Hypertension Flashcards
What is hypertension?
persistently elevated blood pressure
Repeated measurements showing values of ≥ 140mmHg systolic and ≥ 90mmHg diastolic
(≥ 140/90 mmHg)
What are the 2 classifications of HTN?
1.Primary/essential/idiopathic
2.secondary
What is the primary classification?
– No clear underlying cause
-95% of cases
Incidence increases with age
Increased resistance in the peripheral arteries/arterioles
What is secondary HTN?
– caused by the presence of another disorder
– e.g. endocrine disorders, kidney disease, medications, tumours
– Accounts for 5% cases
What is stage 1 HTN?
Clinical blood pressure ≥ 140/90 mmHg
Average ambulatory BP ≥ 135/85 mmHg
What is stage 2 HTN?
Clinical blood pressure ≥ 160/100 mmHg
Average ambulatory BP ≥ 150/95 mmHg
What is stage 3 HTN?
Clinical systolic BP ≥180mmHg
or Clinical diastolic BP ≥110 mmHg
What are the risk factors for HTN?
- Family history
- Afro-Caribbean race
- Diabetes
- Hypercholesterolemia
- Obesity
- Smoking
If you are at risk of HTN , you are at increased risk of
increased risk of arterial sclerosis and athereresclerosis
which causes increased peripheral resistance
which causes increased bp
Blood vessels constrict to protect the tissues and organs from high pressure (vasoconstriction)
Results in: Decreased blood flow to vital organs and heart working harder to push blood through the narrow vessels
End organ damage: e.g. Heart disease, Heart attack, Stroke, Renal insufficiency, Retinopathy
What causes Hypertensive choroidopathy
1.Acute rise in blood pressure leads to shut down of the
choriocapillaries – choroidal vascular insufficiency
- Lack of blood supply to the choroid and overlying RPE – tissue infarction=
- Elschnig Spots, Siegrist Streaks and Exudative Retinal Detachment
Elschnig spots = small black spots surrounded by yellow haloes
1.RPE changes resulting from non-perfusion of the choriocapillaries (focal choroidal infarcts)
- Early stages: yellow demarcated lesions
3.Late stages: central pigment spot within the yellow atrophic area
Siegrist Streaks
-linear hyperpigmented streaks.
-over choroidal arteries
-Indicates sclerosis / necrosis of the underlying choroidal vessels
exudative RD
Accumulation of subretinal fluid between the neurosensory retina and RPE
Increased choroidal vascular permeability interferes with the RPE pumping mechanism – fluid accumulates and pushes the neurosensory retina away
What is hypertensive retinopathy?
systemic ocular disorder
why is it important to recognise the signs off hypertensive retinopathy?
Accumulation of subretinal fluid between the neurosensory retina and RPE
Increased choroidal vascular permeability interferes with the RPE pumping mechanism – fluid accumulates and pushes the neurosensory retina away
What are the symptoms of hypertensive retinopathy ?
-asymptomatic
Possible history of systemic hypertension (or could be
undiagnosed)
– Evidence of risk factors for hypertension
What are the signs of hypertensive retinopathy?
signs classified by the Keith-wagener barker system
Vasoconstriction
Arteriosclerotic changes
Vascular leakage
Bilateral and symmetrical
G1 : Arteriolar attenuation
vasoconstriction of retinal arterioles / narrowing of retinal arteries in response to systemic HTN
difficult o view on ophthalmoscopy
Indicator of chronically elevated BP
Grade 3
focal attenuation and arteriosclerotic changes with retinal vessels
FOCAL ATTENUATION
Strong indicator that blood pressure is raised
* May be easier to identify than generalised narrowing
What are the grade 2 arteriosclerotic change?
g1: broadening of arteriolar light reflex
g2: deflection of the veins when crossing the arteries (Salus’ Sign)
g3- ‘ (Bonnet’s sign)
-(Gunn’s sign)
- ‘copper wiring’ of the retinal arterioles
- right angled deflection of veins
g4:‘silver wiring’ of retinal arterioles