Infectious causes of posterior uveitis and panuveitis in Thailand

Diagnostic and therapeutic results of aqueous real-time polymerase chain reaction in infectious uveitis

OBJECTIVE

This study was aimed primarily at describing the results of aqueous real-time polymerase chain reaction (RT-PCR) and reporting the rate of therapeutic modifications directly attributable to this procedure (profitability). Our secondary outcome was to compare demographic and clinical characteristics between patients with RT-PCR positivity and those with RT-PCR negative results.

DESIGN

Retrospective observational study conducted at the Uveitis Service of San Raffaele Hospital (Milan, Italy) between November 2016 and July 2022.

PARTICIPANTS

Patients with infectious uveitis suspect (anterior, intermediate, posterior uveitis, or panuveitis).

METHODS

Patients with suspected infectious uveitis underwent aqueous RT-PCR for detection of herpes simplex 1 (HSV-1), herpes simplex 2 (HSV-2), varicella zoster virus (VZV), cytomegalovirus (CMV), and Toxoplasma gondii.

RESULTS

Sixty-five eyes of 61 patients (60 ±16 years of age; 54% males) were included. Aqueous RT-PCR tested positive in 58% and negative in 42% of patients. CMV and HSV-1 were the most frequently detected pathogens. RT-PCR confirmed clinical suspicion in 38% of patients and altered the presumed etiologic diagnosis and treatment in 20% of patients. Profitability was associated with CMV positivity. HSV-1 positivity was related to iris atrophy. CMV positivity was correlated with keratic precipitates. Vitritis and retinitis were related to VZV, CMV, and T. gondii detection. Synechiae, retinitis, and neuritis were related to positive tests regardless of the pathogen investigated. Early complications related to paracentesis were rarely reported.

CONCLUSION

Aqueous RT-PCR was a safe semi-invasive tool to confirm a presumptive diagnosis and to change initial suspicion in ambiguous cases of herpetic uveitis. Thus aqueous RT-PCR may alter therapeutic management.

Prevalence of Ocular Toxoplasmosis in the General Population and Uveitis Patients: A Systematic Review and Meta-Analysis

PURPOSE

The present study aimed to estimate the global prevalence of ocular toxoplasmosis in the general population and patients with uveitis.

METHODS

Four electronic databases were searched and 130 studies for evaluating the prevalence of OT among the general population and uveitis patients were included.

RESULTS

The pooled prevalence of OT among the general population was estimated at 2% (95% CI, 2-3%; 762/486 051). The highest prevalence rate was observed in America 6% (95% CI, 1-11%). In uveitis patients, a prevalence rate of 9% (95% CI, 8-10%; 5668/88 006) was reported. The countries with a lower middle income had higher prevalence rates. The prevalence of OT in posterior uveitis 33% (95%CI, 24-42%) was substantially higher than in panuveitis 7% (95% CI, 5-8%).

CONCLUSION

Our results provide a new perspective on the prevalence of OT. Knowledge of international and regional patterns of disease is essential for the establishment of precise diagnostic protocols and control programs.

Pattern of uveitis in a referral ophthalmology center in Northeastern Thailand

PURPOSE

To report the characteristics and epidemiology of uveitis in a university-based referral center in northeastern Thailand and review the uveitis patterns present in various regions worldwide.

METHODS

A retrospective review of all medical records for new patients visiting the uveitis clinic at Srinagarind hospital, Khon Kaen University, between August 2016 and June 2021, was conducted.

RESULTS

A total of 522 uveitis patients were included in this study. Disease etiologies were categorized as non-infectious 35.8% (187/522), infectious 32.8% (171/522), and undetermined cause 31.4% (164/522). Specific diagnoses were established in 68.6% of cases. Vogt-Koyanagi-Harada (VKH) (14.2%) was identified as the most common specific diagnosis, and tuberculosis (6.7%) ranked highest among infectious causes.

CONCLUSIONS

Although non-infectious uveitis is observed predominantly in this region, the proportion of infectious uveitis is relatively more common than in developed countries. We have found no cause for one-third of our patients despite the utilization of PCR and serology for diagnostic purposes.

Performance of Metagenomic Next-Generation Sequencing of Cell-Free DNA From Vitreous and Aqueous Humor for Diagnoses of Intraocular Infections

BACKGROUND

Delayed diagnosis and improper therapy for intraocular infections usually result in poor prognosis. Due to limitations of conventional culture and polymerase chain reaction methods, most causative pathogens cannot be identified from vitreous humor (VH) or aqueous humor (AH) samples with limited volume.

METHODS

Patients with suspected intraocular infections were enrolled from January 2019 to August 2021. Metagenomic next-generation sequencing (mNGS) was used to detected causative pathogens.

