Essential renal haemorrhages.

On the basis of the conception of renal hypertension, worked out by the authors, the new interpretation of the cause of 'essential' renal haemorrhages is discussed. Special attention is drawn to secondary 'arterial' venous hypertension in the kidney, which happens in cases when there are no obvious reasons for the distortion of the outflow through the renal vein. In a case of renal haematuria, the origin of which is not connected with the distortion of the venous blood outflow from the kidney, it is necessary to bear in mind the relationship between the venous pressure in the kidney and the systemic arterial pressure. In arterial hypertension the contralateral kidney may become the source of haematuria. The rarity of isolating a calycovenous canal as a separate definite cause is discussed.