT) as reference indices.

METHODS

A systematic literature search of the PubMed, EBSCOHost, Scopus, and Google Scholar databases was performed using the standardized PRISMA guideline. Observational studies reporting both PCR MTb positivity and ATT response were included. Meta-analysis was performed to estimate the pooled positivity rate, sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratios (DOR), and summary receiver operating curves (SROC).

RESULTS

The pooled positivity rate for PCR MTb was 0.55 (95% CI 0.44-0.67). The overall sensitivity and specificity were 88% (95% CI 83-92) and 71% (95% CI 60-80), respectively. The pooled DOR was 12.15 (95% CI 5.55-26.62). The area under the SROC was 0.83.

CONCLUSIONS

The diagnostic accuracy of PCR Mtb is not sufficient for use as a benchmark for ocular TB diagnosis routinely based on ATT response. A negative result may help avoid prescribing unnecessary ATT in dilemmatic cases.

Extraocular spread following evisceration for rapidly progressive intraocular tuberculosis

We describe a case of right eye tubercular (TB) panuveitis with corneal involvement where repeated intraocular sampling was unsuccessful. Finally, evisceration and histopathology of ocular tissue confirmed the diagnosis of ocular tuberculosis. A chest X-ray showed signs of pulmonary TB. The patient was lost to follow-up but reported 2 months later with the right eyelid margin nodules with surface ulceration. Both eyelid and pulmonary lesions were resolved with anti-TB therapy.

Recent Advances in Diagnosis and Treatment of Infectious Uveitis Prevalent in Asia-Pacific Region

ABSTRACT

The role of infections in intraocular inflammation is being increasingly recognized across the world. The Asia-Pacific region, being the single largest and most populous geographical entity on the planet, is home to a wide variety of such infections. Not surprisingly, there has been an explosion in the literature on infectious uveitis emerging from Asia-Pacific countries. In this review, we have covered recent advances in the diagnosis, treatment, and pathogenesis of common forms of infectious uveitis from the Asia-Pacific region. Much of the literature is focussed on the diagnosis of these infections by clinical criteria and laboratory investigations. There has also been an increased emphasis on the application of newer modes of ocular imaging and understanding pathomechanisms of ocular inflammation in these infections. Together this research has significantly improved our understanding of the diagnosis and management of infectious uveitis.

Endogenous Tuberculous Endophthalmitis and Panophthalmitis: A Systematic Review of Case Reports and Case Series

Purpose

To systematically review the characteristics of patients with endogenous tuberculous (TB) endophthalmitis and panophthalmitis in an effort to help clinicians with diagnosis and treatment.

Patients and Methods

We conducted a systematic literature search in MEDLINE/PubMed, EMBASE and Web of Science from inception to August 2020. References and abstracts were screened independently by two authors. Included studies were case reports and case series reporting endogenous TB endophthalmitis and panophthalmitis secondary to Mycobacterium tuberculosis complex (MTBC). Available-case analysis was employed to handle missing data.

Results

A total of 1343 articles were found using the search strategy. Following abstract screening, 51 articles were selected for full text-review, from which 26 were deemed eligible for inclusion in the study. Forty-four cases from 26 articles were included in the quantitative analysis. The median age of presentation was 29.5 (range: 1 to 81), and 11/44 patients (25.0%) were pediatric. Immunosuppression was seen in 9/36 cases (25.0%). Most patients (24/38, 63.2%) had no prior history of tuberculosis. Systemic symptoms were absent in half of the patients (16/32, 50.0%). Visual acuity was poor, with 23/27 cases (85.2%) being 20/200 or worse at presentation. Poor organ and visual outcomes were reported: 36/43 cases (83.7%) resulted in enucleation/evisceration or exenteration. Intraocular tumors were suspected in 5/34 cases (14.7%). Pulmonary tuberculosis was seen in 15/35 cases (42.8%), and miliary tuberculosis was seen in 7/35 cases (20.0%). The earliest source of TB diagnosis was through histopathologic specimen after eye removal in 32/44 cases (72.7%), vitreous specimen in 6/44 cases (13.6%) and aqueous specimen in 3/44 cases (6.8%).

Conclusion

TB endophthalmitis is a rare and sight-threatening manifestation of ocular tuberculosis. It can occur in apparently healthy individuals and can mimic intraocular tumors and other infectious etiologies. Diagnosis remains a significant challenge, which, often delayed, leads to profound visual loss. Early detection and treatment of intraocular tuberculosis may be associated with better ocular and systemic outcomes.

