Role of polymerase chain reaction-based viral detection in pterygia.

Purpose: Pterygium is a fibrovascular disease that originates in the conjunctiva and commonly spreads to the corneal surface, thereby posing a threat to eyesight. Despite intensive research, the pathophysiology of this disease remains unclear. Recent research suggests that oncogenic viruses, such as human papillomavirus (HPV), cytomegalovirus, and Epstein-Barr virus (EBV), may play a role in pterygia development. Although there are questions concerning the function of oncogenic viruses in pterygium pathogenesis, existing research shows a lack of consensus on the subject, demonstrating the heterogeneity of pterygium pathophysiology. Therefore, we aimed to simultaneously detect the three common viral pathogens that have been reported in pterygium tissue obtained after excision. Methods: Thirty-five tissue specimens of pterygium from patients undergoing pterygium surgery (as cases) were analyzed for evidence of viral infection with multiplex polymerase chain reaction (PCR), and virus-specific real-time quantitative PCR was used for the samples that were detected positive by multiplex PCR. Results: Of the 35 patients, one sample was positive for EBV and two samples were positive for HPV. Further PCR-based DNA sequencing of the HPV PCR-positive product showed identity with HPV-16. Real-time quantitative PCR on samples that showed EBV or HPV positivity did not yield any detectable copy number. Conclusion: Our study results confirmed that PCR positivity could be due to transient flora, but it was not quantitatively significant to conclude as the causative factor of pterygium pathogenesis. However, additional studies with larger sample populations are warranted to fully determine the role of the virus in pterygium.

A Rare Fungal Orbital Infection in an Immunocompetent Young Male Caused by Lichtheimia corymbifera (Absidia corymbifera).

AIM: To present a case of orbital fungal infection caused by a rare fungus, Lichtheimia corymbifera (Absidia corymbifera) in an immunocompetent individual. MATERIALS AND METHODS: A retrospective case study. RESULT: A 23-year-old male presented with painful proptosis of the right eye for 3 months. Examination revealed normal vision and pupillary light reflex but restricted ocular movements in the right eye. A tender, firm mass was palpable along the inferomedial quadrant of the right orbit. He had acute worsening of proptosis with loss of light perception within 24 hours. Magnetic resonance imaging (MRI) showed a heterogeneously enhancing lesion in the right orbit. Urgent incisional biopsy revealed the growth of Absidial fungal infection. He received intravenous Amphotericin B for 2 weeks with no response. Repeat MRI revealed an extension of the infection up to the cavernous sinus and intracranial optic nerve. He was managed by subtotal exenteration, socket irrigation with Amphotericin B, and intravenous Amphotericin B. CONCLUSION: Invasive orbital fungal infection, though rare, should be considered a differential diagnosis in immunocompetent patients with fulminant proptosis and vision loss.

Diagnostic Challenge with Nocardia Subretinal Abscess: A Case Report from Tuberculosis-Endemic Region.

Purpose: To describe a case of Nocardia subretinal abscess, which posed a diagnostic challenge due to the presence of mycobacterial genome in sample obtained from fine needle aspiration biopsy (FNAB). Methods: A retrospective chart review. Results: A 25-year-old male presented with sudden, painless onset diminution of vision of left eye and found to have placoid patch of choroiditis just temporal to the macula in right eye and showed vitritis, subretinal abscess with exudative retinal detachment and vitreous hemorrhage in left eye. Both aqueous and vitreous samples were negative microbiologically and polymerase chain reaction for various genomes. Sample obtained from FNAB was positive for mycobacterial genome and yielded Nocardia arthritidis on culture. She was treated with antitubercular therapy and intravenous and intravitreal antimicrobials. Conclusions: Nocardia subretinal abscess can be a diagnostic challenge in tuberculosis-endemic region, especially in conditions when there is co-infection with Mycobacterium tuberculosis.

Real-time polymerase chain reaction for diagnosis and management of HIV-induced uveitis.

Intraocular (IO) inflammation in patients with Human immune deficiency virus (HIV) infection can be due to opportunistic infections, immune recovery uveitis, drugs used in the management or a primary manifestation of HIV itself. We studied the role of RT-PCR for HIV RNA in confirming the diagnosis of HIV induced uveitis and its useful in the management and follow-up of these patients.

Utility of QuantiFERON®-TB Gold test in diagnosis and management of suspected tubercular uveitis in India.

