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The many causes of hypertension
If you suffer from high blood pressure, here's what may be triggering the problem.
Hypertension, also known as high blood pressure, is a medical condition in which a person's blood pressure in the body's arteries remains chronically elevated.
Many types of hypertension exist, like systemic or arterial hypertension, portal hypertension and others, but the term 'hypertension' in general implies systemic or arterial hypertension.
There are two types of hypertension that are usually defined, ie primary and secondary hypertension.
Primary hypertension is also known as essential hypertension. Primary hypertension or essential hypertension will not have any cause predefined, while secondary hypertension is secondary to any other medical causes like a tumour or some systemic diseases.
More than 90 per cent of patients have essential hypertension, which means that no cause is found.
Hypertension is one of the risk factors for strokes, heart attacks, heart failure and arterial aneurysms, and it can lead to chronic renal failure also.
Moderate elevation of arterial blood pressure can even lead to shortened life expectancy, which decreases further with the increase in the average blood pressure.
Essential hypertension
Hypertension is one of the most common disorders and it generally affects 90 per cent of hypertensive patients.
Risk factors for essential hypertension are sedentary lifestyle, obesity, salt, alcohol intake, smoking and Vitamin D deficiency. It is also related to increased age and to some inherited genetic mutations; a family history of hypertension will increase the risk of a person getting hypertension.
Elevated renin -- which is an enzyme secreted by the juxtaglomerular apparatus of the kidney and linked with aldosterone -- is one of the risk factors.
Secondary hypertension
Secondary hypertension results from an identifiable cause.
The recognition of this type of high blood pressure is necessary, as the management will depend on the underlying causes, like Cushing's syndrome, for instance. Cushing's syndrome is a condition where both adrenal glands overproduce the hormone cortisol, which leads to hypertension. More than 80 per cent of patients with Cushing's syndrome have hypertension.
Other causes
- Mineral corticoid excess syndrome: This is an autosomal recessive disorder, which results from mutations in gene encoding. The enzyme 11β-hydroxysteroid dehydrogenase, which normally inactivates circulating cortisol to the less-active metabolite cortisone, is inhibited.
- Prolonged ingestion of liquorice.
- Conn's disease: It is an adrenocortical tumour which causes excess release of aldosterone, which in turn leads to hypertension.
- Polycystic kidney disease: It is characterised by the presence of multiple cysts. It can be autosomal dominant or autosomal recessive in nature. It leads to progressive cyst development and bilaterally enlarged kidneys with multiple cysts, with concurrent development of hypertension, renal insufficiency and renal pain.
- Chronic glomerulonephritis: It is characterised by inflammation of the glomeruli, or small blood vessels in the kidneys.
- Renal arterial hypertension: It is known as renovascular hypertension due to the decreased perfusion of renal tissue. This is causes by stenosis of a main or branch renal artery that activates the renin-angiotensin system.
- Juxtaglomerular cell tumour
- Wilms' tumour
- Renal cell carcinoma
- Pheochromocytoma: It leads to increased secretion of catecholamines such as epinephrine and norepinephrine, causing excessive stimulation of adrenergic receptors, which results in peripheral vasoconstriction and cardiac stimulation.
- Medications: Some medications like NSAIDs and steroids can cause hypertension. Rebound Hypertension is due to sudden withdrawal of various antihypertensive medications. Medications commonly associated with rebound hypertension include centrally-acting antihypertensive agents, such as clonidine and beta-blockers.
- Pregnancy: It is associated with increased blood pressure and it may lead to certain complications of pregnancy like pre-eclampsia, HELLP syndrome and eclampsia.
- Sleep disturbances like sleep apnea, Binswanger's disease and other neurological syndromes are also associated with hypertension.