Use of polymerase chain reaction in detection of Mycobacterium tuberculosis complex DNA from vitreous sample of Eales' disease

A Review of Eales' Disease and Mycobacterium tuberculosis

Eales' Disease is an idiopathic peripheral retinal vasculopathy first described by British ophthalmologist Henry Eales in 1880. Most prevalent in healthy young males, Eales' Disease often presents with symptoms of sudden blurry or decreased vision and floaters. Although no clear, standardized stage of the disease exists, it progresses through three overlapping phases-peripheral periphlebitis, ischemic capillary ischemia, and retinal neovascularization. The etiology of Eales' Disease is unknown and appears to be multifactorial, but post-TB hypersensitivity to tuberculoprotein and M. tuberculosis DNA is the most potential cause in the etiology of Eales' Disease. With a thorough examination of the clinical presentation and diagnosis of Eales' Disease-incorporating the latest clinical findings related to the condition-the investigation for Eales' Disease extends to explore recent potential connections with other ocular conditions or possible cofactors, such as glaucoma, uncontrolled diabetes, drug abuse, or inherited medical conditions. Moreover, focusing on critical insights into the treatment of Eales' Disease across its various stages of progression, the overarching goal of the paper is to refine and suggest possible future diagnostic and therapeutic strategies. Widening our understanding of pathophysiology and utilizing various treatment options for individual patients holds immense potential for advancing ocular medicine and optimizing patient care for people with this disease with unknown pathophysiology.

Histopathological, immunohistochemical and molecular biologic study of an enucleated specimen of a case of Eales' disease

Eales' disease is a retinal vasculitis characterized by retinal inflammation, ischemia, and neovascularization. Exact pathogenesis of this disease is yet to be found out. We present a 29-year-old male, diagnosed with Eales' disease in both eyes with persistent intraocular inflammation. Enucleation of the pthisical right eye was subjected for histopathological examination immunohistochemistry and molecular biologic study for mycobacterial tuberculosis DNA. Our study showed that Eales disease is probably a T cell mediated disease which is triggered by mycobacterial TB DNA. Further studies are needed to confirm our findings.

Eales' Disease: When the Rare Sounds Frequent

Eales' disease is a peripheral occlusive retinal phlebitis, with an unclear pathogenesis. The classic association with hypersensitivity to Mycobacterium tuberculosis protein infers that immunologic disturbance may be involved. Here, we described three cases of Eales' disease. All patients are Caucasian men aged 27-58 years and presented with vitreous hemorrhage and/or peripheral venous vasculitis. Tuberculin skin sensitive test (Mantoux screening test) and interferon-gamma release assay (IGRA) were positive in all patients. Therapeutic approach included antituberculosis therapy and systemic steroids, associated or not to immunosuppressive therapy, and retinal scatter photocoagulation in all cases. Antivascular endothelial grow factor (VEGF) intravitreal injections were also required in two cases. Since various retinal diseases can resemble this presentation, Eales' disease is considered a diagnosis of exclusion. Early diagnosis and appropriate therapeutic approach are both essential to accomplish disease control and reduce ophthalmologic complications.

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.

Pediatric Eales Disease: An Indian Tertiary Eye Center Experience

PURPOSE

To report the clinical profiles, etiologies, treatment modalities, and outcomes for Eales disease in patients younger than age 16 years in India.

METHODS

Retrospective review of medical records of patients with Eales disease who had a minimum 5-year follow-up period.

RESULTS

A total of 25 eyes of 13 patients were included. Of these 13 patients, 12 (94%) had bilateral Eales disease and 11 (84.6%) were men. Mean patient age was 14.1 years (range: 11 to 16 years). Diminution of vision (36%) was the most common presenting complaint, followed by both diminutions of vision and floaters (32%). Sclerosed vessels were seen in all eyes, and 21 (84%) eyes had active periphlebitis at presentation. Neovascularization elsewhere was seen in 20 (80%) eyes and neovascularization of the optic disc was seen in 1 (4%) eye. Veno-venous shunts were found in 12 (48%) eyes, and 18 (72%) eyes had vitreous hemorrhage. All eyes received photocoagulation; 84.6% of patients received oral steroids, with 7.7% of patients treated with azathioprine and 38.4% treated with anti-tubercular therapy. Vitrectomy was performed in 36% of eyes for non-clearing vitreous hemorrhage and tractional retinal detachment. Vision improved in 7 (28%) eyes, was stable in 12 (48%) eyes, and worsened in 6 (24%) eyes. Recurrence of the disease more than five times during the 5-year follow-up period occurred in 20% of patients.