The tuberculin skin test, used to detect latent systemic tuberculosis (TB), has its limitations. The utility of interferon-gamma assays, found useful in the diagnosis of latent TB, is still unestablished in tubercular uveitis. We present the results of QuantiFERON(®)-TB Gold (QFT-G) test and its relevance in the diagnosis and management of suspected tubercular uveitis in India. All suspected tubercular uveitis patients seen at our uveitis clinic between October 2006 and June 2008 who underwent relevant blood investigations, chest X-rays, Mantoux tests and QFT-G tests were included. Clinical profile, systemic correlation and outcome with treatment were analysed. Fifty suspected tubercular uveitis patients underwent QFT-G testing. The age range of the patients was 6-55 years (mean 32.66 years). Seven patients presented with active and three with a past history of systemic TB. The QFT-G test was positive in 29 patients. Radiological findings of TB were seen in four patients with a positive QFT-G and one patient with a negative QFT-G test. In 11 patients both QFT-G and Mantoux tests were positive. Eighteen Mantoux-negative patients were QFT-G-positive. Significantly, no patient with a positive Mantoux had a negative QFT-G test. Of the 32 patients with posterior uveitis, 17 patients had serpiginous choroiditis, four patients had a choroidal granuloma, six patients had multifocal choroiditis, four patients had retinal vasculitis, and one patient had a subretinal abscess. All QFT-G-positive patients were treated with anti-tuberculosis therapy as well as systemic steroids with a favorable clinical outcome. Our study shows that the QFT-G test is very useful in the diagnosis and management of suspected ocular TB. It was found to be very sensitive in identifying latent TB patients who, upon treatment, had a significantly reduced frequency of recurrences. It was more sensitive than the Mantoux test and is not significantly affected by previous treatment with systemic steroids or immunosuppressives. A negative QFT-G test can also be used as an adjunct before initiation of systemic steroids or immunosuppressives in uveitic patients particularly in an endemic setting like India.

Polymerase chain reaction in intraocular inflammation.

Polymerase chain reaction (PCR) is a technique involving enzymatic amplification of nucleic acid sequences in repeated cycles of denaturation, oligonucleotide annealing and DNA polymerase extension. It is a powerful molecular biologic tool that allows the rapid production of analytic quantities of DNA from small amounts of starting material. PCR can be performed on nearly any ocular specimen or biopsy. For diagnosis of uveitis, the obtained sample is usually an anterior chamber paracentesis or vitreous tap. PCR potentially is more sensitive than culture for detection of many organisms. By utilizing a secondary detection system in concert with the initial PCR reaction, perfect specificity can be assured. The initial application of PCR diagnostics to ophthalmic disease was in the detection of viral uveitis. PCR has also been implicated in studies of noninfectious uveitis. The most common application is HLA typing. A universal bacterial PCR can be very helpful for the diagnosis of bacterial endophthalmitis at an early stage of the disease.

Anterior chamber exudative mass due to Scedosporium apiospermum in an immunocompetent individual.

Endogenous intraocular infection of fungal etiology is extremely rare in an immunocompetent individual. Usually, an antecedent history of trauma, surgery, intravenous drug abuse or an immunocompromized state can be elicited. Scedosporium apiospermum is a known cause of keratomycosis after traumatic implantation and can cause fatal disseminated infection in immunocompromized patients. However, cases of S. apiospermum intraocular infection in immunocompetent individuals have been very rarely reported in literature. We report here a case of an anterior chamber exudative mass due to S. apiospermum in an immunocompetent individual which was managed successfully with anterior chamber wash and intravitreal injection of voriconazole.

Ocular tuberculosis in acquired immunodeficiency syndrome.

PURPOSE: To present the clinical, histopathological, and molecular biologic findings in fifteen cases of ocular tuberculosis (TB) in patients with acquired immune deficiency syndrome (AIDS). DESIGN: Retrospective, observational, noncomparative case series of HIV-infected patients with ophthalmic complaints and/or with advanced disease (CD4+ cell count < 200), seen between the years 1993 to 2005 at tertiary care ophthalmic and AIDS care hospitals. METHODS: Each patient underwent a complete ophthalmic examination and relevant laboratory and radiologic investigations and was treated accordingly. The study was carried out in this cohort to describe the ocular manifestations of TB. The main outcome measures were to describe the clinical course histopathologic and molecular biologic features of ocular lesions attributable to tuberculosis in AIDS patients in our center. RESULTS: Ocular TB was seen in 15 (1.95%) out of 766 consecutive cases of HIV/AIDS. Nineteen eyes of 15 patients were affected. Four cases (26.66%) had bilateral presentation. Presentations of ocular TB included choroidal granulomas in 10 eyes (52.63%), subretinal abscess in seven eyes (36.84%), worsening to panophthalmitis in three eyes, conjunctival tuberculosis, and panophthalmitis each in one eye (5.26%). All cases had evidence of pulmonary tuberculosis. Coexistent central nervous system (CNS) tuberculosis was seen in two cases and one case had abdominal tuberculosis. CD4+ cell counts were done in 14 patients; the count ranged from 14 to 560 cells/microl--mean 160.85 cells/microl. CONCLUSIONS: Ocular TB in AIDS is relatively rare and can occur even at CD4+ cell counts greater than 200 cells/microl. It can have varied presentations with severe sight-threatening complications.

Detection of mycobacterium tuberculosis by nested polymerase chain reaction in a case of subconjunctival tuberculosis.

PURPOSE: To highlight the importance of nested polymerase chain reaction (PCR) in the detection of Mycobacterium tuberculosis in a case of subconjunctival tuberculosis. METHODS: We report a case of a 60-year-old man with subconjunctival nodule in the right eye for duration of 6 weeks. Biopsy of the nodule showed a granuloma with extensive caseation necrosis. Ziehl Neelsen staining for acid-fast bacilli (AFB) was negative. However, because of a strong suspicion of Mycobacterium infection, PCR for M. tuberculosis genome was done, using the nested PCR technique. RESULTS: Polymerase chain reaction for M. tuberculosis showed amplification of Mycobacterium tuberculosis genome with the nested PCR technique. CONCLUSION: Our case indicates that PCR can be a valuable tool in the diagnosis of conjunctival tuberculosis from paraffin sections.