Week 1: Pathophysiology of hypertension Flashcards
Define hypertension
Hypertension = high blood pressure, blood vessels have persistently raised pressure
How does blood pressure relate to risk of CV events?
How do drugs alter this risk?
How do we know which patients to give drug therapy to?
The higher the BP the greater the risk of CV events (Stroke and MI).
Blood pressure lowering drugs reduce that risk accordingly, however need a clinical definition to know which patients to give drug therapy to.
Drug vs non drug approach –> high risk vs population approach
Why do we treat Hypertension?
3/5 deaths in UK from vascular disease
Blood pressure predicts the risk of vascular disease
Risks of hypertension can be reversed by treatment
List different types of hypertension
- Essential or Primary hypertension
- Secondary hypertension
- Pesudo resistant –> sever High BP on several drugs and remains uncontrolled (often due to lack of adherence)
- Resistant or refractory –> does not respond well to drugs
- Isolated systolic hypertension –> only high systolic common in ageing population, reflective of stiffening of large arteries
- In pregnancy
- Paedatric hypertension
What are the stages of essential or primary hypertension?
Reference figures
Stage 1:
- Clinic BP : 140 / 90 mmHg or ABPM under 135/85 mmHg
Stage 2:
- Clinic BP 140/90 to 179/119 mmHg or ABPM of 135/85 to 149/94 mmHg
Severe:
- Clinic BP: 180/ 120 mmHg or more, ABPM 150/95 mmHg or more
How should you manage stage 1 hypertension?
Check BP every 5 yrs and more often if close to 140/ 90 mmHg
How should you manage stage 2 hypertension?
Offer ABPM
investigate for target organ damage (includes both micro (retinopathy, vascular dementia) and macrovascular damage (stroke, myocardial infarction)
Assess cardiovascular risk
How should you manage severe hypertension?
assess for target organ damage as soon as possible
Consider starting drug treatment immediately without ABPM if target organ damage
Repeat clinic BP in 7 days if no target organ damage
Refer for same day specialist if retinal haemorrhage, papilloedema or life threatening sx
What is ABPM?
How does BP change over 24 hrs?
Ambulatory blood pressure monitoring:
Top = systolic, bottom = diastolic
Middle line = heart rate
Two lines = boundaries for normal blood pressure
Often have a nocturnal dip which is a normal physiological variation in blood pressure. 10% or more drop in BP at night compared to the day. Drops due to low activity and posture, increased parasympathetic output.
Also morning rise in BP
What is labile hypertension?
24HR monitoring, BP often normallu fluctuates but more than normal and above normal blood pressure
What is non dipping?
How does this affect risk for cardiovascular disease?
Non dipping is when an individuals blood pressure does not drop overnight, pt’s have increased risk of cardiovascular disease than others.
What are some causes of secondary HTN?
1) Primary hyperaldosteronism (Conn’s syndrome) –> e.g. due to adrenal adenoma or adrenal bilateral hyperplasia
2) renovascular disease –> Fibromuscular dysplasia and atherosclerotic
3) Obstructive Sleep Apnoea
4) Chronic Kidney disease
5) Phaeochromocytoma –> rare but lethal, overproduction of Adrenaline and NA from the medulla, intermittent HTN, can be highly severe
6) Aortic coarctation –> narrowing of aorta congential or sclerotic, upper body HTN (measure BP in both arms)
7) Cushing’s disease
8) Hyperparathyroidism
What is Conn’s syndrome?
Causes?
How can electrolytes be affected?
How do you treat?
Conns syndrome = HTN difficult to control with standard therapy ass. with tendency to hypokalemia and hypernatraemia. If pt presenting with hypoK, HTN in abscence of other factors e.g. diuretic then refer
1-5% of causes of secondary HTN
50% adrenal adenoma, 50% bilateral adenoma
Treatment –> spironolactone plus/ minus surgery (Surgery only if discrete adeonma, not if bilateral adrenal hyperplasia, surgical removal would cause Addison’s disease).
Describe some of the key investigations of Conn’s syndrome
What other condition may be found during these investigations?
Conn’s syndrome: measure plasma aldosterone, need to find if it is raised in the supine position vs standing position. (In this patient it is raised).
Measure Renin angiotensin system by measurin the Renin production. If there is a volume expansion you will suppress Renin, as primary production of aldosterone will suppress Renin. Primary production of Aldosterone should be matched by a suppression of Renin. This is diagnostic of Conn’s syndrome.
High aldosterone and high renin means secondary hyperaldosteronism due to something else e.g. heamorrhage, low salt etc.
Can also measure 24 hr urine exrection of k+ –> will be very high when there is a lot of aldosterone, leads to hypokalaemia.
What is shown in this patient’s CT?
Bilateral adenoma:
12 mm nodule in root of lateral limb of R adrenal gland
11 mm nodule in the body of the L adrenal gland
