Rickettsial retinitis: Direct bacterial infection or an immune-mediated response?

Optical Coherence Tomography and Optical Coherence Tomography Angiography in Neglected Diseases

A group of self-limiting and frequently neglected diseases exist in the literature like Rickettsial disease, Malaria, Dengue fever, Chikungunya, West Nile virus infection, Rift Valley fever, Bartonellosis, or Lyme disease which are poorly understood due to lack of proper diagnostic testing. Currently, multimodal imaging has become a critical modality in the diagnosis and management of ocular diseases. Optical coherence tomography (OCT) is one such remarkable imaging modality in the field of ophthalmology providing high-resolution, cross-sectional images of the retina and choroid with the recent advances such as enhanced depth imaging and swept source OCT. Additionally, OCT angiography (OCTA) has further revolutionised dynamic imaging of retinal and choroidal vasculature non-invasively. This review article highlights the OCT and OCTA biomarkers in the diagnosis and prognosis of the aforementioned neglected diseases.

Treatment Outcomes of Presumed Rickettsial Retinitis: Evidence from OCTA Based Quantitative Analysis

AIM

To quantify retinal ischemia following presumed rickettsial retinitis (RR). To compare outcomes between initial treatment with Doxycycline (Group 1) versus steroids (Group 2).

METHODS

Retrospective analysis of patients with presumed RR was done. ImageJ software was used to obtain %area of ischemia on swept-source optical coherence tomography angiography (SS-OCTA).

RESULTS

Eleven eyes of 8 patients belonged to Group1 and 6 eyes of 3 patients belonged to Group 2. The BCVA improved from logMAR 0.8 ∓ 0.7 to logMAR 0.06 ∓ 0.08 (p < 0.002) and central foveal thickness (CFT) changed from 479μ ∓ 341.3μ to 163.5μ ∓ 20.5μ (p < 0.005) after a median of 5 weeks in Group 1. In Group 2, BCVA improved from logMAR 1.03 ∓ 0.05 to logMAR 0.23 ∓ 0.23 (p < 0.004) and CFT changed from 286.5μ ∓ 158.8μ to 177.5μ ∓ 25.9μ (>0.05) following a mean of 11 weeks. Mean %area of ischemia was 4.6 ∓ 1.5 in Group 1 and 13.9 ∓ 4.1 in Group 2.

CONCLUSION

Analysis of flow deficit on SS-OCTA confirms that treatment with Doxycycline in presumed RR results in less ischemia and quicker recovery than initial treatment with steroids.

Post-fever Retinitis With a Positive Weil-Felix Test: A Study From a Tertiary Center in South India

Background Post-fever retinitis (PFR) is reported two to six weeks after fever and affects one or both eyes. Rickettsial fever is one of the most common causes of PFR. This study aimed to report the clinical features and treatment outcomes of PFR cases with a positive Weil-Felix test. Methodology In this study, we collected demographic data, fever details, eye symptoms, ocular examination findings, optical coherence tomography (OCT) and fundus fluorescein angiography findings, laboratory findings, and length of follow-up of consecutive PFR cases with a positive Weil-Felix test. All cases were treated with oral doxycycline and prednisolone. Final best-corrected visual acuity (BCVA) and ocular examination findings were recorded. Visual field examination and follow-up OCT results were noted if available. Results A total of nine patients (eight males) with a mean age of 39.1 years with fever before ocular symptoms and positive Weil-Felix test were included. Six patients had bilateral disease. The mean initial and final BCVA in the affected eyes was 1.16 and 0.35 logMAR units, respectively (p < 0001). All 15 eyes had typical white retinitis patches and retinal hemorrhages which resolved after treatment. OCT showed hyperreflectivity and inner retinal disorganization over retinitis patches. White subretinal lines were noted in three patients and retinal nerve fiber bundle defect with corresponding visual field defect was seen in one eye. Conclusions In this study, PFR due to rickettsia infections has been reported from our region for the first time. Hence, eye specialists in the region should be aware of this entity.

A Review of Rickettsial Diseases Other Than Scrub Typhus in India

Rickettsial diseases (RD) are widely reported all over the world. Scrub typhus (ST) is a major tropical infection which is well documented all over India. Therefore, the index of suspicion of scrub typhus is high among physicians with regard to patients presenting with acute febrile illness (AFI) and acute undifferentiated febrile illness (AUFI) in India. Rickettsial diseases other than ST (non-ST RDs), which include spotted fever group (SFG) rickettsioses and typhus group (TG) rickettsioses are not uncommon in India, but the index of suspicion is not as high as ST unless there is a history of the presence of fever with rashes and/or recent arthropod bites. This review aims to look into the Indian scenario on the epidemiology of non-ST RDs, especially the SFG and TG rickettsioses based on various investigations, spectrum of clinical presentation, challenges and gaps in knowledge to suspect and diagnose these infections.