CONCLUSIONS

Recurrent vasculitis and vitreous hemorrhage in children should raise the suspicion of pediatric Eales disease. [J Pediatr Ophthalmol Strabismus. 2018;55(4):270-274.].

Effect of Antituberculous Therapy on Uveitis Associated With Latent Tuberculosis

PURPOSE

To describe the clinical features of patients with uveitis associated with latent tuberculosis (TB) and examine the effect of anti-TB treatment (ATT) on uveitis outcome.

DESIGN

Retrospective cohort study.

METHODS

One hundred ninety-nine eyes of 129 patients diagnosed with uveitis associated with latent TB were evaluated for recurrence of disease following treatment. Eighty-nine of the patients (69%) received ATT and information was gathered retrospectively regarding clinical outcome, vision, and treatment. Outcome measures included best-corrected visual acuity (BCVA) and rate of disease recurrence.

RESULTS

This study included 89 patients (69%) who received ATT and 40 patients who did not. The uveitis was treated with local and systemic anti-inflammatory and immunosuppressive therapy in all patients. The mean change in BCVA following treatment was 4.5 ± 1.4 letters over the follow-up period, with no difference between eyes of patients receiving ATT and those who did not. Sixty-eight eyes (34.9%) had a recurrence of uveitis (0.64 ± 0.08 recurrences per year), with eyes of patients receiving ATT less likely to develop a recurrence compared to those not receiving ATT (29.5% vs 48.2%, odds ratio 0.47, 95% confidence interval 0.29-0.77, P = .003). Eyes treated with ATT recurred at an estimated median of 120 months, compared with 51 months in eyes with no treatment (P = .005).

CONCLUSIONS

Treatment with ATT halved the risk of uveitis recurrence and delayed the onset of the first recurrence in eyes with uveitis associated with latent TB.

Ocular Tuberculosis

Ocular tuberculosis is an extrapulmonary mycobacterial infection with variable manifestations. The reported incidence of ocular involvement varies considerably, depending on the criteria used for diagnosis and the population sampled. However, tuberculosis is thought to affect the lungs in 80% of patients, with the remaining 20% being affected in other organs, such as the eye. It is imperative for physicians to consider this diagnosis in their differential, as ocular tuberculosis can present in a fashion similar to that of more common conditions causing ocular inflammation. In addition, prompt recognition of the clinical signs and symptoms leads to quicker initiation of antituberculosis therapy.

Intraocular manifestations of mycobacterium tuberculosis: A review of the literature

Mycobacterium tuberculosis: is most commonly associated with pulmonary infection. However, tuberculosis (TB) can also affect the eye. TB can affect nearly any tissue in the eye, and a high index of suspicion is required for accurate diagnosis, as many of the intraocular manifestations of TB can mimic other, more common diseases. Correct diagnosis is critical because systemic anti-tuberculosis treatment may be required, and vision loss or even loss of the affected eye can occur without proper treatment. Thus, it is important for ophthalmologists and infectious disease specialists to work together to accurately diagnose and treat intraocular TB. This article reports the various known presentations of intraocular TB and reviews important elements of diagnosis and treatment.

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.

Vanishing retinal arterial aneurysms with anti-tubercular treatment in a patient presenting with idiopathic retinal vasculitis, aneurysms, and neuroretinitis

Background

Idiopathic retinal vasculitis, aneurysms, and neuroretinitis (IRVAN) syndrome presents with characteristic clinical manifestations such as aneurysms at arteriolar bifurcations and optic nerve and retinal vascular inflammation. Regression of such features on treatment with anti-tubercular therapy (ATT) combined with corticosteroids has not been reported in literature.

