REBEL Core Cast 97.0 – Acute Vision Loss II

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Take Home Points:

  • Assess patients with floaters or flashers for retinal or vitreous detachment. Rapid diagnosis and emergency referral improves outcomes of ophthalmologic interventions.
  • CRAO is a stroke of the eye; patients should be considered for a complete stroke work up.

REBEL Core Cast 97.0 – Acute Vision Loss II

Definition: Decrease of visual acuity due to a non-traumatic cause. Transient vision loss defined as vision loss <24 hours. Persistent vision loss defined as loss of vision >24 hours. (Bagheri 2015 ).

Causes: There are multitude of causes of vision loss. This post focuses on the following pathologies:

  • Glaucoma
  • Giant Cell Arteritis
  • Vitreous Detachment
  • Retinal Detachment
  • Central Retinal Vein Occlusion
  • Central Retinal Artery Occlusion
  • Amaurosis Fugax

Vitreous Detachment (Guluma 2018)

Definition: Separation between the posterior vitreous cortex and the internal limiting membrane (ILM) of the retina (which is the most external portion of the retina).

Background

  • Risk factors – Increasing age, myopia (nearsightedness)
  • Many older individuals have essentially asymptomatic vitreous detachments.
  • Often occurs as the vitreous shrinks with increasing age, pulling away from the retina.

Symptoms

  • Floaters > flashers
  • No change in visual fields
  • May have decreased visual acuity.

Signs

  • Shafer’s sign (tobacco dust)
  • May see a Weiss ring when the posterior vitreous (PV) detaches from the optic disc margin
  • Visualization with ultrasound.

Emergency Department Management:

  • Emergency ophthalmology consultation.
  • Emergency surgical management indicated if concomitant retinal tear, vitreous hemorrhage, or retinal detachment.

Retinal Detachment (Hollands 2009 )

Pathophysiology

  • Posterior vitreous shrinks with advancing age (aka synchysis senilis), pulling on the retina.
  • Pulling can cause tears in the retina (10-15% of the time) (Hollands 2009 )
  • Tear allows liquefied vitreous leaks in, causing the retina to separate from the retinal pigment epithelium (33-46% of the time) (Hollands 2009 )

Symptoms

  • Blurry vision/decreased peripheral vision
  • Flashers(photopsia)/floaters
    • 14% of pts referred to ophthalmology with flashers/floaters end up having retinal tears.
    • Photopsia is from vitreoretinal traction, floaters are from vitreous cells/blood in the eye.
    • Symptom characteristics (Hollands 2009 )
      • Any flashers/floaters: (+) LR 1.2 and (–) LR 0.9.
      • >10 floaters, (+) LR 8.1-36

Signs

  • Pigmented cells (‘‘tobacco dust’’ aka Shafer’s sign) in the vitreous and occasionally in the anterior chamber (caused by pigmented epithelial cells that spilled into vitreous)
  • Visual field loss
  • Vitreous hemorrhage: (+) LR 10
  • Visualization on ultrasound

Emergency Department Management

  • Emergency ophthalmology consultation for possible surgical repair

Central Retinal Vein Occlusion (CRVO) (McAllister 2012 )

Background

  • Pathophysiology not fully understood; possibly due to thrombus located in the central retinal vein (CRV), in the region of the lamina cribrosa
  • Second most common cause of vision loss due to retinal vascular disease (Most common cause: Diabetic retinopathy)

Symptoms

  • Floaters – CRVO can cause neovascularization which causes leaky vessels leading to debris in vitreous.
  • Blurry vision
  • Glaucoma symptoms – due to leaky vessels.
  • May be asymptomatic

Signs

  • Visual acuity deficit – Variable degree.
  • Funduscopic exam-
    • Flame-shaped, dot and blot hemorrhages
    • Retinal edema: May be limited to a certain section of the retina (if branch occlusion) or in all quadrants (if central vein occluded) (aka pizza pie eye)
    • May have macular edema

Emergency Department Management

  • Ophthomology consultation
  • Treatment traditionally laser for neovascularization complications, although newer treatments are emerging.

Central Retinal Artery Occlusion (CRAO)

Background

    • Anatomy: First branch of the internal carotid artery is the ophthalmic artery which splits into the posterior ciliary and central retinal arteries which supply the eye.
    • Causes:
      • Carotid artery stenosis (most common)
      • Cardioembolic sources also important cause.

Symptoms

  • Sudden painless monocular vision loss
  • May have some temporal sparing.

Signs

  • APD in affected eye
  • Funduscopic exam: Whitening of ischemic inner retinal layers with sparing in the foveal region (which is supplied by the intact choroidal circulation) creating the classic “cherry-red spot”

Emergency Department Management

  • Emergency ophthalmology consult, stroke work-up
  • Treatment options:
    • No clinical trials have demonstrated improvement with any treatment compared with observation.
    • Management options described in the literature
      • Tissue plasminogen activator (tPA)
      • Ocular massage
      • Ocular pressure lowering agents / maneuvers
      • Topical agents such as timolol
      • IV agents such as acetazolamide or mannitol
      • Anterior chamber paracentesis
      • Vasodilatory Agents (nitroglycerin, pentoxifylline, isosorbide, carbogen, breathing into a bag – causes increase in CO leading to vasodilation)

Read More

Bhatia K, Sharma R: Eye Emergencies in Adams J.G. et al, Emergency Medicine Clinical Essentials ed 2. Philadelphia: Elsevier, 2013 (Ch) 26: p. 209-225

Walker R, Adhikari S.: Eye Emergencies, in Tintinalli J et al (eds): Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, Seventh Edition New York City: McGraw-Hill 2016 (Ch) 241

Guluma K, Lee JE. Ophthalmology, in Marx J et al (eds): Rosens Emergency Medicine: Concepts and Practice, ed 9. Philadelphia: Elsevier, 2018 (Ch) 61: p. 790-819

Core Ultrasound: Vitreous vs Retinal Detachmen t

Post Created By: Anand Swaminathan MD, MPH

Post Peer Reviewed By: Salim R. Rezaie, MD (Twitter: @srrezaie)

The post REBEL Core Cast 97.0 – Acute Vision Loss II appeared first on REBEL EM - Emergency Medicine Blog.


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