Sudden Vision Loss Flashcards
MOA of digitalis
NAK blocker
Increased CA2+ in heart
Can block PR NAK channels-entopic phenomenon
Can block NAK on NPCE-decreased IOP
LASIX MOA
Looses K+
Hypokalemia
CRVO
The CRV drains blood from the retina, on occlusion in this vessel results in a build up of blood within the retinal veins, resulting in extensive intraretinal hemorrhages extending towards the periphery in all 4 quadrants
CRVO stats
Prevalence of 0.1-0.4% in the general population (mostly 60-80s); they are the 3rd most commonly vascular cause of vision loss (1. DR, 2.BRVO). Appx 7% of patients will eventually have a CRVO in the fellow eye
Risk factors for CRVO
HTN
DM
Cardio disease
Open angle glaucoma
Open angle glaucoma and CRVO
POAG is the ocualr disease that is most commonly associated with CRVOs; 40-60% of patients with CRVO also have a diagnosis of POAG
Etiology of CRVOs
Compression of an artery on a vein; this causes turbulent blood flow, with subsequent venous vessel wall damage and thrombus formation
- thrombus formation results in eternal ischemia and the release of VEGF, leading to the classic retinal signs of retinal hemorrhages in all quadrants, collaterals, dilated tortuous retinal veins, CWS, and optic disc edema
Vision threatening complications of CRVO
Macular disease and complications from neo. VEGF stimulates neo of the anterior and posterior segment, and has also been proven to cause capillary leakage leading to macular edema
Treatment for neo in CRVO
PRP
Treatment of mac edema in CRVO
AntoVEGF
Macular diseases from CRVO includes
Macular ischemia
Macular edema
Intramacular hemorrhages
What is the leading cause of vision loss in CRVOs
Mac edema
Neo complications in CRVO
Results in NVG, pre-retinal or vitreous hemorrhage, and TRD
NVG
Significant concern in patients with CRVOs. It is most likely to develop within the first 3 months of Dx (90 day glaucoma), but may develop anywhere from 2 weeks to 6 months after the inital diagnosis. 60% of ischemic CRVOs develop iris neo, and 33% develop NVG. 6% of nonischemic CRVOs develop iris rubeosis or angle neo
Ischemic CRVO
10DD or more of capillary non perfusion on FA. 90% of cases present with 20/200 vision or worse, and the prognosis is poor (final BCVA of CF or worse)
Non-ischemic CRVO
Assocaited with a better prognosis compared to patietns with ischemic CRVOs; 16% of non ischemic progress to ischemic
Papillophlebitis
Described as a 3rd category of CRVOs; characterized by marked optic disc edema in an otherwise healthy young patient
FU for CRVO patients
Q1 month for 6 months, do gonio every time
Risk factors for BRVO
HTN DM Heart disease POAG And increased BMI (diff from CRVO)
Main culprit in BRVO and CRVO
Thrombus
Main culprit in CRAO and BRAO
Embolus
FU for CRAO
Refer to MD ASAP to check heart and carotid. Acute CRAO=MRI, possible stroke
BRVO stats
Most common retinal vascular occlusive disease; pts have a similar health histroy compared to CRVOs.
Etiology of BRVO
Thrombus at an AV crossing; 60% occur at AV crossing within the ST quadrant
BRVOs that do not occur at AV crossing
Should be evaluated for vasculitis, retinal arteries and veins share a common adventitia at AV crossings, allowing thickened arteries to compress the veins, resulting in occlusion
Signs of BRVO
Occur in the area of distribution of the occluded vessel and include dilated tortuous veins,CWS, collateral vessels, an intraretinal hemorrhages (confined to one quadrant).
Vision threatening complications of BRVOs
Mac disease (ischemia, edema, hemorrhages) Neo (pre-retinal or vitreous hem)