Findings

A 30-year-old female with sudden painless decreased vision in the left eye was referred with a diagnosis of presumed tuberculous retinal vasculitis and a positive tuberculin skin test. Based on the clinical and angiographic features of the right eye, a diagnosis of IRVAN syndrome was made. In the left eye, the patient had vitreous hemorrhage for which pars plana vitrectomy was performed. The vitreous sample was positive for Mycobacterium tuberculosis using multiplex polymerase chain reaction, and the patient was started on standard four-drug ATT and oral corticosteroids. At 6-month follow-up, vanishing of retinal arterial aneurysms was observed.

Conclusions

The pathogenesis of IRVAN syndrome is uncertain. One of the postulates is that the features of arterial aneurysms and other retinal vascular alterations occur secondary to acquired inflammatory reaction. We hypothesize that IRVAN syndrome may be a morphological diagnosis possibly associated with various entities, one of which could be ocular tuberculosis. It may be prudent to rule out intraocular tuberculosis in cases labeled as IRVAN syndrome in an endemic population.

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.

Detection of Mycobacterium tuberculosis with nested polymerase chain reaction analysis in enucleated eye ball in Eales' disease

Nested polymerase chain reaction (nPCR) was performed on enucleated eyeball for detection of Mycobacterium tuberculosis (M. tb) genome in a patient with Eales' disease. PCR analysis in all previous studies has been done mainly using aqueous, vitreous and epiretinal membranes from these patients. Paraffin wax embedded tissue section of the enucleated eyeball was analyzed by histopathology and nPCR targeting MPB64 gene and IS6110 region of M. tb genome. Lymphocytic infiltration was seen in the vitreous, iris and the retinal tissue. Ziehl Neelsen stain was negative for acid fast bacilli. Caseation necrosis was not seen in any section. Agarose gel electrophoretogram showed positive results with 200 bp specific amplified product targeting MPB64 gene, whereas nPCR targeting IS6110 region was negative. Since biopsy proven M. tb is extremely difficult in ocular tissues due to extensive necrosis, the nPCR technique aided in the diagnosis.

Role of molecular diagnostics in ocular microbiology

Although microbial culture remains the gold standard for diagnosis of many ocular infections, the technique is limited by low yield, inability to detect certain organisms, and potentially long delays to results. DNA-based molecular diagnostic techniques use detection of specific nucleic acid sequences as evidence for presence of suspected pathogens. The polymerase chain reaction (PCR) is a powerful molecular biology technique that allows for detection of fewer than 10 copies of pathogen genome. Recent technical advances in PCR have permitted quantitation of pathogen load using quantitative PCR (qPCR), and have permitted multiplexing of primer sets. Use of pan-bacterial and pan-fungal primers for ribosomal DNA sequences has allowed diagnosis of bacterial and fungal infections using molecular techniques. In this review, we highlight recent advances in the application of PCR to the diagnosis of anterior segment and posterior segment ocular infectious diseases.

Differential diagnosis of behçet uveitis

The diagnosis of Behçet disease is clinical and based on the presence of characteristic ocular and systemic inflammatory manifestations. Patients may present with anterior, posterior, or panuveitis in one or both eyes. The differential diagnosis includes a variety of infectious and noninfectious causes of acute nongranulomatous anterior uveitis, intermediate uveitis, occlusive retinal vasculitis, focal or multifocal retinitis, and necrotizing retinitis. A course characterized by sudden onset with improvement followed by recurrence of inflammatory signs is most typical for Behçet uveitis.

Tubercular retinal vasculitis

Intraocular tuberculosis (TB) infection can have different clinical manifestations including retinal vasculitis. It more frequently involves the veins and is associated with retina haemorrhages and neovascularisation. The diagnosis may be difficult and presumptive being based on clinical findings and evidence of systemic TB infection. The authors present a case of a 61-year-old woman with blurred vision and floaters in her left eye for 6 years, associated with recurrent vitreous haemorrahages. A temporal branch retinal vein occlusion was presumed. Four years later her right eye was also involved. Her best-corrected visual acuity (BCVA) was 20/50 in both eyes. Fundoscopic examination showed bilateral venous occlusion with vascular staining on fluorescein angiography suggestive of vasculitis secondary to Eales Disease (ED). The interferon gamma release assay (IGRA-QuantiFERON-TB Gold) was positive and antituberculosis treatment (ATT) was started. Her final BCVA was 20/20 bilaterally, without recurrences over a follow-up of 15 months. The use of ATT is likely to reduce recurrent vitreous haemorrhages and eliminate future recurrences.

