Hypertension Flashcards

1
Q

What is hypertension?

A

Level of blood pressure above which investigation and treatment do more good than harm

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2
Q

What is the epidemiology of Htn?

A

Affects 1bn worldwide and is leading cause of global death, however normal-abnormal distinction is arbitrary

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3
Q

What is the effect of ageing on Htn diagnosis?

A

Mean SBP and pulse pressure increase with age (as DBP stays constant) - almost all >80 would be hypertensive by current definition

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4
Q

What is ambulatory BP?

A

Recorded automatically at regular intervals over 24hour period, often 5-10mmHg lower than recorded in clinic (white coat effect)

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5
Q

What are the aetiologies of Htn?

A

Genetics: monogenic (rare), complex polygenic (common)

Environment: dietary salt (sodium), obesity, lack of exercise, alcohol, pre-natal environment, pregnancy (pre-eclampsia)

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6
Q

What are the genetics of Htn?

A

30-50% variation in BP attributable to genetic variation

Monogenic disease = <1% hypertension e.g. Liddle’s syndrome and apparent mineralocorticoid excess

Complex polygenic causes are much more significant; multiple genes with small effect

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7
Q

What is the major cause of primary Hypertension?

A

Idiopathic 85-95% of cases

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8
Q

What is the threshold for Htn?

A

140/90 mmHg

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9
Q

What are the causes of secondary Hypertension?

A

Renal disease

Tumours secreting aldosterone (e.g. Conn’s)

Tumours secreting catecholamines

Oral contraceptive pill

Pre-eclampsia

Rare genetic causes

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10
Q

What percentage of cases of Htn are secondary?

A

5-15%

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11
Q

What are the causes of primary Htn?

A

Kidneys: have a key role in BP regulation based on salt intake (if low salt diet then BP does not increase with age - monogenic causes usually related to genes affecting renal Na+ excretion)

Endocrine

Sympathetic Nervous System: high SNS activity linked to hypertension

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12
Q

What is the equation relating MAP and cardiac output?

A

MAP = CO x TPR

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13
Q

What is Htn often associated with?

A

Increased TPR (active narrowing of arteries, structural narrowing and capillary loss)

Decreased arterial compliance

Normal CO

Normal blood volume

Central shift in volume 2/2 reduced venous compliance

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14
Q

What is isolated systolic hypertension?

A

Larger arteries become stiff for idiopathic reasons, rather than increased TPR, leading to SBP >140, DBP <90 mmHg and incidence increases with age

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15
Q

What are the main consequences of Htn?

name 10

A

CHD, CVA, HF, AF, Dementia, Retinopathy, Vascular disease, Cardiomegaly, CHF, Aneurysms

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16
Q

What are the effects of Htn on the heart?

A

Hypertension leads to increase in left ventricular wall mass leading to Cardiomegaly

17
Q

What are the effects of Htn on the eyes?

A

Microvascular damage to the retina in hypertension, leading to swelling of the optic disc, vasospasm, impaired perfusion, narrowed arteries and increased leakage to surrounding tissue

18
Q

What are the effects of Htn on the kidneys?

A

Renal dysfunction common, and extreme hypertension leads to rapidly progressive renal failure

19
Q

What is Microalbuminuria?

A

Hypertension increases albumin loss in the urine, due to a reduced glomerular filtration rate (also decreases with age, BP speeds up rate)

20
Q

What are the first treatments for Htn?

A

Weight loss, exercise, diet, alcohol reduction, smoking cessation.
All things I should do….

21
Q

What do ACE inhibitors do?

A

Reduce production of AGTII via RAAS

22
Q

What are Angiotensin receptor blockers?

A

Reduce AGTII binding to target organs - needed as can make AGTII without RAAS

23
Q

What are the aims of RAAS drugs on Tx?

A

Stop arteriolar vasoconstriction, ADH/aldosterone secretion and tubular sodium resorption, decreasing TPR and water retention

24
Q

What are Loop Diuretics?

A

Used in a crisis to block water reabsorption

25
What are Thiazide diuretics?
Do not work through diuresis, but slowly reduce Peripheral vascular resistance
26
What are Beta Blockers?
beta1 (endogenous catecholamine receptors) receptors blocked in heart to reduce rate and force of contraction to reduce output and in the kidneys to stop renin secretion/RAAS activity
27
What are calcium channel blockers?
Major effect in vascular smooth muscle to reduce Ca2+ influx to reduce cross bridge cycling, and have a minor effect to reduce contractility and rate of conduction in the heart