Vascular disease: Hypertension Flashcards
what is arteriosclerosis
is hardening of the arteries, condition not only thickens the wall of arteries, but also causes stiffness and a loss of elasticity
what is atherosclerosis
is the most common type of arteriosclerosis, or hardening of the arteries, and caused by plaque building up in the vessel
over time the plaque causes thickening of the walls of the artery. Stiffness and a loss of elasticity also result.
a patient with arteriosclerosis (hardened arteries) may not have…
atherosclerosis (plaque), but a patient with atherosclerosis does have arteriosclerosis
what is blood pressure and what does it refer to
Pressure exerted by circulating blood upon the walls of blood vessels
Usually refers to systemic arterial pressure measured at a person’s upper arm
what is blood pressure recorded as and what does each component stand for
Systolic Pressure (mmHg)/Diastolic Pressure (mmHg)
Systolic = Peak pressure due to ventricular contraction (systole)
Diastolic = Pressure during ventricular relaxation (diastole) when chambers of heart are filling with blood
describe the distribution of blood pressure
Blood pressure is normally distributed in the population
The avg systolic = 110mmHg with the long tail off to the higher pressure end
No definitive cut-off for normality – risk of disease increases continuously with increasing pressure
what is normal blood pressure range according to the NHS
90/60mmHg to 140/90mmHg
when is hypertension diagnosed
when the systolic blood pressure is above 140mmHg or the diastolic blood pressure is above 90mmHg on TWO successive occasions
when is malignant hypertension diagnosed
when the systolic blood pressure is above 200mmHg or the diastolic blood pressure is above 140mmHg
what is the prevalence of HTN in the population and what is the prevalence in over 60’s
more than 25% of the UK population
and
more than 50% of those aged over 60yrs
what 2 classifications can HTN be
can be primary 90% of cases
or
secondary 10% of cases
what can a secondary HTN be from and what is the prevalence
to renovascular disease, ~10%
list the 5 conditions that are risk factors for HTN
Stroke Heart failure, Chronic kidney disease Peripheral vascular disease (e.g retinopathy) Cognitive decline Premature death
list all 4 non modifiable risk factors of HTN
Increasing age
Race (higher risk at younger age in afro-caribbean people)
Family history
Pregnancy
for these patients you can’t do anything about, but its worth being aware of these px’s so we can monitor them closely and their retinal appearance carefully
list 6 modifiable factors that all have a positive affect on HTN
regular exercise healthy diet relaxation alcohol reduction reduced sodium intake increased magnesium intake
what can be studies non-invasively regarding HTN
the retinal arterioles by looking at the back of the eye
give 2 reasons why looking at the retinal arterioles via the eye a reliable method for detecting HTN
Similar anatomically to cerebral and coronary micro circulation, fundus examination may diagnose life-threatening hypertension at an early stage
Hypertension can also cause hypertensive retinopathy (a direct affect on the eyes), and optic nerve and cranial neuropathies, which threaten sight
what causes hypertensive retinopathy
Increased blood pressure causes constriction of retinal arterioles (autoregulatory mechanism).
Chronic vasospasm leads to diffuse and focal arteriolar narrowing and increased vascular tortuosity.
Long term hypertension causes arteriolosclerosis (thickening of arteriolar wall due to progressive hyalinisation and increase of elastic and muscular components).
Difficult to separate effects on arterioles of hyptertension from effects of arteriolosclerosis.
what does long term HTN cause to the arterioles in retinopathy
causes arteriolosclerosis
thickening of arteriolar wall due to progressive hyalinisation and increase of elastic and muscular components
which stages of hypertensive retinopathy are chronic and which stages are acute
chronic: stages 1 and 2 (happen in the retina in a long period of time which is asymptomatic)
acute: stages 3 and 4 (comes about when theres a rapid rise in BP which is symptomatic)
describe what is seen in stage 1 (chronic) of hypertensive retinopathy
Mild to moderate narrowing/sclerosis of arterioles
describe 4 signs seen in stage 2 (chronic) of hypertensive retinopathy
Mild to moderate narrowing/sclerosis of arterioles
Local and/or generalised narrowing of the arterioles
Exaggeration of the light reflex from the arterioles
Arteriovenous crossing changes
describe 4 signs seen in stage 3 (acute) of hypertensive retinopathy
Retinal arteriolar narrowing and focal constriction
Retinal oedema
Cotton wool spots
Retinal haemorrhages and hard exudates
describe what signs is seen in stage 4 (acute) of hypertensive retinopathy
As for Stage 3 plus optic disc swelling
what changes in stage 1 and 2 happen as generalised and focal
straightening and narrowing of arterioles
describe all the 6 changes that are seen in stage 1 and 2 of hypertensive retinopathy
Generalised/focal straightening and narrowing of arterioles
In older px, arteriosclerosis prevents excessive narrowing = a/v ratio isn’t always a accurate marker for HTN
Tortusoity
Arteriolosclerosis causes change in light reflex from vessels:
Normally see thin column of blood and longitudinal, bright reflex
Sclerosis leads to reflex becoming broader, duller and more diffuse. Vessel walls become opaque
Light reflex duller reddish brown (“copper-wire” appearance)
As sclerosis advances, reflex encompasses whole vessel and “silver wire” appearance is seen (or “sheathing”)
Crossing changes caused where underlying venule is compressed by sclerosed arteriole.
Causes ‘nipping’ (‘nicking’)
Further hardening of arteriole may cause deflection of venule, right angling, bridging may be seen.
