Hypertension

Introduction
Hypertension is the most important risk factor for heart disease, stroke, and kidney failure. The incidence of hypertension varies widely throughout the world and the prevalence increases with age. The age-adjusted incidence in Norway is around 40% for both men and women.
 
Definitions

Systolic BPDiastolic BP
Measurement during a consultation
Normal<130 mmHgand<85 mmHg
High normal130-139 mmHgand/or85-89 mmHg
Grade 1 hypertension140-159 mmHgand/or90-99 mmHg
Grade 2 hypertension160-179 mmHgand/or100-109 mmHg
Grade 3 hypertension>180 mmHgand/or>110 mmHg
 
Isolated systolic hypertension>140 mmHgand<90 mmHg
 
Pulse pressureDifference between systolic and diastolic blood pressure
 
Orthostatic hypertension20% fall in systolic blood pressure after standing for 3 minutes, or 10% fall in diastolic blood pressure
 
Ambulatory blood pressure monitoring (ABPM)
Hypertension>130 mmHgand/or>80 mmHg
Daytime hypertension (07-23)>135 mmHgand/or>85 mmHg
Nocturnal hypertension (23-07)>130 mmHgand/or>70 mmHg
 
White coat hypertensionElevated blood pressure measured in the office, normal ABPM
Masked hypertensionNormal office blood pressure, elevated ABPM
 
Home blood pressure measurement
hypertension>135 mmHgand/or>85 mmHg
 
Hypertensive crises (indication for i.v. blood pressure reduction)
Malignant hypertensionSeverely elevated blood pressure, usually diastolic >130 mmHg and hypertensive retinopathy grade 3-4 (papilloedema, bleeding, cotton wool spots).
 
Hypertensive emergencyDiastolic blood pressure > 120 mmHg with cerebral symptoms, heart failure, angina, acute kidney failure or aorta dissection

 
Causes
In most cases, a cause for the hypertension cannot be identified and it is described as essential hypertension. Blood pressure should be understood as a function of cardiac output and total peripheral resistance. The sympathetic nervous system and the renin-angiotensin-aldosterone system (RAAS) are involved in regulating the blood pressure, and defects in renal salt regulation are considered to be central in the development of hypertention. The diagnosis essential hypertension is dependent on exclusion of known secondary causes of high blood pressure. Genetic factors are considered to contribute about 50% of the causal chain, while environmental factors such as overweight, salt intake, physical inactivity and stress are modifiable causal factors in the development of hypertension. Known secondary causes to hypertension are cronic kidney disease (5% of those with hypertension), primary hyperaldosteronism, pheochromocytoma, renovascular hypertension and sleep apnea. Medicines, alcohol, and drug abuse can also lead to secondary hypertension.
 
Clinical presentation
High blood pressure is often asymptomatic and should be discovered early through routine checkups. Elevated blood pressure over time can damage organs. Often, one will find left ventricular hypertrophy, microvascular changes in the eye, and microalbuminuria as signs of hypertensive organ damage, before symptoms of organ damage occur. When the diagnosis is established, the clincian should ask 3 questions.
 
Prognosis and treatment
Hypertension is an important risk factor for cerebrovascular disease, kidney damage, coronary disease, and heart failure, together with age, sex, smoking, overweight, diabetes mellitus, physical inactivity, lipid profile, and kidney disease. Blood pressure should always be considered in relation to other risk factores, and the total cardiovascular risk is the main consideration when deciding indications for treatment and treatment goals.