Pathogenesis of ocular tuberculosis: New observations and future directions

Ocular tuberculosis (OTB) encompasses all forms of intra- and extra-ocular inflammation associated with Mycobacterium tuberculosis (Mtb) infection. However, the organism is rarely found in ocular fluid samples of diseased eyes, rendering the pathomechanisms of the disease unclear. This confounds clinical decision-making in diagnosis and treatment of OTB. Here, we critically review existing human and animal data related to ocular inflammation and TB pathogenesis to unravel likely pathomechanisms of OTB. Broadly there appear to be two fundamental mechanisms that may underlie the development of TB-associated ocular inflammation: a. inflammatory response to live/replicating Mtb in the eye, and b. immune mediated ocular inflammation induced by non-viable Mtb or its components in the eye. This distinction is significant as in direct Mtb-driven mechanisms, diagnosis and treatment would be aimed at detection of Mtb-infection and its elimination; while indirect mechanisms would primarily require anti-inflammatory therapy with adjunctive anti-TB therapy. Further, we discuss how that most clinical phenotypes of OTB likely represent a combination of both mechanisms, with one being predominant than the other.

Clinicopathological, Microbiological and Polymerase Chain Reaction Study in a Case of Nocardia Scleritis

PURPOSE

To describe the clinicopathological, microbiological and polymerase chain reaction (PCR) study in a case of Nocardia scleritis.

METHODS

A retrospective chart review.

RESULTS

A 32-year old male presented with pain, redness and nodular scleral swelling in the left eye for the past two and a half months following an accidental rice powder injury. He was earlier diagnosed to have tubercular scleritis and treated with oral steroids and anti-tubercular therapy. A repeat scleral biopsy on histopathological examination showed granulomatous inflammation. Microbiological investigations revealed the growth of Gram +ve branching filamentous bacilli in culture suggestive of Nocardia sp. PCR based DNA sequencing identified the bacterium as Nocardia cyriacigeorgica. The patient responded to topical fortified amikacin (2.5%), fortified cefuroxime, oral sulfamethoxazole and trimethoprim with complete healing of scleritis.

CONCLUSIONS

Nocardia scleritis can be a diagnostic challenge for clinicians. Newer molecular techniques along with histopathological and microbiological investigations can clinch the diagnosis.

Global Variations and Challenges With Tubercular Uveitis in the Collaborative Ocular Tuberculosis Study

Purpose

The aim of this study was to examine regional variation management practices and outcomes for tubercular uveitis (TBU).

Methods

In this retrospective multinational cohort study, patients from 25 international eye care centers diagnosed with TBU with a minimum follow-up of 1 year were included. The geographic variation in treatment outcomes on survival analysis in patients with TBU were analyzed. Treatment failure is defined as a persistence or recurrence of inflammation within 6 months of completing antitubercular therapy, the inability to taper oral corticosteroids to less than 10 mg/d or topical corticosteroid drops to less than 2 drops daily, and/or recalcitrant inflammation necessitating corticosteroid-sparing immunosuppressive therapy.

Results

Records of 945 patients (1485 eyes) with TBU were analyzed. The mean age was 41.3 ± 15.0 years (range, 4-90 years), with more males (52.9%, n = 500/945) and predominant Asian ethnicity (74.4%, n = 690/927). Most patients had no symptoms (92.0%, n = 655/712) or history (76.7%, n = 604/787) suggestive of pulmonary tuberculosis (TB). Some patients had evidence of inactive pulmonary TB on chest X-rays (26.9%, n = 189/702) or chest computed tomography (68.6%, n = 109/159). Patients with western geographic origin (log-rank = 6.47, P = 0.010), African or Hispanic ethnicity (log-rank = 19.9, P < 0.001), and positive immigrant status (log-rank = 4.89, P = 0.027) had poorer survival outcomes.

Conclusions

This is a first-ever multinational analysis of TBU that highlights regional differences in treatment outcomes for this elusive form of extrapulmonary TB. Our findings will help in the design of future collaborative studies together with internists to develop best practice guidelines for this early opportunity to address TB infection and strategies to target at-risk groups such as immigrants.