RESULTS

This multicenter prospective study enrolled 488 patients, from whom VH (152) and AH (336) samples were respectively collected and analyzed using mNGS of cell-free DNA (cfDNA). Taking final comprehensive clinical diagnosis as the gold standard, there were 39 patients with indefinite final diagnoses, whereas 288 and 161 patients were diagnosed as definite infectious and noninfectious diseases, respectively. Based on clinical adjudication, the sensitivity (92.2%) and total coincidence rate (81.3%) of mNGS using VH samples were slightly higher than those of mNGS using AH samples (85.4% and 75.4%, respectively).

CONCLUSIONS

Using mNGS of cfDNA, an era with clinical experience for more rapid, independent, and impartial diagnosis of bacterial and other intraocular infections can be expected.

Infectious Uveitis in Horses and New Insights in Its Leptospiral Biofilm-Related Pathogenesis

Uveitis is a sight-threatening eye disease in equids known worldwide that leads to considerable pain and suffering. By far the most common type of uveitis in Germany and neighboring countries is classical equine recurrent uveitis (ERU), which is caused by chronic intraocular leptospiral infection and is the main cause of infectious uveitis in horses. Other infectious causes are extremely rare and are usually clinically distinguishable from ERU. ERU can be treated very effectively by vitreous cavity lavage (vitrectomy). For proper indications of this demanding surgery, it is necessary to differentiate ERU from other types of uveitis in which vitrectomy is not helpful. This can be conducted on the basis of anamnesis in combination with ophthalmologic findings and by aqueous humor examination. During vitrectomy, vitreous material is obtained. These vitreous samples have historically been used for numerous etiologic studies. In this way, a chronic intraocular leptospiral infection has been shown to be the cause of typical ERU and, among other findings, ERU has also been recognized as a biofilm infection, providing new insights into the pathogenesis of ERU and explaining some thus far unexplainable phenomena of ERU. ERU may not only have transmissible aspects to some types of uveitis in humans but may also serve as a model for a spontaneously occurring biofilm infection. Vitreous material obtained during therapeutically indicated vitrectomy can be used for further studies on in vivo biofilm formation, biofilm composition and possible therapeutic approaches.

Usefulness of aqueous and vitreous humor analysis in infectious uveitis

OBJECTIVE

To evaluate the role of intraocular fluid analysis as a diagnostic aid for uveitis.

METHODS

Twenty-eight samples (27 patients including 3 HIV-infected patients) with active (n=24) or non-active (n=4) uveitis were submitted to aqueous (AH; n=12) or vitreous humor (VH) analysis (n=16). All samples were analyzed by quantitative PCR for herpes simplex virus (HSV), varicella zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV) and Toxoplasma gondii.

RESULTS

The positivity of the PCR in AH was 41.7% (5/12), with 50% (2/4) in immunocompetent and 67% (2/3) in HIV+ patients. The positivity of the PCR in VH was 31.2% (5/16), with 13% (1/8) in immunocompetent and 50% (4/8) in immunosuppressed HIV negative patients. The analysis was a determinant in the diagnostic definition in 58% of HA and 50% of VH.

CONCLUSION

Even in posterior uveitis, initial AH analysis may be helpful. A careful formulation of possible clinical diagnosis seems to increase the chance of intraocular sample analysis being meaningful.

Infectious uveitis in immunodeficient HIV-negative patients: A retrospective study

AIMS

Cases of infectious uveitis in immunodeficient patients may present with atypical clinical features because the clinical course of disease is usually affected by the compromised immune system. Therefore, it is sometimes difficult to determine the correct diagnosis. The aim of this study was to evaluate a prevalence of immunodeficient HIV-negative individuals among patients with infectious uveitis and to assess diagnostic and therapeutic approaches.

METHODS

A retrospective study.

RESULTS

In years 2003-2017, we diagnosed 594 patients with infectious uveitis. In 35 of them, infectious uveitis occurred on the basis of immunodeficiency (malignancy, immunosuppressive therapy etc.). The most common infectious uveitis was cytomegalovirus retinitis, followed by acute retinal necrosis, herpetic anterior uveitis, endogenous fungal endophthalmitis, toxoplasmic retinochoroiditis, progressive outer retinal necrosis and syphilis. In indicated cases, intraocular fluid examination was a valuable diagnostic tool. After initiation of treatment, improvement of BCVA was observed in 13 eyes, stabilization in 13 eyes and deterioration in 11 eyes. In some patients who experienced adverse effects of medication, the recommended doses were decreased.