Detection of Mycobacterium tuberculosis directly from sputum specimens & phenotypic drug resistance pattern of M. tuberculosis isolates from suspected tuberculosis patients in Chennai

BACKGROUND & OBJECTIVES

mRNA is more rapidly destroyed in cells than rRNA or genomic DNA, an assay targeting bacterial mRNA would provide a better guide to mycobacterial viability than amplification tests directed at DNA or rRNA targets. This study was carried out to standardize reverse transcriptase PCR (RT-PCR) targeting 85B gene for the rapid detection of viable Mycobacterium tuberculosis from sputum specimens of suspected TB patients at Chennai, South India and to detect MDR-TB circulating in this population.

METHODS

Sputum samples from clinically suspected tuberculosis patients (n=301) and 78 controls were included in the study. The sputum samples were collected in sterile diethyl pyrocarbonate (DEPC) treated containers and transported in ice to the laboratory within 2 h to prevent degradation of RNA. RT-PCR targeting 85B gene, mycobacterial culture and phenotypic drug susceptibility testing for the first line drugs streptomycin (S), isoniazid (H), rifampicin (R), ethambutol (E) and pyrazinamide (Z) were performed by BACTEC microMGIT culture system for all the sputum specimens.

RESULTS

All the 78 controls were negative for culture and RT-PCR. Among the 301 sputum specimens from patients, 231 (76.8%) were RT-PCR positive and 70 (23.2%) were negative. There were 166 M. tuberculosis isolates, of which 11 (2.9%) were MDR-TB, 33 (8.7%) were polyresistant, 31 (8.2%) were monoresistant and 91 (30.2%) were sensitive to all five first line anti-tuberculous drugs by phenotypic drug susceptibility testing. Monoresistance was higher with Z [20 (20.8%)], followed by S [6 (3%)].

INTERPRETATION & CONCLUSIONS

RT-PCR targeting 85B gene of M. tuberculosis was a specific, rapid, reliable technique to detect the M. tuberculosis directly from sputum specimens. Our results showed that 2.9 per cent of M. tuberculosis isolates in the study population of Chennai were MDR.

Quantitative polymerase chain reaction for Mycobacterium tuberculosis in so-called Eales' disease

PURPOSE

To report mycobacterial load in the vitreous of patients labeled as having Eales' disease.

METHODS

Eighty-eight patients were prospectively enrolled into 3 groups: 28 patients with so-called Eales' disease (group A); 30 positive controls with specific uveitis syndromes (group B), and 30 negative controls (group C). The undiluted vitreous humor samples were collected and subjected to real-time PCR assay for MPB64 gene of Mycobacterium tuberculosis (MTB) and load quantified.

RESULTS

Sixteen (57.14%) vitreous fluid samples in group A; 1 sample in group B, and none of the samples in group C were positive for MTB genome from the vitreous. The copies of MTB genomes in the positive samples in group A were 1.52 × 10(4) to 1.01 × 10(6).

CONCLUSION

MTB genome was demonstrated in more than 50% of vitreous fluid samples with significant bacillary load, indicating that half of patients with so-called Eales' disease are indeed cases of tubercular vasculitis.

Retinal Vasculitis

Retinal vasculitis is a sight-threatening intraocular inflammation affecting the retinal vessels. It may occur as an isolated ocular condition, as a manifestation of infectious or neoplastic disorders, or in association with a systemic inflammatory disease. The search for an underlying etiology should be approached in a multidisciplinary fashion based on a thorough history, review of systems, physical examination, and laboratory evaluation. Discrimination between infectious and noninfectious etiologies of retinal vasculitis is important because their treatment is different. This review is based on recently published articles on retinal vasculitis and deals with its clinical diagnosis, its link with systemic diseases, and its laboratory investigation.

Tuberculosis

PURPOSE OF REVIEW

The purpose of this report is to present an update on the manifestations and management of ocular tuberculosis.

