Hypertension
Definition
chronically elevatedblood pressure
Normal BP for adults aged 18 years or older is as follows:
Normal - Systolic lower than 120, diastolic lower than 80
Prehypertension - Systolic 120-139, diastolic 80-99
Stage 1 - Systolic 140-159, diastolic 90-99
Stage 2 - Systolic equal to or more than 160, diastolic equal to or more than 100
Based on the average of 2 or more readings taken at each of 2 or more visits after initial screening
Classification
Essential (primary)
Secondary.
Essential hypertension - no specific medical cause
Secondary hypertension - is a result of another condition, such as kidney disease or tumours (pheochromocytoma and paraganglioma).
Causes
obesity
salt sensitivity
renin homeostasis
insulin resistance
genetics
age
sleep apnoea
Pathophysiology
Hypertension is one of the risk factors for strokes, heart attacks, heart failure and arterial aneurysm, and is a leading cause of chronic renal failure.
Even moderately high B.P. leads to shortened life expectancy
Arterial blood pressure is a product of cardiac output and systemic vascular resistance.
Determinants of blood pressure : -
Factors that affect both cardiac output and arteriolar vascular physiology.
Blood viscosity
Vascular wall sheer conditions (rate and stress)
Changes in vascular wall thickness
The factors affecting cardiac output : -
Sodium intake,
Renal function
Mineralocorticoids
The factors affecting the Peripheral vascular resistance : -
Sympathetic nervous system - effects via the vasoconstrictor alpha effect or the vasodilator beta effect.
Humoral factors - via vasoconstrictors (angiotensin and catecholamines) or vasodilators (prostaglandins and kinins).
Local autoregulation.
Incidence
Between 40-70
Males affected more than females
In persons older than 70 years, no sex predilection exists.
More in type 1 diabetics
Clinical Features
Persistent hypertension - risk factor for strokes, heart attacks, heart failure and arterial aneurysm, and is a leading cause of chronic renal failure. Even moderate elevation of arterial blood pressure leads to shortened life expectancy.
Patients with blood pressures over 130/80 mm Hg along with Type 1 or Type 2 diabetes, or kidney disease require further treatment
Resistant hypertension is defined as the failure to reduce BP to the appropriate level after taking a three-drug regimen
Investigations
to identify possible causes of secondary hypertension
to seek evidence for end-organ damage to the heart or the eyes and kidneys.
to detect Diabetes
Serum Creatinine
Electrolytes (sodium, potassium)
Blood Glucose
Cholesterol
Testing of urine samples for proteinuria
Electrocardiogram (ECG)
Chest X-ray - ( cardiac enlargement or evidence of cardiac failure.)
Management
Modifiable factors include diet, weight, exercise levels and stress management.
Low-sodium and low-fat diets
Losing at least 10% of body weight
Exercise
Stress management
Drug Treatment
ACE inhibitors : captopril, enalapril, fosinopril, lisinopril, quinapril, ramipril
Angiotensin II receptor antagonists: eg, telmisartan, losartan, valsartan, candesartan
Alpha blockers : prazosin, or terazosin.
Beta blockers : atenolol, metoprolol, propranolol.
Calcium channel blockers : nifedipine amlodipine, diltiazem, verapamil
Direct renin inhibitors : aliskiren
Diuretics: eg, bendroflumethiazide, chlortalidone, hydrochlorothiazide
Complications
Cerebrovascular accident
Myocardial infarction
Hypertensive cardiomyopathy
Hypertensive retinopathy
Hypertensive nephropathy - chronic renal failure
Hypertensive encephalopathy - confusion, headache, convulsion
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