Pathology- Hypertension Flashcards
what is hypertension
a disorder in which the level of sustained arterial pressure is higher than the expected for the patient (age, sex and race)
why are repeat measurements important
normal variation throughout day,
white coat hypertension,
stable or labile (fluctuates in response to e.g. emotional stress) hypertension
what does hypertension ultimately cause
cardiac failure
what is hypertension a risk factor for
cerebral haemorrhage,
atheroma,
renal failure,
sudden cardiac death
what is essential in the prevention of risk factors associated with hypertension
early detection and treatment
how does the incidence of hypertension vary
varies between countries, ethnic groups, genetic link, rises with age
what are the aetiological classifications of hypertension (according to cause)
primary (no underlying cause, genetics = environment)
secondary (underlying disease)
what are the classifications of hypertension depending on consequences
benign- often primary
malignant- often secondary, extreme kills quickly
how is blood pressure tested
CO x TPR
what affects CO
HR, contractility, blood volume
what affects peripheral resistance
constrictors (angiotensin II, catecholamines)
dilators (nitric oxide, prostaglandins)
what is the primary site of resistance
end arterioles
when is renin released by the kidneys
when renal blood flow increases
when is ACE found
the lungs
how does angiotensin 2 increase blood pressure
by vasoconstriction and by increasing blood flow
hoe does agiotensin 2 increase blood flow
aldosterone release (salt and fluid retention)
how do ACE inhibitors reduce blood flow
stop conversion of angiotensin 1 to angiotensin 2
what is salt sensitive hypertension and how is it controlled
increase in dietary salts leads to increase in BP
controlled by reduction in salt in diet
what conditions can cause secondary hypertension
Renal disease Endocrine disease Aortic disease Renal artery stenosis Drug therapy
hoe can renal diseases cause high BP
reduced renal blood flow
excess renin release
salt and water overload
what renal diseases can cause secondary hypertension
renal artery stenosis, acute or chronic glomerulonephritis, chronic pyelonephritis, cystic diseases, interstitial nephritis
describe the layers of the adrenal cortex
3 layers, each producing different thing (aldosterone, steroid hormone (corticosteroid), noraldrenaline (adrenal medulla))
what are the endrocrine causes of secondary hypertension
Adrenal gland hyperfunction / tumours
Conn’s syndrome - excess Aldosterone Cushing’s syndrome - excess corticosteroid Phaeochromocytoma - excess noradrenaline
what is coarctation of the aotra
congenital narrowing of segments of the aorta (causes paradoxical hypertension- high in upper body, lower in legs)
give an example of a drug that can cause hypertension
corticosteroids
what does benign hypertension eventually cause
Left ventricular hypertrophy
Congestive cardiac failure
Increases atheroma
Increases aneurysm rupture - aortic dissection, Berry aneurysms
Renal disease
what is an aneurysm
weakening of an artery wall that creates a bulge, or distention, of the artery
what does hypertension cause in the in the heart
left ventricular hypertrophy
increased LV load
poor myocardial perfusion
interstitial fibrosis
micro-infarcts (myocyte necrosis)
diastolic dysfunction
increased susceptibility to arrhythmias
cardiac failure
what does left ventricular hypertrophy cause
sudden cardiac death, arrhythmia and poor perfusion, cardiac failure
also affects outcome of other diseases
how is hypertension associated with atheroma
predisposes and complicates
what is aortic dissection
where the inner layer of the aorta tears, associated with hypertension
what is a subarachnoid haemorrhage
when blood leaks into the space between two of the membranes that surround the brain. It is usually caused by a ruptured (berry) aneurysm
how does benign hypertension increase the risk of MI
Every 10mmHg of diastolic pressure above 85 doubles risk of MI
how does benign hypertension increase the risk of stroke
Every 8mmHg of diastolic pressure above 85 doubles risk of stroke
give four examples of microvascular injuries and its consequences
Blood vessel wall changes - small arteries and arterioles
Retina and kidney Thickening of media (smooth muscle) Hyaline arteriosclerosis - plasma proteins forced into vessel wall (cf ageing)
what is Hypertensive arteriolosclerosis and how is it seen pathologically
form of cardiovascular disease involving hardening and loss of elasticity of arterioles or small arteries (associated with hypertension)
scarred granular cortex
what diastolic pressure range suggests malignant hypertension
more than 130-140
what can malignant hypertension develop from
benign primary or secondary hypertension
what are the complications of malignant hypertension
Causes cerebral oedema - seen as papilloedema (swelling of optic disc)
Acute renal failure
Acute heart failure
Headache and cerebral haemorrhage
Blood vessels show fibrinoid necrosis and endarteritis proliferans of their walls
what is seen pathologically in afferent kidney arterioles as a result of malignant hypertension
Onion skinning of vessel wall and fibrin deposition
what does pregnancy associated hypertension increase
maternal and fetal morbidity and mortality
what is pre-eclampsia
hypertension and proteinuria (protein in urine)
what is the difference between pre-eclampsia and eclampsia
pre resolves at birth
eclampsia obsteric emergency
