Renovascular hypertension

In most Westernized countries, and especially among older individuals, renovascular hypertension is the most remediable cause of elevated blood pressure.

Renovascular hypertension is a reversible cause of hypertension secondary to a decrease in renal perfusion pressure which activates the renin-angiotensin system and leads to the release of rennin and the production of angiotensin II.  It is a progressive disorder that can result in serious complications without adequate treatment.

Angiotensin II increases sodium reabsorption and induces postglomeruler and systemic arterial vasoconstriction, causing renovascular hypertension. The prevalence of renovascular hypertension was estimated at about 5% of all hypertensive individuals but it is varied form less than 1% to more than 50% depending on the degree of screening in the study population.

With prevalence of about 5%, renovascular disease represents the most frequent cause of secondary hypertension.

Unlike the diagnosis of most other cardiovascular and nephorologic conditions, renovascular hypertension can be diagnosed only retrospectively, by means of a physiologic blood pressure (BP) response to an intervention.
Renovascular hypertension

Causes of secondary hypertension

Hypertension can be primary or secondary to a defined process. Secondary hypertension meaning the hypertension is secondary to a specific cause.

Secondary causes of hypertension are uncommon, and account for less than 5% of all cases of high blood pressure in and unselected hypertension population.

The rate of secondary forms of hypertension ranges between 4 and 8% in different patient populations (primary care, secondary care clinics, or specialized cardiovascular centers).

Secondary hypertension is usually associated with a specific organ and /or vascular abnormalities, a metabolic abnormality, or endocrine disorder.

The majority of secondary hypertension cases are due to chronic renal disease, and therapy often in includes antihypertensive medications.

Secondary hypertension must always be identified because treatment will be based on the specific underlying disorder. Its onset is often sudden, it may be more severe, a family history is frequently absent and it may occur in patients of all ages.

If left undiagnosed, secondary hypertension may lead to progressive target organ damage, as well as cardiovascular and renal complications.

Treatment usually differs from that of ordinary essential hypertension and with the right treatment, the amount of medication often can be reduced.
Secondary hypertension

What causes high blood pressure?

What causes high blood pressure?
There is still a lot of uncertainly about the causes of high blood pressure.

For the vast majority of people, over 95% an underlying cause is not found.

These are the people also have ‘essential’ hypertension. It is likely that several factors contribute to high blood pressure in most people.

The chief suspects include:

• An overactive hormone system that relates to the kidney (the rennin-angiotensin system)
  
• An overactive autonomic nervous system (the part of the nervous system responsible for our unconscious nervous response)
  
• A fault in the cells of the smaller blood vessels that produce substances leading to blood vessel and increased blood pressure (endothelial cell dysfunction)
  
• Genetic predisposition (when you may have inherited a tendency to high blood pressure)
  
• Intrauterine factors, particularly birth weight, that may reflect undernourishment in the fetus and that ‘programme’ our body to develop high blood pressure in later life.

What causes high blood pressure?

Secondary Causes of Hypertension

Secondary Causes of Hypertension

• Chronic kidney disease

• Coarctation of aorta

• Cushing syndrome and other glucocorticoid excess states including chronic steroid therapy

• Drug induced or drug-related

• Pheochromocytoma

• Primary aldosteronism and other mineralocorticoid excess states

• Renovascualr hypertension

• Sleep apnea

• Thyroid/parathyroid disease

Secondary Causes of Hypertension

Causes of High Blood Pressure

Causes of High Blood Pressure
The causes of short term rises in blood pressure high last only seconds or minutes are well understood, but these are not what we normally mean by high blood pressure. High blood pressure is important only when it is maintained for months or years – it is a high average pressure which is significant, not occasional high peaks. The causes of a long term rises in average pressure are not fully known, but we do know that it runs in families. This inherited tendency seems to account for about half the differences between people; the rest seems to depend on how they live and what they eat (not just in adult life, but they ate in infancy and childhood and how well nourished they were before they born).

One cause we do know about is overweight and weight reduction is a sensible first step in treatment. Weight loss depends mainly on using up more energy by taking more exercise and reducing energy input. In practice the most healthy way to do this is by reducing the amount of fats, oils, meats, sugar and alcohol in the diet, and instead eating more fruit, vegetables, cereal foods and fish. Eating less fat and oil is by far the most important of these changes. Another benefit from these changes in diet is that they help lower blood cholesterol levels and so reduce the risk of developing coronary heart disease.

Another known cause us excessive alcohol (which means more than 4 units of alcohol a day for a man or 3 units a day for woman – a unit alcohol is one glass of wine or one single measure of spirits or half a pint of average strength beer or lager). Again the biggest effect is in young people, limiting alcohol intake often brings high blood pressure back to normal without any other treatment.
Causes of High Blood Pressure