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