RECENT FINDINGS

Tuberculosis affects one-third of the world's population. The incidence of tuberculosis has increased with the increase in the HIV infected population. Following a resurgence of the disease in the US, the incidence has recently declined. Patients may develop scleritis that can be focal, nodular or diffuse with or without keratitis. Anterior granulomatous uveitis may occur. The posterior segment reveals vitritis, choroiditis, and can mimic serpiginous choroiditis and other entities. Patients who are immunosuppressed or HIV infected may develop active mycobacterial disease in the eye leading to rapid destruction of the ocular structures. The diagnosis of ocular tuberculosis is made by isolation of Mycobacterium tuberculosis on Löwestein-Jensen medium or by PCR. The diagnosis is supported by the clinical findings, imaging techniques including optical coherence tomography, fluorescein angiography, indocyanine green and ultrasonography. Tuberculin skin test helps to confirm the diagnosis.

SUMMARY

Ocular tuberculosis may occur in the absence of pulmonary disease. Patients present with a spectrum of clinical signs. The disease may mimic several clinical entities. Early diagnosis and prompt treatment of ocular tuberculosis may prevent ocular morbidity and blindness.

Tuberculous uveitis, a resurgent and underdiagnosed disease

BACKGROUND

Over the last decade ocular involvement due to tuberculosis has re-emerged. In non-endemic areas the low frequency of active tuberculosis is at the origin of an underestimation of the disease. The purpose of this study is to report a group of patients with presumed tuberculous uveitis and to analyse the pre-diagnostic course, the diagnostic delay and the evolution of ocular inflammation after diagnosis and anti-tuberculous treatment.

METHODS

Criteria for presumed tuberculous uveitis included the presence of a hyperpositive tuberculin skin test with compatible uveitis and the exclusion of other possible etiologies.

RESULTS

Thirty-five patients fulfilled the diagnostic criteria for presumed tuberculous uveitis and were included in the study. The diagnosis was performed at presentation in only seven patients, while the correct diagnosis was delayed in the other 30 patients. The mean diagnostic delay was 5.7 +/- 4 years. Anti-tuberculous therapy was given for a minimum of 6 to a maximum of 24 months. Post-diagnostic mean follow-up was 30.4 +/- 13.4 months. Anti-tuberculous therapy resulted in a highly significant increase in visual acuity, from 0.53 to 0.78 (P < 0.001), a highly significant decrease of recurrences, from 100 to 10% (P < 0.001), with only three recurrences observed during the follow-up, and a highly significant decrease in intra-ocular pressure, from 18.3 to 13.7 (P < 0.001).

CONCLUSIONS

Our study tends to confirm the existence of tuberculous uveitis and supports the validity of the proposed diagnostic criteria. Recognition of the correct diagnosis and specific therapy, even with substantial delay, avoids recurrences, improves visual acuity and intra-ocular inflammation and decreases intra-ocular pressure.

Intérêt des prélèvements intraoculaires dans le diagnostic étiologique des uvéites présumées infectieuses

PURPOSE

To study the etiologic distribution of patients with presumed infectious uveitis who underwent ocular fluid analysis.

PATIENTS AND METHODS

We retrospectively analyzed vitreous and or aqueous humor samples of patients with presumed infectious uveitis, referred to the department of Ophthalmology of the University Hospital of Rouen, France, between January 1997 and June 2004. We excluded patients with postsurgical or endogenous endophthalmitis. We noted clinical features and intraocular sample analysis methods for each pathogen.

RESULTS

The study included 42 patients, 24 men and 18 women, aged between 6 and 79 years (mean, 39.5 years). Uveitis was unilateral in 88% of cases and bilateral in 12%. Posterior uveitis was predominant (52%), followed by panuveitis (24%), anterior (14%), and intermediate uveitis (10%). Aqueous humor and vitreous analysis confirmed etiological diagnosis for 13 of 41 patients (31%) and three of six cases (50%), respectively. Inflammation was controlled or stabilized in all cases. The most pejorative visual outcome was observed for candidiasis and viral retinitis. Positivity of intraocular samples was variable, depending on the suspected pathogen, with results similar to those reported in other studies.

DISCUSSION

Atypical features in potential infectious uveitis justify ocular paracentesis or vitrectomy, which are more efficient since molecular biological tools have become available. Sensitivity of aqueous humor analysis is high for posterior uveitis and suspicion of viral retinitis. New molecular variants applied to ocular samples will improve the etiological diagnosis of infectious uveitis, particularly for pathogens that are difficult to culture, such as fungi and bacteria.

