Severe herpetic keratitis. I: Prevalence of visual impairment in a clinic population

Clinical and Demographic Characteristics of Herpetic Keratitis Patients-Tertiary Centre Experience

Background and Objectives: Herpes simplex keratitis (HSK) is the leading infectious cause of corneal damage and associated loss of visual acuity. Because of its frequent recurrence, it represents a major health problem; thus, timely and accurate diagnosis is the key to successful treatment. To enable this, we aimed to determine HSK patients' demographic and clinical features. Materials and Methods: This prospective study included 55 patients diagnosed with HSK between March 2019 and August 2022 at the Department of Ophthalmology, Clinical Hospital Rijeka. Results: We found that HSK is most prevalent in the elderly, with 72.73% of patients older than 60. The most common HSK types were dendritic (HSK-D; 43.64%) and stromal with epithelial ulceration (HSK-SEU 23.64%). HSK recurrences occurred in 65.45% of patients, with most having two to five recurrences (55.56%). Visual acuity at presentation (65.5%) and after treatment (50.9%) was mostly in the 20/50 range. The longest period until the disease symptoms were resolved was in the group with stromal HSK without epithelial ulceration (HSK-SnEU), for which symptoms lasted more than 11 weeks in 87.5% of patients. The overall incidence of HSK-related complications was high (85.45%), with 76.4% of patients having corneal scarring. The average time from symptom to treatment was 15.78 days. Interestingly, we observed a strong seasonality in the incidence of HSK, which was most prevalent in the colder months, with 63.6% of cases occurring between October and March. Conclusions: To the best of our knowledge, this is the first prospective study in Croatia, and one of the few in Europe, to describe the demographic and clinical features of HSK patients. We found that HSK is most common in the elderly population, with its dendritic form as a clinical presentation. We have shown that HSK is prone to recurrence and secondary complications, with a worryingly long time between symptom and treatment, indicating the need for diagnostic testing in routine practice.

Appearance of herpes simplex keratitis on anterior segment optical coherence tomography

PURPOSE

To describe the anterior segment AS-OCT findings of herpetic simplex keratitis.

METHODS

Forty-two eyes of 42 patients with proven herpetic keratitis of varying severity were included in this prospective, observational, non-comparative case series study. All subjects underwent ophthalmologic examination and AS-OCT imaging.

RESULTS

Twenty-five of the 42 eyes (59.5%) had sub-epithelial infiltrates. In 11 of these cases, the overlying epithelium appeared intact, but in 14 cases, hydropic changes, heaping, and defects were observed. Seventeen eyes (40.5%) showed stromal involvement: six cases with scar at presentation and one case associated with uveitis. Stromal infiltrates were also seen, in ten cases, as a diffuse or local lentiform or spindle-shaped hyper-reflective area in the stroma.

CONCLUSION

Herpetic keratouveitis has characteristic features on AS-OCT images. This study demonstrates that herpetic keratitis also has characteristic AS-OCT features, including sub-epithelial infiltration and specific stromal hyper-reflective patterns. These features are not unique to herpetic keratitis, but AS-OCT imaging may provide useful supplementary information for diagnosing and monitoring herpetic keratitis.

Lytic HSV-1 infection induces the multifunctional transcription factor Early Growth Response-1 (EGR-1) in rabbit corneal cells

BACKGROUND

Herpes simplex virus type-1 (HSV-1) infections can cause a number of diseases ranging from simple cold sores to dangerous keratitis and lethal encephalitis. The interaction between virus and host cells, critical for viral replication, is being extensively investigated by many laboratories. In this study, we tested the hypothesis that HSV-1 lytic infection triggers the expression of important multi-functional transcription factor Egr1. The mechanisms of induction are mediated, at least in part, by signaling pathways such as NFκB and CREB.

METHODS

SIRC, VERO, and 293HEK cell lines were infected with HSV-1, and the Egr-1 transcript and protein were detected by RT-PCR and Western blot, respectively. The localization and expression profile of Egr-1 were investigated further by immunofluorescence microscopy analyses. The recruitment of transcription factors to the Egr-1 promoter during infection was studied by chromatin immunoprecipitation (ChIP). Various inhibitors and dominant-negative mutant were used to assess the mechanisms of Egr-1 induction and their effects were addressed by immunofluorescence microscopy.

RESULTS

Western blot analyses showed that Egr-1 was absent in uninfected cells; however, the protein was detected 24-72 hours post treatment, and the response was directly proportional to the titer of the virus used for infection. Using recombinant HSV-1 expressing EGFP, Egr-1 was detected only in the infected cells. ChIP assays demonstrated that NFкB and cAMP response element binding protein (CREB) were recruited to the Egr-1 promoter upon infection. Additional studies showed that inhibitors of NFкB and dominant-negative CREB repressed the Egr-1 induction by HSV-1 infection.

