D: Vascular 3 Systemic Hypertension - Week 8 Flashcards
Define systemic hypertension. What is considered borderline? What is considered normotensive?
Hypertension: BP > 160/95
Borderline: BP = 140/90 - 160/95
Normotensive: BP <140/90
In general, what level of diastolic BP is considered too high and worthy of reducing?
Any diastolic BP > 100 mmHg
List 5 risk factors for hypertension
Obesity (bad cholesterol)
Smoking
Family history
Older age
Race: black
Define malignant hypertension
Diastolic BP > 120mmHg with associated exudative vasculopathy in retina and kidney
What percentage of hypertension are secondary? What 2 types of conditions can they be secondary to?
5% of cases.
Renal conditions (e.g. nephritis, renal failure, tumour)
Endocrine conditions (e.g. DM, hyperthyroid, cushing)
What is pre-eclampsia?
A pregnancy complication that generally occurs 20 weeks in where the mother experiences a sudden onset of high blood pressure
What can the height of blood pressure predict risk of? (5)
coronary artery occlusion
stroke
renal failure
heart failure
peripheral vascular disease
How can high blood pressure affect the brain? (2)
Damage to cerebral vessels can lead to:
TIA
Stroke
How can high blood pressure affect the kidneys? (2)
Endarteritic changes in renal bed
Ultimate renal failure from sclerosis
How can high blood pressure affect the heart? (2)
Left ventricular hypertrophy –> cardiac failure
BP damage to cardiac vessels –> myocardial infarction
What proportion of hypertension patients have a normal fundus?
1/3rd
What are the 2 main effects of hypertension on retinal vessels?
Constriction of arterioles
Arteriolar sclerosis
Why do arterioles constrict in response to hypertension?
to maintain homeostatic blood flow as perfusion pressure drops
A drop in perfusion pressure (as a result of systemic HT) means less blood flow. So the arterioles constrict, increasing TPR, and hence increasing blood flow back to normal values. this process is “autoregulation”
(remember. Occ. perfusion pressure = BP - IOP. Wait what? Shouldn’t it increase then? Come back to this)
How does arteriolar sclerosis affect the arterioles and how does this present on a fundus examination? (4)
Loss of wall transparency: copper wiring
Lumen narrowing: nicking
Deflection of veins at AV crossings: right angle X-ing
Vein lumen compression: banking
Retinopathy grading (Wong & Mitchell):
- No retinopathy?
No detectable retinal signs with no systemic associations
Retinopathy grading (Wong & Mitchell):
- Mild retinopathy? (description)
One or more of:
Generalised arteriole narrowing
Focal arteriole narrowing
AV nicking
Silver wiring
Retinopathy grading (Wong & Mitchell):
- Moderate retinopathy? (description)
One or more of:
Haem (blot, dot, flame)
Microaneurysm
CWP
Hard exudates
Retinopathy grading (Wong & Mitchell):
- Malignant retinopathy? (description)
Moderate retinopathy plus:
- optic disc oedema
Retinopathy grading (Wong & Mitchell):
- Systemic associations:
- mild retinopathy
- moderate
- malignant
Mild: Modest association with risk of stroke, coronary heart disease, mortality
Moderate: same but strong + cognitive decline risk
Malignant: strong assoc. with mortality
How is focal arteriolar constriction seen on fundus? Where?
Alternating zones of passive dilation and spasm
Most readily seen within 1-2DD of disc
How common is focal arteriolar constriction in established hypertension?
very common
What level of sensitivity does focal arteriolar constriction have for systemic hypertension?
Good sensitivity and specificity
What is venous banking and what causes it? What does this mean in relation to hypertension?
Refers to the increased dilation of the vein distal to the AV crossing (aka Bonet Sign) away from the disc. This occurs in response to restriction of venous return and is a reliable guide to the possibility of hypertension.
Define distal
away from the centre (in the case of distal dilation that means away from ONH)
