BARTONELLA HENSELAE NEURORETINITIS ASSOCIATED WITH CENTRAL RETINAL VEIN OCCLUSION, CHOROIDAL ISCHEMIA, AND ISCHEMIC OPTIC NEUROPATHY

Neurobartonelloses: emerging from obscurity!

BACKGROUND

Bartonella species are fastidious, intracellular bacteria responsible for an expanding array of human pathologies. Most are considered to be transmitted by direct inoculation with infected bodily fluids from a mammalian reservoir species or vector-transmitted through a variety of arthropod species and their excrement. However, there are mounting reports of infection in the absence of documented animal or vector contact. A variety of Bartonella species have been documented in conditions affecting both the peripheral and central nervous systems. More common conditions, including neuroretinitis, are often associated with Bartonella henselae. However, Bartonella quintana, the agent of trench fever, as well as emerging pathogens related to rodent reservoir species, B. grahamii and B. elizabethae, have also been documented. Encephalitis and encephalopathy, also most often associated with B. henselae, have been reported with B. quintana, B. washoensis (ground squirrels) and B. vinsonii subsp. vinsonii (voles) infections. Bartonella infections have also been associated with peripheral neuropathies, such as cranial nerve paresis and neuropathic pain, including infection with less commonly encountered species such as Bartonella koehlerae. Recently, molecular diagnostic testing revealed that DNA from Bartonella spp. was found to be more prevalent in blood of patients with neuropsychiatric disorders such as schizophrenia and psychoses compared to healthy controls.

METHODS

A systematic literature search was conducted on PubMed, Google Scholar and Web of Science. Search terms included Bartonella and specific neurological conditions and focused on peer-reviewed case reports published after 2012 pursuant to a prior review, with limited exceptions for conditions not previously covered. Published diagnostic testing, serology, molecular testing or pathology, were necessary for inclusion, except for one case which had clinical and epidemiological evidence consistent with diagnosis along with follow-up.

RESULTS

Neurobartonelloses included neuralgic amyotrophy, complex regional pain syndrome, chronic inflammatory demyelinating polyneuropathy, cranial nerve paralysis, Guillain-Barré syndrome, peripheral vasculitic polyneuropathy, acute transverse myelopathy, neuroretinitis, encephalitis/encephalopathy, cerebral vasculitis/aneurysm and neuropsychiatric conditions.

CONCLUSIONS

The breadth of reported symptoms and clinical syndromes associated with an increasing number of Bartonella species continues to expand. Increased clinical awareness of this important zoonotic pathogen is necessary to advance One Health among the medical and veterinary communities.

Central retinal vein occlusion associated with Bartonella henselae infection

PURPOSE

To report the clinical features and treatment course of a case of central retinal vein occlusion (CRVO) as the initial sign of ocular Bartonella henselae (B. henselae) infection.

OBSERVATION

A 36-year-old male was evaluated for unilateral vision loss. He denied prodromal symptoms but reported prior exposure to fleas. Best corrected visual acuity (BCVA) was 20/400 in the left eye. Clinical examination revealed a CRVO with atypical features including significant peripapillary exudates and peripheral vascular sheathing. Laboratory testing revealed elevated B. henselae IgG titers (1:512) with no abnormalities on hypercoagulability testing. The patient was treated with doxycycline and aflibercept with an excellent clinical response and improvement in BCVA to 20/25 in the left eye two months later.

CONCLUSION

CRVO is a rare but sight-threatening complication of ocular bartonellosis and can be the presenting sign of infection, even in the absence of cat exposure or prodromal symptoms.

CRVO associated with COVID-19 and MTHFR mutation in a 15-year-old male

Purpose

To report a case of a central retinal vein occlusion (CRVO) associated with COVID-19 in a patient predisposed to clotting due to a genetic mutation in methylenetetrahydrofolate reductase (MTHFR).

Observations

A 15-year-old male presented with 1 day of painless blurry vision in the left eye. Exam disclosed trace anterior chamber cell, anterior vitreous cell, optic nerve head edema, temporally displaced macular star, dilated tortuous veins, and diffuse intraretinal hemorrhages. Exam and FA was consistent with CRVO, however the macular star and OCT were suggestive of a neuroretinitis.The patient then presented to a children's hospital for further evaluation. A routine screen for COVID-19 via nasopharyngeal swab was positive with a high viral load. He also had a known history of an MTHFR mutation. Extensive laboratory and neuroradiologic evaluation excluded other infectious, inflammatory, and coagulopathic etiologies.

Conclusions and Importance

This is a case of CRVO associated with COVID-19 infection and an underlying systemic hypercoagulable mutation, with an initial presentation that mimicked neuroretinitis. This case provides valuable diagnostic learning points and expands our knowledge of possible ocular complications of COVID-19.

Posterior Segment Manifestations of Cat-scratch Disease: A Mini-review of the Clinical and Multi-modal Imaging Features

Bartonella henselae, an intracellular gram-negative bacillus, is usually transmitted from infected cats to humans by direct or indirect contact. The bacterium mainly infects erythrocytes and endothelial cells thereby leading to so called cat-scratch disease (CSD) and may present with various localised and/or systemic manifestations. The eye is the most commonly affected organ in disseminated CSD and ocular bartonellosis has been reported in 5-10% of CSD patients. The most well-known clinical feature of ocular bartonellosis is neuroretinitis but various sight-threatening posterior segment lesions involving the optic nerve, retinal vasculature, retinal and choroidal tissues may occur during the disease course. This mini-review aims to overview both the clinical and multi-modal imaging characteristics of posterior ocular segment manifestations of CSD.

Not cat-scratch disease: Bartonella henselae neuroretinitis associated with non-feline pet mammals

To describe the ocurrence of Bartonella-associated neuroretinitis secondary to non-feline pet exposure, we retrospectively reviewed medical records and imaging from patients with a clinical and serologic diagnosis of Bartonella henselae (BH). Retinal imaging included color fundus photography, optical coherence tomography (OCT) and fluorescein angiography (FA). Four eyes of two patients with cat-scratch disease were included in this study, with a mean age of 35 years. The mean follow-up was 13 months, after presentation of infectious neuroretinitis. Both patients suffered from bilateral neuroretinitis after direct contact with family pets (ferret and guinea pig). All patients were treated with a long-term systemic antimicrobial therapy. Visual acuity in all improved to 20/30 or better at six months. In conclusion, humans may develop cat-scratch disease when they are exposed to Bartonella henselae (BH) in the saliva of infected cats or BH-containing flea feces reaching the systemic circulation through scratches or mucous membranes. As the cat flea (Ctenocephalides felis) may reside on non-feline mammals, Bartonella-associated neuroretinitis may result from contact with other furred family pets.