Case Report: Optic neuritis as the initial presentation of Orientia tsutsugamushi infection detected by metagenomic next-generation sequencing

Scrub typhus is an acute febrile illness caused by Orientia tsutsugamushi infection, and typically manifested as fever, eschar, lymphadenopathy, rash, and other flu-like signs. Ocular involvement was not uncommon, and mostly occurred at post-fever or recovery stage in scrub typhus cases. We hereby report a case of scrub typhus presenting as unilateral optic neuritis (ON). A 56-year-old man going wild fishing nearly every day complained of a blurred vision and an inferior visual field defect in the right eye two or three days after an insect-bite like shin induration in his left leg. He was diagnosed as ON, and treated with dexamethasone in the local hospital. Unfortunately, his right eye vision progressively deteriorated during steroid therapy. Three days after steroid therapy ceased, he suffered from a high fever and painful subcutaneous masses in the left groin. Peripheral blood test by metagenomic next-generation sequencing (mNGS) was positive for Orientia tsutsugamushi, but negative for other pathogens. The diagnosis was then revised to scrub typhus and ON. His systemic symptoms rapidly disappeared after oral doxycycline and omadacycline therapy. However, his right eye vision continuously deteriorated to hand motion. Further serum tests for aquaporin 4-IgG antibody and myelin oligodendrocyte glycoprotein-IgG antibody were both negative, but for anticardiolipin IgM and beta-2-glycoprotein-I IgM were both positive. The patient's right eye vision gradually improved after doxycycline combined with steroid pulse therapy. Our case indicates that ON in scrub typhus cases may present as a parainfectious inflammation, and that mNGS is a useful and valuable method for early diagnosis of scrub typhus.

Rickettsia rickettsii infection as an unusual cause of pediatric retinitis: A case report

Purpose

To report a case of infectious pediatric retinitis attributed to Rocky Mountain spotted fever which is rarely reported in the United States.

Observations

A previously healthy 14-year-old male return traveler from Mexico was admitted to the pediatric ICU with septic shock and a diffuse rash. He subsequently complained of blurry vision and was found to have evidence of retinitis on exam. Infectious workup revealed high titers of rickettsial IgM and IgG antibodies. He was treated successfully with 14 days doxycycline and followed up in clinic with improvement in his visual complaints and retinitis.

Conclusions and importance

Rickettsioses are worldwide endemic zoonotic infections caused by Gram negative obligate intracellular bacteria and spread to humans by infected ticks. Rickettsial infections, including Rocky Mountain spotted fever caused by Rickettsia rickettsii, are a cause of infectious retinitis, and atypical and zoonotic infections should remain on the differential diagnosis for patients presenting with rash, systemic illness, and visual complaints, even if the patient's travel or exposure history do not immediately suggest a likely rickettsial infection. In general, the ocular manifestations of rickettsial infection improve with systemic doxycycline treatment of the underlying infection.

Macular infarction in presumed rickettsial retinitis with late vascular remodelling

A middle-aged man had been diagnosed as retinitis and treated with steroids previously. The patient had developed macular infarction in the course of illness. We diagnosed him to have rickettsial retinitis on the basis of clinical features and positive Weil-Felix test. The patient's condition improved after treatment with oral antibiotics. The vasculature of the infarcted macula showed partial reperfusion late in the course of follow-up.

Clinical features, optical coherence tomography findings and treatment outcomes of post-fever retinitis

Objectives:

To study the clinical features, optical coherence tomography (OCT) findings, treatment options and follow-up outcomes of post-fever retinitis (PFR).

Subjects:

A total of 19 eyes of 13 patients, diagnosed with PFR (retinitis following febrile episode) over 2 years were retrospectively studied.

Methods:

Documented history, baseline clinical features and systemic investigations performed for PFR were reviewed. Fundus findings, foveal architecture on swept-source OCT, the treatment options and the follow-up outcomes including best-corrected visual acuity (BCVA) and central foveal thickness (CFT) were reviewed and analyzed.

