Hypertension. Flashcards
how is blood pressure calculated?
Cardiac output x peripheral resistance.
What is hypertension?
A disorder in which the level of sustained arterial pressure is higher than expected for the age, sex, and race of the individual. WHO defines this as being greater than 140/90. It must be measured over a sustained period of time due to normal fluctuation.
What can alter cardiac output?
HR, contractility of the heart and the blood volume.
What can alter peripheral resistance?
Constrictors e.g. Angiotensin II and catecholamines and dilators e.g. Nitric oxide and prostaglandins.
What is the global incidence of hypertension?
Varies between countries, higher in black populations, lower in the South Pacific. Age (main driving factor) and genetics are key.
What is the ideal blood pressure?
120/75
What is normal blood pressure?
120-129/75-84
What is high normal blood pressure?
130-139/85-89.
What is stage 1 (mild) hypertension?
140-159/90-99.
What is stage 2 (moderate) hypertension?
160-179/100-109.
What is severe hypertension?
Grater than or equal to 180/110.
Who do we treat for hypertension?
All with stage 2 hypertension. For those with stage 1 the choice depends on the risk of coronary events, the presence of DM or end organ damage.
How do we classify hypertension?
Either according to cause (primary or secondary) or consequences (benign or malignant).
What is primary hypertension?
Also called essential hypertension. Makes up 90-95% of cases. It has no obvious cause but has genetic factors and is linked to salt intake, protein intake (RAAS) and sympathetic activity.
What amount of primary hypertension cases are said to be salt sensitive?
Around 25%
What is salt sensitive hypertension?
Increased dietary salts lead to increased bp. It can be controlled by a low salt diet.
What is a common type of secondary hypertension in renal disease?
Salt sensitive.
What is secondary hypertension?
Hypertension where an underlying cause is implicated. Comprises about 5% of cases.
What is the most common cause of secondary hypertension?
Renal disease.
What are the two different types of renal diseases that cause secondary hypertension?
75% Intrinsic and 25 % renovascular disease.
What are some examples of intrinsic renal diseases?
Glomerulonephritis, polyarteritis nodosa (PAN). Systemic sclerosis, chronic polynephritis or polycystic kidneys.
What different types of renovascular disease and who gets them?
Fibromuscular dysplasia - rare but usually young females.
More commonly atheromatous - elderly male smokers with PVD for example.
What types of disease and factors are liable to cause secondary hypertension?
Renal, endocrine and others e.g. Coarctation, pregnancy and drugs e.g. MAOIs and the pill.
Give examples of endocrine diseases that cause secondary hypertension?
Cushings, Conn’s syndrome, phaeochromocytoma, acromegaly and hyperparathyroidism.
What does cushings result in?
Results in an over secretion of corticosteroids.
What does Conn’s syndrome result in?
Excess aldosterone.