Treatment of neuro-ophthalmologic manifestations of tuberculosis

In the absence of obvious pulmonary or disseminated tuberculosis, ocular and central nervous system (CNS) tuberculosis may represent a significant diagnostic challenge. Refinements in polymerase chain reaction techniques and neuroimaging have strengthened the battery of tests used to diagnose CNS and ocular tuberculosis, yet in many cases, the diagnosis remains one of exclusion; it may ultimately be determined through exacerbation by anti-inflammatory therapy with subsequent improvement by antitubercular medication treatment. Because of emerging drug resistance, at least a two-drug regimen is required for therapeutic testing and treatment of isolated ocular tuberculosis. If pulmonary or miliary disease coexists, a 6-month, four-drug regimen with isoniazid, rifampin, pyrazinamide, and ethambutol is required for treatment. Tubercular meningitis is treated with the same four-drug regimen for at least 9 to 12 months. Burden of therapeutic compliance rests on the treating physician and public health sector. Best compliance is realized with directly observed therapy.

A new staging system for idiopathic retinal periphlebitis

PURPOSE

To develop and standardize a universally acceptable new staging system for idiopathic retinal periphlebitis (Eales disease).

METHODS

A new staging system was established and standardized based on standard terminology and features. Idiopathic retinal periphlebitis was classified as peripheral and central types. Peripheral disease consisted of four stages. Stage 1 is periphlebitis of small (1a) and large (1b) caliber vessels with superficial retinal hemorrhages. Stage 2a denotes capillary nonperfusion and 2b neovascularization elsewhere/of the disc. Stage 3a is classified as fibrovascular proliferation and 3b vitreous hemorrhage. Stage 4a is traction/combined rhegmatogenous retinal detachment whereas 4b is rubeosis iridis, neovascular glaucoma, complicated cataract, and optic atrophy. A total of 253 cases of idiopathic retinal periphlebitis (mean age, 24.7 +/- 4.7 years, all male) presenting at this tertiary care center were classified prospectively according to the new staging system, by two independent observers (interobserver correlation = 0.7).

RESULTS

The new staging system was consistent, simple, and easy to recall. Peripheral and central types of idiopathic retinal periphlebitis were found in 94.07% and 5.93% of cases, respectively. The new staging system also defined the severity of the disease. Vitreous hemorrhage was found to be the commonest presenting feature (51.68%), whereas traction/combined rhegmatogenous detachment was found in 5.88% of cases.

CONCLUSIONS

The new staging system is useful in classifying and assessing the severity of disease. Management strategy can also be defined according to the stage of the disease. It is designed to promote the use of standard assessment with applications to clinical management and research.

Uvéites chroniques sévères : classification, démarche diagnostique et principes thérapeutiques

PURPOSE

Severe chronic and refractory uveitis is a major diagnostic and therapeutic challenge for ophthalmologists and internists. Molecular tools, such as PCR but also new imaging techniques, have significantly changed the diagnostic approach during the last 10 years. Presumed and empirical diagnosis should be excluded in the face of atypical clinical presentations.

CURRENT KNOWLEDGE AND KEY POINTS

A retrospective study based on 927 consecutive patients presenting with severe uveitis between 1991-1996, has recently defined the epidemiological characteristics and the visual outcome of this group of patients. An associated condition was determined in 67.5% of cases, divided in 4 different subgroups: infectious uveitis; uveitis associated with a systemic disease; eye-limited, presumed immune-mediated disorder and idiopathic eye-limited disorder. The management of patients with sight-threatening forms of uveitis is efficiently performed in collaboration with internists and depends on a complete diagnostic procedure and a well-adapted treatment.

FUTURE PROSPECTS AND PROJECTS

Extensive work-up is mandatory when the therapeutic response seems atypical with resistance to corticosteroids and classical immunosuppressive drugs. Infectious uveitis should be excluded in severe and intractable forms of uveitis. Thereafter, new therapeutic strategies based on type I interferon and anti-TNF molecules can be proposed in order to decrease the potential risk of blindness in this young group of patients.