Tuberculosis and other causes of uveitis in Indonesia

PurposeThe purpose of this study is to assess the causes of uveitis in Indonesia and determine the importance of tuberculosis (TB) as a cause of uveitis.Patients and methodsProspective cohort study examining 146 consecutive new human immunodeficiency virus-negative patients with active uveitis between June 2014 and May 2015. We assessed the anatomic locations and specific causes of uveitis, as well as associations with infectious and non-infectious systemic diseases. We determined the prevalence of positive QuantiFERON Tb Gold test (QFT) results in Indonesian patients with uveitis and calculated the number of patients with active systemic TB.ResultsPosterior and panuveitis were the most common anatomic entities (38% each). Infections represented the most frequent cause of uveitis (33%); the most prevalent were toxoplasmosis (19%) and active systemic TB (8%). The majority of patients were QFT positive (61%). A specific diagnosis could not be established in 45% of the patients. At first presentation to the ophthalmologist, the majority of patients (66%) had a visual acuity of less than finger counting at 3 m and already exhibited various complications of uveitis. When classifying the QFT-positive patients with unexplained uveitis into a TB-related group, the percentage of 'TB-associated' uveitis cases increased from 8-48%. Highly elevated QFT levels were observed in patients with uveitis of unknown cause and no signs of active systemic TB.ConclusionsIn Indonesia, infectious uveitis was the most common type of uveitis and the leading causes consisted of toxoplasmosis and TB. The association observed between highly elevated QFT results and uveitis of otherwise unexplained origins indicates that a link exists between the latent TB infection and the development of uveitis.

MTBDRplus for the rapid diagnosis of ocular tuberculosis and screening of drug resistance

PurposeTimely diagnosis of intraocular tuberculosis (IOTB) along with detection of drug resistance can save many eyes from visual impairment. With the growing incidence of IOTB and rising drug resistance, a reliable diagnostic platform for simultaneous detection of the agent and mutated gene is urgently needed. The MTBDRplus assay was evaluated directly on vitreous fluid samples for the same.Patients and methodsIn a prospective study, The MTBDRplus assay was performed on 127 vitreous fluid samples (77 'study group' comprising cases of presumed ocular tuberculosis and 50 'control group' cases of disease controls (n=25) and non-uveitic controls (n=25)). All samples positive by MTBDRplus assay were subjected to gene sequencing to confirm the mutations for rifampicin and isoniazid resistance.ResultsThe MTBDRplus assay produced a sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 36.36%, 100%, 100%, and 50.50%, respectively, for the detection of IOTB. Among the 28 cases from study group that were positive by MTBDRplus assay, rifampicin resistance was reported in six and isoniazid resistance in two cases. On sequencing of rpoB and katG gene, one case of false rifampicin-resistant by MTBDRplus was found. The other resistant isolates showed concordant mutations between MTBDRplus assay and sequencing.ConclusionThe MTBDRplus assay is an effective tool for the rapid diagnosis of IOTB along with detection of drug resistance, thereby improving the outcome in IOTB.

Clinical Outcomes of Adjunctive Sustained-Release Intravitreal Dexamethasone Implants in Tuberculosis-Associated Multifocal Serpigenoid Choroiditis

PURPOSE

To analyze the safety and efficacy of sustained-release intravitreal dexamethasone implant (Ozurdex) in management of TB-associated multifocal serpiginoid choroiditis (MSC).

METHODS

Retrospective review of TB-associated MSC patients, treated with anti-TB therapy (ATT) and adjunctive intravitreal Ozurdex.

RESULTS

Nine eyes of six patients were included. Four patients required Ozurdex implant for progressive or new lesions following ATT and two for additional systemic contraindications to corticosteroids - hyperglycemia and uncontrolled hypertension, respectively. The mean time to resolution was 9.17 ± 7.71 weeks. The mean follow-up post-injection was 13.11 ± 6.05 months (median 12 months [range 6-24.5 months]). Only one of nine eyes developed recurrent MSC lesions and this was attributed to possible autoimmune etiology. Two eyes (22.2%) developed steroid-induced glaucoma - one required implant removal.

CONCLUSIONS

Sustained-release intravitreal dexamethasone is a safe and efficacious adjunctive anti-inflammatory therapy for TB-associated MSC patients with contraindication for systemic corticosteroids or requiring supplemental anti-inflammatory therapy.

Orbital tuberculosis: Clinicopathological correlation and diagnosis using PCR in formalin-fixed tissues

This article describes the clinicopathological correlation and challenges encountered in the diagnosis of orbital tuberculosis (TB). Retrospective, interventional case series. A chart review of six patients who underwent biopsy for an orbital mass between January 2012 and December 2013 was performed. Institutional review board approval was obtained for the study. Clinical, radiological, and laboratory findings were documented, and response to antitubercular therapy (ATT) was noted. Age at presentation ranged from 18 to 64 years and duration of complaints varied from 2 weeks to 2 months. Pain, redness, and swelling with an orbital mass on computerized tomography (CT) were the common features. None of the patients was clinically suspected to have orbital TB at presentation. History of prior contact with a patient of TB and history of prior TB were present in one case each. Chest radiography (CXR) showed pulmonary consolidation in one case. Tuberculin skin test (TST) readings ranged from nonreactive to 23 mm. The presence of sputum acid fast bacilli (AFB) was tested in three cases and was negative. Polymerase chain reaction (PCR) for MPB64 gene was positive in all six cases. All cases responded to ATT. Clinical presentation of orbital TB can be variable and can simulate conditions like inflammatory disease and malignancy. Biopsy with histopathology plays a key role in diagnosis. Supportive laboratory investigations are necessary to clinch the diagnosis in cases where histopathology is suggestive of TB. In this regard, PCR for Mycobacterium tuberculosis (MTB) on tissue biopsy specimens may be a sensitive diagnostic tool.

