View source for Central retinal artery occlusion

==Background==
[[File:Schematic diagram of the human eye en.png|thumb|Eye anatomy.]]
*Abbreviation: CRAO
*The first branch of internal carotid artery is the ophthalmic artery
*More common in the elderly with carotid artery disease
*Restoration of blood flow within 100min may lead to complete recovery 
**Occlusion >240min leads to irreversible damage
*5-10% of CRAO is associated with giant cell arteritis<ref>Miller N, Newman N. Walsh & Hoyt’s Clinical Neuro-ophthalmology. 5th Edition. Baltimore: Williams and Wilkins 1998. pp. 3758-9.</ref>

===Etiology===
*[[thromboembolism|Embolism]] 
*Thrombosis 
*[[Temporal Arteritis]] 
*[[Vasculitis]] 
*[[Sickle Cell Disease]] 
*[[Blunt orbital trauma|Trauma]]
*Vasospasm ([[migraine]]) 
*[[Acute_Angle-Closure_Glaucoma|Glaucoma]]
*Low retinal blood flow ([[carotid stenosis]] or [[hypotension]])

==Clinical Features==
*Sudden, [[Acute vision loss (noninflamed)|painless, monocular vision loss]]
**Often preceded by episodes of [[amaurosis fugax]]
*APD

===[[Fundoscopy]]===
[[File:CRAO.png|thumb|Typical central retinal artery occlusion with cherry-red spot, retinal edema and narrowing of the vessels.]]
*Pale retina, cherry red macula 
*Boxcar segmentation of blood column
*Cherry red spot
**Macula is thinnest portion of retina 
**Intact underlying choroidal circulation remains visible through this section 
***Macular area maintains normal color (red) versus surrounding ischemic, pale retina due to differing blood supplies

==Differential Diagnosis==
{{Acute vision loss noninflamed DDX}}

==Evaluation==
*Etiology work-up
**ESR and CRP
**Carotid [[ultrasound|US]]
**[[ECG]]
**[[Echocardiography]] for embolus or atrial shunt
**CBC, coags, ANA, syphilis

==Management==
*Consult ophtho with goals for reducing [[intraocular pressure]], dislodging  the embolus or increasing arterial flow

*Start high dose systemic [[corticosteroids]] if high ESR/CRP (especially high CRP) and sudden vision loss
**Median starting PO [[prednisone]] 80mg/day, with 40% of patients on > 100mg/day
**Treat until BOTH ESR and CRP stabilize (~2-3 wks)<ref>Hayreh SS. Anterior Ischemic Optic Neuropathy. [Internet]. 2013 Available from: http://www.medicine.uiowa.edu/eye/AION-part2/.</ref>

No evidence supporting or refuting the following treatments: <ref>Rudkin A et al. Clinical characteristics and outcome of current standard management of central retinal artery occlusion. Clin Experiment Ophthalmol 2010; 38:496-501</ref>
*Ocular massage 
**Intermittent direct digital pressure applied through closed eyelid x 10-15 sec with rapid release to create pressure gradient to dislodge embolism 
*[[Timolol]] ophthalmic 0.5% to decrease intraocular pressure
**Alternative [[acetazolamide]] 500mg IV or PO<ref>Gerstenblith BI, Fecarotta CM. The Wills Eye Manual. Lippincott 2012.</ref>
*Increase PCO2 leading to retinal artery vasodilation/increased retinal blood flow   
**Rebreathe into paper bag x10 min q hr 
**Inhale 95% O2 and 5% CO2 (Carbogen)<ref>Atebara N. Efficacy of anterior chamber paracentesis and carbogen in treating nonarteritic central retinal artery occlusion. Ophthalmology 1995; 102:2029-2038</ref>
*Anterior chamber paracentesis 
**Causes acute drop in IOP to dislodge embolism 
*Intraarterial fibrinolysis or low dose systemic [[thrombolytics]]<ref>Schumacher M, et al: Central retinal artery occlusion: Local intraarterial fibrinolysis versus conservative treatment, a multicenter
randomized trial. Ophthalmology 2010; 117:1367-1375</ref><ref>Chen C et al: Efficacy of intravenous tissue-type plasminogen activator in central retinal artery occlusion: Report from a randomized, controlled trial. Stroke 2011; 42:2229-2234.</ref>
*[[Acetazolamide]], 500mg IV or PO 
*[[Mannitol]]

==Disposition==
*Immediate ophthalmology consult

==See Also==

*[[Acute vision loss (noninflamed)]]

==References==
<references/> 

[[Category:Ophthalmology]]
[[Category:Vascular]]