Types of hypertension are as follows:
Essential
Hypertension is called essential when no apparent cause is suspected or detected. This accounts for almost 90 per cent of patients seen.
Systolic
Isolated Systolic Hypertension (ISH) is defined as a systolic BP 140 or more and a diastolic BP less than 90 mmHg. The cause of this condition is attributed to be increasing rigidity of the aortic wall.
Secondary
The term secondary hypertension is used when one or more causes are identified for the high blood pressure. The usual causes are:
Renal
Renal Parenchymal Disease
Renal parenchymal disease is the commonest cause of secondary hypertension. Hypertensive and diabetic nephropathy and chronic glomerulonephritis are the main causes. Eventually, the vicious cycle develops where hypertension produces renal damage which leads to further hypertension.
A detailed search for kidney pathology must be made in hypertension because some of them can be totally curable. Examples of such reversible renal diseases are acute glomerulonephritis, acute oliguric renal failure which may occur due to hypotension, vasculitis, lithotrypsy, uilateral parenchymal disease and certain cases of polycystic kidneys.Added emphasis is given to the treatment of hypertension in chronic renal disease with renal failure because of the increasing success rate of kidney transplants.
Renovascular Hypertension
Atherosclerotic or fibroplastic disease producing partial occlusion of one or both renal arteries is one of the causes of hypertension. Since this condition may be correctable, one should actively search for this condition. Suggestive clinical settings are:
1) Severe hypertension: Diastolic of > 120 mmHg
2) Hypertension in young
3) Abrupt onset of moderate hypertension
4) Presence of abdominal bruit
5) Malignant hypertension with papilloedema
Diagnostic Tests for Renovascular Hypertension
1) Isotope renography
2) Plasma rennin measurements
3) Renal Doppler flow measurements
4) Renal arteriography
Endocrine
Adrenal causes of hypertension are:
1) Excess of aldosterone production in primary aldosteronism. The diagnosis may be suspected when persistent hypokalemia is detected. Most often a CT scan of the adrenals will identify the presence of an adenoma or hyperplasia.
2) Excess cortisol levels in cushing’s syndrome. This syndrome is suspected in patients with truncal obesity, thin skin and weakness. The diagnosis can be arrived at by measuring 24 hour urinary cortisol or by doing dexamethasone suppression test.
3)Hypertension caused by increased catecholamines is found in Pheochromocytoma, which usually is found in the adrenal medulla. The striking feature in this condition is the marked fluctuations in blood pressure. The associated symptoms are spells of headache, sweating,palpitations, nervousness, nausea and tremors. These symptoms could be mistaken for anxiety and as postmenopausal syndrome. The diagnostic tests are 24 hour urinary metanephrine estimation and CT and MRI scans of the adrenals.
Coarctation of Aorta
Careful palpation of the upper and lower limb pulses would make one suspect coarctation as the cause of hypertension. The lower limb pulses are weak and delayed.Confirmation can be made with cardiac ultrasound and angiograms.
Pregnancy
An increase of blood pressure of 30/15 mmHg or more from a normal of 140/80, in pregnancy is called gestational hypertension. This usually happens in primigravida in the 20 week. When hypertension is associated with proteinuria and oedema it is termed pre-eclampsia. This can progress to eclampsia with cerebral involvement and seizures.
Essential
Hypertension is called essential when no apparent cause is suspected or detected. This accounts for almost 90 per cent of patients seen.
Systolic
Isolated Systolic Hypertension (ISH) is defined as a systolic BP 140 or more and a diastolic BP less than 90 mmHg. The cause of this condition is attributed to be increasing rigidity of the aortic wall.
Secondary
The term secondary hypertension is used when one or more causes are identified for the high blood pressure. The usual causes are:
Renal
Renal Parenchymal Disease
Renal parenchymal disease is the commonest cause of secondary hypertension. Hypertensive and diabetic nephropathy and chronic glomerulonephritis are the main causes. Eventually, the vicious cycle develops where hypertension produces renal damage which leads to further hypertension.
A detailed search for kidney pathology must be made in hypertension because some of them can be totally curable. Examples of such reversible renal diseases are acute glomerulonephritis, acute oliguric renal failure which may occur due to hypotension, vasculitis, lithotrypsy, uilateral parenchymal disease and certain cases of polycystic kidneys.Added emphasis is given to the treatment of hypertension in chronic renal disease with renal failure because of the increasing success rate of kidney transplants.
Renovascular Hypertension
Atherosclerotic or fibroplastic disease producing partial occlusion of one or both renal arteries is one of the causes of hypertension. Since this condition may be correctable, one should actively search for this condition. Suggestive clinical settings are:
1) Severe hypertension: Diastolic of > 120 mmHg
2) Hypertension in young
3) Abrupt onset of moderate hypertension
4) Presence of abdominal bruit
5) Malignant hypertension with papilloedema
Diagnostic Tests for Renovascular Hypertension
1) Isotope renography
2) Plasma rennin measurements
3) Renal Doppler flow measurements
4) Renal arteriography
Endocrine
Adrenal causes of hypertension are:
1) Excess of aldosterone production in primary aldosteronism. The diagnosis may be suspected when persistent hypokalemia is detected. Most often a CT scan of the adrenals will identify the presence of an adenoma or hyperplasia.
2) Excess cortisol levels in cushing’s syndrome. This syndrome is suspected in patients with truncal obesity, thin skin and weakness. The diagnosis can be arrived at by measuring 24 hour urinary cortisol or by doing dexamethasone suppression test.
3)Hypertension caused by increased catecholamines is found in Pheochromocytoma, which usually is found in the adrenal medulla. The striking feature in this condition is the marked fluctuations in blood pressure. The associated symptoms are spells of headache, sweating,palpitations, nervousness, nausea and tremors. These symptoms could be mistaken for anxiety and as postmenopausal syndrome. The diagnostic tests are 24 hour urinary metanephrine estimation and CT and MRI scans of the adrenals.
Coarctation of Aorta
Careful palpation of the upper and lower limb pulses would make one suspect coarctation as the cause of hypertension. The lower limb pulses are weak and delayed.Confirmation can be made with cardiac ultrasound and angiograms.
Pregnancy
An increase of blood pressure of 30/15 mmHg or more from a normal of 140/80, in pregnancy is called gestational hypertension. This usually happens in primigravida in the 20 week. When hypertension is associated with proteinuria and oedema it is termed pre-eclampsia. This can progress to eclampsia with cerebral involvement and seizures.
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