Clinical Features and Prognostic Factors in Presumed Ocular Tuberculosis

PURPOSE

To characterize the clinical features in patients with presumed ocular tuberculosis (TB) and determine prognostic factors of visual outcomes and complications in this disease.

MATERIAL AND METHODS

Retrospective case series of 35 patients (29 females, 6 males) with presumed ocular TB from referral centers in Chile and Spain between 2002 and 2012. Medical records were reviewed, and data regarding clinical features, complications, best-corrected visual acuity (BCVA), duration of disease, extraocular manifestations, and therapy were retrieved. Prognostic factors for low vision (BCVA 20/50 or less), legal blindness (BCVA 20/200 or less), and complications (cataract, glaucoma, and macular lesion) were evaluated. To calculate correlations, we used Spearman's rank correlation test. To determine clinical predictors, we used the binary logistic regression test.

RESULTS

Anterior and non-granulomatous uveitis was the most common types of inflammation. Only 2 (5.7%) patients had respiratory symptoms, and 6 (17.1%) patients had an abnormal chest X-ray at diagnosis. All patients received combined antitubercular therapy with a mean duration of 6.9 ± 2.3 months. A longer duration of symptoms at diagnosis was associated with both low vision and legal blindness. Older patients had a higher risk of legal blindness. A longer duration of symptoms as well as anterior inflammation demonstrated an increased risk for cataract formation. The duration of the symptoms and baseline BCVA had a positive correlation with the final BCVA. Prognostic factors of macular lesions were not found.

CONCLUSIONS

The diagnosis of ocular TB can be difficult due to the lack of extraocular manifestations and the broad spectrum of ocular features. A longer duration of symptoms at diagnosis was associated with poorer visual outcomes and cataracts. Therefore, efforts should be made to avoid a delay in the diagnosis of ocular TB and to identify prognostic factors for visual outcomes and complications.

The Prevalence of Intraocular Tuberculosis in HIV-positive and HIV-negative Patients in South Africa Using a Revised Classification System

PURPOSE

To report the prevalence of intraocular tuberculosis in South Africa using a revised classification system.

METHODS

A prospective study to determine the underlying etiology in patients presenting with uveitis to a tertiary Eye Clinic.

RESULTS

A total of 35 out of 106 patients (33.0%) were diagnosed with intraocular tuberculosis, of which 11 (31.4%) had HIV infection; 23 patients (65.7%) had possible intraocular tuberculosis and 12 (34.3%) had probable intraocular tuberculosis. Patients with probable intraocular tuberculosis were younger than those with possible intraocular tuberculosis (p = 0.003). More males (66.7%) had probable intraocular tuberculosis and more females (73.9%) had possible intraocular tuberculosis (p = 0.031). More HIV-positive patients had probable intraocular tuberculosis and more HIV-negative patients had possible intraocular tuberculosis (p = 0.002).

CONCLUSIONS

South Africa has a high prevalence of intraocular tuberculosis. Younger, male, HIV-positive patients are more likely to have probable intraocular tuberculosis, while older, female, HIV-negative patients are more likely to have possible intraocular tuberculosis.

Ocular tuberculosis: Position paper on diagnosis and treatment management

Delay in diagnosis or treatment of ocular tuberculosis can result in loss of vision. However, due to the fact that early diagnosis is rarely achieved, there are still a broad variety of diagnostic and treatment approaches. Our aim was to reach a consensus on the management of diagnosis and treatment of ocular tuberculosis.

METHODS

Critical appraisal of the literature and expert opinion on diagnosis and treatment of ocular tuberculosis.

RESULTS AND CONCLUSION

The currently recommended method for ocular TB diagnosis is screening for tuberculosis in any uveitis of unknown etiology, recurrent or not responding to conventional therapy; in ocular findings highly suggestive of ocular TB and before immunosuppression (particularly biologic agents). TB screening in these cases includes tuberculosis skin testing and interferon gamma testing, along with complete medical history, ophthalmologic evaluation and chest imaging. Positively screened patients should be treated for active tuberculosis with 4 drugs (isoniazid, rifampicin, pyrazinamide and ethambutol) for 6-9 months. Patients should be reviewed at the end of the initiation phase (two months) and at the end of the overall treatment (6-9 months).

