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8. Central Retinal Artery Occlusion with Sudden Vision Loss—“Ay, Ay, My Eye!”
Keywords
Central retinal artery occlusion Central retinal vein occlusionMacular sparingTemporal arteritisRetinal detachmentRetinal hemorrhageVitreous detachmenttPA Hyperbaric OxygenTemporal arteritisAnterior chamber paracentesisCase
Sudden Monocular Blindness
Pertinent History
This patient is a 62-year-old male with a history of hypertension and hyperlipidemia who presents left-sided vision loss. Patient says that he had sudden onset of painless, unilateral (left-sided), vision loss approximately 24 hours ago. He said his left eye went completely dark over about 25 seconds. He had no headache or any other focal neurologic symptoms. He was seen at an outside hospital within 60 minutes of onset of symptoms and had a CT scan of his brain and a CT angiogram (CTA) of his head and neck. He had a normal intraocular pressure. Ophthalmology was contacted and the decision was made to have the patient follow-up as an outpatient. The patient was not seen by ophthalmology that evening. A retinal and pupillary exam was not documented in the outside hospital (OSH) record. He followed up the next afternoon with ophthalmology and was told that he may have a central retinal artery occlusion (CRAO) and nothing could be done this far after onset. He was sent to the emergency department to have a workup for possible embolic sources.
Pertinent Physical Exam
Except as noted below, the findings of the complete physical exam are within normal limits.
Constitutional: He is oriented to person, place, and time. He appears well-developed and well-nourished.
Head: Normocephalic and atraumatic.
Eyes: Conjunctivae and extraocular movements are normal. Right eye exhibits no discharge. Left eye exhibits no discharge. Left eye demonstrates an afferent pupillary defect. R eye is reactive to light.
Fundoscopic Exam: Right—Normal, L—Cherry red spot with pale retina.
Neck: Neck supple.
Cardiovascular: Normal rate, regular rhythm, and normal heart sounds. No murmur.
Neurological: He is alert and oriented to person, place, and time. He has normal strength. No sensory deficit.
Past medical history (PMH)
Hypertension and hyperlipidemia.
Social History (SH)
Daily tobacco use. Occasional alcohol (ETOH) use. No illicit drug use.
Family History (FH)
Coronary artery disease (CAD), Hypertension (HTN), Diabetes
Pertinent Test Results
- 1.
No extracranial carotid or vertebral artery stenosis.
- 2.
Unremarkable intracranial CT angiogram without focal branch occlusion seen.
- 3.
No intracranial mass lesion, acute hemorrhage, or midline shift.
- 4.
No cervical soft tissue mass or pathological lymphadenopathy seen.
Emergency Department Management
The patient was admitted to the hospital for further testing for cardiovascular disease and possible initiation of hyperbaric therapy.
Learning Points
Priming Questions
- 1.
What is the differential and management of painless unilateral vision loss in the ED?
- 2.
What treatment options are available to those presenting with CRAO?
- 3.
Does hyperbaric therapy offer any therapeutic benefit to patients presenting with CRAO?
Introduction/Background
- 1.
Pattern recognition can frequently get you out of potential trouble. Acute ischemia of the retina is a very specific pattern that every EM physician MUST know! Missing a patient with a classic presentation can be financially and emotionally unrewarding. Sudden, rapidly evolving (20–30 seconds) painless, mostly complete, monocular vision loss is central retinal artery occlusion (CRAO), until proven otherwise. Similar, vision loss can occur with central retinal vein occlusion (CRVO) and retinal detachment; however, it is usually subacute and incomplete.
- 2.
The incidence of CRAO is estimated to be around 1–10/100,000 persons with at least one study showing that 80% of the patients present with a visual acuity of <20/400.
Risk factors include hypertension, carotid artery disease, diabetes mellitus, cardiac disease (especially atrial fibrillation and valvular disease), vasculitis, temporal arteritis, and sickle cell disease.
Irreversible vision loss is typically thought to occur within 90 minutes based on primate studies; however, irreversible vision loss has been demonstrated with occlusion times of as little as 15 minutes, while other studies have noted some visual recovery with up to 48 hours of ischemic time [7, 13].
Physiology/Pathophysiology
- 1.
Understanding the blood flow to the retina is useful in helping to understand the presentation and prognosis of CRAO.
The central retinal artery (CRA) is a branch of the ophthalmic artery that is a branch of the internal carotid artery. It supplies blood to the optic disk. It then branches into superior and inferior branches, which then divide into the nasal and temporal branches. These all together supply blood to all 4 quadrants of the retina [6].
The outer retina is perfused by a branch of the ciliary artery called the choriocapillaris.
- 2.
About 15–25% of the population has an anatomical variation with the presence of an additional artery called the cilioretinal artery. It supplies the macula where the highest number of photoreceptors live. Since this artery is not a branch of the central retinal artery, the macula may remain perfused in these patients who develop CRAO. This might allow for preservation of the most important part of the visual field [8].
Making the Diagnosis
Differential Diagnosis [14]
CRAO
CRAO
CRAO
CRAO
CRAO
CRVO
Retinal detachment
Vitreous hemorrhage
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