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Forth stage
Medicine
Lec-7
د.جاسم محمد
23/11/2015
Hypertension
Definition:
The level of BP at which the benefits of treatment outweigh the costs and hazards.
Aetiology of Hypertension:
• Primary – 90-95% of cases – also termed “essential” of “idiopathic”
• Secondary – about 5% of cases
-Alcohol ,Obesity, Pregnancy (pre-eclampsia)
-Renal disease : Parenchymal renal disease, particularly glomerulonephritis Renal
vascular disease.
-Endocrine disease : Phaeochromocytoma , Cushing’s syndrome , Primary
hyperaldosteronism (Conn’s syndrome) , Acromegaly , Primary hypothyroidism ,
Thyrotoxicosis , Congenital adrenal hyperplasia .
-Drugs : e.g. Oral contraceptives containing oestrogens, anabolic steroids,
corticosteroids, NSAIDs, carbenoxolone, ----Coarctation of the aorta.
Stages:
• Identification of hypertensive patients
• Baseline investigations
• Initiating therapy
• Reviewing patients
• Stepping up therapy
• Motivation and compliance
Approach to newly diagnosed hypertension:
Hypertension is predominantly an asymptomatic condition and the diagnosis is
usually made at routine examination or when a complication arises.
The objectives of the initial evaluation of a patient with high BP readings are:
• To obtain accurate, representative BP measurements .
• To identify contributory factors and any underlying cause (secondary hypertension) .
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• To assess other risk factors and quantify cardiovascular risk .
• To detect any complications (target organ damage) that are already present .
• To identify comorbidity that may influence the choice of antihypertensive therapy.
History
• Family history, lifestyle (exercise, salt intake, smoking habit) and other risk
factors should be recorded.
• A careful history will identify those patients with drug- or alcohol-induced
hypertension and may elicit the symptoms of other causes of secondary
hypertension, such as phaeochromocytoma (paroxysmal headache, palpitation
and sweating, or complications such as coronary artery disease (e.g. angina,
breathlessne
Examination
• -Left ventricular hypertrophy (apical heave), accentuation of the aortic
component of the second heart sound, and a fourth heart sound. ------Radio-
femoral delay (coarctation of the aorta; -----Enlarged kidneys (polycystic kidney
disease), -----Abdominal bruits (renal artery stenosis) and the ---Characteristic
facies and habitus of Cushing’s syndrome secondary hypertension.
• -Risk factors, such as central obesity and hyperlipidaemia .
• -Most abnormal signs are due to the complications of hypertension.
Target organ damage:
• Central nervous system Stroke is a common complication of hypertension and may
be due to cerebral haemorrhage or infarction. TIAs are more common in
hypertensive patients. Subarachnoid haemorrhage is also associated with
hypertension.
• Hypertensive encephalopathy is a rare condition characterised by high BP and
neurological symptom.
Heart
• CAD The excess cardiac mortality and morbidity associated with hypertension
are largely due to a higher incidence of coronary artery disease.
• LVH
• Atrial fibrillation
• Heart failure
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Hypertensive retinopathy:
• Grade 1 Arteriolar thickening, tortuosity and increased reflectiveness (‘silver
wiring’) .
• Grade 2 Grade 1 plus constriction of veins at arterial crossings (‘arteriovenous
nipping’) .
• Grade 3 Grade 2 plus evidence of retinal ischaemia (flame-shaped or blot
haemorrhages and ‘cotton wool’ exudates) .
• Grade 4 Grade 3 plus papilloedema.
Hypertension: investigation of all patients:
-Urinalysis for blood, protein and glucose.
-Blood urea, electrolytes and creatinine.
-Blood glucose.
-Serum total and HDL cholesterol.
-Thyroid function tests.
-12-lead ECG (left ventricular hypertrophy, coronary artery disease.
Hypertension: investigation of selected patient:
• Chest X-ray: to detect cardiomegaly.
• Ambulatory BP recording
• Echocardiogram:
• Renal ultrasound:
• Renal angiography: renal artery stenosis.
• Urinary catecholamines: to detect possible phaeochromocytoma.
• Urinary cortisol : Cushing’s syndrome.
• Plasma renin activity and aldosteron
Management:
The sole objective of antihypertensive therapy is to reduce the incidence of adverse
cardiovascular events, particularly coronary artery disease, stroke and heart failure.
• Threshold for intervention >140/90
• Treatment targets <140/90
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Non-drug therapy:
• Correcting obesity, reducing alcohol intake, restricting salt intake, taking regular
physical exercise and increasing consumption of fruit and vegetables can all
lower BP.
• Moreover, quitting smoking, eating oily fish and adopting a diet that is low in
saturated fat may produce further reductions in cardiovascular risk.
Antihypertensive drugs:
• Thiazide and other diuretics
• ACE inhibitor
• Angiotensin receptor blockers
• Calcium channel antagonists.
• Beta-blockers
• Other drugs. Vasodilators
How to measure blood pressure:
• Use a machine that has been validated, well maintained and properly calibrated.
• Measure sitting BP routinely, with additional standing BP in elderly and diabetic
patients and those with possible postural hypotension.
• Remove tight clothing from the arm , Support the arm at the level of the heart.
• Use a cuff of appropriate size (the bladder must encompass more than two-thirds of
the arm).
• Lower the pressure slowly (2 mmHg per second).
• Use phase V (disappearance of sounds) to measure diastolic BP • Take two
measurements at each visit.
white coat’ hypertension
Sphygmomanometry, particularly when performed by a doctor, can cause an
unrepresentative surge in BP which has been termed ‘white coat’ hypertension, and
as many as 20% of patients with apparent hypertension in the clinic may have a
normal BP when it is recorded by automated devices used at home
.
Malignant’ or ‘accelerated’ phase hypertension
Very high BP and rapidly progressive end organ damage, such as retinopathy (grade 3 or 4),
renal dysfunction (especially proteinuria) and/or hypertensive encephalopathy)or Left
ventricular failure.
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Practical point:
• Emergency treatment of accelerated phase or malignant hypertension, lowering BP
too quickly may compromise tissue perfusion (due to altered autoregulation) and can
cause cerebral damage, including occipital blindness, and precipitate coronary or
renal insufficiency. Even in the presence of cardiac failure or hypertensive
encephalopathy, a controlled reduction to a level of about 150/90 mmHg over a
period of 24–48 hours is ideal.
Follow-up
• For patients with BP stabilised by management, follow up should normally be three
monthly (interval should not exceed 6 months), at which the following should be
assessed by a trained nurse:
• * Measurement of BP and weight
* Reinforcement of non-pharmacological advice
* General health and drug side-effects
* Test urine for proteinuria (annually)