Diagnosis of Ocular Tuberculosis

Ocular tuberculosis remains a presumptive clinical diagnosis, as the gold standard tests for diagnosing ocular tuberculosis are often not useful: Mycobacterium tuberculosis cultures require weeks to process on Lowenstein-Jenson media and have low yield from ocular samples; while acid-fast bacilli smears or polymerase chain reaction detection of M. tuberculosis DNA have low sensitivities. Thus, diagnosis is often based on suggestive clinical signs, which are supported by positive investigations: tuberculin skin test or interferon-gamma release assays; chest X-ray findings suggestive of pulmonary tuberculosis, and/or evidence of associated systemic tuberculosis infections in the absence of other underlying disease. The aim of this review is to provide an update on the methods of diagnosing ocular tuberculosis, and discuss the challenges of its diagnosis. We also suggest a step-ladder approach to a more accurate diagnosis of ocular tuberculosis by combining the available diagnostic tests.

Comparative Evaluation of Several Gene Targets for Designing a Multiplex-PCR for an Early Diagnosis of Extrapulmonary Tuberculosis

PURPOSE

Diagnosis of extrapulmonary tuberculosis (EPTB) poses serious challenges. A careful selection of appropriate gene targets is essential for designing a multiplex-polymerase chain reaction (M-PCR) assay.

MATERIALS AND METHODS

We compared several gene targets of Mycobacterium tuberculosis, including IS6110, devR, and genes encoding MPB-64 (mpb64), 38kDa (pstS1), 65kDa (hsp65), 30kDa (fbpB), ESAT-6 (esat6), and CFP-10 (cfp10) proteins, using PCR assays on 105 EPTB specimens. From these data, we chose the two best gene targets to design an M-PCR.

RESULTS

Among all gene targets tested, mpb64 showed the highest sensitivity (84% in confirmed cases and 77.5% in clinically suspected cases), followed by IS6110, hsp65, 38kDa, 30kDa, esat6, cfp10, and devR. We used mpb64+IS6110 for designing an M-PCR assay. Our M-PCR assay demonstrated a high sensitivity of 96% in confirmed EPTB cases and 88.75% in clinically suspected EPTB cases with a high specificity of 100%, taking clinical diagnosis as the gold standard.

CONCLUSION

These M-PCR results along with the clinical findings may facilitate an early diagnosis of EPTB patients and clinical management of disease.

devR PCR for the diagnosis of intraocular tuberculosis

PURPOSE

To compare the efficacy of devR and MPB64 PCR in the diagnosis of intraocular tuberculosis.

METHODS

Prospective, nonrandomized study. Seventy-five patients were enrolled in 3 groups. Group A had 25 patients with presumed intraocular tubercular uveitis, group B had 25 controls with specific uveitis other than tubercular uveitis, and group C included 25 non-uveitic negative controls. The undiluted vitreous/aqueous samples were collected and subjected to PCR assay for devR and MPB64 gene sequence of Mycobacterium tuberculosis (MTB) to detect sensitivity and specificity.

RESULTS

devR PCR was positive in 16 (64%) out of 25 patients with presumed tubercular uveitis. MPB64 PCR was positive in 18 (72%) out of 25 patients with presumed tubercular uveitis. The sensitivity and specificity of devR were 64 and 100%, respectively. The sensitivity and specificity of MPB64 PCR were 72 and 100%, respectively.

CONCLUSION

devR PCR is not a better tool than MPB64 PCR for diagnosing intraocular tuberculosis.

Pathogenesis and Pathology of Intraocular Tuberculosis

Intraocular tuberculosis (TB) is an extremely paucibacillary form of extrapulmonary TB. It likely results from bacterial dissemination to the eye from lungs, localization in ocular tissues, followed later by reactivation and appearance of clinical signs. These have been partly demonstrated in the guinea pig model of ocular TB. Alternative hypotheses have been suggested but are not supported by adequate evidence. Mycobacterial recognition by macrophages and dendritic cells probably leads to activation of several immune pathways, primarily the Th1 and Th17 pathways, as in other TB infections. Histopathology of bacteriologically proven ocular TB tissues reveals granulomatous inflammation with central caseous necrosis containing occasional acid-fast organisms. Recent reports have also demonstrated intraretinal granuloma in the vicinity of retinal vessels and T-cell infiltration of epiretinal membranes, in cases of TB retinal vasculitis.