CONCLUSION

Collectively, these results demonstrate that Egr-1 is expressed rapidly upon HSV-1 infection and that this novel induction could be due to the NFкB/CREB-mediated transactivation. Egr-1 induction might play a key role in the viral gene expression, replication, inflammation, and the disease progression.

The spectrum of herpes simplex virus disease of the anterior segment in the 1990s

We have sampled our clinic population in order to ascertain the proportion with herpetic eye disease of the anterior segment. The age, gender predominance, and incidence of bilateral disease amongst such patients has not changed over the past 20 years. The predominant disease type was stromal keratitis, with significant morbidity and visual handicap. Herpetic eye disease of the anterior segment utilizes only 1% of out-patient clinic resources overall, but 17% of specialist external disease clinic time. There was a statistically significant correlation between total length of follow-up and reduced visual acuity. It would seem that the prevalence of herpetic eye disease of the anterior segment appears to have halved since comparable reports were published. In addition, the prognosis of the disease, in terms of the prevalence of visual impairment, has worsened.

Herpetic eye attacks: variability of circannual rhythms

BACKGROUND

The issue of seasonal variation of herpetic ocular infections is still controversial. This study was designed to examine whether this variation exists and can be defined as a significant circannual rhythm.

METHODS

The patterns of recurrent attacks were monitored in 541 patients over a period of 15 years. Rhythm parameters were analysed according to age, sex, and clinical signs.

RESULTS

The majority of herpetic eye attacks exhibited the highest peak in January (p < 0.04), except in the group of atopic children where the incidence of the disease peaked in September (p < 0.05). Among the various clinical forms, significant circannual periodicities were found only in the occurrence of epithelial herpetic keratitis (p < 0.03). The rhythms were detected among males (p < 0.03) but not among females. No direct correlation was demonstrated between the presence of the rhythms and the triggering effect of upper respiratory tract infections.

CONCLUSIONS

Chronoepidemiological evaluation of individual reactivation patterns may be beneficial to certain patients and contribute to the optimisation of the treatment when prophylaxis is considered.

Herpetic Eye Disease Study. A controlled trial of topical corticosteroids for herpes simplex stromal keratitis

PURPOSE

To evaluate the efficacy of topical corticosteroids in treating herpes simplex stromal keratitis.

METHODS

The authors performed a randomized, double-masked, placebo-controlled, multicenter clinical trial of 106 patients with active herpes simplex stromal keratitis who had not received any corticosteroids for at least 10 days before study enrollment. Patients were assigned to the placebo group (n = 49) or the steroid group (topical prednisolone phosphate; n = 57); both regimens were tapered over 10 weeks. Both groups received topical trifluridine. Visual acuity assessment and slit-lamp biomicroscopy were performed weekly for 10 weeks, every other week for an additional 6 weeks or until removal from the trial, and at 6 months after randomization.

RESULTS

The time to treatment failure (defined by specific criteria as persistent or progressive stromal keratouveitis or an adverse event) was significantly longer in the steroid group compared with the placebo group. Compared with placebo, corticosteroid therapy reduced the risk of persistent or progressive stromal keratouveitis by 68%. The time from randomization to resolution of stromal keratitis and uveitis was significantly shorter in the steroid group compared with the placebo group even though both groups included patients who were removed from the study and treated with topical corticosteroids according to best medical judgment. Nineteen (33%) of the steroid-treated patients and 11 (22%) of the placebo-treated patients completed the 10 weeks of protocol therapy and had stable, noninflamed corneas after 16 weeks. At 6 months after randomization, no clinically or statistically significant differences in visual outcome or recurrent herpetic eye disease were identified between the steroid and placebo groups.

CONCLUSIONS

The topical corticosteroid regimen used in this study was significantly better than placebo in reducing persistence or progression of stromal inflammation and in shortening the duration of herpes simplex stromal keratitis. Postponing steroids during careful observation for a few weeks delayed resolution of stromal keratitis but had no detrimental effect as assessed by visual outcome at 6 months.

Anterior segment ischemia in chronic herpes simplex keratouveitis

Six patients with chronic herpes simplex keratouveitis developed a rapidly progressive ocular inflammation unresponsive to corticosteroid and antiviral therapy. Severe secondary glaucoma unresponsive to maximum medical therapy ensued and was treated by cyclocryotherapy in five patients. Ocular ischemia with secondary corneal and scleral calcification subsequently developed in all six patients. All had also received prolonged topical therapy with topical antiviral agents, corticosteroids, beta adrenergic blockers and epinephrine compounds. Three eyes eventually required enucleation for the relief of pain; one stabilized, and two others became phthisical. One of the phthisical eyes developed a secondary fungal endophthalmitis. Histopathologic examination of the three enucleated globes revealed extensive corneal, scleral and conjunctival calcification, secondary angle closure, iris and ciliary body necrosis, focal choroiditis, retinal necrosis and atrophy. The syndrome recognized in these patients appears to be a rare but devastating complication of herpes simplex keratouveitis, possibly exacerbated by the application of cyclocryotherapy and other factors.