Nested polymerase chain reaction for Mycobacterium tuberculosis DNA detection in aqueous and vitreous of patients with uveitis

BACKGROUND

Tuberculosis may be a lethal disease. Its ocular manifestations are commonly associated with severe difficulties in diagnosis and therapy; furthermore, it may cause blindness. DNA amplification methods may allow early detection of small amounts of Mycobacterium tuberculosis DNA to afford the possibility of prompt diagnosis. We evaluated a nested polymerase chain reaction (nPCR) assay for detection of Mycobacterium tuberculosis DNA in aqueous and vitreous.

METHODS

In a case-control study, 22 cases of diagnosed TB uveitis (three HIV-infected patients) and 38 controls (18 HIV-infected patients) with other types of uveitis (syphilis, nine; cytomegalovirus, seven; toxoplasmosis, five; herpes simplex, one; autoimmune vasculitis, eight; Vogt-Koyanagi-Harada, four; pars planitis, one; serpinginous choroiditis, one; Wegener granulomatosis, one; and Fuchs iridocyclitis, one studied). Samples from aqueous or vitreous were cultured and analyzed by nPCR for presence of M. tuberculosis nucleic acids. We used two sets of primers corresponding to IS6110 region coding for 219 bp and 123 bp DNA sequences.

RESULTS

Results were confirmed by Southern blot. All samples were tested by PCR simultaneously for Herpes simplex I, Herpes zoster, cytomegalovirus (CMV) and Toxoplasma gondii. nPCR was positive in 17 cases (77.2%) and only in three controls (8.8%) p = 0.022. All cultures were negative. Southern blot confirmed all positive nPCR tests. According to our definition of cases, there were five false negative results: two in patients with pulmonary tuberculosis; two in patients with tuberculous lymphadenitis, and one with positive skin test and hematuria. There were three cases considered false positives for nPCR: one with autoimmune vasculitis, and two with toxoplasmic uveitis.

CONCLUSIONS

nPCR for TB in ocular fluids was positive in the majority of cases of ocular TB. This method is useful in early confirmation of ocular tuberculosis.

Full panretinal photocoagulation and early vitrectomy improve prognosis of retinal vasculitis associated with tuberculoprotein hypersensitivity (Eales' disease)

BACKGROUND/AIMS

Eales' disease is an uncommon vasoproliferative retinal disease affecting otherwise healthy young men that is characterised by obliterative retinal periphlebitis, with sequelae such as recurrent vitreous haemorrhage and traction retinal detachment. This study was undertaken to determine whether visual prognosis of Eales' disease could be improved by appropriate medical and surgical treatment.

METHODS

The authors retrospectively studied 30 patients (46 eyes) who were treated from 1992 to 2001. Recorded data included patient age, sex, race, medical history, medications, results of the ophthalmological examination, results of diagnostic laboratory evaluation, and details of systemic and surgical treatments. The mean follow up was 10.6 months.

RESULTS

19 patients (23 eyes) who presented with active periphlebitis received systemic steroids and antituberculous therapy. Extensive full panretinal photocoagulation was performed in 21 eyes that presented with new vessel formation and peripheral capillary closure with or without vitreous haemorrhage. Vitrectomy and endolaser panretinal photocoagulation was necessary in 15 eyes, for severe non-clearing vitreous haemorrhage in 11 eyes and vitreous haemorrhage with traction retinal detachment in four eyes. Complete regression of the disease was achieved in all eyes. Vitrectomy resulted in a significant visual improvement with 14 of the 15 eyes (93.3%) achieving > or =20/200 visual acuity. Overall, the distribution of visual acuities among eyes improved from presentation to final follow up, with 36.4% of eyes having 20/40 or better acuity at presentation compared with 63.6% of eyes by final follow up.

CONCLUSIONS

These results suggest that aggressive treatment of Eales' disease with systemic steroids and antituberculous therapy, full panretinal photocoagulation and early vitrectomy, when necessary, may result in improving the anatomic and visual outcome.

Polymerase chain reaction based detection of fungi in infected corneas

AIMS

To evaluate a polymerase chain reaction (PCR) based assay to detect fungi in scrapings from infected corneas.

