Vascular Retinopathies



Vascular Retinopathies


Avnish Deobhakta

Daniel J. Egan



THE CLINICAL CHALLENGE

Vascular retinopathies can represent a sentinel event for serious systemic illness. As such, once the diagnosis of a vascular retinopathy is made or suspected, careful examination and testing for the underlying cause is critical. For patients with ischemic retinopathy, secondary prevention of further vascular insults like stroke can prevent significant morbidity. Identification of these processes can be challenging for the emergency provider given the heterogeneity of the descriptions of symptoms by patients. The experience of visual changes described by patients overlaps between diagnoses. Therefore, maintaining a broad differential diagnosis with a systematic approach to the complaints is important to prevent future events or progression of vision loss.




APPROACH/THE FOCUSED EXAM

The American Heart and National Stroke Associations have amended the definition of stroke to include brain, spinal cord, or retinal cell death attributable to ischemia. As such, patients with acute vascular retinopathies are evaluated similarly to patients experiencing other stroke syndromes, including an assessment of risk factors. For all patients with a complaint of visual disturbances, the emergency provider should obtain a thorough medical history, including past ophthalmologic history, medications, and history of similar problems in the past. Focusing on the present illness, it is important to clarify certain key elements: onset of symptoms, monocular or binocular symptoms, duration of symptoms, associated symptoms (eg, headache or neck pain), and neurologic deficits. Furthermore, because GCA is associated with vascular retinopathies, a review of systems for this disease is critical. These patients are over age 50 and may report a history of jaw claudication, headache (particularly in the region of the temporal artery), tenderness of the scalp, constitutional symptoms, arthralgias, and fever (see Chapter 49). The physical examination will focus primarily on the eye, including a thorough examination of the retina, usually performed by an ophthalmologist after pupillary dilation. When GCA is suspected, measurement of inflammatory markers is recommended (erythrocyte sedimentation rate [ESR], C-reactive protein [CRP], and platelets).

Visual acuity and an assessment of the visual fields may uncover deficits. A comprehensive neurologic examination including cranial nerves is warranted. Given the association with underlying vascular disease, evaluation of the carotid arteries for bruits or evidence of other vascular disease on examination is important. Auscultation of the heart and assessment with electrocardiogram may identify a causative dysrhythmia like atrial fibrillation.


Transient Monocular Vision Loss

Patients will occasionally endorse a “vertically dropping black curtain” when describing their visual disturbance, although others may simply describe a “graying or darkening” of vision instead.
Symptoms are typically “negative” symptoms with loss of vision and do not characteristically include colors or flashes of light. It is important to keep in mind the inconsistency of symptomatic descriptions by patients. Most patients will report these episodes lasting anywhere from 2 to 30 minutes. Patients typically present for evaluation after symptoms have resolved. As a result, examination of the retina is expected to be normal.


Retinal Artery Occlusion

Like TMVL, this condition presents with sudden, painless, often profound, monocular vision loss that does not resolve. RAO is considered a stroke of the retina, and assessment of these patients should mirror a general stroke evaluation. Medical history will often reveal some combination of cerebrovascular risk factors like hypertension, hyperlipidemia, diabetes mellitus, or tobacco use. Examination includes a complete neurologic examination. Visual acuity often demonstrates profound vision loss when the occlusion is central. Some preservation of vision is possible with a BRAO or in patients with a cilioretinal artery. On assessment of the pupils, the affected eye will usually have an afferent pupillary defect. On fundoscopic examination, the retina demonstrates a white appearance because of retinal edema. The most obvious clinical finding for a CRAO is a cherry red spot noted in the central fundus, which is seen in 90% of patients (Figure 41.1) and related to preserved choroidal blood flow to the fovea.7 In other cases, a frank embolus (termed a “Hollenhorst plaque”) can be seen within the lumen of a vessel (Figure 41.2). In BRAO, segmental white discoloration of the retina is seen. The optic nerve should appear normal in both CRAO and BRAO.

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Apr 18, 2023 | Posted by in OTOLARYNGOLOGY | Comments Off on Vascular Retinopathies

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