SECONDARY HYPERTENSION

Cases of hypertension secondary to an identifiable cause fall into two broad groups ; those in whom the cause may be removed with the probability of relief of the hypertension, and those for whom no radical treatment is feasible. Included in the first group are coarctation of the aorta, phseochromocytoma, and cases of strictly unilateral renal disease.
Unfortunately, the majority of patients with secondary hypertension fall into the second category, radical treatment of the underlying cause being impossible. In this group are bilateral kidney disease, particularly chronic glomerulonephritis and pyelonephritis, the latter ranking as one of the com¬monest renal causes of hypertension. In addition there are cases secondary to the chronic degenerative renal lesions of diabetes (Kimmelstiel-Wilson syndrome) and cases of renal amyloidosis. The management of high blocd pressure in such conditions differs from that of essential hypertension only in respect of the limitations imposed on drug therapy by renal damage. The slow excretion of hypotensive drugs by damaged kidneys, and the reduction of glomerular- filtration rate which may result, necessitate particular care in the use of these potent drugs, as otherwise renal failure may result.