METHODS

A PCR assay was developed to amplify a portion of the fungal 18S ribosome gene. Corneal scrapings from 30 patients with presumed infectious keratitis were evaluated using this assay, as well as by standard microbiological techniques, and the results were compared. Conjunctival swabs from each patient's healthy, fellow eye were also evaluated by PCR.

RESULTS

PCR and fungal culture results matched (were both positive or both negative for fungi) in 22 (74%) of 30 scrapings from infected corneas. Three (10%) of 30 samples were PCR positive but fungal culture negative; two of these appeared clinically to represent fungal infections, and the third was clinically indeterminate. Four (13%) scrapings were positive by PCR but also by bacterial and not fungal culture. One specimen (3%) was PCR negative but fungal culture positive. Of the conjunctival swabs from each patient's healthy fellow eye, five (17%) of 30 were positive by PCR, and the opposite, infected eye of all five of these harboured a fungal infection.

CONCLUSIONS

PCR is promising as a means to diagnose fungal keratitis and offers some advantages over culture methods, including rapid analysis and the ability to analyse specimens far from where they are collected.

Eales disease--an update

Eales disease, first described by Henry Eales in 1880, remains an enigma. The disease, observed more commonly in the Indian subcontinent than in the rest of the world, occurs in young healthy adult males, initially presenting as retinal periphlebitis and later as retinal ischemia that may lead to vascular alterations and neovascularization. Recurrent vitreous hemorrhage with or without retinal detachment is the common sequelae. In recent years, immunological, molecular biological, and biochemical studies have indicated the role of human leukocyte antigen, retinal autoimmunity, mycobacterium tuberculosis genome, and free radical mediated damage in the etiopathogenesis of this disease. However, its etiology appears to be multifactorial. The management depends on the stage of the disease and consists of medical treatment with oral corticosteroids in the active inflammatory stage and laser photocoagulation in the advanced retinal ischemia and neovascularization stages. The results of vitreoretinal surgery have been found to be satisfactory in case of vitreous hemorrhage with or without retinal detachment.

Applications of the polymerase chain reaction to diagnosis of ophthalmic disease

The polymerase chain reaction (PCR) is a powerful molecular biologic technique for the analysis of very small amounts of DNA. This technique has found increasing use in the past 10 years for the detection of pathogenic organisms associated with many forms of ocular inflammatory and infectious disease. PCR has shown utility in the diagnosis of viral uveitis, infectious endophthalmitis, and parasitic eye disease. The strengths and weaknesses of this diagnostic technique are discussed. Additionally, uses of PCR in linking known pathogens to disease, and to discovering novel pathogens, are addressed.

New diagnostic approach for ocular tuberculosis by ELISA using the cord factor as antigen

BACKGROUND/AIMS

Diagnosis of ocular tuberculosis is difficult, particularly the retinal vasculitis type, because most cases occur without concurrent active pulmonary tuberculosis. Recently, it has been reported that detection of antibodies against purified cord factor (trehalose-6,6'-dimycolate, TDM), the best studied, most antigenic, and most abundant cell wall component of tubercule bacilli, is very useful for rapid serodiagnosis of pulmonary tuberculosis. In this study, an attempt was made to evaluate whether the detection of anticord factor antibody is also useful for diagnosis of ocular tuberculosis and the necessity of antituberculous therapy for tuberculous retinochoroiditis was discussed.

METHODS

Cases consisted of 15 patients with uveitis and retinal vasculitis, nine patients with presumed ocular tuberculosis, three patients with sarcoidosis, and three patients with Behçet's disease. IgG antibodies against purified cord factor prepared from Mycobacterium tuberculosis H37Rv were detected by enzyme linked immunosorbent assay.

RESULTS

All cases of clinically presumed ocular tuberculosis were positive, whereas all of the cases of sarcoidosis or Behçet's disease were negative for anticord factor antibodies. When the anticord factor antibody titres were compared on the basis of the presence or absence of previous antituberculosis chemotherapy, the mean anticord factor antibody titre of the untreated group showed a tendency to be higher than in the treated group, but not significantly (p=0.07).

CONCLUSIONS

The detection of anticord factor antibody may be useful to support the diagnosis of ocular tuberculosis. Additionally, a positive result for anticord factor antibody may indicate that tubercule bacilli are present in some organ(s) of the patient even in the absence of active systemic disease.