Results:

Common fundus findings included whitish retinitis lesions (100%), macular star (95%, 18eyes), retinal flame-shaped hemorrhages (63%, 12 eyes), inflammatory retinal vessels (30%, 6 eyes), vitreous hemorrhage (one eye) and OCT findings included neuro-sensory detachment (79%, 15 eyes), intraretinal white dots (89.5%,17 eyes). The baseline median log MAR BCVA and CFT were 1.30 (interquartile range (IQR):0.8–1.8) and 423 microns (IQR:182–555). Overall, nine patients (12 eyes) received a combination of oral doxycycline and oral steroids and four patients (7 eyes) received a combination of oral doxycycline, oral steroid and intravitreal anti-vascular endothelial growth factor (IVA). Significant improvement was evident at 8 weeks in median BCVA (0.50, IQR: 0.3–0.8, p < 0.05) and median CFT (223 micron, IQR: 170–256, p < 0.05) though only 26% (5 eyes) attained BCVA > = 6/12.

Conclusion:

Our study puts forth certain characteristic fundus and OCT features of PFR. A combination of oral doxycycline and oral steroids as a treatment option showed improvement in BCVA and CFT. Additional IVA helps in faster visual recovery in patients presenting with severe macular edema at onset.

Post-fever retinitis - Newer concepts

Post-fever retinitis (PFR) is an infectious or para-infectious uveitic entity caused by bacterial or viral agents and seen mainly in tropical countries. Systemic symptoms such as joint pain, skin rash are common during the febrile stage. On the basis of only clinical presentation, it is difficult to pin-point the exact etiology for PFR. Serological investigations, polymerase chain reaction, and knowledge of concurrent epidemics in the community may help to identify the etiological organism. Bacterial causes of PFR such as rickettsia and typhoid are treated with systemic antibiotics, with or without systemic steroid therapy, whereas PFR of viral causes such as chikungunya, dengue, West Nile virus, and Zika virus have no specific treatment and are managed with steroids. Nevertheless, many authors have advocated mere observation and the uveitis resolved with its natural course of the disease. In this article, we have discussed the clinical features, pathogenesis, investigations, and management of PFR.

Rickettsia conorii retinitis: an emerging infection in the southeast of the Iberian Peninsula

CASE REPORT

A case is presented of a 60-year-old patient with loss of visual acuity in both eyes after fever and skin rash with palmoplantar involvement. After a complete examination and relevant complementary tests, the diagnosis of retinitis was made in the context of Rickettsia conorii infection. The evolution after treatment with doxycycline and prednisone at six weeks with significant anatomical and functional improvement is presented. Rickettsiosis is an emerging zoonosis that can present with ocular involvement. This is usually a multifocal retinitis affecting posterior pole with macular serous detachment and vitritis. Clinical suspicion will require serological confirmation for a definitive diagnosis. Treatment with antibiotics and corticosteroids has been shown to be effective. It should be taken into account in Mediterranean endemic areas, and in in the summer period, where the risk is much higher.

Comparison of the Vitreous Fluid Bacterial Microbiomes between Individuals with Post Fever Retinitis and Healthy Controls

Ocular microbiome research has gained momentum in the recent past and has provided new insights into health and disease conditions. However, studies on sight threatening intraocular inflammatory diseases have remained untouched. In the present study, we attempted to identify the bacterial microbiome associated with post fever retinitis using a metagenomic sequencing approach. For this purpose, bacterial ocular microbiomes were generated from vitreous samples collected from control individuals (VC, n = 19) and individuals with post fever retinitis (PFR, n = 9), and analysed. The results revealed 18 discriminative genera in the microbiomes of the two cohorts out of which 16 genera were enriched in VC and the remaining two in PFR group. These discriminative genera were inferred to have antimicrobial, anti-inflammatory, and probiotic function. Only two pathogenic bacteria were differentially abundant in 20% of the PFR samples. PCoA and heatmap analysis showed that the vitreous microbiomes of VC and PFR formed two distinct clusters indicating dysbiosis in the vitreous bacterial microbiomes. Functional assignments and network analysis also revealed that the vitreous bacterial microbiomes in the control group exhibited more evenness in the bacterial diversity and several bacteria had antimicrobial function compared to the PFR group.

Epidemic Retinitis with Macular Edema -Treatment Outcome with and without Steroids

Purpose: To study treatment outcomes with and without oral corticosteroids in epidemic retinitis (ER).Method: A retrospective, observational study of 35 eyes of 29 patients diagnosed as ER. Days taken for resolution of macular edema and retinitis lesions were compared in patients treated with oral antibiotics (Group 1) and with corticosteroids-antibiotics combination (Group 2).Result: Eighteen eyes of 14 patients and 17 eyes of 15 patients formed Groups 1 and 2, respectively. At the presentation, mean best-corrected visual acuity (BCVA) was 40 and 44 letters and mean central macular thickness was 648 (±243) and 626 (±256) microns in Groups 1 and 2, respectively. Macular edema resolved in 30.83 and 31.94 days; retinitis lesions resolved in 36.71 and 41.41 days in Groups 1 and 2, respectively. BCVA improved to 74 and 77 letters in Groups 1 and 2, respectively.Conclusion: ER with macular edema can be well managed without corticosteroids.