If blood flow is impeded, may see segment of vein after crossing is larger, darker and more tortuous
when and why can a/v ratio sometimes not be a accurate marker for HTN
In older px = arteriosclerosis prevents excessive narrowing
what is the appearance of normal light reflex of the arteriole
what is the appearance with arteriosclerosis
Normally see thin column of blood and longitudinal, bright reflex
Sclerosis leads to reflex becoming broader, duller and more diffuse. Vessel walls become opaque
Light reflex duller reddish brown = copper-wire appearance
As sclerosis advances, reflex encompasses whole vessel = “silver wire” appearance is seen (or “sheathing”)
what is meant by: crossing changes nipping deflection bridging segment of vein
crossing changes: caused where underlying venule is compressed by sclerosed arteriole
nipping: seen when the underlying venule is compressed by the sclerosis arteriole passing over it, gives a narrowing appearance of the vein
deflection: from further hardening of the arteriole, changes in the direction of the venule as the artery passes over it
bridging: venule has to bridge up to pass over the hardened arteriole
segment of vein: happens when blood flow is impeded, see segment of vein is larger after crossing, darker and more tortuous
what can severe changes at the AV crossings lead to in hypertensive retinopathy
branch retinal vein occlusion (BRVO)
what does the acute rise in BP seen in stage 3 and 4 hypertensive retinopathy cause and what 4 signs in the retina can this cause
Disruption of blood retinal barrier leads to increased vascular permeability (leakage of vessels)
Can cause:
Haemorrhages (often flame shaped)
Retinal oedema
Hard exudates
Deposition of hard exudates around fovea in Henles layer Macular star
what happens to the arteries with severe HTN (as seen in stages 3 and 4)
arteries lose ability to auto regulate and this damages capillary and arteriole vessel walls as unregulated pressure reaches small vessels
what can the inability of arteries to auto regulate causing damage to capillary and arteriole vessel walls in severe HTN lead to in the retina (3 signs)
May lead to: micro aneurysms obstruction of arterioles and formation of cotton wool spots (sign of retinal ischaemia)
what is the cause of cotton wool spots seen in stage 3 and 4 HTN
indication of disruption of axonal fluid transport as a result of retinal ischaemia
what gives a macula star its appearance in stage 4 hypertensive retinopathy
exudates are following the fibres of henle up the walls of the foveal pit
what signs in the retina indicates malignant HTN
swelling of the optic disc in addition to features in stage 3:
Retinal arteriolar narrowing and focal constriction
Retinal oedema
Cotton wool spots
Retinal haemorrhages and hard exudates
which retinopathy is malignant HTN associated with
stage 4 hypertensive retinopathy
characterised by the swollen optic disc
what do 1% of primary HTN px develop
malignant HTN
what 4 things can malignant HTN be rapidly fatal due to
heart failure stroke myocardial infarction or renal failure
list 9 symptoms a px with malignant HTN will complain of
headaches diplopia scotomata dimness in vision photopsia chest pain nausea/vomiting shortness of breath weakness
as well as hypertensive retinopathy, what else can be seen in patients with stage 3-4
Hypertensive Choroidopathy
what is hypertensive choroidopathy and what does it cause
Necrosis of choroidal vessels causes choroidal ischaemia
lack of blood supply through the choroidal circulation which results in the RPE being ischaemic = presence of yellow spots
what signs are seen in Hypertensive Choroidopathy
Yellow spots seen in RPE i.e. ischaemic infarcts of RPE
what is the sign of chronic/long term Hypertensive Choroidopathy
and what are the signs of acute Hypertensive Choroidopathy
chronic effects: Yellow spots replaced by regions of RPE pigment clumping surrounded by atrophic areas (Elschnig spots)
acute effects: Linear RPE abnormalities (Siegrist streaks) develop overlying sclerosed choroidal vessels
what other systemic condition has high prevalence with HTN
diabetes
because be because they share pathophysiological mechanisms e.g. inflammation, endothelial dysfunction
what happens if both HTN and DM is present in a px
retinopathy becomes more severe and rapidly progressive
how can you distinguish between the retinopathy of a patient who has both DR and hypertensive retinopathy
Hypertensive retinopathy (stage 3/4) tends to show a ‘drier’ retina than DR (R3): lots of cotton wool spots, but sparse haemorrhage, oedema, exudates
Px may have DR and hypertensive retinopathy in the same eye
what external ocular sign can be seen with HTN
Subconjunctival Haemorrhage = strong link with HTN
how many % of patients presenting with sub conjunctival haemorrhage have HTN and what must you do if you see this
~46% of patients
Advise BP check, especially if recurrent
what is the main management advice if you see someone with hypertensive retinopathy
Need to manage systemic hypertension
as the 3 years survival rates got lower and lower from stage 1 to 4 hypertensive retinopathy
what was the mortality rate of untreated malignant HTN in 2 months and in 1 year
2 months: 50%
1 year: 90%
how will you manage a px with stage 1 and 2 of hypertensive retinopathy
Refer to GP for investigation and management of systemic hypertension
how will you manage a px with stage 3 hypertensive retinopathy
Refer to GP for investigation and management of systemic hypertension
and
should also be referred for ophthalmological assessment
what features of stage 3 hypertensive retinopathy will resolve when treated and which feature will remain even after treatment
haemorrhage, exudate, oedema - will resolve when blood pressure reduces
Stage 1+2 features - arteriolar changes will remain
how will you manage a px with stage 3 hypertensive retinopathy
Is a medical emergency
Very high blood pressure will be reduced in a controlled fashion to prevent autoregulation malfunction and optic nerve head ischaemia