CONCLUSION

Our experience shows that patients with diagnoses of acute retinal necrosis or progressive outer retinal necrosis have a poor visual prognosis. The occurrence of cytomegalovirus retinitis signifies a very unfavorable survival prognosis in patients who underwent hematopoietic stem cell transplantation; the patients in our study died within 1 year from cytomegalovirus retinitis diagnosis.

Coinfections and differential diagnosis in immunocompetent patients with uveitis of infectious origin

BACKGROUND

Making a definite diagnosis of infectious uveitis is a challenging task because many other infectious, and non-infectious uveitis, may have similar non-specific symptoms and overlapping clinical appearances. Co-infections in immunocompetent patients are not frequently proved with traditional serologic-diagnostic tools.

METHODS

Descriptive transversal study, in a Uveitis Service of an Ophthalmology Reference Center, in Bogotá, Colombia, from July 2014 to February 2016. Aqueous humor (AH) and/or vitreous fluid, blood and serum samples were collected from consecutive patients suspected of having infectious uveitis. The diagnosis of ocular toxoplasmosis (OT) was confirmed by the Goldmann-Witmer coefficient (GWC) and by polymerase chain reaction (PCR). Differential diagnosis by PCR in AH was done for viral origin such as Cytomegalovirus (CMV), Herpes simplex virus type 1 (HSV1), Herpes simplex virus type 2 (HSV2), Varicella zoster virus (VZV), Epstein-Barr virus (EBV) and Mycobacterium tuberculosis.

RESULTS

In 66 Colombian patients with uveitis of presumed infectious origin: 22 (33.3%) were confirmed as OT, 16 (24.2%) as undetermined OT, five (7.5%) as co-infections and 23 (34.8%) as other uveitis. Toxoplasma coinfection with M. tuberculosis was identified in one case by PCR and in four cases with HSV by GWC. The initial clinical diagnosis changed, after laboratory examination, in 21 cases (31.8%).

CONCLUSIONS

Clinical diagnosis can be changed by laboratory examination in a significant proportion of cases of uveitis. Diagnosis of OT should combine the use of PCR and GWC to reach the maximum of confirmation of cases. The use of multiple laboratory methods is necessary to identify co-infections and viral infections that can mimic OT in immunocompetent patients.

Polymerase Chain Reaction and Goldmann-Witmer Coefficient to Examine the Role of Epstein-Barr Virus in Uveitis

PURPOSE

To use polymerase chain reaction (PCR) and Goldmann-Witmer Coefficient (GWC) calculation to search for evidence that Epstein-Barr virus (EBV) causes uveitis.

METHODS

A prospective cross-sectional study where participants with positive multiplex EBV PCR results were further investigated by: 1) real-time PCR for EBV viral loads (VL) and 2) EBV GWC.

RESULTS

Eleven of 106 consecutive uveitis patients (10.4%) had positive multiplex PCR for EBV on aqueous humor sampling and 7/11 (63.6%) were HIV-positive. Only 4/10 (40%) cases had detectable intraocular EBV VLs which were always lower than the blood or plasma VL. EBV GWC was negative in all 10 cases tested. In 9/11 (81.8%) of these cases an alternative, more plausible cause of uveitis was identified.

CONCLUSION

We found no evidence of active intraocular replication or antibody production to prove that EBV caused uveitis in these cases. In most cases an alternative treatable cause of uveitis was identified.

Comparison of the ocular characteristics of anterior uveitis caused by herpes simplex virus, varicella-zoster virus, and cytomegalovirus

PURPOSE

To compare the clinical characteristics of anterior uveitis (AU) caused by herpes simplex virus (HSV), varicella-zoster virus (VZV), or cytomegalovirus (CMV).

METHODS

The medical records were reviewed of 46 patients whose diagnoses were based on their clinical characteristics [e.g., unilateral involvement, presence of keratic precipitates (KPs), and elevation of intraocular pressure (IOP)] and on PCR detection of herpes virus DNA in the aqueous humor. The demographics, chief complaints, and clinical characteristics of the three types of herpetic AU were compared.

RESULTS

Of the 46 patients with AU, eight had HSV-AU, 20 had VZV-AU, and 18 had CMV-AU. HSV-AU and VZV-AU shared common features, i.e., a relatively acute disease process and the presence of large KPs. Among the three groups of patients, the characteristic features of those with VZV-AU were severe intraocular inflammation, as shown by severe aqueous flare, highest viral load in the aqueous humor, and presence of segmental iris atrophy. In comparison, patients with CMV-AU had the mildest intraocular inflammation, lowest corneal endothelial cell density, and highest IOP.

CONCLUSIONS

Although the AU caused by each of the three types of herpes viruses has a number of common features, each disease also has distinct features that should facilitate an accurate diagnosis.