Retinal vasculitis with Chronic Recurrent Multifocal Osteomyelitis: a case report and review of the literature

Background

Concurrent presentation of retinal vasculitis with mixed sclerotic and lytic bone lesions is rare.

Case presentation

We present the case of a 37-year old woman with a several year history of episodic sternoclavicular pain who presented for rheumatologic evaluation due to a recent diagnosis of retinal vasculitis. We review the differential diagnosis of retinal vasculitis, along with the differential diagnosis of mixed sclerotic and lytic bone lesions. Ultimately, bone marrow biopsy confirmed diagnosis of chronic recurrent multifocal osteomyelitis (CRMO). Concurrent presentation of CRMO with retinal vasculitis is extremely rare but important to recognize. The patient demonstrated clinical response to prednisone and tumor necrosis factor-alpha inhibition (TNF-i).

Conclusion

This case reports and unusual presentation of CRMO spectrum disease involving the sternum and sternoclavicular joint with concurrent retinal vasculitis.

Ocular manifestations of Rickettsia conorii in South India

Purpose:

Among the major groups of rickettsiosis, the commonly reported diseases in India are: (a) Typhus group induced—scrub typhus, murine flea-borne typhus; (b) Spotted fever group induced—Indian tick typhus; and (c) Q fever. Though many scrub typhus outbreaks have been reported from India, only one outbreak of spotted fever—serologically proven Indian tick typhus (Rickettsia conorii)—has been reported. We report for the first time ocular manifestations of serologically proven R. conorii infection in a cluster of patients.

Methods:

In this retrospective study, case records patients with serologically proven Indian tick typhus (Rickettsia conorii) were reviewed for clinical manifestations and treatment outcomes.

Results:

In the months of February to April 2016, a cluster of 12 patients (23 eyes) visited us with defective vision. Examination showed multifocal retinitis; mostly bilateral; patients had a history of fever approximately 4 weeks prior to onset of symptoms. After excluding other causes of multifocal retinitis, a diagnosis of rickettsial retinitis was made after Weil–Felix test (WFT) was significantly positive, and enzyme-linked immunosorbent assay was positive for R. conorii. Course of the disease, visual outcome, and investigations are discussed. Doxycycline along with oral corticosteroids was effective in treating the condition.

Conclusion:

Systematic fundus examination should be part of the routine evaluation of any patient who presents with fever and/or skin rash living in or returning from a specific endemic area. Clinical clues to diagnosing ocular rickettsiosis could be multifocal retinitis predominantly involving the posterior pole and macular involvement in the form of serous macular detachment or macular hard exudates. A positive WFT still serves as a useful and cheap diagnostic tool for laboratory diagnosis of rickettsial disease. Doxycycline along with oral corticosteroids was effective in treating the condition.

An imaging-based treatment algorithm for posterior focal retinitis

Background:

In this paper, our aim was to describe an imaging-based empirical approach for categorizing and initiating treatment of immunocompetent patients with posterior focal retinitis, prior to the availability of results of expensive laboratory investigations.

Materials and methods:

The hospital records of 13 patients with posterior focal retinitis were reviewed.

Results:

Of the 13 patients, 9 were women and 4 were men. The mean age was 24 ± 8 years. Based on similarities in clinical presentation and imaging, we categorized our cases into three groups with different first-line therapeutic strategies. In the first group, patients had presumed toxoplasmosis (treated with oral cotrimoxazole); in the second group, patients had presumed viral (herpetic) etiology (treated with oral valacyclovir); and in the third group, patients had presumed nonherpetic, nontoxoplasma retinitis (treated with oral doxycycline). Positive serology results included Rickettsia (two patients), Borrelia (one patient), Toxoplasma (two patients), and herpes simplex virus (one patient).

Conclusion:

An empirical approach for early initiation of therapy in retinitis cases based on imaging features is described.

Ocular manifestations of rickettsia in children: common but frequently overlooked

We review two cases of ocular manifestations of Rickettsia conorii infection in children. A girl who presented unilateral visual loss with focal retinitis and macular oedema and a boy with unilateral central scotoma and bilateral anterior uveitis. Progressive functional and anatomic recovery was observed after oral antibiotics and steroids were initiated.