B14-1 Hypertensive Retinopathy Flashcards
What is defined as “Elevated Blood pressure”?
120-129 mmHg systolic & < 80 mmHg diastolic
What is defined as “Stage 1 Hypertension”?
130-139 mmHg systolic or 80-89 diastolic
What is defined as “Stage 2 Hypertension”?
140 mmHg or higher systolic, 90 mmHg or higher diastolic
What is defined as a “Hypertensive Crisis”?
Higher than 180 mmHg systolic and/or higher than 120 mmHg diastolic
How is blood flow controlled in the retina in terms of retinal vasculature?
Via “Autoregulation”, where the vessels have an intrinsic ability to contrict or dilate depending on hyper-/hypo- perfusion.
How does systemic hypertension affect retinal perfuson?
The vessel’s ability to “Autoregulate” only works within a range of perfusion pressure; when pressures go above (malignant hypertension) or fall below (arteriaal hypotension) this critical range, the retina becomes ischemic
How does Hypertensive retinopathy affect terminal arterioles? (2 ways)
- Dilation - causes increased permeability & plasmatic deposits flowing into the retinal tissues, forming “Focal Intraretinal Periarteriolar Transudates (FIPTs)”
- Occlusion - Hypertensive closure of arterioles and capillaries leading to focal ischemia and “Cotton wool spots (CWS)”
What are some acute signs of diabetic retinopathy?
Flame-shaped hemorrhages are common, but Roth spots can also occur
What retinal lesions can occur with Chronic Hypertensive Retinopathy?
- Microaneurysms
- IRMA’s (Intraretinal Microvascular Abnormalities)
- Blot hemorrhages
- Lipid exudates
- Venous beading
- Neovascularization
What are the guidelines for grading HTN Retinopathy via the “Historic Modified Scheie” system?
- Grade 0: No changes (A/V ratio is 2/3)
- Grade 1: Barely detectable arterial narrowing (A/V ratio of 1/2)
- Grade 2: Obvious arterial narrowing (A/V ratio of 1/3), crossing changes, copper-wire appearance
- Grade 3: Grade 2 + retinal hemorrhages, CWS, FIPT’s, exudates, retinal edema &/or macular star
- Grade 4: Grade 3 + optic nerve head swelling (Straight to ER)
Describe the 4 A/V crossing changes that can be seen with HTN Retinopathy. What stage (in each grading system) would these be present in?
- “Gunn’s Sign”: When the vein is being occluded by the artery and is tapered on both sides
- “Bonnet’s Sign”: When the vein is being occluded by the artery and is chunked-up on one side
- “Salus’ sign”: When the vein bends as it goes over the artery
- “S-shaped bending of a vein”: “when it looks like the artery is detoring the vein as the vein goes underneath it
Explain the Wong Mitchell Hypertensive Retinopathy Grading System
Mild: Vessel &/or crossing changes
Moderate: Anything beyond crossing changes
Severe: Moderate + Optic Disc Edema
The 3rd proposed “grading scheme” for HTN retinopathy is using OCT. Explain how OCT can be used for grading the severety of HTN retinopathy
Mild - Moderate retinopathy is consistent with the other 2 schemes, but OCT can be used to evaluate Malignant Retinopathy (optic disc edema) for the presence of subretinal fuid, and this corrrelates well to predicting the final VA
What is arteriosclerosis? How does it relate to HTN retinopathy?
Arteriosclerosis is the hardening of arterial walls and luminal destruction secondary to cholestrol, clotting components, and inflammatory deposits within the vessel walls. Typically, this goes hand-and-hand w/ HTN
Describe the “Scheie Grading System of Retinal Arteriosclerosis”
Stage 1: Widening of the ALR
Stage 2: Stage 1 + crossing changes
Stage 3: Copper wiring of arterioles
Stage 4: Silver wiring of arterioles
