A Traveling “Spot Sign” in Recurrent Amaurosis Fugax and Central Retinal Artery Occlusion

Monocular Painless Vision Loss in the Emergency Department: Multipurpose Utility of Point-of-Care Ultrasound

BACKGROUND

Eye-related symptoms are a common presentation in the emergency department (ED). The cases range from simple viral conjunctivitis to trauma-related eye injuries. One pathological condition that could lead to vision loss is retinal artery occlusion (RAO). Evaluating a patient with an eye symptom requires thorough eye examination and advanced imaging in certain instances. Consultation with an ophthalmologist is also necessary for cases that require treatment recommendations and further testing. In the ED, point-of-care ultrasound (POCUS) is a commonly used diagnostic tool that can be used for ocular examination.

CASE REPORT

We reported a case of a 60-year-old man who presented with painless partial right-eye vision loss. POCUS showed decreased flow in the right central retinal artery with an area of the pale retina seen on the image from the retinal camera, suggesting a possible branch RAO. Further examination with POCUS showed plaque formation at the carotid bifurcation, a potential cause of the patient's symptoms. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians and other providers should be encouraged to use POCUS to diagnose eye symptoms accurately and promptly. Abnormal findings will prompt immediate specialty consult and early appropriate management. Our case and other reported cases highlight POCUS's reliability and rapid diagnostic ability.

Structural and Functional Imaging of the Retina in Central Retinal Artery Occlusion - Current Approaches and Future Directions

Central retinal artery occlusion (CRAO) is a form of acute ischemic stroke which affects the retina. Intravenous thrombolysis is emerging as a compelling therapeutic approach. However, it is not known which patients may benefit from this therapy because there are no imaging modalities that adequately distinguish viable retina from irreversibly infarcted retina. The inner retina receives arterial supply from the central retinal artery and there is robust collateralization between this circulation and the outer retinal circulation, provided by the posterior ciliary circulation. Fundus photography can show canonical changes associated with CRAO including a cherry-red spot, arteriolar boxcarring and retinal pallor. Fluorescein angiography provides 2-dimensional imaging of the retinal circulation and can distinguish a complete from a partial CRAO as well as central versus peripheral retinal non-perfusion. Transorbital ultrasonography may assay flow through the central retinal artery and is useful in the exclusion of other orbital pathology that can mimic CRAO. Optical coherence tomography provides structural information on the different layers of the retina and exploratory work has described its utility in determining the time since onset of ischemia. Two experimental techniques are discussed. 1) Retinal functional imaging permits generation of capillary perfusion maps and can assay retinal oxygenation and blood flow velocity. 2) Photoacoustic imaging combines the principles of optical excitation and ultrasonic detection and - in animal studies - has been used to determine the retinal oxygen metabolic rate. Future techniques to determine retinal viability in clinical practice will require rapid, easily used, and reproducible methods that can be deployed in the emergency setting.

Retrobulbar Spot Sign Predicts Thrombolytic Treatment Effects and Etiology in Central Retinal Artery Occlusion

BACKGROUND AND PURPOSE

Transorbital sonography may help establish diagnosis of central retinal artery occlusion (CRAO). Next to Doppler sonographic proof of CRAO, an intra-arterial spot sign can be detected in some cases. We hypothesized that it reflects calcified components. It may be associated with embolization from atherosclerotic plaques and may negatively influence thrombolysis.

METHODS

Prospective monocenter study of 46 patients with ophthalmologically confirmed CRAO. Systemic tissue-type plasminogen activator thrombolysis was performed when appropriate. All patients received etiologic workup.

RESULTS

CRAO was confirmed by Doppler in all patients. Fifty-nine percent of patients with arterio-arterial embolization were spot sign-positive compared with 20% from cardiac source (P<0.05) and none with vasculitis. Eleven patients underwent thrombolysis. Clinically relevant visual improvement was only found in absence of a spot sign (P<0.05).

CONCLUSIONS

Transbulbar ultrasound is valuable for initial diagnosis and diagnostic workup of CRAO. In the light of inconsistent results of previous thrombolysis trials, ultrasound may identify patients more likely to benefit from thrombolytic treatment.